U.S. patent application number 09/924247 was filed with the patent office on 2002-03-21 for tetrazolyl-phenyl acetamide glucokinase activators.
Invention is credited to Sidduri, Achyutharao.
Application Number | 20020035266 09/924247 |
Document ID | / |
Family ID | 22845106 |
Filed Date | 2002-03-21 |
United States Patent
Application |
20020035266 |
Kind Code |
A1 |
Sidduri, Achyutharao |
March 21, 2002 |
Tetrazolyl-phenyl acetamide glucokinase activators
Abstract
Tetrazolyl-phenyl acetamides are active as glucokinase
activators, and are able to increase insulin secretion, which makes
them useful for treating type II diabetes.
Inventors: |
Sidduri, Achyutharao;
(Livingston, NJ) |
Correspondence
Address: |
HOFFMANN-LA ROCHE INC.
PATENT LAW DEPARTMENT
340 KINGSLAND STREET
NUTLEY
NJ
07110
|
Family ID: |
22845106 |
Appl. No.: |
09/924247 |
Filed: |
August 8, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60225494 |
Aug 15, 2000 |
|
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Current U.S.
Class: |
548/253 |
Current CPC
Class: |
C07D 257/04 20130101;
C07D 401/12 20130101; C07D 417/12 20130101; A61P 3/10 20180101 |
Class at
Publication: |
548/253 |
International
Class: |
C07D 257/04 |
Claims
1. A tetrazole selected from the group consisting of a compound of
the formula: 37wherein one of R.sup.1 or R.sup.2 is 38 and the
other is hydrogen, halogen, lower alkyl sulfonyl, perfluoro-lower
alkyl, cyano, or nitro; R.sup.3 is cycloalkyl; R.sup.4 is
--C(O)--NHR.sup.6 or a five- or six-membered heteroaromatic ring
connected by a ring carbon atom to the amide group shown, which
heteroaromatic ring contains from 1 to 3 heteroatoms selected from
the group consisting of oxygen, sulfur and nitrogen with a first
heteroatom being nitrogen adjacent to the connecting ring carbon
atom, said heteroaromatic ring being unsubstituted or
monosubstituted with halogen at a position on a ring carbon atom
other than that adjacent to said connecting carbon atom; R.sup.5 is
lower alkyl, or perfluoro lower alkyl; R.sup.6 is hydrogen or lower
alkyl; n is 0 or 1; .DELTA. denotes a trans configuration across
the double bond; and its pharmaceutically acceptable salts.
2. A tetrazole of claim 1 wherein R.sup.4 is a five- or
six-membered heteroaromatic ring connected by a ring carbon atom to
the amide group shown, which heteroaromatic ring contains from 1 to
3 heteroatoms selected from the group consisting of oxygen, sulfur
and nitrogen with a first heteroatom being nitrogen adjacent to the
connecting ring carbon atom, said heteroaromatic ring being
unsubstituted or monosubstituted with halogen at a position on a
ring carbon atom other than that adjacent to said connecting carbon
atom.
3. A tetrazole of claim 2 wherein R.sup.1 is 39
4. A tetrazole of claim 3 wherein R.sup.5 is lower alkyl.
5. A tetrazole of claim 4 wherein R.sup.3 is cyclopentyl.
6. A tetrazole of claim 5 wherein R.sup.4 is a six-membered
heteroaromatic ring.
7. A tetrazole of claim 6 wherein R.sup.4 is substituted or
unsubstituted pyridine.
8. A tetrazole of claim 7 wherein R.sup.2 is halogen.
9. A tetrazole of claim 8 which is
(E)-N-(5-bromo-pyridin-2-yl)-3-cyclopen-
tyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-acrylamide.
10. A tetrazole of claim 5 wherein R.sup.4 is a 5-membered
heteroaromatic ring.
11. A tetrazole of claim 10 wherein R.sup.4 is substituted or
unsubstituted thiazole.
12. A tetrazole of claim 11 wherein R.sup.2 is halogen or perfluoro
lower alkyl.
13. A tetrazole of claim 12 which is
(E)-3-cyclopentyl-2-[4-(5-methyl-tetr-
azol-1-yl)-3-trifluoromethyl-phenyl-]-N-thiazol-2-yl-acrylamide.
14. A tetrazole of claim 12 which is
(E)-4-cyclopentyl-2-[4-(5-methyl-tetr-
azol-1-yl)-3-trifluoromethyl-phenyl-]-but-2-enoic
acid-thiazol-2-ylamide.
15. A tetrazole of claim 12 which is
(E)-2-[3-chloro-4-(5-methyl-tetrazol--
1-yl)-phenyl]-3-cyclopentyl-N-thiazol-2-yl-acrylamide.
16. A tetrazole of claim 12 which is
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-me-
thyl-tetrazol-1-yl)-phenyl]-N-thiazol-2-yl-acrylamide.
17. A tetrazole of claim 11 wherein R.sup.2 is lower alkyl
sulfonyl.
18. A tetrazole of claim 17 which is
(E)-3-cyclopentyl-2-[3-methanesulfony-
l-4-(5-methyl-tetrazol-1-yl)-phenyl-]-N-thiazol-2-yl-acrylamide.
19. A tetrazole of claim 3 wherein R.sup.2 is halogen and R.sup.4
is substituted or unsubstituted thiazole.
20. A tetrazole of claim 19 wherein R.sup.5 is lower alkyl or
perfluoro lower alkyl.
21. A tetrazole of claim 20 wherein R.sup.3 is cyclohexyl.
22. A tetrazole of claim 21 which is
(E)-2-[3-chloro-4-(5-methyl-tetrazol--
1-yl)-phenyl]-3-cyclohexyl-N-thiazol-2-yl-acrylamide.
23. A tetrazole of claim 21 which is
(E)-2-[3-chloro-4-(5-trifluoromethyl--
tetrazol-l1-yl)-phenyl]-3-cyclohexyl-N-thiazol-2-yl-acrylamide.
24. A tetrazole of claim 20 wherein R.sup.3 is cycloheptyl.
25. A tetrazole of claim 24 which is
(E)-2-[3-chloro-4-(5-methyl-tetrazol--
1-yl)-phenyl]-3-cycloheptyl-N-thiazol-2-yl-acrylamide.
26. A tetrazole of claim 24 which is
(E)-N-(5-bromo-thiazol-2-yl)-2-[3-chl-
oro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycloheptyl-acrylamide.
27. A tetrazole of claim 1 wherein R.sup.4 is --C(O)--NHR.sup.6 and
R.sup.6 is hydrogen or lower alkyl.
28. A tetrazole of claim 27 wherein R.sup.1 is 40
29. A tetrazole of claim 28 wherein R.sup.5 is lower alkyl.
30. A tetrazole of claim 29 wherein R.sup.3 is cyclopentyl.
31. A tetrazole of claim 30 wherein R.sup.6 is methyl.
32. A tetrazole of claim 31 wherein R.sup.2 is halogen.
33. A tetrazole of claim 32 which is
(E)-1-{3-cyclopentyl-2-[3-fluoro-4-(5-
-methyl-tetrazol-1-yl)-phenyl-acryloyl}3-methyl-urea.
34. A tetrazole selected from the group consisting of a compound of
the formula: 41wherein one of R.sup.1 or R.sup.2 is 42 and the
other is hydrogen, halogen, lower alkyl sulfonyl, perfluoro-lower
alkyl, cyano, or nitro;. R.sup.3 is cycloalkyl; R.sup.4 is
--C(O)--NHR.sup.6 or a five- or six-membered heteroaromatic ring
connected by a ring carbon atom to the amide group shown, which
heteroaromatic ring contains from 1 to 3 heteroatoms selected from
the group consisting of oxygen, sulfur and nitrogen with a first
heteroatom being nitrogen adjacent to the connecting ring carbon
atom, said heteroaromatic ring being unsubstituted or
monosubstituted with halogen at a position on a ring carbon atom
other than that adjacent to said connecting carbon atom; R.sup.5 is
lower alkyl, or perfluoro lower alkyl; R.sup.6 is hydrogen or lower
alkyl; n is 0 or 1; the * represents the asymmetric carbon atom and
its pharmaceutically acceptable salts.
35. A tetrazole of claim 34 wherein R.sup.4 is a five- or
six-membered heteroaromatic ring connected by a ring carbon atom to
the amide group shown, which heteroaromatic ring contains from 1 to
3 heteroatoms selected from the group consisting of oxygen, sulfur
and nitrogen with a first heteroatom being nitrogen adjacent to the
connecting ring carbon atom, said heteroaromatic ring being
unsubstituted or monosubstituted with halogen at a position on a
ring carbon atom other than that adjacent to said connecting carbon
atom.
36. A tetrazole of claim 35 wherein R.sup.1 is 43
37. A tetrazole of claim 36 wherein R.sup.5 is lower alkyl.
38. A tetrazole of claim 37 wherein R.sup.3 is cyclopentyl.
39. A tetrazole of claim 38 wherein R.sup.4 is a six-membered
heteroaromatic ring.
40. A tetrazole of claim 39 wherein R.sup.4 is substituted or
unsubstituted pyridine.
41. A tetrazole of claim 40 wherein R.sup.2 is halogen.
42. A tetrazole of claim 41 which is
N-(5-bromo-pyridin-2-yl)-3-cyclopenty-
l-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-propionamide.
43. A tetrazole of claim 41 which is
N-(5-bromo-pyridin-2-yl)-3-cyclopenty-
l-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-propionamide.
44. A tetrazole of claim 40 wherein R.sup.2 is perfluoro lower
alkyl.
45. A tetrazole of claim 44 which is
N-(5-bromo-pyridin-2-yl)-3-cyclopenty-
l-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-propionamide.
46. A tetrazole of claim 38 wherein R.sup.4 is a 5-membered
heteroaromatic ring.
47. A tetrazole of claim 46 wherein R.sup.4 is substituted or
unsubstituted thiazole.
48. A tetrazole of claim 47 wherein R.sup.2 is halogen or perfluoro
lower alkyl.
49. A tetrazole of claim 48 which is
3-cyclopentyl-2-[3-fluoro-4-(5-methyl-
-tetrazol-1-yl)-phenyl]-N-thiazol-2-yl-propionamide.
50. A tetrazole of claim 48 which is
2-[3-chloro-4-(5-methyl-tetrazol-1-yl-
)-phenyl]-3-cyclopentyl-N-thiazol-2-yl-propionamide.
51. A tetrazole of claim 48 which is
3-cyclopentyl-2-[4-(5-methyl-tetrazol-
-1-yl)-3-trifluoromethyl-phenyl]-N-thiazol-2-yl-propionamide.
52. A tetrazole of claim 36 wherein R.sup.3 is cyclohexyl and
R.sup.4 is substituted or unsubstituted thiazole.
53. A tetrazole of claim 52 wherein R.sup.2 is halogen.
54. A tetrazole of claim 53 wherein R.sup.5 is lower alkyl.
55. A tetrazole of claim 54 which is
2-[3-chloro-4-(5-methyl-tetrazol-1-yl-
)-phenyl]-3-cyclohexyl-N-thiazol-2-yl-propionamide.
56. A tetrazole of claim 53 wherein R.sup.5 is perfluoro lower
alkyl.
57. A tetrazole of claim 56 which is
2-[3-chloro-4-(5-trifluoromethyl-tetr-
azol-1-yl)-phenyl]-3-cyclohexyl-N-thiazol-2-yl-propionamide.
58. A tetrazole of claim 35 wherein R.sup.2 is 44
59. A tetrazole of claim 58 wherein R.sup.1 is lower alkyl
sulfonyl.
60. A tetrazole of claim 59 wherein R.sup.4 is substituted or
unsubstituted thiazole.
61. A tetrazole of claim 60 wherein R.sup.3 is cyclopentyl.
62. A tetrazole of claim 61 which is
3-cyclopentyl-2-[4-methanesulfonyl-3--
(5-methyl-tetrazol-1-yl)-phenyl]-N-thiazol-2-yl-propionamide.
63. A tetrazole of claim 34 wherein R.sup.4 is --C(O)--NHR.sup.6
and R.sup.6 is hydrogen or lower alkyl.
64. A tetrazole of claim 63 wherein R.sup.1 is 45
65. A tetrazole of claim 64 wherein R.sup.3 is cyclopentyl.
66. A tetrazole of claim 65 wherein R.sup.6 is methyl.
67. A tetrazole of claim 66 wherein R.sup.2 is perfluoro lower
alkyl or halogen.
68. A tetrazole of claim 67 which is
1-{3-cyclopentyl-2-[4-(5-methyl-tetra-
zol-1-yl)-3-trifluoromethyl-phenyl}-propionyl-3-methyl-urea
69. A tetrazole of claim 67 which is
1-{2-[3-chloro-4-(5-methyl-tetrazol-1-
-yl)-phenyl]-3-cyclopentyl-propionyl-3-methyl-urea.
Description
BACKGROUND OF THE INVENTION
[0001] Glucokinase (GK) is one of four hexokinases found in mammals
[Colowick, S. P., in The Enzymes, Vol. 9 (P. Boyer, ed.) Academic
Press, New York, N.Y., pages 1-48, 1973]. The hexokinases catalyze
the first step in the metabolism of glucose, i.e., the conversion
of glucose to glucose-6-phosphate. Glucokinase has a limited
cellular distribution, being found principally in pancreatic
.beta.-cells and liver parenchymal cells. In addition, GK is a
rate-controlling enzyme for glucose metabolism in these two cell
types that are known to play critical roles in whole-body glucose
homeostasis [Chipkin, S. R., Kelly, K. L., and Ruderman, N. B. in
Joslin's Diabetes (C. R. Khan and G. C. Wier, eds.), Lea and
Febiger, Philadelphia, Pa., pages 97-115, 1994]. The concentration
of glucose at which GK demonstrates half-maximal activity is
approximately 8 mM. The other three hexokinases are saturated with
glucose at much lower concentrations (<1 mM). Therefore, the
flux of glucose through the GK pathway rises as the concentration
of glucose in the blood increases from fasting (5 mM) to
postprandial (.apprxeq.10-15 mM) levels following a
carbohydrate-containing meal [Printz, R. G., Magnuson, M. A., and
Granner, D. K. in Ann. Rev. Nutrition Vol. 13 (R. E. Olson, D. M.
Bier, and D. B. McCormick, eds.), Annual Review, Inc., Palo Alto,
Calif., pages 463-496, 1993]. These findings contributed over a
decade ago to the hypothesis that GK functions as a glucose sensor
in .beta.-cells and hepatocytes (Meglasson, M. D. and Matschinsky,
F. M. Amer. J. Physiol. 246, E1-E13, 1984). In recent years,
studies in transgenic animals have confirmed that GK does indeed
play a critical role in whole-body glucose homeostasis. Animals
that do not express GK die within days of birth with severe
diabetes while animals overexpressing GK have improved glucose
tolerance (Grupe, A., Hultgren, B., Ryan, A. et al., Cell 83,
69-78, 1995; Ferrie, T., Riu, E., Bosch, F. et al., FASEB J., 10,
1213-1218, 1996). An increase in glucose exposure is coupled
through GK in .beta.-cells to increased insulin secretion and in
hepatocytes to increased glycogen deposition and perhaps decreased
glucose production.
[0002] The finding that type II maturity-onset diabetes of the
young (MODY-2) is caused by loss of function mutations in the GK
gene suggests that GK also functions as a glucose sensor in humans
(Liang, Y., Kesavan, P., Wang, L. et al., Biochem. J. 309, 167-173,
1995). Additional evidence supporting an important role for GK in
the regulation of glucose metabolism in humans was provided by the
identification of patients that express a mutant form of GK with
increased enzymatic activity. These patients exhibit a fasting
hypoglycemia associated with an inappropriately elevated level of
plasma insulin (Glaser, B., Kesavan, P., Heyman, M. et al., New
England J. Med. 338, 226-230, 1998). While mutations of the GK gene
are not found in the majority of patients with type II diabetes,
compounds that activate GK and, thereby, increase the sensitivity
of the GK sensor system will still be useful in the treatment of
the hyperglycemia characteristic of all type II diabetes.
Glucokinase activators will increase the flux of glucose metabolism
in .beta.-cells and hepatocytes, which will be coupled to increased
insulin secretion. Such agents are useful for treating type II
diabetes.
SUMMARY OF THE INVENTION
[0003] This invention provides a tetrazole selected from the group
consisting of a compound of the formula: 1
[0004] where one of R.sup.1 or R.sup.2 is 2
[0005] (this tetrazole is linked to the remainder of the molecule
by the N, as represented here) and the other is hydrogen, halogen,
lower alkyl sulfonyl, perfluoro-lower alkyl, cyano, or nitro;
R.sup.3 is cycloalkyl; R.sup.4 is --C(O)--NHR.sup.6 or a five- or
six-membered heteroaromatic ring connected by a ring carbon atom to
the amide group shown, which heteroaromatic ring contains from 1 to
3 heteroatoms selected from the group consisting of oxygen, sulfur
and nitrogen with a first heteroatom being nitrogen adjacent to the
connecting ring carbon atom, said heteroaromatic ring being
unsubstituted or monosubstituted with halogen at a position on a
ring carbon atom other than that adjacent to said connecting carbon
atom; n is 0 or 1; R.sup.5 is lower alkyl, or perfluoro lower
alkyl; R.sup.6 is hydrogen or lower alkyl; and pharmaceutically
acceptable salts of the tetrazole.
[0006] Formula I-A depicts the isomeric bond when it is not
hydrogenated. Formula I-B depicts the bond when it is hydrogenated.
Accordingly the .DELTA. denotes a trans configuration across the
double bond in formula I-A, and the * represents the asymmetric
carbon atom in formula I-B. Tetrazoles which are compounds of
formula I-B are preferably in the R configuration.
[0007] The compounds of formula IA or IB are glucokinase activators
useful for increasing insulin secretion in the treatment of type II
diabetes.
DETAILED DESCRIPTION OF THE INVENTION
[0008] One embodiment of formula I-A or of formula I-B is a
tetrazole where R.sup.4 is a five- or six-membered heteroaromatic
ring connected by a ring carbon atom to the amide group shown,
which heteroaromatic ring contains from 1 to 3 heteroatoms selected
from the group consisting of oxygen, sulfur and nitrogen with a
first heteroatom being nitrogen adjacent to the connecting ring
carbon atom, said heteroaromatic ring being unsubstituted or
monosubstituted with halogen at a position on a ring carbon atom
other than that adjacent to said connecting carbon atom. Formula
I-A1 represents this embodiment as a compound of formula I-A, and
Formula I-B 1 represents this embodiment as a compound of formula
I-B.
[0009] Another embodiment of formula I-A or formula I-B is a
tetrazole where R.sup.4 is --C(O)--NHR.sup.6 where R.sup.6 is
hydrogen or lower alkyl. Formula I-A2 represents this embodiment as
a compound of formula I-A. Formula I-B2 represents this embodiment
as a compound of formula I-B.
[0010] In most tetrazoles of this invention, it is preferred that
R.sup.1 be 3
[0011] It is also preferred that R.sup.5 be lower alkyl (such as
methyl). It is further preferred that R.sup.3 be cyclopentyl,
although cyclohexyl and cycloheptyl are also possible. When R.sup.4
is a six-membered heteroaromatic ring, it is preferably substituted
or unsubstituted pyridine. When R.sup.4 is a 5-membered
heteroaromatic ring, it is preferably substituted or unsubstituted
thiazole. When substituted, either ring is preferably
monosubstituted, and the preferred substituent is halogen such as
bromo. R.sup.2 is preferably halogen (such as fluoro or chloro) or
perfluoro lower alkyl (such as trifluoromethyl) and R.sup.6 is
preferably methyl. Thus, a tetrazole of formula IA or IB may
include any one or more of these conditions in any selected
combination. In addition, any one or more of these conditions may
be applied to any tetrazole of this invention as described herein.
For example, in any tetrazole of this invention with substituted
pyridine, the preferred substituent is bromo.
[0012] In particular, in tetrazoles of formula I-A1, R.sup.1 is
4
[0013] R.sup.5 is lower alkyl, and R.sup.3 is cyclopentyl (formula
I-A1a). In one embodiment of formula I-A1a, R.sup.4 is a
six-membered heteroaromatic ring, in particular substituted or
unsubstituted pyridine. In such a tetrazole, R.sup.2 may be
halogen. An example is:
[0014]
(E)-N-(5-bromo-pyridin-2-yl)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl--
tetrazol-1-yl)-phenyl]-acrylamide
[0015] In another embodiment of formula I-A1a, R.sup.4 is a
5-membered heteroaromatic ring, in particular substituted or
unsubstituted thiazole. In such a tetrazole, R.sup.2 may be halogen
or perfluoro lower alkyl, or R.sup.2 may be lower alkyl sulfonyl.
Examples of the former tetrazoles are
[0016]
(E)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-p-
henyl-]-N-thiazol-2-yl-acrylamide
[0017]
(E)-4-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-p-
henyl-]-but-2-enoic acid-thiazol-2-ylamide
[0018]
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-N--
thiazol-2-yl-acrylamide
[0019]
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-N--
thiazol-2-yl-acrylamide
[0020] An example of the latter tetrazole is
[0021]
(E)-3-cyclopentyl-2-[3-methanesulfonyl-4-(5-methyl-tetrazol-1-yl)-p-
henyl-]-N-thiazol-2-yl-acrylamide
[0022] In another tetrazole of formula I-A1, R.sup.1 is 5
[0023] R.sup.2 is halogen and R.sup.4 is substituted or
unsubstituted thiazole. In these tetrazoles, R.sup.5 is lower alkyl
or perfluoro lower alkyl. R.sup.3 may be cyclohexyl, as in
[0024]
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-N-t-
hiazol-2-yl-acrylamide
[0025]
(E)-2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cyclo-
hexyl-N-thiazol-2-yl-acrylamide
[0026] Or R.sup.3 may be cycloheptyl, as in
[0027]
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycloheptyl-N--
thiazol-2-yl-acrylamide
[0028]
(E)-N-(5-bromo-thiazol-2-yl)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-
-phenyl]-3-cycloheptyl-acrylamide
[0029] This invention is also directed to tetrazoles of formula
I-A2 (i.e. tetrazoles of formula I-A) where R.sup.4 is
--C(O--NHR.sup.6 where R.sup.6 is hydrogen or lower alkyl. In
preferred such tetrazoles, R.sup.1 is 6
[0030] R.sup.5 is lower alkyl, R.sup.3 is cyclopentyl, and R.sup.6
is methyl, especially where R.sup.2 is halogen. An example of such
a tetrazole is
[0031]
(E)-1-{3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl--
acryloyl}3-methyl-urea
[0032] This invention is also directed to tetrazoles of formula
I-B, for example tetrazoles of formula I-B1 (where R.sup.4 is a
five- or six-membered heteroaromatic ring as described in detail
above). In such tetrazoles, R.sup.1 is preferably 7
[0033] R.sup.5 is lower alkyl, and R.sup.3 is cyclopentyl (formula
I-B1a). In one embodiment of formula I-B1a, R.sup.4 is a
six-membered heteroaromatic ring, in particular substituted or
unsubstituted pyridine. In such a tetrazole, R.sup.2 may be
halogen. Examples of such tetrazoles are
[0034]
N-(5-bromo-pyridin-2-yl)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetr-
azol-1-yl)-phenyl]-propionamide
[0035]
N-(5-bromo-pyridin-2-yl)-3-cyclopentyl-2-[3-chloro-4-(5-methyl-tetr-
azol-1-yl)-phenyl]-propionamide
[0036] Alternatively, R.sup.2 may be perfluoro lower alkyl, for
example in
[0037]
N-(5-bromo-pyridin-2-yl)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl-
)-3-trifluoromethyl-phenyl]-propionamide
[0038] In another embodiment of formula I-B1a, R.sup.4 is a
5-membered heteroaromatic ring, in particular substituted or
unsubstituted thiazole. In such a tetrazole, R.sup.2 may be halogen
or perfluoro lower alkyl, or R.sup.2 may be lower alkyl sulfonyl.
Examples of these tetrazoles are
[0039]
3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-N-thia-
zol-2-yl-propionamide
[0040]
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-N-thia-
zol-2-yl-propionamide
3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-triflu-
oromethyl-phenyl]-N-thiazol-2-yl-propionamide
[0041] In another tetrazole of formula I-B1, R.sup.1 is 8
[0042] R.sup.3 is cyclohexyl and R.sup.4 is substituted or
unsubstituted thiazole. In these tetrazoles, R.sup.2 is halogen.
R.sup.5 may be lower alkyl as in
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-N-
-thiazol-2-yl-propionamide or perfluoro lower alkyl as in
2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-N-th-
iazol-2-yl-propionamide.
[0043] In any tetrazoles of this invention, R.sup.2 and R.sup.1 can
be exchanged so that R.sup.2 is 9
[0044] in particular certain tetrazoles of formula I-B1. In these
tetrazoles, it is preferred that R.sup.1 is lower alkyl sulfonyl,
R.sup.4 is substituted or unsubstituted thiazole, and R.sup.3 is
cyclopentyl. An example of such a tetrazole is
[0045]
3-cyclopentyl-2-[4-methanesulfonyl-3-(5-methyl-tetrazol-1-yl)-pheny-
l]-N-thiazol-2-yl-propionamide
[0046] This invention is also directed to tetrazoles of formula
I-B2 (i.e. tetrazoles of formula I-B) where R.sup.4 is
--C(O)--NHR.sup.6 where R.sup.6 is hydrogen or lower alkyl. In such
tetrazoles, it is preferred that R.sup.1 is 10
[0047] R.sup.3 is cyclopentyl, R.sup.6 is methyl, and R.sup.2 is
perfluoro lower alkyl or halogen. Examples of such tetrazoles
are
[0048]
1-{3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-ph-
enyl}-propionyl-3-methyl-urea
[0049]
1-{2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-pro-
pionyl-3-methyl-urea
[0050] As used herein, the term "lower alkyl" means straight chain
or branched chain alkyl groups having from 1 to 4 carbon atoms,
such as methyl, ethyl, propyl, isopropyl, preferably methyl and
ethyl. As used herein, "cycloalkyl" means a saturated hydrocarbon
ring having from 3 to 8 carbon atoms, preferably from 5 to 7 carbon
atoms. As used herein, "perfluoro-lower alkyl" means any lower
alkyl group wherein all of the hydrogens of the lower alkyl group
are substituted or replaced by fluoro, such as trifluoromethyl,
pentafluoroethyl, heptafluoropropyl, etc.
[0051] As used herein, "lower alkyl sulfonyl" means a lower alkyl
group as defined above bound to the rest of the molecule through
the sulfur atom in the sulfonyl group.
[0052] As used herein, the term "halogen" or "halo" unless
otherwise stated designates all four halogens, i.e. fluorine,
chlorine, bromine and iodine (fluoro, chloro, bromo, and iodo).
[0053] The heteroaromatic ring defined by R.sup.4 is five- or
six-membered heteroaromatic ring (e.g. an aromatic ring having at
least one heteroatom) which is connected by a ring carbon to the
amide group shown in formula IA or formula IB. This ring has from 1
to 3 heteroatoms selected from the group consisting of oxygen,
nitrogen, and sulfur. The nitrogen is found adjacent to the
connecting ring carbon atom. Preferred heteroaromatic rings include
pyridinyl and thiazolyl. The rings may be unsubstituted, or
mono-substituted with a halogen at a position on a ring carbon
which is not adjacent to the connecting ring carbon atom.
[0054] The term "trans" as used herein designates that the largest
substituents attached across the double bond are on opposite sides
of the double bond and have the "E" configuration. The term "cis"
designates that the two largest substituents attached across the
double bond are on the same side as the double bond.
[0055] In the compounds of formula I-B, the "*" designates the
asymmetric carbon atom in the compounds with the R optical
configuration being preferred. The compounds of formula I-B may be
present in the R form or as a racemic or other mixture of compounds
having the R and S optical configuration at the asymmetric carbon
shown. The pure R enantiomers are preferred. As stated above, the
compounds of this invention are useful as glucokinase activators
for increasing insulin secretion for treatment of type II diabetes.
Compounds of formula I-A having the trans configuration across the
double bond (represented by the .DELTA.) have this glucokinase
activity.
[0056] The term "pharmaceutically acceptable salts" as used herein
include any salt with both inorganic or organic pharmaceutically
acceptable acids such as hydrochloric acid, hydrobromic acid,
nitric acid, sulfuric acid, phosphoric acid, citric acid, formic
acid, maleic acid, acetic acid, succinic acid, tartaric acid,
methanesulfonic acid, para-toluene sulfonic acid and the like. The
term "pharmaceutically acceptable salts" also includes any
pharmaceutically acceptable base salt such as amine salts, trialkyl
amine salts and the like. Such salts can be formed quite readily by
those skilled in the art using standard techniques.
[0057] The three Schemes that follow demonstrate how to make
tetrazoles of formulae IA or IB from known starting materials. 11
12 13
[0058] R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and n are as in
formulae I-A and I-B. As shown in the Schemes, the R.sup.1 and
R.sup.2 positions are interchangeable. Therefore the Schemes
include and demonstrate the same reactions, intermediates, and
compounds with the tetrazole or its precursors in the R.sup.2
position and the other R.sup.1/R.sup.2 variables (hydrogen,
halogen, lower alkyl sulfonyl, perfluoro lower alkyl, cyano, or
nitro) in the R.sup.1 position and vice versa.
[0059] The compounds of this invention are produced by reacting
phenyl-substituted tetrazoles (II, II', IV, or IV') with
cycloalkyl-substituted acrylic acid lower alkyl esters (VII) to
obtain tetrazolyl-phenyl cycloalkyl propenoic ester (VIII), which
is hydrolyzed or reduced and hydrolyzed to give the corresponding
propenoic or acrylic acid (IX or XIII), to which is added the
desired heteroaromatic ring or urea/substituted urea to obtain a
compound of formula I-A or formula I-B. The phenyl-substituted
tetrazoles (II, II', IV, or IV') may be produced from the
appropriate substituted anilines which are known and available
materials or can be produced by a skilled person from known
materials. The cycloalkyl-substituted acrylic acid lower alkyl
esters may be produced from cycloalkyl halides, which are similarly
known and available materials or can be produced by a skilled
person from known materials. These reactions are discussed in more
detail below.
[0060] Scheme 1 shows how to obtain starting materials for
compounds of this invention. For compounds where R.sup.5 is lower
alkyl or perfluoro lower alkyl, substituted aniline I is reacted
with lower alkyl or perfluoro lower alkyl carboxylic acid
(corresponding to R.sup.5) using conventional methods for
converting an amine to an imine, for example in a suspension of
triphenylphosphine in carbon tetrachloride treated with an organic
base such as triethylamine. Accordingly the reaction proceeds by
way of an imidoyl halide (e.g. chloride) intermediate, which is
reacted with an azide such as sodium azide as to obtain tetrazole
II by conventional methods for tetrazole formation from an imidoyl
chloride.
[0061] For compounds of this invention where R.sup.5 is lower
alkyl, an alternate route is acylation of aniline I as described
above to acetamide III under standard conditions (such as acetic
anhydride in tetrahydrofuran), followed by reaction with an azide
to obtain tetrazole IV by conventional methods for tetrazole
formation from a lower alkyl amide.
[0062] Aniline I where X is either iodo or bromo and either of
R.sup.1 or R.sup.2 is hydrogen, nitro, fluorine, chlorine, bromine,
thiol, and trifluoromethyl or where R.sup.1 is thiomethyl or where
R.sup.2 is cyano, is known and commercially available, and may also
be made by a skilled chemist from known materials. Other aniline I
compounds may be made by a skilled chemist from known
materials.
[0063] For example aniline 1 where R.sup.1 or R.sup.2 is
C.sub.1-C.sub.4 lower alkyl sulfonyl can be made from aniline I
where R.sup.1 or R.sup.2 is thiol. The thiol is alkylated under
standard conditions to provide the lower alkyl thio, which can then
be oxidized to the corresponding lower alkyl sulfonyl. Any
conventional method of oxidizing alkyl thio substituents to
sulfones can be used to effect this conversion.
[0064] Aniline I where R.sup.1 is cyano (and X is bromo) can be
made from aniline I where R.sup.1 is nitro and X is bromo by
reducing the nitro to an amine by any conventional method, then
diazotizing the amine to the corresponding diazonium salt, and
reacting with a standard cyano group transferring agent to obtain
aniline I where R.sup.1 is cyano.
[0065] Aniline I where R.sup.1 or R.sup.2 are perfluoro lower alkyl
can be made from the corresponding halo compounds of formula VIII.
Any conventional method for converting an aromatic halo group to a
desired perfluoro lower alkyl group may be used (see for example,
Katayama, T.; Umeno, M., Chem. Lett. 1991, 2073; Reddy, G. S.;
Tam., Organometallics, 1984, 3, 630; Novak, J.; Salemink, C. A.,
Synthesis, 1983, 7, 597; Eapen, K. C.; Dua, S. S.; Tamboroski, C.,
J. Org. Chem. 1984, 49, 478; Chen, Q, -Y.; Duan, J. -X. J. Chem.
Soc. Chem. Comm. 1993, 1389; Clark, J. H.; McClinton, M. A.; Jone,
C. W.; Landon, P.; Bisohp, D.; Blade, R. J., Tetrahedron Lett.
1989, 2133; Powell, R. L.; Heaton, C. A, U.S. Pat. No.
5,113,013).
[0066] Aniline I where R.sup.1 or R.sup.2 is iodo may be made from
the corresponding nitro compounds of formula VIII. The nitro is
reduced to an amine and the amine is diazotized to the diazonium
salt, which is then converted to the iodo compound by conventional
methods (see for example Lucas, H. J. and Kennedy, E. R., Org.
Synth. Coll. Vol. II 1943, 351).
[0067] For compounds of formula I-A, the above tetrazoles are
coupled with acrylic acid lower alkyl ester (VIII) to ultimately
provide tetrazolyl-phenyl cycloalkyl propenoic acid IX to which may
be coupled a heteroaromatic amine or a urea or lower alkyl urea to
obtain a compound of formula I-A.
[0068] Scheme 2 shows how to obtain compounds of formula I-A in
more detail. R.sup.3 is cycloalkyl. To obtain
cycloalkyl-2-iodo-acrylic acid methyl ester VII, organozinc reagent
Va (obtained by conventional methods from commercially available
iodide V) or commercially available Grignard reagent Vb and soluble
copper reagent is reacted with lower alkyl propiolate in a regio-
and stereo-selective 1,4-conjugate addition to obtain a vinylcopper
intermediate which upon iodonolysis under standard conditions
produces VII where R.sup.3 and the iodo substituent are in syn
relationship to each other. The addition operates by way of a
cycloalkyl copper cyano zinc or magnesium halide intermediate
obtained by treating Va or Vb with copper cyanide and lithium
chloride in an aprotic solvent such as tetrahydrofuran. Compound
VII is then reacted with activated zinc metal (Knochel and Rao,
Tetrahedron 49:29, 1993) to give a vinylzinc intermediate which may
be coupled with either compound II or compound IV in the presence
of a source of Pd(0) to give tetrazole-phenyl-cycloalkyl-- acrylic
acid methyl ester VIII with the phenyl-substituted tetrazole
replacing the iodide to yield the trans orientation across the
double bond.
[0069] Compound VIII is then hydrolyzed under standard alkaline
conditions to the corresponding acid IX. Heterocyclic compound X
may then be formed by coupling the desired heteroaromatic amine to
compound IX under conventional conditions for adding an amine to an
acid. Urea compound XI may be obtained by coupling urea or lower
alkyl urea to compound IX under conventional conditions for
converting an acid to a urea.
[0070] Compound VIII is the starting material for compounds of
formula I-B. As shown in Scheme 3, these compounds may be obtained
by reducing compound VIII to tetrazole-phenyl-cycloalkyl propanoic
acid lower alkyl ester XII. This can be accomplished using
conventional metal catalysts such as nickel in the presence of a
reducing agent under standard conditions. Compound XII is then
hydrolyzed under standard conditions to provide the corresponding
acid XIII. Heterocyclic compound XIV may then be formed by coupling
the desired heteroaromatic amine to compound XIII under
conventional conditions for adding an amine to an acid. Urea
compound XV may be obtained by coupling urea or lower alkyl urea to
compound XIII under conventional conditions for converting an acid
to a urea.
[0071] If it is desired to produce the R enantiomer of the compound
of formula I-B free of the other enantiomers, the compound of
formula XIII can be separated into this isomer from its racemate by
any conventional chemical means. Among the preferred chemical means
is to react the compound of formula XIII with an optically active
base. Any conventional optically active base can be utilized to
carry out this resolution. Among the preferred optically active
bases are the optically active amine bases such as
alpha-methylbenzylamine, quinine, dehydroabietylamine and
alpha-methylnaphthylamine. Any of the conventional techniques
utilized in resolving organic acids with optically active organic
amine bases can be utilized in carrying out this reaction.
[0072] In the resolution step, the compound of formula XIII is
reacted with the optically active base in an inert organic solvent
medium to produce salts of the optically active amine with both the
R and S isomers of the compound of formula XIII. In the formation
of these salts, temperatures and pressure are not critical and the
salt formation can take place at room temperature and atmospheric
pressure. The R and S salts can be separated by any conventional
method such as fractional crystallization. After crystallization,
each of the salts can be converted to the respective compounds of
formula XIII in the R and S configuration by hydrolysis with an
acid. Among the preferred acids are dilute aqueous acids, i.e.,
from about 0.001N to 2N aqueous acids, such as aqueous sulfuric or
aqueous hydrochloric acid. By means of measuring the optical
rotation of the optically pure crystallized acid of formula XIII,
one can obtain the configuration of this crystalline material. If
this crystallized acid has a negative rotation, then this
crystallized acid has the R configuration. The configuration of
formula XIII which is produced by this method of resolution is
carried out throughout the entire reaction scheme to produce the
desired R of formula IB. The separation of R and S isomers can also
be achieved using an enzymatic ester hydrolysis of any lower alkyl
esters corresponding to the compound of the formula XII (see, for
example, Ahmar, M.; Girard, C.; Bloch, R., Tetrahedron Lett, 1989,
7053), which results in the formation of corresponding chiral acid
and chiral ester. The ester and the acid can be separated by any
conventional method of separating an acid from an ester. The
preferred method of resolution of racemates of the compounds of the
formula XIII is via the formation of corresponding diastereomeric
esters or amides. These diastereomeric esters or amides can be
prepared by coupling the carboxylic acids of the formula XIII with
a chiral alcohol or a chiral amine. This reaction can be carried
out using any conventional method of coupling a carboxylic acid
with an alcohol or an amine. The corresponding diastereomers of
compounds of the formula XIII can then be separated using any
conventional separation methods. The resulting pure diastereomeric
esters or amides can then be hydrolyzed to yield the corresponding
pure R and S isomers. The hydrolysis reaction can be carried out
using any conventional method to hydrolyze an ester or an amide
without racemization.
[0073] All of the compounds of formula IA or formula IB described
in the Examples activated glucokinase in vitro in accordance with
the procedure described in Example A.
[0074] The following compounds were tested and found to have
excellent glucokinase activating activity in vivo when administered
orally in accordance with the procedure described in Example B.
[0075]
N-(5-bromo-pyridin-2-yl)-3-cyclopentyl-2-[3-chloro-4-(5-methyl-tetr-
azol-1-yl)-phenyl]-propionamide
[0076]
N-(5-bromo-pyridin-2-yl)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl-
)-3-trifluoromethyl-phenyl]-propionamide
[0077]
3-Cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-pheny-
l]-N-thiazol-2-yl-propionamide
[0078]
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-N-t-
hiazol-2-yl-acrylamide
[0079]
(E)-2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cyclo-
hexyl-N-thiazol-2-yl-acrylamide
[0080]
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycloheptyl-N--
thiazol-2-yl-acrylamide
[0081]
(E)-N-(5-bromo-thiazol-2-yl)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-
-phenyl]-3-cycloheptyl-acrylamide
[0082]
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-N--
thiazol-2-yl-acrylamide
[0083]
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-N--
thiazol-2-yl-acrylamide
[0084] This invention will be better understood from the following
examples, which are for purposes of illustration and are not
intended to limit the invention defined in the claims that follow
thereafter.
EXAMPLE 1
2-[4-[(5-methyl)-1-tetrazolyl]-3-fluoro phenyl]-3-cyclopentyl
N-thiazol-2-yl propionamide
[0085] 14
[0086] A solution of 2-fluoro-4-iodoaniline (4.74 g, 20 mmol) in
dry tetrahydrofuran (20 mL) was cooled to 0.degree. C. and then
treated with acetic anhydride (8.2 g, 80 mmol). The reaction
mixture was stirred for 10 min at 0.degree. C. and then was allowed
to warm to 25.degree. C. where it was stirred for 2 h. After this
time, thin layer chromatography analysis of the reaction mixture
indicated the absence of starting material. The reaction mixture
was then concentrated in vacuo to afford a crude residue. The
residue precipitated from diethyl ether (50 mL) and hexanes (50
mL). The solid was collected by filtration and washed with hexanes
to afford N-(2-fluoro-4-iodo-phenyl)-acetamide (5.12 g, 92%) as a
white crystalline solid: mp 152-154.degree. C.; EI-HRMS m/e calcd
for C.sub.8H.sub.7FINO (M.sup.+) 278.9556, found 278.9559.
[0087] A suspension of N-(2-fluoro-4-iodo-phenyl)-acetamide (5 g,
18.24 mmol) in acetonitrile (100 mL) was cooled to 0.degree. C. and
then treated with sodium azide (3.56 g, 54.7 mmol). The reaction
mixture was then treated with trifluoromethanesulfonic anhydride
(13.6 g, 48 mmol). The resulting reaction mixture was allowed to
warm to 25.degree. C. where it was stirred overnight, at which
time, thin layer chromatography analysis of the reaction mixture
indicated the absence of starting material. The reaction mixture
was then concentrated in vacuo. The resulting residue was diluted
with ethyl acetate (100 mL) and water (100 mL). The two layers were
separated, and the aqueous layer was extracted with ethyl acetate
(1.times.50 mL). The combined organic extracts were washed with a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo. Biotage chromatography (FLASH 40M, Silica, 4/1 hexanes/ethyl
acetate) afforded 1-(2-fluoro-4-iodo-phenyl)-5-methyl-1H-tetrazole
(3.45 g, 62%) as a white solid: mp 122-124.degree. C.; EI-HRMS m/e
calcd for C.sub.8H.sub.6FIN.sub.4 (M.sup.+) 303.9621, found
303.9615.
[0088] A mixture of zinc dust (650 mg, 10 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (prepared in
Example 7, 2.21 g, 7.5 mmol) in dry tetrahydrofuran (3 mL) over 3
min. The resulting reaction mixture was then stirred at
40-45.degree. C. for 1 h and then stirred overnight at 25.degree.
C. The reaction mixture was then diluted with dry tetrahydrofuran
(5 mL), and the stirring was stopped to allow the excess zinc dust
to settle down (.about.2 h). In a separate reaction flask,
bis(dibenzylideneacetone)palladium(0) (90 mg, 0.16 mmol) and
triphenylphosphine (160 mg, 0.6 mmol) in dry tetrahydrofuran (10
mL) was stirred at 25.degree. C. under argon for 10 min and then
treated with 1-(2-fluoro-4-iodo-phenyl)-5-methyl-1H-tetrazole (1.52
g, 5 mmol) and the freshly prepared zinc compound in
tetrahydrofuran. The resulting brick red solution was stirred at
25.degree. C. over the weekend and then heated at 40-45.degree. C.
for 4 h. The reaction mixture was cooled to 25.degree. C. and then
poured into a saturated aqueous ammonium chloride solution (50 mL),
and the organic compound was extracted into ethyl acetate
(3.times.50 mL). The combined organic extracts were washed with a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 4/1
to 1/1 hexanes/ethyl acetate) afforded
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-
-tetrazol-1-yl)-phenyl]-acrylic acid methyl ester (1.14 g, 68%) as
a light yellow solid: mp 111-114.degree. C.; EI-HRMS m/e calcd for
C.sub.17H.sub.19FN.sub.4O.sub.2 (M.sup.+) 330.1492, found
330.1493.
[0089] A solution of nickel (II) chloride hexahydrate (115 mg, 0.24
mmol) and
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-acry-
lic acid methyl ester (400 mg, 1.21 mmol) in methanol (10 mL) was
cooled to 0.degree. C. and then treated with sodium borohydride
(275 mg, 3.63 mmol) in two portions. After the addition, the black
reaction mixture was stirred for 15 min at 0.degree. C. and then
allowed to warm to 25.degree. C. where it was stirred for 15 h. The
reaction mixture was concentrated in vacuo, and the residue was
diluted with a 3N aqueous hydrochloric acid solution (30 mL) and
ethyl acetate (50 mL). The two layers were separated. The organic
layer was washed with a saturated aqueous sodium chloride solution
(1.times.50 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo to afford racemic
3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-propionic
acid methyl ester (400 mg, 99%) as a viscous oil: EI-HRMS m/e calcd
for C.sub.17H.sub.21FN.sub.4O.sub.2 (M.sup.+) 332.1648, found
332.1645.
[0090] A solution of
3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)--
phenyl]-propionic acid methyl ester (400 mg, 1.2 mmol) in ethanol
(8 mL) was treated with a 1N aqueous sodium hydroxide solution (2.5
mL). The solution was heated at 45-50.degree. C. for 5 h, at which
time, thin layer chromatography analysis of the reaction mixture
indicated the absence of starting material. The reaction mixture
was concentrated in vacuo to remove ethanol. The residue was
diluted with water (40 mL) and extracted with diethyl ether
(1.times.50 mL) to remove any neutral impurities. The aqueous layer
was then acidified with a 1N aqueous hydrochloric acid solution,
and the resulting acid was extracted into ethyl acetate (2.times.50
mL). The combined organic layers were washed with a saturated
aqueous sodium chloride solution (1.times.50 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo to
afford
3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-propi-
onic acid (360 mg, 94%) as a yellow solid: EI-HRMS m/e calcd for
C.sub.16H.sub.19FN.sub.4O.sub.2 (M.sup.+) 318.1487, found
318.1492.
[0091] A solution of triphenylphosphine (288 mg, 1.1 mmol) in
methylene chloride (6 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (196 mg, 1.1 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with 3-cyclopentyl-2-[3-fluor-
o-4-(5-methyl-tetrazol-1-yl)-phenyl]-propionic acid (175 mg, 0.55
mmol). The clear solution was stirred for 15 min at 0.degree. C.
and then allowed to warm to 25.degree. C. where it was stirred for
1.5 h. The reaction mixture was then treated with 2-aminothiazole
(275 mg, 2.75 mmol), and the resulting suspension was stirred for 2
d at 25.degree. C. The reaction mixture was then concentrated in
vacuo to remove methylene chloride, and the residue was diluted
with ethyl acetate (50 mL) and a 1N aqueous hydrochloric acid
solution (25 mL). The two layers were separated, and the aqueous
layer was extracted with ethyl acetate (1.times.25 mL). The
combined organic extracts were successively washed with a 1N
aqueous hydrochloric acid solution (1.times.50 mL), a saturated
aqueous sodium bicarbonate solution (1.times.50 mL) and a saturated
aqueous sodium chloride solution (1.times.50 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40S, Silica, 2/1 hexanes/ethyl
acetate) afforded
3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-N-thiazol-2--
yl-propionamide (80 mg, 36%) as an amorphous white solid: EI-HRMS
m/e calcd for C.sub.19H.sub.21FN.sub.6OS (M.sup.+) 400.1482, found
400.1476.
EXAMPLE 2
N-(5-Bromo-pyridin-2-yl)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1--
yl)-phenyl]-propionamide
[0092] 15
[0093] A solution of triphenylphosphine (288 mg, 1.1 mmol) in
methylene chloride (6 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (196 mg, 1.1 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with 3-cyclopentyl-2-[3-fluor-
o-4-(5-methyl-tetrazol-1-yl)-phenyl]-propionic acid (prepared in
Example 1, 175 mg, 0.55 mmol). The clear solution was stirred for
15 min at 0.degree. C. and then allowed to warm to 25.degree. C.
where it was stirred for 1.5 h. The reaction mixture was then
treated with 2-amino-5-bromopyridine (476 mg, 2.75 mmol), and the
resulting suspension was stirred for 2 d at 25.degree. C. The
reaction mixture was then concentrated in vacuo to remove methylene
chloride, and the residue was diluted with ethyl acetate (50 mL)
and water (50 mL). The two layers were separated, and the aqueous
layer was extracted with ethyl acetate (1.times.25 mL). The
combined organic extracts were successively washed with a saturated
aqueous sodium bicarbonate solution (1.times.50 mL) and a saturated
aqueous sodium chloride solution (1.times.50 mL), dried over
anhydrous magnesium sulfate, filtered, hexanes/ethyl acetate)
afforded
N-(5-bromo-pyridin-2-yl)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-
-yl)-phenyl]-propionamide (190 mg, 73%) as a white solid: mp
73-78.degree. C.; EI-HRMS m/e calcd for C.sub.21H.sub.22BrFN.sub.6O
(M.sup.+) 472.1022, found 472.1022.
EXAMPLE 3
2-[3-Chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-N-thiazol-2-y-
l-propionamide
[0094] 16
[0095] A mixture of zinc dust (650 mg, 10 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (prepared in
Example 7, 1.26 g, 4.5 mmol) in dry tetrahydrofuran (2 mL) over 3
min. The reaction mixture was then stirred at 40-45.degree. C. for
1 h and then stirred overnight at 25.degree. C. The reaction
mixture was then diluted with dry tetrahydrofuran (3 mL), and the
stirring was stopped to allow the excess zinc dust to settle down
(.about.2 h). In a separate reaction flask,
bis(dibenzylideneacetone)palladium(0) (54 mg, 0.1 mmol) and
triphenylphosphine (104 mg, 0.4 mmol) in dry tetrahydrofuran (4 mL)
was stirred at 25.degree. C. under arson for 10 min and then
treated with 1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-tetrazole
(prepared in Example 4, 875 mg, 2.73 mmol) and the freshly prepared
zinc compound in tetrahydrofuran. The resulting brick red solution
was stirred at 25.degree. C. over the weekend and then heated at
40-45.degree. C. for 4 h. The reaction mixture was cooled to
25.degree. C. and then poured into a saturated aqueous ammonium
chloride solution (50 mL), and the organic compound was extracted
into ethyl acetate (3.times.35 mL). The combined organic extracts
were washed with a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Flash chromatography (Merck Silica gel
60, 230-400 mesh, 4/1 to 1/1 hexanes/ethyl acetate) afforded
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-acrylic
acid methyl ester (859 mg, 91%) as a light yellow semi-solid:
EI-HRMS m/e calcd for C.sub.17H.sub.19ClN.sub.4O.sub.2 (M.sup.+)
346.1196, found 346.1190.
[0096] A solution of nickel (II) chloride hexahydrate (180 mg, 0.8
mmol) and
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-acry-
lic acid methyl ester (695 mg, 2.0 mmol) in methanol (15 mL) was
cooled to 0.degree. C. and then treated with sodium borohydride
(454 mg, 12 mmol) in five portions. After the addition, the black
reaction mixture was stirred for 15 min at 0.degree. C. and then
allowed to warm to 25.degree. C. where it was stirred for 2 d. The
reaction mixture was concentrated in vacuo, and the residue was
diluted with a 3N aqueous hydrochloric acid solution (50 mL) and
ethyl acetate (75 mL). The two layers were separated. The organic
layer was washed with a saturated aqueous sodium chloride solution
(1.times.50 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo to afford racemic
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-propionic
acid methyl ester (815 mg, 99%) as a viscous oil: EI-HRMS m/e calcd
for C.sub.17H.sub.21ClN.sub.4O.sub.2 (M.sup.+) 348.1353, found
348.1359.
[0097] A solution of
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycl-
opentyl-propionic acid methyl ester ester (690 mg, 2.0 mmol) in
ethanol (20 mL) was treated with a 1N aqueous sodium hydroxide
solution (4 mL). The solution was heated at 45-50.degree. C. for 3
h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was concentrated in vacuo to remove ethanol. The
residue was diluted with water (50 mL) and extracted with diethyl
ether (1.times.60 mL) to remove any neutral impurities. The aqueous
layer was then acidified with a 1N aqueous hydrochloric acid
solution, and the resulting acid was extracted into ethyl acetate
(2.times.50 mL). The combined organic layers were washed with a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-propi-
onic acid (604 mg, 90%) as an amorphous white solid: EI-HRMS m/e
calcd for C.sub.16H.sub.19ClN.sub.4O.sub.2 (M.sup.+) 334.1196,
found 334.1193.
[0098] A solution of triphenylphosphine (236 mg, 0.9 mmol) in
methylene chloride (6 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (160 mg, 0.9 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with the
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-propionic
acid (151 mg, 0.45 mmol). The clear solution was stirred for 15 min
at 0.degree. C. and then allowed to warm to 25.degree. C. where it
was stirred for 2 h. The reaction mixture was then treated with
2-aminothiazole (135 mg, 1.35 mmol), and the resulting suspension
was stirred for 20 h at 25.degree. C. The reaction mixture was then
concentrated in vacuo to remove methylene chloride, and the residue
was diluted with ethyl acetate (30 mL) and a 1N aqueous
hydrochloric acid solution (30 mL). The two layers were separated,
and the aqueous layer was extracted with ethyl acetate (1.times.20
mL). The combined organic extracts were successively washed with a
saturated aqueous sodium bicarbonate solution (1.times.50 mL) and a
saturated aqueous sodium chloride solution (1.times.50 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo. Biotage chromatography (FLASH 40S, Silica, 1/1 hexanes/ethyl
acetate) afforded
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-N-thiazol-2--
yl-propionamide (80 mg, 42%) as a white solid: mp 190-193.degree.
C.; EI-HRMS m/e calcd for C.sub.19H.sub.21ClN.sub.6OS (M.sup.+)
416.1186, found 416.1183.
EXAMPLE 4
2-[3-Chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-N-thiazol-2-yl-
-propionamide
[0099] 17
[0100] A mixture of zinc dust (16.34 g, 250 mmol, Aldrich, -325
mesh) and dry tetrahydrofuran (6 mL) under argon was treated with
1,2-dibromoethane (0.94 g, 5 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (0.54 g, 5 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of cyclohexyl
iodide (21 g, 100 mmol) in dry tetrahydrofuran (30 mL) over 15 min.
During the addition, the temperature rose to 60.degree. C. The
reaction mixture was then stirred for 3 h at 40-45.degree. C. The
reaction mixture was then cooled to 25.degree. C. and diluted with
dry tetrahydrofuran (60 mL). The stirring was stopped to allow the
excess zinc dust to settle down (.about.3 h). In a separate
reaction flask, a mixture of lithium chloride (8.48 g, 200 mmol,
predried at 130.degree. C. under high vacuum for 3 h) and copper
cyanide (8.95 g, 100 mmol) in dry tetrahydrofuran (110 mL) was
stirred for 10 min at 25.degree. C. to obtain a clear solution. The
reaction mixture was cooled to -70.degree. C. and then slowly
treated with the freshly prepared zinc solution using a syringe.
After the addition, the reaction mixture was allowed to warm to
0.degree. C. where it was stirred for 5 min. The reaction mixture
was again cooled back to -70.degree. C. and then slowly treated
with methyl propiolate (7.56 g, 90 mmol). The resulting reaction
mixture was stirred for 15 h at -70.degree. C. to -50.degree. C.
and then slowly treated with a solution of iodine (34.26 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (400 mL) and
ammonium hydroxide (100 mL), and the organic compound was extracted
into ethyl acetate (3.times.250 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.500 mL) and a saturated aqueous
sodium chloride solution (1.times.500 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Flash
chromatography (Merck Silica gel 60, 230-400 mesh, 9/1
hexanes/diethyl ether) afforded (E)-3-cyclohexyl-2-iodo-acrylic
acid methyl ester (26.3 g, 99%) as a light pink oil: EI-HRMS m/e
calcd for C.sub.10H.sub.15IO.sub.2 (M.sup.+) 294.0117, found
294.0114.
[0101] A suspension of triphenylphospine (11.7 g, 44.8 mmol) in
carbon tetrachloride (8 mL, 83 mmol) was cooled to 0.degree. C. and
then treated with triethylamine (2.5 mL, 18 mmol) and acetic acid
(1.15 mL, 20 mmol). The reaction mixture was stirred at 0.degree.
C. for 10 min and then treated with a solution of
2-chloro-4-iodoaniline (5.07 g, 20 mmol) in carbon tetrachloride
(12 mL, heated to obtain a solution). The resulting light brown
suspension was allowed to warm to 25.degree. C. and then it was
refluxed overnight. The reaction mixture was cooled to 25.degree.
C. and then concentrated in vacuo. The resulting solid residue was
then diluted with hexanes (50 mL) and methylene chloride (50 mL).
The precipitated solid was collected by filtration and washed with
hexanes. The filtrate was concentrated in vacuo, and the resulting
residue was diluted with diethyl ether (100 mL). The precipitated
solid was collected by filtration and washed with hexanes, and the
filtrate was concentrated in vacuo. The resulting residue was again
diluted with hexanes (100 mL), and the precipitated solid was
collected by filtration. The filtrate was finally concentrated in
vacuo to afford the imidoyl chloride intermediate (4.08 g) as a
liquid. This crude imidoyl chloride intermediate (4.08 g, .about.13
mmol) was treated with sodium azide (1.04 g, 16 mmol) and acetic
acid (10 mL). The reaction was exothermic, and the resulting
reaction mixture was stirred for 1 h at 25.degree. C. The reaction
mixture was then heated at 70.degree. C. for 2 h, at which time,
thin layer chromatography analysis of the reaction mixture
indicated the absence of the imidoyl chloride intermediate. The
cloudy yellow suspension was cooled to 25.degree. C. and then
diluted with water (100 mL) and extracted with ethyl acetate
(2.times.75 mL). The combined organic extracts were washed
successively with a saturated aqueous sodium bicarbonate solution
(1.times.100 mL) and a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40M,
Silica, 6/1 hexanes/diethyl ether) afforded
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-tetrazole (350 mg, 6%) as a
white solid: mp 128-130.5.degree. C.; EI-HRMS m/e calcd for
C.sub.8H.sub.6ClIN.sub.4 (M.sup.+) 319.9327, found 319.9325.
[0102] A mixture of zinc dust (320 mg, 5 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (94 mg, 0.5 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (55 mg, 0.5 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclohexyl-2-iodo-acrylic acid methyl ester (588 mg, 2 mmol)
in dry tetrahydrofuran (2 mL). After the addition, the reaction
mixture was stirred for 1 h at 40-45.degree. C. and then stirred
overnight at 25.degree. C. The reaction mixture was then diluted
with dry tetrahydrofuran (2 mL), and the stirring was stopped to
allow the excess zinc dust to settle down (.about.2 h). In a
separate reaction flask, bis(dibenzylideneacetone)-palladium(0) (27
mg, 0.05 mmol) and triphenylphosphine (57 mg, 0.2 mmol) in dry
tetrahydrofuran (4 mL) was stirred at 25.degree. C. under argon for
10 min and then treated with
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-tetrazole (320.5 mg, 1 mmol)
and the freshly prepared zinc compound in tetrahydrofuran. The
resulting brick red solution was heated at 50.degree. C. for 15 h.
The reaction mixture was cooled to 25.degree. C. and then poured
into a saturated aqueous ammonium chloride solution (30 mL), and
the organic compound was extracted into ethyl acetate (3.times.20
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.50 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40S, Silica, 4/1/1 hexanes/ethyl
acetate/methylene chloride) afforded
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-acrylic
acid methyl ester (233 mg, 64%) as an amorphous white solid:
EI-HRMS m/e calcd for C.sub.18H.sub.21ClN.sub.4O.sub.2 (M.sup.+)
360.1353, found 360.1354.
[0103] A solution of nickel (II) chloride hexahydrate (78 mg, 0.328
mmol) and
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-acryl-
ic acid methyl ester (295 mg, 0.82 mmol) in methanol (8 mL) was
cooled 0.degree. C. and then treated with sodium borohydride (186
mg, 4.92 mmol) in four portions. After the addition, the black
reaction mixture was stirred for 15 min at 0.degree. C. and then
allowed to warm to 25.degree. C. where it was stirred for 24 h. The
reaction mixture was then concentrated in vacuo, and the residue
was diluted with water (30 mL) and ethyl acetate (50 mL). The two
layers were separated. The organic layer was washed successively
with a 3N aqueous hydrochloric acid solution (1.times.50 mL), a
saturated aqueous sodium bicarbonate solution (1.times.50 mL) and a
saturated aqueous sodium chloride solution (1.times.50 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford racemic 2-[3-chloro-4-(5-methyl-tetrazol--
1-yl)-phenyl]-3-cyclohexyl-propionic acid methyl ester (285 mg,
96%) as a viscous oil: EI-HRMS m/e calcd for
C.sub.18H.sub.23ClN.sub.4O.sub.2 (M.sup.+) 362.1509, found
362.1516.
[0104] A solution of
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycl-
ohexyl-propionic acid methyl ester (278 mg, 0.76 mmol) in ethanol
(6 mL) was treated with a 1N aqueous sodium hydroxide solution (1.5
mL). The solution was heated at 45-50.degree. C. for 5 h, at which
time, thin layer chromatography analysis of the mixture indicated
the absence of starting material. The reaction mixture was then
concentrated in vacuo to remove ethanol, and the residue was
diluted with water (20 mL) and extracted with diethyl ether
(1.times.40 mL) to remove any neutral impurities. The aqueous layer
was acidified with a 1N aqueous hydrochloric acid solution. The
resulting acid was extracted into ethyl acetate (2.times.50 mL).
The combined organic layers were washed with a saturated aqueous
sodium chloride solution (1.times.50 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo to afford
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-propio-
nic acid (226 mg, 85%) as an amorphous solid: EI-HRMS m/e calcd for
C.sub.17H.sub.21ClN.sub.4O.sub.2 (M.sup.+) 348.1353, found
348.1354.
[0105] A solution of triphenylphosphine (281 mg, 1.07 mmol) in
methylene chloride (5 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (190.4 mg, 1.07 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with a solution of
2-[3-chloro-4-(5-methyl-tetrazol-1yl)-phenyl]-3-cyclohexyl-propionic
acid (220 mg, 0.63 mmol) in methylene chloride (4 mL). The clear
solution was stirred for 15 min at 0.degree. C. and then allowed to
warm to 25.degree. C. where it was stirred for 2 h. The reaction
mixture was then treated with 2-aminothiazole (189 mg, 1.89 mmol),
and the resulting suspension was stirred for 15 h at 25.degree. C.
The reaction mixture was concentrated in vacuo to remove methylene
chloride, and the residue was diluted with ethyl acetate (50 mL)
and a 1N aqueous hydrochloric acid solution (50 mL). The two layers
were separated, and the aqueous layer was extracted with ethyl
acetate (1.times.30 mL). The combined organic extracts were
successively washed with a saturated aqueous sodium bicarbonate
solution (1.times.50 mL) and a saturated aqueous sodium chloride
solution (1.times.50 mL), dried over anhydrous magnesium sulfate,
filtered, and concentrated in vacuo. Biotage chromatography (FLASH
40S, Silica, 4/1 hexanes/ethyl acetate) afforded
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-N-thiazol-2-y-
l-propionamide (79 mg, 29%) as an amorphous solid: EI-HRMS m/e
calcd for C.sub.20H.sub.23ClN.sub.6OS (M.sup.+) 430.1343, found
430.1343.
EXAMPLE 5
N-(5-Bromo-pyridin-2-yl)-3-cyclopentyl-2-[3-chloro-4-(5-methyl-tetrazol-1--
yl)-phenyl]-propionamide
[0106] 18
[0107] A solution of triphenylphosphine (236 mg, 0.9 mmol) in
methylene chloride (6 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (160 mg, 0.9 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with the
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-propionic
acid (prepared in Example 3, 151 mg, 0.45 mmol). The clear solution
was stirred for 15 min at 0.degree. C. and then allowed to warm to
25.degree. C. where it was stirred for 2 h. The reaction mixture
was then treated with 2-amino-5-bromopyridine (234 mg, 1.35 mmol),
and the resulting suspension was stirred for 2 d at 25.degree. C.
The reaction mixture was then concentrated in vacuo to remove
methylene chloride, and the residue was diluted with ethyl acetate
(30 mL) and water (30 mL). The two layers were separated, and the
aqueous layer was extracted with ethyl acetate (1.times.20 mL). The
combined organic extracts were successively washed with a saturated
aqueous sodium bicarbonate solution (1.times.50 mL) and a saturated
aqueous sodium chloride solution (1.times.50 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40S, Silica, 2/1 hexanes/ethyl
acetate) afforded
N-(5-bromo-pyridin-2-yl)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-
-cyclopentyl-propionamide (90 mg, 42%) as an amorphous white solid:
EI-HRMS m/e calcd for C.sub.21H.sub.22BrClN.sub.6O (M.sup.+)
489.0727, found 489.0727.
EXAMPLE 6
2-[3-Chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-N-thi-
azol-2-yl-propionamide
[0108] 19
[0109] A suspension of triphenylphospine (13.11 g, 50 mmol) in
carbon tetrachloride (8 mL, 83 mmol) was cooled to 0.degree. C. and
then treated with triethylamine (2.78 mL, 20 mmol) and
trifluoroacetic acid (1.3 mL, 16.6 mmol). The reaction mixture was
stirred at 0.degree. C. for 10 min and then treated with a solution
of 2-chloro-4-iodoaniline (5.07 g, 20 mmol) in carbon tetrachloride
(10 mL). The resulting light brown suspension was allowed to warm
to 25.degree. C. and then it was refluxed overnight. The reaction
mixture was cooled to 25.degree. C. and then concentrated in vacuo.
The resulting solid residue was then diluted with hexanes (50 mL)
and methylene chloride (50 mL). The precipitated solid was
collected by filtration and washed with hexanes. The filtrate was
concentrated in vacuo, and the resulting residue was diluted with
diethyl ether (100 mL). The precipitated solid was collected by
filtration and washed with hexanes, and the filtrate was
concentrated in vacuo. The resulting residue was again diluted with
hexanes (100 mL), and the precipitated solid was collected by
filtration. The filtrate was finally concentrated in vacuo to
afford the imidoyl chloride intermediate (5.88 g) as brown liquid.
This crude imidoyl chloride intermediate (5.88 g, .about.16 mmol)
was treated with sodium azide (1.04 g, 16 mmol) and acetic acid (10
mL). The resulting reaction mixture was then heated at 70.degree.
C. for 2 h, at which time, thin layer chromatography analysis of
the reaction mixture indicated the absence of the imidoyl chloride
intermediate. The cloudy yellow suspension was cooled to 25.degree.
C. and then diluted with water (100 mL) and extracted with ethyl
acetate (2.times.75 mL). The combined organic extracts were washed
successively with a saturated aqueous sodium bicarbonate solution
(1.times.100 mL) and a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40M,
Silica, 8/1 hexanes/diethyl ether) afforded
1-(2-chloro-4-iodo-phenyl)-5-trifluoromethyl-1H-tetrazole (5.2 g,
69%) as a light yellow solid: mp 71-73.degree. C.; EI-HRMS m/e
calcd for C.sub.8H.sub.3ClF.sub.3IN.sub.4 (M.sup.+) 373.9043, found
373.9044.
[0110] A mixture of zinc dust (650 mg, 10 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (2 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (110 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclohexyl-2-iodo-acrylic acid methyl ester (prepared in
Example 4, 1.32 g, 4.5 mmol) in dry tetrahydrofuran (2 mL) over 5
min. After the addition, the reaction mixture was stirred for 1 h
at 40-45.degree. C. and then stirred overnight at 25.degree. C. The
reaction mixture was then diluted with dry tetrahydrofuran (4 mL),
and the stirring was stopped to allow the excess zinc dust to
settle down (.about.2 h). In a separate reaction flask,
bis(dibenzylideneacetone)palladium(0) (54 mg, 0.1 mmol) and
triphenylphosphine (104 mg, 0.4 mmol) in dry tetrahydrofuran (8 mL)
was stirred at 25.degree. C. under argon for 10 min and then
treated with
1-(2-chloro-4-iodo-phenyl)-5-trifluoromethyl-1H-tetrazole (1.12 g,
3 mmol) and the freshly prepared zinc compound in tetrahydrofuran.
The resulting brick red solution was heated at 50.degree. C. for 15
h. The reaction mixture was cooled to 25.degree. C. and then poured
into a saturated aqueous ammonium chloride solution (70 mL), and
the organic compound was extracted into ethyl acetate (3.times.50
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.100 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40M, Silica, 6/1 hexanes/ethyl
acetate) afforded (E)-2-[3-chloro-4-(5-trifluor-
omethyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-acrylic acid methyl
ester (908 mg, 73%) as an amorphous white solid: EI-HRMS m/e calcd
for C.sub.18H.sub.18ClF.sub.3N.sub.4O.sub.2 (M.sup.+) 414.1070,
found 414.1075.
[0111] A solution of nickel (II) chloride hexahydrate (77 mg, 0.324
mmol) and
(E)-2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cyclohe-
xyl-acrylic acid methyl ester (674 mg, 1.62 mmol) in methanol (15
mL) was cooled to 0.degree. C. and then treated with sodium
borohydride (184 mg, 4.86 mmol) in four portions. After the
addition, the black reaction mixture was stirred for 15 min at
0.degree. C. and then allowed to warm to 25.degree. C. where it was
stirred for 20 h. The reaction mixture was then concentrated in
vacuo, and the residue was diluted with water (50 mL) and ethyl
acetate (100 mL). The two layers were separated. The organic layer
was washed successively with a 3N aqueous hydrochloric acid
solution (1.times.50 mL), a saturated aqueous sodium bicarbonate
solution (1.times.50 mL) and a saturated aqueous sodium chloride
solution (1.times.50 mL), dried over anhydrous magnesium sulfate,
filtered, and concentrated in vacuo to afford racemic
2-[3-chloro-4-(5-trifluoromethyl--
tetrazol-1-yl)-phenyl]-3-cyclohexyl-propionic acid methyl ester
(640 mg, 95%) as a viscous oil: EI-HRMS m/e calcd for
C.sub.18H.sub.20ClF.sub.3N.s- ub.4O.sub.2 (M.sup.+) 416.1527, found
416.1529.
[0112] A solution of
2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-pheny-
l]-3-cyclohexyl-propionic acid methyl ester (634 mg, 1.52 mmol) in
ethanol (10 mL) was treated with a 1N aqueous sodium hydroxide
solution (3 mL). The solution was heated at 45-50.degree. C. for 5
h, at which time, thin layer chromatography analysis of the mixture
indicated the absence of starting material. The reaction mixture
was then concentrated in vacuo to remove ethanol, and the residue
was diluted with water (50 mL) and extracted with diethyl ether
(1.times.60 mL) to remove any neutral impurities. The aqueous layer
was acidified with a 1N aqueous hydrochloric acid solution The
resulting acid was extracted into ethyl acetate (2.times.50 mL).
The combined organic layers were washed with a saturated aqueous
sodium chloride solution (1.times.100 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo to afford
2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cyclohex-
yl-propionic acid (375 mg, 61%) as a viscous oil: EI-HRMS m/e calcd
for C.sub.17H.sub.18ClF.sub.3N.sub.4O.sub.2 (M.sup.+) 402.1070,
found 402.1067.
[0113] A solution of triphenylphosphine (409 mg, 1.56 mmol) in
methylene chloride (8 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (277 mg, 1.56 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with a solution of
2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-prop-
ionic acid (370 mg, 0.92 mmol) in methylene chloride (5 mL). The
clear solution was stirred for 15 min at 0.degree. C. and then
allowed to warm to 25.degree. C. where it was stirred for 2 h. The
reaction mixture was then treated with 2-aminothiazole (276 mg,
2.76 mmol), and the resulting suspension was stirred for 15 h at
25.degree. C. The reaction mixture was concentrated in vacuo to
remove methylene chloride, and the residue was diluted with ethyl
acetate (100 mL) and a 1N aqueous hydrochloric acid solution (50
mL). The two layers were separated, and the aqueous layer was
extracted with ethyl acetate (1.times.50 mL). The combined organic
extracts were successively washed with a saturated aqueous sodium
bicarbonate solution (1.times.100 mL) and a saturated aqueous
sodium chloride solution (1.times.100 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Biotage
chromatography (FLASH 40S, Silica, 3/2 hexanes/ethyl acetate)
afforded
2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-N-th-
iazol-2-yl-propionamide (83 mg, 18%) as an amorphous solid: EI-HRMS
m/e calcd for C.sub.20H.sub.20ClF.sub.3N.sub.6OS (M.sup.+)
484.1060, found 484.1068.
EXAMPLE 7
3-Cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-N-th-
iazol-2-yl-propionamide
[0114] 20
[0115] A solution of 2-(trifluoromethyl)-4-bromoaniline (4.8 g, 20
mmol) in dry tetrahydrofuran (20 mL) was cooled to 0.degree. C. and
then treated with acetic anhydride (8.2 g, 80 mmol). The reaction
mixture was stirred at 0.degree. C. for 10 min and then allowed to
warm to 25.degree. C. The reaction mixture was stirred at
25.degree. C. for 2 h, at which time, thin layer chromatography
analysis of the reaction mixture indicated the absence of starting
material. The reaction mixture was then concentrated in vacuo. The
crude residue precipitated from diethyl ether (50 mL) and hexanes
(50 mL). The solid was collected by filtration and washed with
hexanes to afford N-(4-bromo-2-trifluoromethyl-phenyl)-acetam- ide
(5.07 g, 90%) as an amorphous white solid: EI-HRMS m/e calcd for
C.sub.9H.sub.7BrF.sub.3NO (M.sup.+) 281.8352, found 281.8348.
[0116] A suspension of
N-(4-bromo-2-trifluoromethyl-phenyl)-acetamide (2.41 g, 8.54 mmol)
in acetonitrile (40 mL) was treated with methylene chloride (5 mL)
to obtain a clear solution at 25.degree. C. The resulting solution
was treated with sodium azide (1.24 g, 19.1 mmol), and the reaction
mixture was then cooled to 0.degree. C. The reaction mixture was
then treated with trifluoromethanesulfonic anhydride (3.59 g, 12.7
mmol). The resulting reaction mixture was allowed to warm to
25.degree. C. where it was stirred overnight, at which time, thin
layer chromatography analysis of the reaction mixture indicated the
absence of starting material. The reaction mixture was then
concentrated in vacuo. The resulting residue was diluted with ethyl
acetate (50 mL) and water (50 mL). The two layers were separated,
and the aqueous layer was extracted with ethyl acetate (1.times.30
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.100 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40M, Silica, 2/1 hexanes/ethyl
acetate) afforded
1-(4-bromo-2-trifluoromethyl-phenyl)-5-methyl-1H-tetraz- ole (1.85
g, 70%) as a white solid: EI-HRMS m/e calcd for
C.sub.9H.sub.6BrF.sub.3N.sub.4 (M.sup.+) 305.9728, found
305.9733.
[0117] A mixture of lithium chloride (8.48 g, 200 mmol, predried at
130.degree. C. under high vacuum for 3 h) and copper cyanide (8.96
g, 100 mmol) in dry tetrahydrofuran (100 mL) was stirred at
25.degree. C. under argon for 10 min to obtain a clear solution.
The reaction mixture was then cooled to -70.degree. C. and then
slowly treated with a 2.0M solution of cyclopentylmagnesium
chloride in diethyl ether (55 mL, 110 mmol). After the addition,
the reaction mixture was allowed to warm to -30.degree. C. where it
was stirred for 5 min. The resulting reaction mixture was again
cooled back to -70.degree. C. and then slowly treated with methyl
propiolate (7.99 g, 95 mmol). The reaction mixture was stirred
overnight at -60.degree. C. to -50.degree. C. The reaction mixture
was then slowly treated with a solution of iodine (34.3 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (200 mL) and
ammonium hydroxide (50 mL), and the organic compound was extracted
into diethyl ether (3.times.100 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.300 mL) and a saturated aqueous
sodium chloride solution (1.times.300 mL). The organic layer was
then dried over anhydrous magnesium sulfate, filtered, and
concentrated in vacuo. Flash chromatography (Merck Silica gel 60,
230-400 mesh, 20/1 hexanes/diethyl ether) afforded
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (25.8 g, 97%) as
a yellow oil: EI-HRMS m/e calcd for C.sub.9H.sub.13IO.sub.2
(M.sup.+) 279.9960, found 279.9961.
[0118] A mixture of zinc dust (710 mg, 11 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (1.54 g, 5.5
mmol) in dry tetrahydrofuran (2 mL) over 3 min. The reaction
mixture was then stirred at 40-45.degree. C. for 1 h and then
stirred overnight at 25.degree. C. The reaction mixture was then
diluted with dry tetrahydrofuran (4 mL), and the stirring was
stopped to allow the excess zinc dust to settle down (.about.2 h).
In a separate reaction flask, bis(dibenzylideneacetone)palladium(0)
(81 mg, 0.15 mmol) and triphenylphosphine (156 mg, 0.6 mmol) in dry
tetrahydrofuran (6 mL) was stirred at 25.degree. C. under argon for
10 min and then treated with
1-(4-bromo-2-trifluoromethyl-phenyl)-5-methyl-1H-tetrazole (1.05 g,
3.5 mmol) and the freshly prepared zinc compound in
tetrahydrofuran. The resulting brick red solution was heated at
40-45.degree. C. over the weekend. The reaction mixture was cooled
to 25.degree. C. and then poured into a saturated aqueous ammonium
chloride solution (50 mL), and the organic compound was extracted
into ethyl acetate (3.times.35 mL). The combined organic extracts
were washed with a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Flash chromatography (Merck Silica gel
60, 230-400 mesh, 4/1 to 1/1 hexanes/ethyl acetate) afforded
(E)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-
-acrylic acid methyl ester (1.03 g, 77.6%) as a light yellow solid:
EI-HRMS m/e calcd for C.sub.18H.sub.19F.sub.3N.sub.4O.sub.2
(M.sup.+) 380.1460, found 380.1453.
[0119] A solution of nickel (II) chloride hexahydrate (102 mg,
0.428 mmol) and
(E)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phe-
nyl]-acrylic acid methyl ester (814 mg, 2.14 mmol) in methanol (20
mL) was cooled to 0.degree. C. and then treated with sodium
borohydride (265 mg, 7 mmol) in five portions. After the addition,
the black reaction mixture was stirred for 15 min at 0.degree. C.
and then allowed to warm to 25.degree. C. where it was stirred for
15 h. The reaction mixture was concentrated in vacuo, and the
residue was diluted with a 3N aqueous hydrochloric acid solution
(50 mL) and ethyl acetate (75 mL). The two layers were separated.
The organic layer was washed with a saturated aqueous sodium
chloride solution (1.times.50 mL), dried over anhydrous magnesium
sulfate, filtered, and concentrated in vacuo to afford racemic
3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-pro-
pionic acid methyl ester (815 mg, 99%) as a viscous oil: EI-HRMS
m/e calcd for C.sub.18H.sub.21F.sub.3N.sub.4O.sub.2 (M.sup.+)
382.1617, found 382.1617.
[0120] A solution of
3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluo- romethyl
phenyl]-propionic acid methyl ester (870 mg, 2.27 mmol) in ethanol
(12 mL) was treated with a 1N aqueous sodium hydroxide solution (8
mL). The solution was heated at 45-50.degree. C. for 3 h, at which
time, thin layer chromatography analysis of the reaction mixture
indicated the absence of starting material. The reaction mixture
was concentrated in vacuo to remove ethanol. The residue was
diluted with water (50 mL) and extracted with diethyl ether
(1.times.60 mL) to remove any neutral impurities. The aqueous layer
was then acidified with a 1N aqueous hydrochloric acid solution,
and the resulting acid was extracted into ethyl acetate (2.times.50
mL). The combined organic layers were washed with a saturated
aqueous sodium chloride solution (1.times.100 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo to
afford 3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluor-
omethyl-phenyl]-propionic acid (781 mg, 93%) as a white solid:
EI-HRMS m/e calcd for C.sub.17H.sub.19F.sub.3N.sub.4O.sub.2
(M.sup.+) 368.1460, found 368.1460.
[0121] A solution of triphenylphosphine (213 mg, 0.84 mmol) in
methylene chloride (12 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (144 mg, 0.84 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with the
3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-pro-
pionic acid (150 mg, 0.4 mmol). The clear solution was stirred for
15 min at 0.degree. C. and then allowed to warm to 25.degree. C.
where it was stirred for 2 h. The reaction mixture was then treated
with 2-aminothiazole (122 mg, 1.22 mmol), and the resulting
suspension was stirred for 15 h at 25.degree. C. The reaction
mixture was then concentrated in vacuo to remove methylene
chloride, and the residue was diluted with ethyl acetate (30 mL)
and a 1N aqueous hydrochloric acid solution (30 mL). The two layers
were separated, and the aqueous layer was extracted with ethyl
acetate (1.times.20 mL). The combined organic extracts were
successively washed with a saturated aqueous sodium bicarbonate
solution (1.times.50 mL) and a saturated aqueous sodium chloride
solution (1.times.50 mL), dried over anhydrous magnesium sulfate,
filtered, and concentrated in vacuo. Biotage chromatography (FLASH
40S, Silica, 1/2 hexanes/ethyl acetate) afforded
3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-N-t-
hiazol-2-yl-propionamide (128 mg, 70%) as an amorphous solid:
EI-HRMS m/e calcd for C.sub.20H.sub.21F.sub.3N.sub.6OS (M.sup.+)
450.1449, found 450.1454.
EXAMPLE 8
N-(5-Bromo-pyridin-2-yl)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-tri-
fluoromethyl-phenyl]-propionamide
[0122] 21
[0123] A solution of triphenylphosphine (213 mg, 0.84 mmol) in
methylene chloride (12 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (144 mg, 0.84 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with the
3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-pro-
pionic acid (prepared in Example 7, 150 mg, 0.4 mmol). The clear
solution was stirred for 15 min at 0.degree. C. and then allowed to
warm to 25.degree. C. where it was stirred for 2 h. The reaction
mixture was then treated with 2-amino-5-bromopyridine (122 mg, 1.22
mmol), and the resulting suspension was stirred for 15 h at
25.degree. C. The reaction mixture was then concentrated in vacuo
to remove methylene chloride, and the residue was diluted with
ethyl acetate (30 mL) and water (30 mL). The two layers were
separated, and the aqueous layer was extracted with ethyl acetate
(1.times.20 mL). The combined organic extracts were successively
washed with a saturated aqueous sodium bicarbonate solution
(1.times.50 mL) and a saturated aqueous sodium chloride solution
(1.times.50 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40S,
Silica, 1/1 hexanes/ethyl acetate) afforded
N-(5-bromo-pyridin-2-yl)-3-cyclopentyl-2-[4-(5-methyl-t-
etrazol-1-yl)-3-trifluoromethyl-phenyl]-propionamide (90 mg, 42%)
as an amorphous white solid: EI-HRMS m/e calcd for
C.sub.22H.sub.22BrF.sub.3N.s- ub.6O (M.sup.+) 522.0991, found
522.0989.
EXAMPLE 9
3-Cyclopentyl-2-[4-methanesulfonyl-3-(5-methyl-tetrazol-1-yl)-phenyl]-N-th-
iazol-2-yl-propionamide
[0124] 22
[0125] A solution of isoamyl nitrite (10.05 mL, 75 mmol) in
dimethyl disulfide (49.5 mL, 550 mmol) at 25.degree. C. was slowly
treated with 4-bromo-2-nitroaniline (10.85 g, 50 mmol). The
reaction was exothermic with gas evolution. The resulting brown
reaction mixture was heated to 80-90.degree. C. for 2 h, at which
time, thin layer chromatography analysis of the reaction mixture
indicated the absence of starting material. The reaction mixture
was cooled to 25.degree. C. and then concentrated in vacuo. The
resulting residue was dissolved in ethyl acetate (300 mL). The
organic layer was washed successively with a 1N aqueous
hydrochloric acid solution (1.times.300 mL) and a saturated aqueous
sodium chloride solution (1.times.300 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Biotage
chromatography (FLASH 40M, Silica, 6/1 to 5/1 hexanes/ethyl
acetate) afforded 4-bromo-1-methylsulfanyl-2-nitro-benzene (12.05
g, 97%) as a brown solid: EI-HRMS m/e calcd for
C.sub.7H.sub.6BrNO.sub.2S (M.sup.+) 246.9372, found 246.9368.
[0126] A solution of 4-bromo-1-methylsulfanyl-2-nitro-benzene
(12.05 g, 48.6 mmol) in methylene chloride (300 mL) was cooled to
-10.degree. C. and then treated with 3-chloroperoxybenzoic acid
(86% grade, 25.2 g, 145.8 mmol). The reaction mixture was stirred
at -10.degree. C. for 10 min and then allowed to warm to 25.degree.
C. where it was stirred for 2 h. At this time, thin layer
chromatography analysis of the reaction mixture indicated the
absence of starting material. The reaction mixture was then
concentrated in vacuo. The resulting residue was dissolved in ethyl
acetate (300 mL). The organic layer was washed successively with a
saturated aqueous sodium bicarbonate solution (4.times.200 mL) and
a saturated aqueous sodium chloride solution (1.times.300 mL),
dried over anhydrous magnesium sulfate, filtered, and concentrated
in vacuo to afford a yellow solid. Recrystallization from hot
ethanol (50 mL) and acetonitrile (10 mL) followed by dilution with
hexanes (300 mL) to obtain a precipitate. The solid was collected
by filtration and washed with hexanes (100 mL) to afford
4-bromo-1-methanesulfonyl-2-nitro-benzene (8.68 g, 62%) as a white
solid: mp 175.5-177.degree. C.; EI-HRMS m/e calcd for
C.sub.7H.sub.6BrNO.sub.4S (M.sup.+) 278.9201, found 278.9210.
[0127] A light brown suspension of
4-bromo-1-methanesulfonyl-2-nitro-benze- ne (8.65 g, 30.9 mmol) in
methanol (300 mL, not completely dissolved in methanol even at hot
condition) was treated sequentially with ammonium chloride (24.8 g,
463.5 mmol), zinc dust (20.2 g, 309 mmol), and water (100 mL).
Initially, the reaction was exothermic, and the brown color
disappeared. The reaction mixture was stirred for 1 h at 25.degree.
C. The reaction mixture was then filtered, and the residue was
washed with methanol (50 mL) and ethyl acetate (100 mL). The
filtrate was concentrated in vacuo, and the organic compound was
extracted into ethyl acetate (3.times.100 mL). The combined organic
extracts were washed with a saturated aqueous sodium chloride
solution (1.times.200 mL), dried over anhydrous sodium sulfate,
filtered, and concentrated in vacuo. Biotage chromatography (FLASH
40M, Silica, 8/1 to 6/1 to 4/1 hexanes/ethyl acetate) afforded
5-bromo-2-methanesulfonyl-phenylamine (5.7 g, 74%) as a white
solid: mp 107-109.degree. C.; EI-HRMS m/e calcd for
C.sub.7H.sub.8BrNO.sub.2S (M.sup.+) 248.9459, found 248.9451.
[0128] A solution of 5-bromo-2-methanesulfonyl-phenylamine (5.7 g,
19.5 mmol) in dry tetrahydrofuran (30 mL) at 25.degree. C. was
treated with acetyl chloride (6.28 g, 80 mmol). The resulting
solution was stirred overnight at 25.degree. C., at which time,
thin layer chromatography analysis of the reaction mixture
indicated the absence of starting material. The reaction mixture
was then diluted with water (100 mL) and ethyl acetate (100 mL).
The two layers were separated, and the aqueous layer was extracted
with ethyl acetate (1.times.100 mL). The combined organic extracts
were washed with a saturated aqueous sodium chloride solution
(1.times.200 mL), dried over anhydrous sodium sulfate, filtered,
and concentrated in vacuo to afford a brown solid. The brown solid
was treated with diethyl ether (50 mL) and hexanes (50 mL). The
white solid was collected by filtration and washed with hexanes (50
mL) to afford N-(5-bromo-2-methanesulfonyl-phenyl)-acetamide (4.55
g, 80%) as a white solid: mp 157-160.degree. C.; EI-HRMS m/e calcd
for C.sub.9H.sub.10BrNO.sub.3S (M.sup.+) 290.9565, found
290.9560.
[0129] A solution of N-(5-bromo-2-methanesulfonyl-phenyl)-acetamide
(350 mg, 1.2 mmol) in acetonitrile (6 mL) at 25.degree. C. was
treated with sodium azide (78 mg, 1.2 mmol). The reaction mixture
was cooled to 0.degree. C. and then treated with
trifluoromethanesulfonic anhydride (0.24 mL, 1.2 mmol). The
resulting reaction mixture was allowed to warm to 25.degree. C.
where it was stirred overnight, at which time, thin layer
chromatography analysis of the reaction mixture indicated the
absence of starting material. The reaction mixture was then
concentrated in vacuo. The resulting residue was diluted with ethyl
acetate (50 mL) and water (50 mL). The two layers were separated,
and the aqueous layer was extracted with ethyl acetate (1.times.30
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.100 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40M, Silica, 8/1 hexanes/ethyl
acetate) afforded 1-(5-bromo-2-methanesulfonyl-phenyl)-5-me-
thyl-1H-tetrazole (254 mg, 67%) as a white solid: mp
174-184.degree. C.; EI-HRMS m/e calcd for
C.sub.9H.sub.9BrN.sub.4O.sub.2S (M.sup.+) 315.9630, found
315.9634.
[0130] A mixture of zinc dust (330 mg, 5 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (93 mg, 0.5 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (54 mg, 0.5 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (prepared in
Example 7, 420 mg, 1.5 mmol) in dry tetrahydrofuran (1 mL). The
resulting reaction mixture was then stirred at 40-45.degree. C. for
1 h and then stirred overnight at 25.degree. C. The reaction
mixture was then diluted with dry tetrahydrofuran (3 mL), and the
stirring was stopped to allow the excess zinc dust to settle down
(.about.2 h). In a separate reaction flask,
bis(dibenzylideneacetone)palladium(0) (27 mg, 0.05 mmol) and
triphenylphosphine (52 mg, 0.2 mmol) in dry tetrahydrofuran (3 mL)
was stirred at 25.degree. C. under argon for 10 min and then
treated with
1-(5-bromo-2-methanesulfonyl-phenyl)-5-methyl-1H-tetrazole (237 mg,
0.75 mmol) and the freshly prepared zinc compound in
tetrahydrofuran. The resulting brick red solution was heated at
40-45.degree. C. over the weekend. The reaction mixture was cooled
to 25.degree. C. and then poured into a saturated aqueous ammonium
chloride solution (30 mL), and the organic compound was extracted
into ethyl acetate (3.times.30 mL). The combined organic extracts
were washed with a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40S,
Silica, 3/1 to 1/1 hexanes/ethyl acetate) afforded
(E)-3-cyclopentyl-2-[4-methanesulfonyl-3-(5-methyl-tetrazol-1-yl)-phenyl]-
-acrylic acid methyl ester (266 mg, 91%) as a white solid: mp
164-166.degree. C.; EI-HRMS m/e calcd for
C.sub.18H.sub.22N.sub.4O.sub.4S (M.sup.+) 390.1362, found
390.1368.
[0131] A solution of nickel (II) chloride hexahydrate (12.2 mg,
0.05 mmol) and
(E)-3-cyclopentyl-2-[4-methanesulfonyl-3-(5-methyl-tetrazol-1-yl)-phe-
nyl]-acrylic acid methyl ester (100 mg, 0.26 mmol) in methanol (5
mL) was cooled to 0.degree. C. and then treated with sodium
borohydride (29 mg, 0.77 mmol). After the addition, the black
reaction mixture was stirred for 15 min at 0.degree. C. and then
allowed to warm to 25.degree. C. where it was stirred for 15 h. The
reaction mixture was concentrated in vacuo, and the residue was
diluted with a 3N aqueous hydrochloric acid solution (10 mL) and
ethyl acetate (25 mL). The two layers were separated. The organic
layer was washed with a saturated aqueous sodium chloride solution
(1.times.25 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo to afford racemic
3-cyclopentyl-2-[4-methanesulfonyl-3-(5-methyl-tetrazol-1-yl)-phenyl]-pro-
pionic acid methyl ester (105 mg, 99%) as a viscous oil: EI-HRMS
m/e calcd for C.sub.18H.sub.24N.sub.4O.sub.4S (M.sup.+) 392.1518,
found 392.1526.
[0132] A solution of
3-cyclopentyl-2-[4-methanesulfonyl-3-(5-methyl-tetraz-
ol-1-yl)-phenyl]-propionic acid methyl ester (102 mg, 0.26 mmol) in
ethanol (3 mL) was treated with a 1N aqueous sodium hydroxide
solution (0.6 mL). The solution was heated at 45-50.degree. C. for
5 h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was concentrated in vacuo to remove ethanol. The
residue was diluted with water (20 mL) and extracted with diethyl
ether (1.times.30 mL) to remove any neutral impurities. The aqueous
layer was then acidified with a 1N aqueous hydrochloric acid
solution, and the resulting acid was extracted into ethyl acetate
(2.times.25 mL). The combined organic layers were washed with a
saturated aqueous sodium chloride solution (1.times.50 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford
3-cyclopentyl-2-[4-methanesulfonyl-3-(5-methyl-tetrazol-1-
-yl)-phenyl]-propionic acid (88 mg, 89%) as an amorphous white
solid: EI-HRMS m/e calcd for C.sub.17H.sub.22N.sub.4O.sub.4S
(M.sup.+) 378.1362, found 378.1364.
[0133] A solution of triphenylphosphine (100 mg, 0.38 mmol) in
methylene chloride (3 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (68 mg, 0.38 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with a solution of
3-cyclopentyl-2-[4-methanesulfonyl-3-(5-methyl-tetrazol-1-yl)-phenyl]-pro-
pionic acid (85 mg, 0.22 mmol) in methylene chloride (3 mL). The
clear solution was stirred for 15 min at 0.degree. C. and then
allowed to warm to 25.degree. C. where it was stirred for 1.5 h.
The reaction mixture was then treated with 2-aminothiazole (55 mg,
0.55 mmol), and the resulting suspension was stirred for 2 d at
25.degree. C. The reaction mixture was then concentrated in vacuo
to remove methylene chloride, and the residue was diluted with
ethyl acetate (30 mL) and a 1N aqueous hydrochloric acid solution
(25 mL). The two layers were separated, and the aqueous layer was
extracted with ethyl acetate (1.times.25 mL). The combined organic
extracts were successively washed with a 1N aqueous hydrochloric
acid solution (1.times.50 mL), a saturated aqueous sodium
bicarbonate solution (1.times.50 mL) and a saturated aqueous sodium
chloride solution (1.times.50 mL), dried over anhydrous magnesium
sulfate, filtered, and concentrated in vacuo. Biotage
chromatography (FLASH 40S, Silica, 2/1 to 1/1 hexanes/ethyl
acetate) afforded 3-cyclopentyl-2-[4-methanesulfonyl-3--
(5-methyl-tetrazol-1-yl)-phenyl]-N-thiazol-2-yl-propionamide (42
mg, 41%) as a white solid: mp 148-154.degree. C.; EI-HRMS m/e calcd
for C.sub.20H.sub.24N.sub.6O.sub.3S.sub.2 (M.sup.+) 460.1351, found
460.1356.
EXAMPLE 10
1-{3-Cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-p-
ropionyl}-3-methyl-urea
[0134] 23
[0135] A solution of 2-(trifluoromethyl)-4-bromoaniline (4.8 g, 20
mmol) in dry tetrahydrofuran (20 mL) was cooled to 0.degree. C. and
then treated with acetic anhydride (8.2 g, 80 mmol). The reaction
mixture was stirred at 0.degree. C. for 10 min and then allowed to
warm to 25.degree. C. The reaction mixture was stirred at
25.degree. C. for 2 h, at which time, thin layer chromatography
analysis of the reaction mixture indicated the absence of starting
material. The reaction mixture was then concentrated in vacuo. The
crude residue precipitated from diethyl ether (50 mL) and hexanes
(50 mL). The solid was collected by filtrated and washed with
hexanes to afford N-(4-bromo-2-trifluoromethyl-phenyl)-acetam- ide
(5.07 g, 90%) as an amorphous white solid: EI-HRMS m/e calcd for
C.sub.9H.sub.7BrF.sub.3NO (M.sup.+) 281.8352, found 281.8348.
[0136] A suspension of
N-(4-bromo-2-trifluoromethyl-phenyl)-acetamide (2.41 g, 8.54 mmol)
in acetonitrile (40 mL) was treated with methylene chloride (5 mL)
to obtain a clear solution at 25.degree. C. The resulting solution
was treated with sodium azide (1.24 g, 19.1 mmol), and the reaction
mixture was then cooled to 0.degree. C. The reaction mixture was
then treated with trifluoromethanesulfonic anhydride (3.59 g, 12.7
mmol). The resulting reaction mixture was allowed to warm to
25.degree. C. where it was stirred overnight, at which time, thin
layer chromatography analysis of the reaction mixture indicated the
absence of starting material. The reaction mixture was then
concentrated in vacuo. The resulting residue was diluted with ethyl
acetate (50 mL) and water (50 mL). The two layers were separated,
and the aqueous layer was extracted with ethyl acetate (1.times.30
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.100 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40M, Silica, 2/1 hexanes/ethyl
acetate) afforded
1-(4-bromo-2-trifluoromethyl-phenyl)-5-methyl-1H-tetraz- ole (1.85
g, 70%) as a white solid: EI-HRMS m/e calcd for
C.sub.9H.sub.6BrF.sub.3N.sub.4 (M.sup.+) 305.9728, found
305.9733.
[0137] A mixture of lithium chloride (8.48 g, 200 mmol, predried at
130.degree. C. under high vacuum for 3 h) and copper cyanide (8.96
g, 100 mmol) in dry tetrahydrofuran (100 mL) was stirred at
25.degree. C. under argon for 10 min to obtain a clear solution.
The reaction mixture was then cooled to -70.degree. C. and then
slowly treated with a 2.0M solution of cyclopentylmagnesium
chloride in diethyl ether (55 mL, 110 mmol). After the addition,
the reaction mixture was allowed to warm to -30.degree. C. where it
was stirred for 5 min. The resulting reaction mixture was again
cooled back to -70.degree. C. and then slowly treated with methyl
propiolate (7.99 g, 95 mmol). The reaction mixture was stirred
overnight at -60.degree. C. to -50.degree. C. The reaction mixture
was then slowly treated with a solution of iodine (34.3 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (200 mL) and
ammonium hydroxide (50 mL), and the organic compound was extracted
into diethyl ether (3.times.100 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.300 mL) and a saturated aqueous
sodium chloride solution (1.times.300 mL). The organic layer was
then dried over anhydrous magnesium sulfate, filtered, and
concentrated in vacuo. Flash chromatography (Merck Silica gel 60,
230-400 mesh, 20/1 hexanes/diethyl ether) afforded
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (25.8 g, 97%) as
a yellow oil: EI-HRMS m/e calcd for C.sub.9H.sub.13IO.sub.2
(M.sup.+) 279.9960, found 279.9961.
[0138] A mixture of zinc dust (710 mg, 11 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (1.54 g, 5.5
mmol) in dry tetrahydrofuran (2 mL) over 3 min. The reaction
mixture was then stirred at 40-45.degree. C. for 1 h and then
stirred overnight at 25.degree. C. The reaction mixture was then
diluted with dry tetrahydrofuran (4 mL), and the stirring was
stopped to allow the excess zinc dust to settle down (.about.2 h).
In a separate reaction flask, bis(dibenzylideneacetone)palladium(0)
(81 mg, 0.15 mmol) and triphenylphosphine (156 mg, 0.6 mmol) in dry
tetrahydrofuran (6 mL) was stirred at 25.degree. C. under argon for
10 min and then treated with
1-(4-bromo-2-trifluoromethyl-phenyl)-5-methyl-1H-tetrazole (1.05 g,
3.5 mmol) and the freshly prepared zinc compound in
tetrahydrofuran. The resulting brick red solution was heated at
40-45.degree. C. over the weekend. The reaction mixture was cooled
to 25.degree. C. and then poured into a saturated aqueous ammonium
chloride solution (50 mL), and the organic compound was extracted
into ethyl acetate (3.times.35 mL). The combined organic extracts
were washed with a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Flash chromatography (Merck Silica gel
60, 230-400 mesh, 4/1 to 1/1 hexanes/ethyl acetate) afforded
(E)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-
-acrylic acid methyl ester (1.03 g, 77.6%) as a light yellow solid:
EI-HRMS m/e calcd for C.sub.18H.sub.19F.sub.3N.sub.4O.sub.2
(M.sup.+) 380.1460, found 380.1453.
[0139] A solution of nickel (II) chloride hexahydrate (102 mg,
0.428 mmol) and
(E)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phe-
nyl]-acrylic acid methyl ester (814 mg, 2.14 mmol) in methanol (20
mL) was cooled to 0.degree. C. and then treated with sodium
borohydride (265 mg, 7 mmol) in five portions. After the addition,
the black reaction mixture was stirred for 15 min at 0.degree. C.
and then allowed to warm to 25.degree. C. where it was stirred for
15 h. The reaction mixture was concentrated in vacuo, and the
residue was diluted with a 3N aqueous hydrochloric acid solution
(50 mL) and ethyl acetate (75 mL). The two layers were separated.
The organic layer was washed with a saturated aqueous sodium
chloride solution (1.times.50 mL), dried over anhydrous magnesium
sulfate, filtered, and concentrated in vacuo to afford racemic
3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-pro-
pionic acid methyl ester (815 mg, 99%) as a viscous oil: EI-HRMS
m/e calcd for C.sub.18H.sub.21F.sub.3N.sub.4O.sub.2 (M.sup.+)
382.1617, found 382.1617.
[0140] A solution of
3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluo-
romethyl-phenyl]-propionic acid methyl ester (870 mg, 2.27 mmol) in
ethanol (12 mL) was treated with a 1N aqueous sodium hydroxide
solution (8 mL). The solution was heated at 45-50.degree. C. for 3
h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was concentrated in vacuo to remove ethanol. The
residue was diluted with water (50 mL) and extracted with diethyl
ether (1.times.60 mL) to remove any neutral impurities. The aqueous
layer was then acidified with a 1N aqueous hydrochloric acid
solution, and the resulting acid was extracted into ethyl acetate
(2.times.50 mL). The combined organic layers were washed with a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford
3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluor-
omethyl-phenyl]-propionic acid (781 mg, 93%) as a white solid:
EI-HRMS m/e calcd for C.sub.17H.sub.19F.sub.3N.sub.4O.sub.2
(M.sup.+) 368.1460, found 368.1460.
[0141] A solution of
3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluo-
romethyl-phenyl]-propionic acid (368 mg, 1.0 mmol) in fluorobenzene
(1.5 mL) and N,N-dimethylformamide (6 .mu.L) at 25.degree. C. was
treated dropwise with oxalyl chloride (107.7 .mu.L, 1.21 mmol) over
2-3 min. The clear solution was stirred for 1 h at 25.degree. C.
and then treated with methyl urea (322 mg, 2.0 mmol). The resulting
suspension was heated at 70.degree. C. (bath temperature) for 10
min and then treated with pyridine (162 .mu.L, 2.0 mmol). The
reaction mixture was then stirred at 70.degree. C. for 20 h. The
reaction mixture was then cooled to 25.degree. C. and diluted with
ethyl acetate (30 mL) and a 3N aqueous hydrochloric acid solution
(30 mL). The two layers were separated, and the aqueous layer was
extracted with ethyl acetate (1.times.20 mL). The combined organic
extracts were successively washed with a saturated aqueous sodium
bicarbonate solution (1.times.50 mL) and a saturated aqueous sodium
chloride solution (1.times.50 mL), dried over anhydrous magnesium
sulfate, filtered, and concentrated in vacuo. Biotage
chromatography (FLASH 40S, Silica, 1/1 to 1/2 hexanes/ethyl
acetate) afforded
1-{3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-
-phenyl]-propionyl}-3-methyl-urea (338 mg, 80%) as an amorphous
white solid: EI-HRMS m/e calcd for
C.sub.19H.sub.23F.sub.3N.sub.6O.sub.2 (M.sup.+) 424.1834, found
424.1833.
EXAMPLE 11
1-{2-[3-Chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-propionyl}-
-3-methyl-urea
[0142] 24
[0143] A suspension of triphenylphospine (11.7 g, 44.8 mmol) in
carbon tetrachloride (8 mL, 83 mmol) was cooled to 0.degree. C. and
then treated with triethylamine (2.5 mL, 18 mmol) and acetic acid
(1.15 mL, 20 mmol). The reaction mixture was stirred at 0.degree.
C. for 10 min and then treated with a solution of
2-chloro-4-iodoaniline (5.07 g, 0 mmol) in carbon tetrachloride (12
mL, heated to obtain a solution). The resulting light brown
suspension was allowed to warm to 25.degree. C. and then it was
refluxed overnight. The reaction mixture was cooled to 25.degree.
C. and then concentrated in vacuo. The resulting solid residue was
then diluted with hexanes (50 mL) and methylene chloride (50 mL).
The precipitated solid was collected by filtration and washed with
hexanes. The filtrate was concentrated in vacuo, and the resulting
residue was diluted with diethyl ether (100 mL). The precipitated
solid was collected by filtration and washed with hexanes, and the
filtrate was concentrated in vacuo. The resulting residue was again
diluted with hexanes (100 mL), and the precipitated solid was
collected by filtration. The filtrate was finally concentrated in
vacuo to afford the imidoyl chloride intermediate (4.08 g) as a
liquid. This crude imidoyl chloride intermediate (4.08 g, .about.13
mmol) was treated with sodium azide (1.04 g, 16 mmol) and acetic
acid (10 mL). The reaction was exothermic, and the resulting
reaction mixture was stirred for 1 h at 25.degree. C. The reaction
mixture was then heated at 70.degree. C. for 2 h, at which time,
thin layer chromatography analysis of the reaction mixture
indicated the absence of the imidoyl chloride intermediate. The
cloudy yellow suspension was cooled to 25.degree. C. and then
diluted with water (100 mL) and extracted with ethyl acetate
(2.times.75 mL). The combined organic extracts were washed
successively with a saturated aqueous sodium bicarbonate solution
(1.times.100 mL) and a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40M,
Silica, 6/1 hexanes/diethyl ether) afforded
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-tetrazole (350 mg, 6%) as a
white solid: mp 128-130.5.degree. C.; EI-HRMS m/e calcd for
C.sub.8H.sub.6ClIN.sub.4 (M.sup.+) 319.9327, found 319.9325.
[0144] A mixture of zinc dust (650 mg, 10 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (prepared in
Example 10, 1.26 g, 4.5 mmol) in dry tetrahydrofuran (2 mL) over 3
min. The reaction mixture was then stirred at 40-45.degree. C. for
1 h and then stirred overnight at 25.degree. C. The reaction
mixture was then diluted with dry tetrahydrofuran (3 mL), and the
stirring was stopped to allow the excess zinc dust to settle down
(.about.2 h). In a separate reaction flask,
bis(dibenzylideneacetone)palladium(0) (54 mg, 0.1 mmol) and
triphenylphosphine (104 mg, 0.4 mmol) in dry tetrahydrofuran (4 mL)
was stirred at 25.degree. C. under argon for 10 min and then
treated with 1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-tetrazole (875
mg, 2.73 mmol) and the freshly prepared zinc compound in
tetrahydrofuran. The resulting brick red solution was stirred at
25.degree. C. over the weekend and then heated at 40-45.degree. C.
for 4 h. The reaction mixture was cooled to 25.degree. C. and then
poured into a saturated aqueous ammonium chloride solution (50 mL),
and the organic compound was extracted into ethyl acetate
(3.times.35 mL). The combined organic extracts were washed with a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 4/1
to 1/1 hexanes/ethyl acetate) afforded
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl-
)-phenyl]-3-cyclopentyl-acrylic acid methyl ester (859 mg, 91%) as
a light yellow semi-solid: EI-HRMS m/e calcd for
C.sub.17H.sub.19ClN.sub.4O.sub.2 (M.sup.+) 346.1196, found
346.1190.
[0145] A solution of nickel (II) chloride hexahydrate (180 mg, 0.8
mmol) and
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-acry-
lic acid methyl ester (695 mg, 2.0 mmol) in methanol (15 mL) was
cooled to 0.degree. C. and then treated with sodium borohydride
(454 mg, 12 mmol) in five portions. After the addition, the black
reaction mixture was stirred for 15 min at 0.degree. C. and then
allowed to warm to 25.degree. C. where it was stirred for 2 d. The
reaction mixture was concentrated in vacuo, and the residue was
diluted with a 3N aqueous hydrochloric acid solution (50 mL) and
ethyl acetate (75 mL). The two layers were separated. The organic
layer was washed with a saturated aqueous sodium chloride solution
(1.times.50 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo to afford racemic
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-propionic
acid methyl ester (815 mg, 99%) as a viscous oil: EI-HRMS m/e calcd
for C.sub.17H.sub.21ClN.sub.4O.sub.2 (M.sup.+) 348.1353, found
348.1359.
[0146] A solution of
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycl-
opentyl-propionic acid methyl ester ester (690 mg, 2.0 mmol) in
ethanol (20 mL) was treated with a 1N aqueous sodium hydroxide
solution (4 mL). The solution was heated at 45-50.degree. C. for 3
h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was concentrated in vacuo to remove ethanol. The
residue was diluted with water (50 mL) and extracted with diethyl
ether (1.times.60 mL) to remove any neutral impurities. The aqueous
layer was then acidified with a 1N aqueous hydrochloric acid
solution, and the resulting acid was extracted into ethyl acetate
(2.times.50 mL). The combined organic layers were washed with a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-propi-
onic acid (604 mg, 90%) as an amorphous white solid: EI-HRMS m/e
calcd for C.sub.16H.sub.19ClN.sub.4O.sub.2 (M.sup.+) 334.1196,
found 334.1193.
[0147] A solution of
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycl-
opentyl-propionic acid (303 mg, 0.9 mmol) in fluorobenzene (1 mL)
and N,N-dimethylformamide (3 .mu.L) at 25.degree. C. was treated
dropwise with oxalyl chloride (97 .mu.L, 1.09 mmol) over 2-3 min.
The clear solution was stirred at 25.degree. C. for 1 h and then
treated with methyl urea (201 mg, 2.72 mmol). The resulting
suspension was heated at 70.degree. C. (bath temperature) for 10
min and then treated with pyridine (146.6 .mu.L, 1.81 mmol). The
reaction mixture was then stirred at 70.degree. C. for 20 h. The
reaction mixture was then cooled to 25.degree. C. and diluted with
ethyl acetate (30 mL) and a 3N aqueous hydrochloric acid solution
(30 mL). The two layers were separated, and the aqueous layer was
extracted with ethyl acetate (1.times.20 mL). The combined organic
extracts were successively washed with a saturated aqueous sodium
bicarbonate solution (1.times.50 mL) and a saturated aqueous sodium
chloride solution (1.times.50 mL), dried over anhydrous magnesium
sulfate, filtered, and concentrated in vacuo. Biotage
chromatography (FLASH 40M, Silica, 1/1 hexanes/ethyl acetate)
afforded
1-{2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-propionyl-
}-3-methyl-urea (110 mg, 31%) as a white solid: mp 185-186.degree.
C. EI-HRMS m/e calcd for C.sub.18H.sub.23ClN.sub.6O.sub.2
(M+H).sup.+ 391.1649, found 391.1659.
EXAMPLE 12
(E)-3-Cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-N-thiazol-
-2-yl-acrylamide
[0148] 25
[0149] A solution of 2-fluoro-4-iodoaniline (4.74 g, 20 mmol) in
dry tetrahydrofuran (20 mL) was cooled to 0.degree. C. and then
treated with acetic anhydride (8.2 g, 80 mmol). The reaction
mixture was stirred for 10 min at 0.degree. C. and then was allowed
to warm to 25.degree. C. where it was stirred for 2 h. After this
time, thin layer chromatography analysis of the reaction mixture
indicated the absence of starting material. The reaction mixture
was then concentrated in vacuo to afford a crude residue. The
residue precipitated from diethyl ether (50 mL) and hexanes (50
mL). The solid was collected by filtration and washed with hexanes
to afford N-(2-fluoro-4-iodo-phenyl)-acetamide (5.12 g, 92%) as a
white crystalline solid: mp 152-154.degree. C.; EI-HRMS m/e calcd
for C.sub.8H.sub.7FINO (M.sup.+) 278.9556, found 278.9559.
[0150] A suspension of N-(2-fluoro-4-iodo-phenyl)-acetamide (5.00
g, 18.24 mmol) in acetonitrile (100 mL) was cooled to 0.degree. C.
and then treated with sodium azide (3.56 g, 54.7 mmol). The
reaction mixture was then treated with trifluoromethanesulfonic
anhydride (13.6 g, 48 mmol). The resulting reaction mixture was
allowed to warm to 25.degree. C. where it was stirred overnight, at
which time, thin layer chromatography analysis of the reaction
mixture indicated the absence of starting material. The reaction
mixture was then concentrated in vacuo. The resulting residue was
diluted with ethyl acetate (100 mL) and water (100 mL). The two
layers were separated, and the aqueous layer was extracted with
ethyl acetate (1.times.50 mL). The combined organic extracts were
washed with a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40M,
Silica, 4/1 hexanes/ethyl acetate) afforded
1-(2-fluoro-4-iodo-phenyl)-5-methyl-1H-tetrazole (3.45 g, 62%) as a
white solid: mp 122-124.degree. C.; EI-HRMS m/e calcd for
C.sub.8H.sub.6FIN.sub.4 (M.sup.+) 303.9621, found 303.9615.
[0151] A mixture of lithium chloride (8.48 g, 200 mmol, predried at
130.degree. C. under high vacuum for 3 h) and copper cyanide (8.96
g, 100 mmol) in dry tetrahydrofuran (100 mL) was stirred at
25.degree. C. under argon for 10 min to obtain a clear solution.
The reaction mixture was then cooled to -70.degree. C. and then
slowly treated with a 2.0M solution of cyclopentylmagnesium
chloride in diethyl ether (55 mL, 110 mmol). After the addition,
the reaction mixture was allowed to warm to -30.degree. C. where it
was stirred for 5 min. The resulting reaction mixture was again
cooled back to -70.degree. C. and then slowly treated with methyl
propiolate (7.99 g, 95 mmol). The reaction mixture was stirred
overnight at -60.degree. C. to -50.degree. C. The reaction mixture
was then slowly treated with a solution of iodine (34.3 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (200 mL) and
ammonium hydroxide (50 mL), and the organic compound was extracted
into diethyl ether (3.times.100 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.300 mL) and a saturated aqueous
sodium chloride solution (1.times.300 mL). The organic layer was
then dried over anhydrous magnesium sulfate, filtered, and
concentrated in vacuo. Flash chromatography (Merck Silica gel 60,
230-400 mesh, 20/1 hexanes/diethyl ether) afforded
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (25.8 g, 97%) as
a yellow oil: EI-HRMS m/e calcd for C.sub.9H.sub.13IO.sub.2
(M.sup.+) 279.9960, found 279.9961.
[0152] A mixture of zinc dust (650 mg, 10 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (2.21 g, 7.5
mmol) in dry tetrahydrofuran (3 mL) over 3 min. The resulting
reaction mixture was then stirred at 40-45.degree. C. for 1 h and
then stirred overnight at 25.degree. C. The reaction mixture was
then diluted with dry tetrahydrofuran (5 mL), and the stirring was
stopped to allow the excess zinc dust to settle down (.about.2 h).
In a separate reaction flask, bis(dibenzylideneacetone)palladium(0)
(90 mg, 0.16 mmol) and triphenylphosphine (160 mg, 0.6 mmol) in dry
tetrahydrofuran (10 mL) was stirred at 25.degree. C. under argon
for 10 min and then treated with
1-(2-fluoro-4-iodo-phenyl)-5-methyl-1H-tetrazole (1.52 g, 5 mmol)
and the freshly prepared zinc compound in tetrahydrofuran. The
resulting brick red solution was stirred at 25.degree. C. over the
weekend and then heated at 40-45.degree. C. for 4 h. The reaction
mixture was cooled to 25.degree. C. and then poured into a
saturated aqueous ammonium chloride solution (50 mL), and the
organic compound was extracted into ethyl acetate (3.times.50 mL).
The combined organic extracts were washed with a saturated aqueous
sodium chloride solution (1.times.100 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Flash
chromatography (Merck Silica gel 60, 230-400 mesh, 4/1 to 1/1
hexanes/ethyl acetate) afforded
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-
-tetrazol-1-yl)-phenyl]-acrylic acid methyl ester (1.14 g, 68%) as
a light yellow solid: mp 111-114.degree. C.; EI-HRMS m/e calcd for
C.sub.17H.sub.19FN.sub.4O.sub.2 (M.sup.+) 330.1492, found
330.1493.
[0153] A solution of
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1--
yl)-phenyl]-acrylic acid methyl ester (720 mg, 2.18 mmol) in
ethanol (15 mL) was treated with a 1N aqueous sodium hydroxide
solution (5 mL). The solution was heated at 45-50.degree. C. for 15
h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was concentrated in vacuo to remove ethanol. The
residue was diluted with water (30 mL) and extracted with diethyl
ether (1.times.50 mL) to remove any neutral impurities. The aqueous
layer was then acidified with a 1N aqueous hydrochloric acid
solution, and the resulting acid was extracted into ethyl acetate
(2.times.50 mL). The combined organic layers were washed with a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-a-
crylic acid (690 mg, 100%) as a white solid: mp 182-185.degree. C.;
EI-HRMS m/e calcd for C.sub.16H.sub.17FN.sub.4O.sub.2 (M.sup.+)
316.1336, found 316.1334.
[0154] A solution of triphenylphosphine (262 mg, 1 mmol) in
methylene chloride (6 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (178 mg, 1 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with (E)-3-cyclopentyl-2-[3-fluo-
ro-4-(5-methyl-tetrazol-1-yl)-phenyl]-acrylic acid (158 mg, 0.5
mmol). The reaction mixture was stirred for 15 min at 0.degree. C.
and then allowed to warm to 25.degree. C. where it was stirred for
1.5 h. The reaction mixture was then treated with 2-aminothiazole
(150 mg, 1.5 mmol), and the resulting suspension was stirred for 2
d at 25.degree. C. The reaction mixture was then concentrated in
vacuo to remove methylene chloride, and the residue was diluted
with ethyl acetate (20 mL) and a 1N aqueous hydrochloric acid
solution (30 mL). The two layers were separated, and the aqueous
layer was extracted with ethyl acetate (1.times.15 mL). The
combined organic extracts were successively washed with a 1N
aqueous hydrochloric acid solution (1.times.50 mL), a saturated
aqueous sodium bicarbonate solution (1.times.50 mL) and a saturated
aqueous sodium chloride solution (1.times.50 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40S, Silica, 1/1 hexanes/ethyl
acetate) afforded
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-N-thiazo-
l-2-yl-acrylamide (39 mg, 20%) as a white solid: mp 158-162.degree.
C.; EI-HRMS m/e calcd for C.sub.19H.sub.19FN.sub.6OS (M.sup.+)
398.1325, found 398.1323.
EXAMPLE 13
(E)-N-(5-Bromo-pyridin-2-yl)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazo-
l-1-yl)-phenyl]-acrylamide
[0155] 26
[0156] A solution of 2-fluoro-4-iodoaniline (4.74 g, 20 mmol) in
dry tetrahydrofuran (20 mL) was cooled to 0.degree. C. and then
treated with acetic anhydride (8.2 g, 80 mmol). The reaction
mixture was stirred for 10 min at 0.degree. C. and then was allowed
to warm to 25.degree. C. where it was stirred for 2 h. After this
time, thin layer chromatography analysis of the reaction mixture
indicated the absence of starting material. The reaction mixture
was then concentrated in vacuo to afford a crude residue. The
residue precipitated from diethyl ether (50 mL) and hexanes (50
mL). The solid was collected by filtration and washed with hexanes
to afford N-(2-fluoro-4-iodo-phenyl)-acetamide (5.12 g, 92%) as a
white crystalline solid: mp 152-154.degree. C.; EI-HRMS m/e calcd
for C.sub.8H.sub.7FINO (M.sup.+) 278.9556, found 278.9559.
[0157] A suspension of N-(2-fluoro-4-iodo-phenyl)-acetamide (5.00
g, 18.24 mmol) in acetonitrile (100 mL) was cooled to 0.degree. C.
and then treated with sodium azide (3.56 g, 54.7 mmol). The
reaction mixture was then treated with trifluoromethanesulfonic
anhydride (13.6 g, 48 mmol). The resulting reaction mixture was
allowed to warm to 25.degree. C. where it was stirred overnight, at
which time, thin layer chromatography analysis of the reaction
mixture indicated the absence of starting material. The reaction
mixture was then concentrated in vacuo. The resulting residue was
diluted with ethyl acetate (100 mL) and water (100 mL). The two
layers were separated, and the aqueous layer was extracted with
ethyl acetate (1.times.50 mL). The combined organic extracts were
washed with a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40M,
Silica, 4/1 hexanes/ethyl acetate) afforded
1-(2-fluoro-4-iodo-phenyl)-5-methyl-1H-tetrazole (3.45 g, 62%) as a
white solid: mp 122-124.degree. C.; EI-HRMS m/e calcd for
C.sub.8H.sub.6FIN.sub.4 (M.sup.+) 303.9621, found 303.9615.
[0158] A mixture of lithium chloride (8.48 g, 200 mmol, predried at
130.degree. C. under high vacuum for 3 h) and copper cyanide (8.96
g, 100 mmol) in dry tetrahydrofuran (100 mL) was stirred at
25.degree. C. under argon for 10 min to obtain a clear solution.
The reaction mixture was then cooled to -70.degree. C. and then
slowly treated with a 2.0M solution of cyclopentylmagnesium
chloride in diethyl ether (55 mL, 110 mmol). After the addition,
the reaction mixture was allowed to warm to -30.degree. C. where it
was stirred for 5 min. The resulting reaction mixture was again
cooled back to -70.degree. C. and then slowly treated with methyl
propiolate (7.99 g, 95 mmol). The reaction mixture was stirred
overnight at -60.degree. C. to -50.degree. C. The reaction mixture
was then slowly treated with a solution of iodine (34.3 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (200 mL) and
ammonium hydroxide (50 mL), and the organic compound was extracted
into diethyl ether (3.times.100 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.300 mL) and a saturated aqueous
sodium chloride solution (1.times.300 mL). The organic layer was
then dried over anhydrous magnesium sulfate, filtered, and
concentrated in vacuo. Flash chromatography (Merck Silica gel 60,
230-400 mesh, 20/1 hexanes/diethyl ether) afforded
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (25.8 g, 97%) as
a yellow oil: EI-HRMS m/e calcd for C.sub.9H.sub.13IO.sub.2
(M.sup.+) 279.9960, found 279.9961.
[0159] A mixture of zinc dust (650 mg, 10 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (2.21 g, 7.5
mmol) in dry tetrahydrofuran (3 mL) over 3 min. The resulting
reaction mixture was then stirred at 40-45.degree. C. for 1 h and
then stirred overnight at 25.degree. C. The reaction mixture was
then diluted with dry tetrahydrofuran (5 mL), and the stirring was
stopped to allow the excess zinc dust to settle down (.about.2 h).
In a separate reaction flask, bis(dibenzylideneacetone)palladium(0)
(90 mg, 0.16 mmol) and triphenylphosphine (160 mg, 0.6 mmol) in dry
tetrahydrofuran (10 mL) was stirred at 25.degree. C. under argon
for 10 min and then treated with
1-(2-fluoro-4-iodo-phenyl)-5-methyl-1H-tetrazole (1.52 g, 5 mmol)
and the freshly prepared zinc compound in tetrahydrofuran. The
resulting brick red solution was stirred at 25.degree. C. over the
weekend and then heated at 40-45.degree. C. for 4 h. The reaction
mixture was cooled to 25.degree. C. and then poured into a
saturated aqueous ammonium chloride solution (50 mL), and the
organic compound was extracted into ethyl acetate (3.times.50 mL).
The combined organic extracts were washed with a saturated aqueous
sodium chloride solution (1.times.100 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Flash
chromatography (Merck Silica gel 60, 230-400 mesh, 4/1 to 1/1
hexanes/ethyl acetate) afforded
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-
-tetrazol-1-yl)-phenyl]-acrylic acid methyl ester (1.14 g, 68%) as
a light yellow solid: mp 111-114.degree. C.; EI-HRMS m/e calcd for
C.sub.17H.sub.19FN.sub.4O.sub.2 (M.sup.+) 330.1492, found
330.1493.
[0160] A solution of
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1--
yl)-phenyl]-acrylic acid methyl ester (720 mg, 2.18 mmol) in
ethanol (15 mL) was treated with a 1N aqueous sodium hydroxide
solution (5 mL). The solution was heated at 45-50.degree. C. for 15
h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was concentrated in vacuo to remove ethanol. The
residue was diluted with water (30 mL) and extracted with diethyl
ether (1.times.50 mL) to remove any neutral impurities. The aqueous
layer was then acidified with a 1N aqueous hydrochloric acid
solution, and the resulting acid was extracted into ethyl acetate
(2.times.50 mL). The combined organic layers were washed with a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-a-
crylic acid (690 mg, 100%) as a white solid: mp 182-185.degree. C.;
EI-HRMS m/e calcd for C.sub.16H.sub.17FN.sub.4O.sub.2 (M.sup.+)
316.1336, found 316.1334.
[0161] A solution of triphenylphosphine (262 mg, 1 mmol) in
methylene chloride (6 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (178 mg, 1 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with (E)-3-cyclopentyl-2-[3-fluo-
ro-4-(5-methyl-tetrazol-1-yl)-phenyl]-acrylic acid (158 mg, 0.5
mmol). The reaction mixture was stirred for 15 min at 0.degree. C.
and then allowed to warm to 25.degree. C. where it was stirred for
1.5 h. The reaction mixture was then treated with
2-amino-5-bromopyridine (260 mg, 1.5 mmol), and the resulting
suspension was stirred for 2 d at 25.degree. C. The reaction
mixture was then concentrated in vacuo to remove methylene
chloride, and the residue was diluted with ethyl acetate (20 mL)
and water (30 mL). The two layers were separated, and the aqueous
layer was extracted with ethyl acetate (1.times.15 mL). The
combined organic extracts were successively washed with a saturated
aqueous sodium bicarbonate solution (1.times.50 mL) and a saturated
aqueous sodium chloride solution (1.times.50 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40S, Silica, 3/1 hexanes/ethyl
acetate) afforded
(E)-N-(5-bromo-pyridin-2-yl)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetraz-
ol-1-yl)-phenyl]-acrylamide (66 mg, 28%) as an amorphous white
solid: EI-HRMS m/e calcd for C.sub.21H.sub.20BrFN.sub.6OS (M.sup.+)
470.0866, found 470.0864.
EXAMPLE 14
(E)-2-[3-Chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-N-thiazol-
-2-yl-acrylamide
[0162] 27
[0163] A solution of 2-chloro-4-iodoaniline (25 g, 96.66 mmol) in
tetrahydrofuran (100 mL) was cooled to 0.degree. C. and then
treated with acetic anhydride (50.6 g, 500 mmol). The reaction
mixture was stirred at 0.degree. C. for 10 min and then allowed to
warm to 25.degree. C. where it was stirred for 15 h. The reaction
mixture was then concentrated in vacuo to remove tetrahydrofuran.
The residue was crystallized from ether (50 mL) and hexanes (50
mL). The solids were collected and washed with hexanes to afford
N-(2-chloro-4-iodo-phenyl)-acetamide (23.87 g, 84%) as a white
crystalline solid: EI-HRMS m/e calcd for C.sub.8H.sub.7ClINO
(M.sup.+) 295.1526, found 295.1532.
[0164] A suspension of N-(2-chloro-4-iodo-phenyl)-acetamide (2.39
g, 8.09 mmol) in acetonitrile (40 mL) at 25.degree. C. was treated
with methylene chloride (5 mL) to obtain a clear solution. The
resulting solution was then treated with sodium azide (1.05 g,
16.18 mmol), and the reaction mixture was cooled to 0.degree. C.
The reaction mixture was then treated with trifluoromethanesulfonic
anhydride (3.42 g, 12.13 mmol), and the resulting reaction mixture
was allowed to warm to 25.degree. C. where it was stirred
overnight. The reaction mixture was then concentrated in vacuo. The
residue was diluted with ethyl acetate (50 mL) and water (50 mL),
and the two layers were separated. The aqueous layer was further
extracted with ethyl acetate (1.times.30 mL). The combined organic
layers were washed with a saturated aqueous sodium chloride
solution (1.times.100 mL), dried over anhydrous magnesium sulfate,
filtered, and concentrated in vacuo. Biotage chromatography
(FLASH-40M, Silica, 4/1 hexanes/ethyl acetate) afforded
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-te- trazole (1.53 g, 59%) as
a white solid: mp 128-130.5.degree. C.; EI-HRMS m/e calcd for
C.sub.8H.sub.6ClIN.sub.4 (M.sup.+) 319.9327, found 319.9325.
[0165] A mixture of lithium chloride (8.48 g, 200 mmol, predried at
130.degree. C. under high vacuum for 3 h) and copper cyanide (8.96
g, 100 mmol) in dry tetrahydrofuran (100 mL) was stirred at
25.degree. C. under argon for 10 min to obtain a clear solution.
The reaction mixture was then cooled to -70.degree. C. and then
slowly treated with a 2.0M solution of cyclopentylmagnesium
chloride in diethyl ether (55 mL, 110 mmol). After the addition,
the reaction mixture was allowed to warm to -30.degree. C. where it
was stirred for 5 min. The resulting reaction mixture was again
cooled back to -70.degree. C. and then slowly treated with methyl
propiolate (7.99 g, 95 mmol). The reaction mixture was stirred
overnight at -60.degree. C. to -50.degree. C. The reaction mixture
was then slowly treated with a solution of iodine (34.3 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (200 mL) and
ammonium hydroxide (50 mL), and the organic compound was extracted
into diethyl ether (3.times.100 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.300 mL) and a saturated aqueous
sodium chloride solution (1.times.300 mL). The organic layer was
then dried over anhydrous magnesium sulfate, filtered, and
concentrated in vacuo. Flash chromatography (Merck Silica gel 60,
230-400 mesh, 20/1 hexanes/diethyl ether) afforded
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (25.8 g, 97%) as
a yellow oil: EI-HRMS m/e calcd for C.sub.9H.sub.13IO.sub.2
(M.sup.+) 279.9960, found 279.9961.
[0166] A mixture of zinc dust (650 mg, 10 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (1.26 g, 4.5
mmol) in dry tetrahydrofuran (2 mL) over 3 min. The reaction
mixture was then stirred at 40-45.degree. C. for 1 h and then
stirred overnight at 25.degree. C. The reaction mixture was then
diluted with dry tetrahydrofuran (3 mL), and the stirring was
stopped to allow the excess zinc dust to settle down (.about.2 h).
In a separate reaction flask, bis(dibenzylideneacetone)palladium(0)
(54 mg, 0.1 mmol) and triphenylphosphine (104 mg, 0.4 mmol) in dry
tetrahydrofuran (4 mL) was stirred at 25.degree. C. under argon for
10 min and then treated with
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-tetrazole (875 mg, 2.73
mmol) and the freshly prepared zinc compound in tetrahydrofuran.
The resulting brick red solution was stirred at 25.degree. C. over
the weekend and then heated at 40-45.degree. C. for 4 h. The
reaction mixture was cooled to 25.degree. C. and then poured into a
saturated aqueous ammonium chloride solution (50 mL), and the
organic compound was extracted into ethyl acetate (3.times.35 mL).
The combined organic extracts were washed with a saturated aqueous
sodium-chloride solution (1.times.100 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Flash
chromatography (Merck Silica gel 60, 230-400 mesh, 4/1 to 1/1
hexanes/ethyl acetate) afforded
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl-
)-phenyl]-3-cyclopentyl-acrylic acid methyl ester (859 mg, 91%) as
a light yellow semi-solid: EI-HRMS m/e calcd for
C.sub.17H.sub.19ClN.sub.4O.sub.2 (M.sup.+) 346.1196, found
346.1190.
[0167] A solution of
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3--
cyclopentyl-acrylic acid methyl ester (160 mg, 0.46 mmol) in
ethanol (5 mL) was treated with a 1N aqueous sodium hydroxide
solution (1 mL). The solution was heated at 45-50.degree. C. for 15
h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was concentrated in vacuo to remove ethanol. The
residue was diluted with water (10 mL) and extracted with diethyl
ether (1.times.30 mL) to remove any neutral impurities. The aqueous
layer was then acidified with a 1N aqueous hydrochloric acid
solution, and the resulting acid was extracted into ethyl acetate
(2.times.20 mL). The combined organic layers were washed with a
saturated aqueous sodium chloride solution (1.times.50 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-a-
crylic acid (155 mg, 100%) as a white solid: mp 216-219.degree. C.;
EI-HRMS m/e calcd for C.sub.16H.sub.17ClN.sub.4O.sub.2 (M.sup.+)
332.1040, found 332.1048.
[0168] A solution of triphenylphosphine (165 mg, 0.63 mmol) in
methylene chloride (5 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (112 mg, 0.63 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with a solution of
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclopentyl-acrylic
acid (123 mg, 0.37 mmol) in methylene chloride (3 mL). The reaction
mixture was stirred for 15 min at 0.degree. C. and then allowed to
warm to 25.degree. C. where it was stirred for 1.5 h. The reaction
mixture was then treated with 2-aminothiazole (92.5 mg, 0.93 mmol),
and the resulting suspension was stirred for 2 d at 25.degree. C.
The reaction mixture was then concentrated in vacuo to remove
methylene chloride, and the residue was diluted with ethyl acetate
(20 mL) and a 1N aqueous hydrochloric acid solution (30 mL). The
two layers were separated, and the aqueous layer was extracted with
ethyl acetate (1.times.15 mL). The combined organic extracts were
successively washed with a 1N aqueous hydrochloric acid solution
(1.times.50 mL), a saturated aqueous sodium bicarbonate solution
(1.times.50 mL) and a saturated aqueous sodium chloride solution
(1.times.50 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40S,
Silica, 1/1 hexanes/ethyl acetate) afforded
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl-
)-phenyl]-3-cyclopentyl-N-thiazol-2-yl-acrylamide (36 mg, 23%) as
an amorphous solid: EI-HRMS m/e calcd for
C.sub.19H.sub.19ClN.sub.6OS (M.sup.+) 414.1029, found 414.1029.
EXAMPLE 15
(E)-2-[3-Chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-N-thiazol--
2-yl-acrylamide
[0169] 28
[0170] A suspension of triphenylphospine (11.7 g, 44.8 mmol) in
carbon tetrachloride (8 mL, 83 mmol) was cooled to 0.degree. C. and
then treated with triethylamine (2.5 mL, 18 mmol) and acetic acid
(1.15 mL, 20 mmol). The reaction mixture was stirred at 0.degree.
C. for 10 min and then treated with a solution of
2-chloro-4-iodoaniline (5.07 g, 20 mmol) in carbon tetrachloride
(12 mL, heated to obtain a solution). The resulting light brown
suspension was allowed to warm to 25.degree. C. and then it was
refluxed overnight. The reaction mixture was cooled to 25.degree.
C. and then concentrated in vacuo. The resulting solid residue was
then diluted with hexanes (50 mL) and methylene chloride (50 mL).
The precipitated solid was collected by filtration and washed with
hexanes. The filtrate was concentrated in vacuo, and the resulting
residue was diluted with diethyl ether (100 mL). The precipitated
solid was collected by filtration and washed with hexanes, and the
filtrate was concentrated in vacuo. The resulting residue was again
diluted with hexanes (100 mL), and the precipitated solid was
collected by filtration. The filtrate was finally concentrated in
vacuo to afford the imidoyl chloride intermediate (4.08 g) as a
liquid. This crude imidoyl chloride intermediate (4.08 g, .about.13
mmol) was treated with sodium azide (1.04 g, 16 mmol) and acetic
acid (10 mL). The reaction was exothermic, and the resulting
reaction mixture was stirred for 1 h at 25.degree. C. The reaction
mixture was then heated at 70.degree. C. for 2 h, at which time,
thin layer chromatography analysis of the reaction mixture
indicated the absence of the imidoyl chloride intermediate. The
cloudy yellow suspension was cooled to 25.degree. C. and then
diluted with water (100 mL) and extracted with ethyl acetate
(2.times.75 mL). The combined organic extracts were washed
successively with a saturated aqueous sodium bicarbonate solution
(1.times.100 mL) and a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40M,
Silica, 6/1 hexanes/diethyl ether) afforded
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-tetrazole (350 mg, 6%) as a
white solid: mp 128-130.5.degree. C.; EI-HRMS m/e calcd for
C.sub.8H.sub.6ClIN.sub.4 (M.sup.+) 319.9327, found 319.9325.
[0171] A mixture of zinc dust (16.34 g, 250 mmol, Aldrich, 325
mesh) and dry tetrahydrofuran (6 mL) under argon was treated with
1,2-dibromoethane (0.94 g, 5 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (0.54 g, 5 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of cyclohexyl
iodide (21 g, 100 mmol) in dry tetrahydrofuran (30 mL) over 15 min.
During the addition, the temperature rose to 60.degree. C. The
reaction mixture was then stirred for 3 h at 40-45.degree. C. The
reaction mixture was then cooled to 25.degree. C. and diluted with
dry tetrahydrofuran (60 mL). The stirring was stopped to allow the
excess zinc dust to settle down (.about.3 h). In a separate
reaction flask, a mixture of lithium chloride (8.48 g, 200 mmol,
predried at 130.degree. C. under high vacuum for 3 h) and copper
cyanide (8.95 g, 100 mmol) in dry tetrahydrofuran (110 mL) was
stirred for 10 min at 25.degree. C. to obtain a clear solution. The
reaction mixture was cooled to -70.degree. C. and then slowly
treated with the freshly prepared zinc solution using a syringe.
After the addition, the reaction mixture was allowed to warm to
0.degree. C. where it was stirred for 5 min. The reaction mixture
was again cooled back to -70.degree. C. and then slowly treated
with methyl propiolate (7.56 g, 90 mmol). The resulting reaction
mixture was stirred for 15 h at -70.degree. C. to -50.degree. C.
and then slowly treated with a solution of iodine (34.26 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (400 mL) and
ammonium hydroxide (100 mL), and the organic compound was extracted
into ethyl acetate (3.times.250 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.500 mL) and a saturated aqueous
sodium chloride solution (1.times.500 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Flash
chromatography (Merck Silica gel 60, 230-400 mesh, 9/1
hexanes/diethyl ether) afforded (E)-3-cyclohexyl-2-iodo-acrylic
acid methyl ester (26.3 g, 99%) as a light pink oil: EI-HRMS m/e
calcd for C.sub.10H.sub.15IO.sub.2 (M.sup.+) 294.0117, found
294.0114.
[0172] A mixture of zinc dust (320 mg, 5 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (94 mg, 0.5 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (55 mg, 0.5 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclohexyl-2-iodo-acrylic acid methyl ester (588 mg, 2 mmol)
in dry tetrahydrofuran (2 mL). After the addition, the reaction
mixture was stirred for 1 h at 40-45.degree. C. and then stirred
overnight at 25.degree. C. The reaction mixture was then diluted
with dry tetrahydrofuran (2 mL), and the stirring was stopped to
allow the excess zinc dust to settle down (.about.2 h). In a
separate reaction flask, bis(dibenzylideneacetone)palladium(0) (27
mg, 0.05 mmol) and triphenylphosphine (57 mg, 0.2 mmol) in dry
tetrahydrofuran (4 mL) was stirred at 25.degree. C. under argon for
10 min and then treated with
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-tetrazole (320.5 mg, 1 mmol)
and the freshly prepared zinc compound in tetrahydrofuran. The
resulting brick red solution was heated at 50.degree. C. for 15 h.
The reaction mixture was cooled to 25.degree. C. and then poured
into a saturated aqueous ammonium chloride solution (30 mL), and
the organic compound was extracted into ethyl acetate (3.times.20
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.50 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40S, Silica, 4/1/1 hexanes/ethyl
acetate/methylene chloride) afforded
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-acrylic
acid methyl ester (233 mg, 64%) as an amorphous white solid:
EI-HRMS m/e calcd for C.sub.18H.sub.21ClN.sub.4O.sub.2 (M.sup.+)
360.1353, found 360.1354.
[0173] A solution of
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3--
cyclohexyl-acrylic acid methyl ester (209 mg, 0.58 mmol) in ethanol
(3 mL) was treated with a 1N aqueous sodium hydroxide solution (1.2
mL). The solution was heated at 45-50.degree. C. for 15 h, at which
time, thin layer chromatography analysis of the mixture indicated
the absence of starting material. The reaction mixture was then
concentrated in vacuo to remove ethanol, and the residue was
diluted with water (10 mL) and extracted with diethyl ether
(1.times.30 mL) to remove any neutral impurities. The aqueous layer
was acidified with a 1N aqueous hydrochloric acid solution. The
resulting acid was extracted into ethyl acetate (2.times.20 mL).
The combined organic layers were washed with a saturated aqueous
sodium chloride solution (1.times.50 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo to afford
(E)-2-[-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-acr-
ylic acid (203 mg, 99%) as a brown solid: FAB-HRMS m/e calcd for
C.sub.17H.sub.19ClN.sub.4O.sub.2 (M+H).sup.+ 347.1275, found
347.1283.
[0174] A solution of triphenylphosphine (290 mg, 1.1 mmol) in
methylene chloride (5 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (195 mg, 1.1 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with a solution of
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-acrylic
acid (192 mg, 0.55 mmol) in methylene chloride (3 mL). The reaction
mixture was stirred for 15 min at 0.degree. C. and then allowed to
warm to 25.degree. C. where it was stirred for 1.5 h. The reaction
mixture was then treated with 2-aminothiazole (166 mg, 1.66 mmol),
and the resulting suspension was stirred for 2 d at 25.degree. C.
The reaction mixture was concentrated in vacuo to remove methylene
chloride, and the residue was diluted with ethyl acetate (40 mL)
and a 1N aqueous hydrochloric acid solution (30 mL). The two layers
were separated, and the aqueous layer was extracted with ethyl
acetate (1.times.25 mL). The combined organic extracts were
successively washed with a 1N aqueous hydrochloric acid solution
(1.times.50 mL), a saturated aqueous sodium bicarbonate solution
(1.times.50 mL) and a saturated aqueous sodium chloride solution
(1.times.50 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40S,
Silica, 7/3 to 2/3 hexanes/ethyl acetate) afforded
(E)-2-[3-chloro-4-(5-methyl-tetrazol--
1-yl)-phenyl]-3-cyclohexyl-N-thiazol-2-yl-acrylamide (86 mg, 36%)
as an amorphous solid: EI-HRMS m/e calcd for
C.sub.20H.sub.21ClN.sub.6OS (M.sup.+) 428.1186, found 428.1189.
EXAMPLE 16
(E-2-[3-Chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycloheptyl-N-thiazol--
2-yl-acrylamide
[0175] 29
[0176] A solution of 2-chloro-4-iodoaniline (25 g, 96.66 mmol) in
tetrahydrofuran (100 mL) was cooled to 0.degree. C. and then
treated with acetic anhydride (50.6 g, 500 mmol). The reaction
mixture was stirred at 0.degree. C. for 10 min and then allowed to
warm to 25.degree. C. where it was stirred for 15 h. The reaction
mixture was then concentrated in vacuo to remove tetrahydrofuran.
The residue was crystallized from ether (50 mL) and hexanes (50
mL). The solids were collected and washed with hexanes to afford
N-(2-chloro-4-iodo-phenyl)-acetamide (23.87 g, 84%) as a white
crystalline solid: EI-HRMS m/e calcd for C.sub.8H.sub.7ClINO
(M.sup.+) 295.1526, found 295.1532.
[0177] A suspension of N-(2-chloro-4-iodo-phenyl)-acetamide (2.39
g, 8.09 mmol) in acetonitrile (40 mL) at 25.degree. C. was treated
with methylene chloride (5 mL) to obtain a clear solution. The
resulting solution was then treated with sodium azide (1.05 g,
16.18 mmol), and the reaction mixture was cooled to 0.degree. C.
The reaction mixture was then treated with trifluoromethanesulfonic
anhydride (3.42 g, 12.13 mmol), and the resulting reaction mixture
was allowed to warm to 25.degree. C. where it was stirred
overnight. The reaction mixture was then concentrated in vacuo. The
residue was diluted with ethyl acetate (50 mL) and water (50 mL),
and the two layers were separated. The aqueous layer was further
extracted with ethyl acetate (1.times.30 mL). The combined organic
layers were washed with a saturated aqueous sodium chloride
solution (1.times.100 mL), dried over anhydrous magnesium sulfate,
filtered, and concentrated in vacuo. Biotage chromatography (FLASH
40M, Silica, 4/1 hexanes/ethyl acetate) afforded
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-te- trazole (1.53 g, 59%) as
a white solid: mp 128-130.5.degree. C.; EI-HRMS m/e calcd for
C.sub.8H.sub.6ClIN.sub.4 (M.sup.+) 319.9327, found 319.9325.
[0178] A mixture of magnesium metal (4.81 g, 200 mmol) and dry
tetrahydrofuran (10 mL) under argon was treated with a solution of
1,2-dibromoethane (0.94 g, 5 mmol) in dry tetrahydrofuran (5 mL).
The resulting reaction mixture was stirred for 10 min to activate
the magnesium metal. The reaction mixture was then treated dropwise
with a solution of cycloheptyl bromide (17.7 g, 100 mmol) in dry
tetrahydrofuran (30 mL), one-fifth portion over a period of 5 min.
The resulting reaction mixture was stirred for 5-10 min to initiate
the exothermic reaction. The remaining portion of the cycloheptyl
bromide solution was then added dropwise while controlling the
inside temperature below 50.degree. C. After complete addition, the
solution was stirred for 1 h and then diluted with dry
tetrahydrofuran (80 mL). In a separate reaction flask, a mixture of
lithium chloride (8.48 g, 200 mmol, predried at 130.degree. C.
under high vacuum for 3 h) and copper cyanide (8.96 g, 100 mmol) in
dry tetrahydrofuran (110 mL) was stirred at 25.degree. C. under
argon for 10 min to obtain a clear solution. The reaction mixture
was cooled to -70.degree. C. and then slowly treated with the
freshly prepared cycloheptylmagnesium bromide. After the addition,
the reaction mixture was allowed to warm to -10 .degree. C. where
it was stirred for 5 min. The resulting reaction mixture was again
cooled back to -70.degree. C. and then treated with methyl
propiolate (7.57 g, 90 mmol). The reaction mixture was stirred for
15 h at -70.degree. C. to -50.degree. C. and then slowly treated
with a solution of iodine (34.3 g, 135 mmol) in dry tetrahydrofuran
(30 mL), with the temperature kept at -70.degree. C. to -60.degree.
C. After addition of the iodine solution, the cooling bath was
removed, and the reaction mixture was allowed to warm to 25.degree.
C. where it was stirred for 2 h. The reaction mixture was then
poured into a solution consisting of a saturated aqueous ammonium
chloride solution (400 mL) and ammonium hydroxide (100 mL), and the
organic compound was extracted into ethyl acetate (3.times.200 mL).
The combined organic extracts were successively washed with a
saturated aqueous sodium thiosulfate solution (1.times.400 mL) and
a saturated aqueous sodium chloride solution (1.times.400 mL). The
organic layer was then dried over anhydrous magnesium sulfate,
filtered, and concentrated in vacuo. Flash chromatography (Merck
Silica gel 60, 230-400 mesh, 20/1 to 10/1 hexanes/diethyl ether)
afforded (E)-3-cycloheptyl-2-iodo-acrylic acid methyl ester (17.86
g, 64%) as a colorless oil: EI-HRMS m/e calcd for
C.sub.11H.sub.17IO.sub.2 (M.sup.+) 308.0273, found 308.0273.
[0179] A mixture of zinc dust (980 mg, 15 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (280 mg, 1.5 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (162 mg, 1.5 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cycloheptyl-2-iodo-acrylic acid methyl ester (1.54 g, 5 mmol)
in dry tetrahydrofuran (3 mL). The reaction mixture was then
stirred at 40-45.degree. C. for 1 h and then stirred overnight at
25.degree. C. The reaction mixture was then diluted with dry
tetrahydrofuran (5 mL), and the stirring was stopped to allow the
excess zinc dust to settle down (.about.2 h). In a separate
reaction flask, bis(dibenzylideneacetone)palladium(0) (81 mg, 0.15
mmol) and triphenylphosphine (156 mg, 0.6 mmol) in dry
tetrahydrofuran (12 mL) was stirred at 25.degree. C. under argon
for 10 min and then treated with
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-tetrazole (1.28 g, 4 mmol)
and the freshly prepared zinc compound in tetrahydrofuran. The
resulting brick red solution was heated at 45-50.degree. C. for 20
h. The reaction mixture was cooled to 25.degree. C. and then poured
into a saturated aqueous ammonium chloride solution (100 mL), and
the organic compound was extracted into ethyl acetate (3.times.50
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.100 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40M, Silica, 4/1 to 1/1 hexanes/ethyl
acetate) afforded (E)-2-[3-chloro-4-(5-methyl-tetrazol--
1-yl)-phenyl]-3-cycloheptyl-acrylic acid methyl ester (1.29 g, 85%)
as a yellow oil: EI-HRMS m/e calcd for
C.sub.19H.sub.23ClN.sub.4O.sub.2 (M.sup.+) 374.1509, found
374.1509.
[0180] A solution of
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3--
cycloheptyl-acrylic acid methyl ester (1.20 g, 3.2 mmol) in ethanol
(15 mL) was treated with a 1N aqueous sodium hydroxide solution
(6.5 mL). The solution was heated at 45-50.degree. C. for 15 h, at
which time, thin layer chromatography analysis of the reaction
mixture indicated the absence of starting material. The reaction
mixture was concentrated in vacuo to remove ethanol. The residue
was diluted with water (50 mL) and extracted with diethyl ether
(1.times.50 mL) to remove any neutral impurities. The aqueous layer
was then acidified with a 1N aqueous hydrochloric acid solution,
and the resulting acid was extracted into ethyl acetate (2.times.70
mL). The combined organic layers were washed with a saturated
aqueous sodium chloride solution (1.times.50 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo to
afford
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycloheptyl-a-
crylic acid (1.01 g, 87%) as a white solid.
[0181] A solution of triphenylphosphine (1.45 g, 5.54 mmol) in
methylene chloride (15 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (986 mg, 5.54 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with a solution of
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycloheptyl-acrylic
acid (1.00 g, 2.77 mmol) in methylene chloride (5 mL). The reaction
mixture was stirred for 15 min at 0.degree. C. and then allowed to
warm to 25.degree. C. where it was stirred for 1.5 h. The reaction
mixture was then treated with 2-aminothiazole (832 g, 8.32 mmol),
and the resulting suspension was stirred for 3 d at 25.degree. C.
The reaction mixture was then concentrated in vacuo to remove
methylene chloride, and the residue was diluted with ethyl acetate
(50 mL) and water (50 mL). The two layers were separated,- and the
aqueous layer was extracted with ethyl acetate (1.times.50 mL). The
combined organic extracts were successively washed with a saturated
aqueous sodium bicarbonate solution (1.times.100 mL) and a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo. Biotage chromatography (FLASH 40M, Silica, 1/1 hexanes/ethyl
acetate) afforded
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycloheptyl-N-thiazo-
l-2-yl-acrylamide (810 mg, 66%) as an amorphous white solid:
EI-HRMS m/e calcd for C.sub.21H.sub.23ClN.sub.6OS (M.sup.+)
442.1343, found 442.1343.
EXAMPLE 17
(E)-N-(5-Bromo-thiazol-2-yl)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl-
]-3-cycloheptyl-acrylamide
[0182] 30
[0183] A solution of 2-chloro-4-iodoaniline (25 g, 96.66 mmol) in
tetrahydrofuran (100 mL) was cooled to 0.degree. C. and then
treated with acetic anhydride (50.6 g, 500 mmol). The reaction
mixture was stirred at 0.degree. C. for 10 min and then allowed to
warm to 25.degree. C. where it was stirred for 15 h. The reaction
mixture was then concentrated in vacuo to remove tetrahydrofuran.
The residue was crystallized from ether (50 mL) and hexanes (50
mL). The solids were collected and washed with hexanes to afford
N-(2-chloro-4-iodo-phenyl)-acetamide (23.87 g, 84%) as a white
crystalline solid: EI-HRMS m/e calcd for C.sub.8H.sub.7ClINO
(M.sup.+) 295.1526, found 295.1532.
[0184] A suspension of N-(2-chloro-4-iodo-phenyl)-acetamide (2.39
g, 8.09 mmol) in acetonitrile (40 mL) at 25.degree. C. was treated
with methylene chloride (5 mL) to obtain a clear solution. The
resulting solution was then treated with sodium azide (1.05 g,
16.18 mmol), and the reaction mixture was cooled to 0.degree. C.
The reaction mixture was then treated with trifluoromethanesulfonic
anhydride (3.42 g, 12.13 mmol), and the resulting reaction mixture
was allowed to warm to 25.degree. C. where it was stirred
overnight. The reaction mixture was then concentrated in vacuo. The
residue was diluted with ethyl acetate (50 mL) and water (50 mL),
and the two layers were separated. The aqueous layer was further
extracted with ethyl acetate (1.times.30 mL). The combined organic
layers were washed with a saturated aqueous sodium chloride
solution (1.times.100 mL), dried over anhydrous magnesium sulfate,
filtered, and concentrated in vacuo. Biotage chromatography (FLASH
40M, Silica, 4/1 hexanes/ethyl acetate) afforded
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-te- trazole (1.53 g, 59%) as
a white solid: mp 128-130.5.degree. C.; EI-HRMS m/e calcd for
C.sub.8H.sub.6ClIN.sub.4 (M.sup.+) 319.9327, found 319.9325.
[0185] A mixture of magnesium metal (4.81 g, 200 mmol) and dry
tetrahydrofuran (10 mL) under argon was treated with a solution of
1,2-dibromoethane (0.94 g, 5 mmol) in dry tetrahydrofuran (5 mL).
The resulting reaction mixture was stirred for 10 min to activate
the magnesium metal. The reaction mixture was then treated dropwise
with a solution of cycloheptyl bromide (17.7 g, 100 mmol) in dry
tetrahydrofuran (30 mL), one-fifth portion over a period of 5 min.
The resulting reaction mixture was stirred for 5-10 min to initiate
the exothermic reaction. The remaining portion of the cycloheptyl
bromide solution was then added dropwise while controlling the
inside temperature below 50.degree. C. After complete addition, the
solution was stirred for 1 h and then diluted with dry
tetrahydrofuran (80 mL). In a separate reaction flask, a mixture of
lithium chloride (8.48 g, 200 mmol, predried at 130.degree. C.
under high vacuum for 3 h) and copper cyanide (8.96 g, 100 mmol) in
dry tetrahydrofuran (110 mL) was stirred at 25.degree. C. under
argon for 10 min to obtain a clear solution. The reaction mixture
was cooled to -70.degree. C. and then slowly treated with the
freshly prepared cycloheptylmagnesium bromide. After the addition,
the reaction mixture was allowed to warm to -10.degree. C. where it
was stirred for 5 min. The resulting reaction mixture was again
cooled back to -70.degree. C. and then treated with methyl
propiolate (7.57 g, 90 mmol). The reaction mixture was stirred for
15 h at -70.degree. C. to -50.degree. C. and then slowly treated
with a solution of iodine (34.3 g, 135 mmol) in dry tetrahydrofuran
(30 mL), with the temperature kept at -70.degree. C. to -60.degree.
C. After addition of the iodine solution, the cooling bath was
removed, and the reaction mixture was allowed to warm to 25.degree.
C. where it was stirred for 2 h. The reaction mixture was then
poured into a solution consisting of a saturated aqueous ammonium
chloride solution (400 mL) and ammonium hydroxide (100 mL), and the
organic compound was extracted into ethyl acetate (3.times.200 mL).
The combined organic extracts were successively washed with a
saturated aqueous sodium thiosulfate solution (1.times.400 mL) and
a saturated aqueous sodium chloride solution (1.times.400 mL). The
organic layer was then dried over anhydrous magnesium sulfate,
filtered, and concentrated in vacuo. Flash chromatography (Merck
Silica gel 60, 230-400 mesh, 20/1 to 10/1 hexanes/diethyl ether)
afforded (E)-3-cycloheptyl-2-iodo-acrylic acid methyl ester (17.86
g, 64%) as a colorless oil: EI-HRMS m/e calcd for
C.sub.11H.sub.17IO.sub.2 (M.sup.+) 308.0273, found 308.0273.
[0186] A mixture of zinc dust (980 mg, 15 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (280 mg, 1.5 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (162 mg, 1.5 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cycloheptyl-2-iodo-acrylic acid methyl ester (1.54 g, 5 mmol)
in dry tetrahydrofuran (3 mL). The reaction mixture was then
stirred at 40-45.degree. C. for 1 h and then stirred overnight at
25.degree. C. The reaction mixture was then diluted with dry
tetrahydrofuran (5 mL), and the stirring was stopped to allow the
excess zinc dust to settle down (.about.2 h). In a separate
reaction flask, bis(dibenzylideneacetone)palladium(0) (81 mg, 0.15
mmol) and triphenylphosphine (156 mg, 0.6 mmol) in dry
tetrahydrofuran (12 mL) was stirred at 25.degree. C. under argon
for 10 min and then treated with
1-(2-chloro-4-iodo-phenyl)-5-methyl-1H-tetrazole (1.28 g, 4 mmol)
and the freshly prepared zinc compound in tetrahydrofuran. The
resulting brick red solution was heated at 45-50.degree. C. for 20
h. The reaction mixture was cooled to 25.degree. C. and then poured
into a saturated aqueous ammonium chloride solution (100 mL), and
the organic compound was extracted into ethyl acetate (3.times.50
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.100 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40M, Silica, 4/1 to 1/1 hexanes/ethyl
acetate) afforded (E)-2-[3-chloro-4-(5-methyl-tetrazol--
1-yl)-phenyl]-3-cycloheptyl-acrylic acid methyl ester (1.29 g, 85%)
as a yellow oil: EI-HRMS m/e calcd for
C.sub.19H.sub.23ClN.sub.4O.sub.2 (M.sup.+) 374.1509, found
374.1509.
[0187] A solution of
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3--
cycloheptyl-acrylic acid methyl ester (1.20 g, 3.2 mmol) in ethanol
(15 mL) was treated with a 1N aqueous sodium hydroxide solution
(6.5 mL). The solution was heated at 45-50.degree. C. for 15 h, at
which time, thin layer chromatography analysis of the reaction
mixture indicated the absence of starting material. The reaction
mixture was concentrated in vacuo to remove ethanol. The residue
was diluted with water (50 mL) and extracted with diethyl ether
(1.times.50 mL) to remove any neutral impurities. The aqueous layer
was then acidified with a 1N aqueous hydrochloric acid solution,
and the resulting acid was extracted into ethyl acetate (2.times.70
mL). The combined organic layers were washed with a saturated
aqueous sodium chloride solution (1.times.50 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo to
afford
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycloheptyl-a-
crylic acid (1.01 g, 87%) as a white solid.
[0188] A solution of triphenylphosphine (1.45 g, 5.54 mmol) in
methylene chloride (15 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (986 mg, 5.54 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with a solution of
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycloheptyl-acrylic
acid (1.00 g, 2.77 mmol) in methylene chloride (5 mL). The reaction
mixture was stirred for 15 min at 0.degree. C. and then allowed to
warm to 25.degree. C. where it was stirred for 1.5 h. The reaction
mixture was then treated with 2-aminothiazole (832 g, 8.32 mmol),
and the resulting suspension was stirred for 3 d at 25.degree. C.
The reaction mixture was then concentrated in vacuo to remove
methylene chloride, and the residue was diluted with ethyl acetate
(50 mL) and water (50 mL). The two layers were separated, and the
aqueous layer was extracted with ethyl acetate (1.times.50 mL). The
combined organic extracts were successively washed with a saturated
aqueous sodium bicarbonate solution (1.times.100 mL) and a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo. Biotage chromatography (FLASH 40M, Silica, 1/1 hexanes/ethyl
acetate) afforded
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3-cycloheptyl-N-thiazo-
l-2-yl-acrylamide (810 mg, 66%) as an amorphous white solid:
EI-HRMS m/e calcd for C.sub.21H.sub.23ClN.sub.6OS (M.sup.+)
442.1343, found 442.1343.
[0189] A suspension of
(E)-2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]--
3-cycloheptyl-N-thiazol-2-yl-acrylamide (300 mg, 0.69 mmol) and
N-bromosuccinimide (123 mg, 0.69 mmol) in carbon tetrachloride (3
mL) at 25.degree. C. was treated with benzoyl peroxide (8.4 mg,
0.035 mmol). The resulting reaction mixture was heated to
90.degree. C. where it was stirred overnight at this temperature.
The reaction mixture was allowed to cool to 25.degree. C. and then
concentrated in vacuo. The residue was dissolved in ethyl acetate
(50 mL). The organic phase was then washed with water (1.times.50
mL) and a saturated aqueous sodium chloride solution (1.times.50
mL), dried over anhydrous magnesium sulfate, filtered, and
concentrated in vacuo. Biotage chromatography (FLASH 40S, Silica,
4/1 hexanes/ethyl acetate) afforded (E)-N-(5-bromo-thiazol-2-yl)--
2-[3-chloro-4-(5-methyl-tetrazol-1-yl)-phenyl]-3
cycloheptyl-acrylamide (118 mg, 33%) as an amorphous solid: EI-HRMS
m/e calcd for C.sub.21H.sub.22BrClN.sub.6OS (M.sup.+) 520.0448,
found 520.0448.
EXAMPLE 18
(E)-2-[3-Chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-N-
-thiazol-2-yl-acrylamide
[0190] 31
[0191] A suspension of triphenylphospine (13.11 g, 50 mmol) in
carbon tetrachloride (8 mL, 83 mmol) was cooled to 0.degree. C. and
then treated with triethylamine (2.78 mL, 20 mmol) and
trifluoroacetic acid (1.3 mL, 16.6 mmol). The reaction mixture was
stirred at 0.degree. C. for 10 min and then treated with a solution
of 2-chloro-4-iodoaniline (5.07 g, 20 mmol) in carbon tetrachloride
(10 mL). The resulting light brown suspension was allowed to warm
to 25.degree. C. and then it was refluxed overnight. The reaction
mixture was cooled to 25.degree. C. and then concentrated in vacuo.
The resulting solid residue was then diluted with hexanes (50 mL)
and methylene chloride (50 mL). The precipitated solid was
collected by filtration and washed with hexanes. The filtrate was
concentrated in vacuo, and the resulting residue was diluted with
diethyl ether (100 mL). The precipitated solid was collected by
filtration and washed with hexanes, and the filtrate was
concentrated in vacuo. The resulting residue was again diluted with
hexanes (100 mL), and the precipitated solid was collected by
filtration. The filtrate was finally concentrated in vacuo to
afford the imidoyl chloride intermediate (5.88 g) as a brown
liquid. This crude imidoyl chloride intermediate (5.88 g, .about.16
mmol) was treated with sodium azide (1.04 g, 16 mmol) and acetic
acid (10 mL). The resulting reaction mixture was then heated at
70.degree. C. for 2 h, at which time, thin layer chromatography
analysis of the reaction mixture indicated the absence of the
imidoyl chloride intermediate. The cloudy yellow suspension was
cooled to 25.degree. C. and then diluted with water (100 mL) and
extracted with ethyl acetate (2.times.75 mL). The combined organic
extracts were washed successively with a saturated aqueous sodium
bicarbonate solution (1.times.100 mL) and a saturated aqueous
sodium chloride solution (1.times.100 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Biotage
chromatography (FLASH 40M, Silica, 8/1 hexanes/diethyl ether)
afforded 1-(2-chloro-4-iodo-phenyl)-5-trifluoromethyl-1H-tetrazole
(5.2 g, 69%) as a light yellow solid: mp 71-73.degree. C.; EI-HRMS
m/e calcd for C.sub.8H.sub.3ClF.sub.3IN.sub.4 (M.sup.+) 373.9043,
found 373.9044.
[0192] A mixture of zinc dust (16.34 g, 250 mmol, Aldrich, -325
mesh) and dry tetrahydrofuran (6 mL) under argon was treated with
1,2-dibromoethane (0.94 g, 5 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (0.54 g, 5 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of cyclohexyl
iodide (21 g, 100 mmol) in dry tetrahydrofuran (30 mL) over 15 min.
During the addition, the temperature rose to 60.degree. C. The
reaction mixture was then stirred for 3 h at 40-45.degree. C. The
reaction mixture was then cooled to 25.degree. C. and diluted with
dry tetrahydrofuran (60 mL). The stirring was stopped to allow the
excess zinc dust to settle down (.about.3 h). In a separate
reaction flask, a mixture of lithium chloride (8.48 g, 200 mmol,
predried at 130.degree. C. under high vacuum for 3 h) and copper
cyanide (8.95 g, 100 mmol) in dry tetrahydrofuran (110 mL) was
stirred for 10 min at 25.degree. C. to obtain a clear solution. The
reaction mixture was cooled to -70.degree. C. and then slowly
treated with the freshly prepared zinc solution using a syringe.
After the addition, the reaction mixture was allowed to warm to
0.degree. C. where it was stirred for 5 min. The reaction mixture
was again cooled back to -70.degree. C. and then slowly treated
with methyl propiolate (7.56 g, 90 mmol). The resulting reaction
mixture was stirred for 15 h at -70.degree. C. to -50.degree. C.
and then slowly treated with a solution of iodine (34.26 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (400 mL) and
ammonium hydroxide (100 mL), and the organic compound was extracted
into ethyl acetate (3.times.250 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.500 mL) and a saturated aqueous
sodium chloride solution (1.times.500 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Flash
chromatography (Merck Silica gel 60, 230-400 mesh, 9/1
hexanes/diethyl ether) afforded (E)-3-cyclohexyl-2-iodo-acrylic
acid methyl ester (26.3 g, 99%) as a light pink oil: EI-HRMS m/e
calcd for C.sub.10H.sub.15IO.sub.2 (M.sup.+) 294.0117, found
294.0114.
[0193] A mixture of zinc dust (650 mg, 10 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (2 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (110 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclohexyl-2-iodo-acrylic acid methyl ester (1.32 g, 4.5
mmol) in dry tetrahydrofuran (2 mL) over 5 min. After the addition,
the reaction mixture was stirred for 1 h at 40-45.degree. C. and
then stirred overnight at 25.degree. C. The reaction mixture was
then diluted with dry tetrahydrofuran (4 mL), and the stirring was
stopped to allow the excess zinc dust to settle down (.about.2 h).
In a separate reaction flask, bis(dibenzylideneacetone)palladium(0)
(54 mg, 0.1 mmol) and triphenylphosphine (104 mg, 0.4 mmol) in dry
tetrahydrofuran (8 mL) was stirred at 25.degree. C. under argon for
10 min and then treated with
1-(2-chloro-4-iodo-phenyl)-5-trifluoromethyl-1H-tetrazole (1.12 g,
3 mmol) and the freshly prepared zinc compound in tetrahydrofuran.
The resulting brick red solution was heated at 50.degree. C. for 15
h. The reaction mixture was cooled to 25.degree. C. and then poured
into a saturated aqueous ammonium chloride solution (70 mL), and
the organic compound was extracted into ethyl acetate (3.times.50
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.100 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40M, Silica, 6/1 hexanes/ethyl
acetate) afforded the (E)-2-[3-chloro-4-(5-trif-
luoromethyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl-acrylic acid methyl
ester (908 mg, 73%) as an amorphous white solid: EI-HRMS m/e calcd
for C.sub.18H.sub.18ClF.sub.3N.sub.4O.sub.2 (M.sup.+) 414.1070,
found 414.1075.
[0194] A solution of
(E)-2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-p-
henyl]-3-cyclohexyl-acrylic acid methyl ester (833 mg, 2 mmol) in
ethanol (10 mL) was treated with a 1N aqueous sodium hydroxide
solution (4 mL). The solution was heated at 45-50.degree. C. for 15
h, at which time, thin layer chromatography analysis of the mixture
indicated the absence of starting material. The reaction mixture
was then concentrated in vacuo to remove ethanol, and the residue
was diluted with water (20 mL) and extracted with diethyl ether
(1.times.50 mL) to remove any neutral impurities. The aqueous layer
was acidified with a 1N aqueous hydrochloric acid solution. The
resulting acid was extracted into ethyl acetate (2.times.50 mL).
The combined organic layers were washed with a saturated aqueous
sodium chloride solution (1.times.100 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo to afford
(E)-2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cycl-
ohexyl-acrylic acid (606 mg, 75%) as a brown solid: FAB-HRMS m/e
calcd for C.sub.17H.sub.16ClF.sub.3N.sub.4O.sub.2 (M+H).sup.+
401.0992, found 401.0987.
[0195] A solution of triphenylphosphine (772 mg, 2.96 mmol) in
methylene chloride (10 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (526 mg, 2.96 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with a solution of
(E)-2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cyclohexyl--
acrylic acid (594 mg, 1.48 mmol) in methylene chloride (5 mL). The
reaction mixture was then stirred for 15 min at 0.degree. C. and
then allowed to warm to 25.degree. C. where it was stirred for 1.5
h. The reaction mixture was then treated with 2-aminothiazole (444
mg, 4.44 mmol), and the resulting suspension was stirred for 2 d at
25.degree. C. The reaction mixture was concentrated in vacuo to
remove methylene chloride, and the residue was diluted with ethyl
acetate (70 mL) and a 1N aqueous hydrochloric acid solution (50
mL). The two layers were separated, and the aqueous layer was
extracted with ethyl acetate (1.times.50 mL). The combined organic
extracts were successively washed with a 1N aqueous hydrochloric
acid solution (1.times.100 mL), a saturated aqueous sodium
bicarbonate solution (1.times.100 mL) and a saturated aqueous
sodium chloride solution (1.times.100 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Biotage
chromatography (FLASH 40S, Silica, 5/1 to 3/2 hexanes/ethyl
acetate) afforded
(E)-2-[3-chloro-4-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-3-cy-
clohexyl-N-thiazol-2-yl-acrylamide (82 mg, 11%) as an amorphous
solid: EI-HRMS m/e calcd for C.sub.20H.sub.18ClF.sub.3N.sub.6OS
(M.sup.+) 482.0903, found 482.0906.
EXAMPLE 19
(E)-3-Cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]--
N-thiazol-2-yl-acrylamide
[0196] 32
[0197] A solution of 2-(trifluoromethyl)-4-bromoaniline (4.8 g, 20
mmol) in dry tetrahydrofuran (20 mL) was cooled to 0.degree. C. and
then treated with acetic anhydride (8.2 g, 80 mmol). The reaction
mixture was stirred at 0.degree. C. for 10 min and then allowed to
warm to 25.degree. C. The reaction mixture was stirred at
25.degree. C. for 2 h, at which time, thin layer chromatography
analysis of the reaction mixture indicated the absence of starting
material. The reaction mixture was then concentrated in vacuo. The
crude residue precipitated from diethyl ether (50 mL) and hexanes
(50 mL). The solid was collected by filtrated and washed with
hexanes to afford N-(4-bromo-2-trifluoromethyl-phenyl)-acetam- ide
(5.07 g, 90%) as an amorphous white solid: EI-HRMS m/e calcd for
C.sub.9H.sub.7BrF.sub.3NO (M.sup.+) 281.8352, found 281.8348.
[0198] A suspension of
N-(4-bromo-2-trifluoromethyl-phenyl)-acetamide (2.41 g, 8.54 mmol)
in acetonitrile (40 mL) was treated with methylene chloride (5 mL)
to obtain a clear solution at 25.degree. C. The resulting solution
was treated with sodium azide (1.24 g, 19.1 mmol), and the reaction
mixture was then cooled to 0.degree. C. The reaction mixture was
then treated with trifluoromethanesulfonic anhydride (3.59 g, 12.7
mmol). The resulting reaction mixture was allowed to warm to
25.degree. C. where it was stirred overnight, at which time, thin
layer chromatography analysis of the reaction mixture indicated the
absence of starting material. The reaction mixture was then
concentrated in vacuo. The resulting residue was diluted with ethyl
acetate (50 mL) and water (50 mL). The two layers were separated,
and the aqueous layer was extracted with ethyl acetate (1.times.30
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.100 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40M, Silica, 2/1 hexanes/ethyl
acetate) afforded
1-(4-bromo-2-trifluoromethyl-phenyl)-5-methyl-1H-tetraz- ole (1.85
g, 70%) as a white solid: EI-HRMS m/e calcd for
C.sub.9H.sub.6BrF.sub.3N.sub.4 (M.sup.+) 305.9728, found
305.9733.
[0199] A mixture of lithium chloride (8.48 g, 200 mmol, predried at
130.degree. C. under high vacuum for 3 h) and copper cyanide (8.96
g, 100 mmol) in dry tetrahydrofuran (100 mL) was stirred at
25.degree. C. under argon for 10 min to obtain a clear solution.
The reaction mixture was then cooled to -70.degree. C. and then
slowly treated with a 2.0M solution of cyclopentylmagnesium
chloride in diethyl ether (55 mL, 110 mmol). After the addition,
the reaction mixture was allowed to warm to -30.degree. C. where it
was stirred for 5 min. The resulting reaction mixture was again
cooled back to -70.degree. C. and then slowly treated with methyl
propiolate (7.99 g, 95 mmol). The reaction mixture was stirred
overnight at -60.degree. C. to -50.degree. C. The reaction mixture
was then slowly treated with a solution of iodine (34.3 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (200 mL) and
ammonium hydroxide (50 mL), and the organic compound was extracted
into diethyl ether (3.times.100 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.300 mL) and a saturated aqueous
sodium chloride solution (1.times.300 mL). The organic layer was
then dried over anhydrous magnesium sulfate, filtered, and
concentrated in vacuo. Flash chromatography (Merck Silica gel 60,
230-400 mesh, 20/1 hexanes/diethyl ether) afforded
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (25.8 g, 97%) as
a yellow oil: EI-HRMS m/e calcd for C.sub.9H.sub.13IO.sub.2
(M.sup.+) 279.9960, found 279.9961.
[0200] A mixture of zinc dust (710 mg, 11 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (1.54 g, 5.5
mmol) in dry tetrahydrofuran (2 mL) over 3 min. The reaction
mixture was then stirred at 40-45.degree. C. for 1 h and then
stirred overnight at 25.degree. C. The reaction mixture was then
diluted with dry tetrahydrofuran (4 mL), and the stirring was
stopped to allow the excess zinc dust to settle down (.about.2 h).
In a separate reaction flask, bis(dibenzylideneacetone)palladium(0)
(81 mg, 0.15 mmol) and triphenylphosphine (156 mg, 0.6 mmol) in dry
tetrahydrofuran (6 mL) was stirred at 25.degree. C. under argon for
10 min and then treated with
1-(4-bromo-2-trifluoromethyl-phenyl)-5-methyl-1H-tetrazole (1.05 g,
3.5 mmol) and the freshly prepared zinc compound in
tetrahydrofuran. The resulting brick red solution was heated at
40-45.degree. C. over the weekend. The reaction mixture was cooled
to 25.degree. C. and then poured into a saturated aqueous ammonium
chloride solution (50 mL), and the organic compound was extracted
into ethyl acetate (3.times.35 mL). The combined organic extracts
were washed with a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Flash chromatography (Merck Silica gel
60, 230-400 mesh, 4/1 to 1/1 hexanes/ethyl acetate) afforded
(E)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-
-acrylic acid methyl ester (1.03 g, 77.6%) as a light yellow solid:
EI-HRMS m/e calcd for C.sub.18H.sub.19F.sub.3N.sub.4O.sub.2
(M.sup.+) 380.1460, found 380.1453.
[0201] A solution of
(E)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-tri-
fluoromethyl-phenyl]-acrylic acid methyl ester (199 mg, 0.52 mmol)
in ethanol (3 mL) was treated with a 1N aqueous sodium hydroxide
solution (2 mL). The solution was heated at 45-50.degree. C. for 15
h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was concentrated in vacuo to remove ethanol. The
residue was diluted with water (10 mL) and extracted with diethyl
ether (1.times.30 mL) to remove any neutral impurities. The aqueous
layer was then acidified with a 1N aqueous hydrochloric acid
solution, and the resulting acid was extracted into ethyl acetate
(2.times.20 mL). The combined organic layers were washed with a
saturated aqueous sodium chloride solution (1.times.50 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford
(E)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl--
phenyl]-acrylic acid (172 mg, 90%) as a yellow paste: EI-HRMS m/e
calcd for C.sub.17H.sub.17F.sub.3N.sub.4O.sub.2 (M.sup.+) 366.1309,
found 366.1309.
[0202] A solution of triphenylphosphine (204 mg, 0.78 mmol) in
methylene chloride (8 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (138 mg, 0.78 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with a solution of
(E)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-
-acrylic acid (143 mg, 0.39 mmol) in methylene chloride (5 mL). The
reaction mixture was stirred for 15 min at 0.degree. C. and then
allowed to warm to 25.degree. C. where it was stirred for 1.5 h.
The reaction mixture was then treated with 2-aminothiazole (117 mg,
1.17 mmol), and the resulting suspension was stirred for 2 d at
25.degree. C. The reaction mixture was then concentrated in vacuo
to remove methylene chloride, and the residue was diluted with
ethyl acetate (20 mL) and a 1N aqueous hydrochloric acid solution
(30 mL). The two layers were separated, and the aqueous layer was
extracted with ethyl acetate (1.times.15 mL). The combined organic
extracts were successively washed with a 1N aqueous hydrochloric
acid solution (1.times.50 mL), a saturated aqueous sodium
bicarbonate solution (1.times.50 mL) and a saturated aqueous sodium
chloride solution (1.times.50 mL), dried over anhydrous magnesium
sulfate, filtered, and -concentrated in vacuo. Biotage
chromatography (FLASH 40S, Silica, 1/2 hexanes/ethyl acetate)
afforded the
(E)-3-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phe-
nyl]-N-thiazol-2-yl-acrylamide (27 mg, 15.5%) as an amorphous white
solid: EI-HRMS m/e calcd for C.sub.20H.sub.19F.sub.3N.sub.6OS
(M.sup.+) 448.1293, found 448.1285.
EXAMPLE 20
(E)-3-Cyclopentyl-2-[3-methanesulfonyl-4-(5-methyl-tetrazol-1-yl)-phenyl]--
N-thiazol-2-yl-acrylamide
[0203] 33
[0204] A solution of 2-nitro-4-bromoaniline (7.07 g, 32.6 mmol) in
dry tetrahydrofuran (33 mL) was cooled to 0.degree. C. and then
treated with acetic anhydride (6.66 g, 65.2 mmol). The reaction
mixture was stirred at 0.degree. C. for 10 min and then allowed to
warm to 25.degree. C. The reaction mixture was stirred at
25.degree. C. for 15 h, at which time, thin layer chromatography
analysis of the reaction mixture indicated the presence of only
starting material. The reaction mixture was then slowly treated
with acetyl chloride (5 mL) and pyridine (5 mL) at 25.degree. C.
The resulting orange suspension was stirred at 25.degree. C. for 2
h and then treated with water (50 mL). The organic compound was
extracted into ethyl acetate (2.times.70 mL). The combined extracts
were washed with a 3N aqueous hydrochloric acid solution
(1.times.100 mL) and a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo to afford a yellow solid. The yellow
solid was treated with diethyl ether (50 ) mL) and hexanes (50 mL).
The solid was collected by filtration and washed with hexanes to
afford N-(4-bromo-2-nitro-phenyl)-acetamide (6.82 g, 81%) as a
yellow solid: mp 100-102.degree. C.; EI-HRMS m/e calcd for
C.sub.8H.sub.7BrN.sub.2O.sub.3 (M.sup.+) 257.9640, found
257.9641.
[0205] A suspension of N-(4-bromo-2-nitro-phenyl)-acetamide (1.18
g, 4.55 mmol) in acetonitrile (25 mL) was cooled to 0.degree. C.
and then treated with sodium azide (838 mg, 13.65 mmol). The
reaction mixture was then treated with trifluoromethanesulfonic
anhydride (2.88 g, 10.25 mmol). The resulting reaction mixture was
allowed to warm to 25.degree. C. where it was stirred overnight, at
which time, thin layer chromatography analysis of the reaction
mixture indicated the absence of starting material. The reaction
mixture was then concentrated in vacuo. The resulting residue was
diluted with ethyl acetate (70 mL) and water (50 mL). The two
layers were separated, and the aqueous layer was extracted with
ethyl acetate (1.times.50 mL). The combined organic extracts were
washed with a saturated aqueous sodium chloride solution
(1.times.100 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40M,
Silica, 4/1 hexanes/ethyl acetate) afforded
1-(4-bromo-2-nitro-phenyl)-5-methyl-1H-tetrazole (1.16 g, 90%) as a
white solid: mp 124-126.degree. C.; EI-HRMS m/e calcd for
C.sub.8H.sub.6BrN.sub.5O.sub.2 (M.sup.+) 282.9705, found
282.9700.
[0206] A suspension of
1-(4-bromo-2-nitro-phenyl)-5-methyl-1H-tetrazole (1.13 g, 3.98
mmol) in methanol (40 mL, not completely dissolved in methanol even
at hot conditions) was treated sequentially with ammonium chloride
(3.19 g, 59.7 mmol), zinc dust (2.60 g, 39.8 mmol), and water (20
mL). Initially after the addition, the reaction was exothermic. The
reaction mixture was then stirred for 1 h at 25.degree. C. The
reaction mixture was then filtered, and the residue was washed with
methanol (50 mL) and ethyl acetate (100 mL). The filtrate was
concentrated in vacuo, and the organic compound was extracted into
ethyl acetate (3.times.50 mL). The combined organic extracts were
washed with a saturated aqueous sodium chloride solution
(1.times.200 mL), dried over anhydrous sodium sulfate, filtered,
and concentrated in vacuo to afford
5-bromo-2-(5-methyl-tetrazol-1-yl)-phenylamine (0.90 g, 97%) as a
white solid: EI-HRMS m/e calcd for C.sub.8H.sub.8BrN.sub.5
(M.sup.+) 252.9963, found 252.9962.
[0207] A solution of isoamyl nitrite (402 .mu.L, 3 mmol) in
dimethyl disulfide (2 mL, 22 mmol) at 25.degree. C. was slowly
treated with 5-bromo-2-(5-methyl-tetrazol-1-yl)-phenylamine (0.51
g, 2 mmol). The reaction was exothermic with gas evolution. The
resulting brown reaction mixture was heated to 80-90.degree. C. for
2 h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was cooled to 25.degree. C. and then concentrated
in vacuo. The resulting residue was dissolved in ethyl acetate (50
mL). The organic layer was washed successively with a 1N aqueous
hydrochloric acid solution (1.times.50 mL) and a saturated aqueous
sodium chloride solution (1.times.50 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Biotage
chromatography (FLASH 40M, Silica, 6/1 to 5/1 hexanes/ethyl
acetate) afforded
1-(4-bromo-2-methylsulfanyl-phenyl)-5-methyl-1H-tetrazole (0.8 g)
as a brown solid that was used without further purification and
characterization.
[0208] A solution of
1-(4-bromo-2-methylsulfanyl-phenyl)-5-methyl-1H-tetra- zole (0.8 g,
.about.2 mmol) in methylene chloride (12 mL) was cooled to
-10.degree. C. and then treated with 3-chloroperoxybenzoic acid
(86% grade, 2.0 g, 12 mmol). The reaction mixture was stirred at
-10.degree. C. for 10 min and then allowed to warm to 25.degree. C.
where it was stirred over the weekend. At this time, thin layer
chromatography analysis of the reaction mixture indicated the
absence of starting material. The reaction mixture was then
concentrated in vacuo. The resulting residue was dissolved in ethyl
acetate (60 mL). The organic layer was washed successively with a
saturated aqueous sodium bicarbonate solution (2.times.50 mL) and a
saturated aqueous sodium chloride solution (1.times.50 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford a yellow solid. Biotage chromatography (FLASH 40M,
Silica, 3/1 hexanes/ethyl acetate) afforded
1-(4-bromo-2-methanesulfonyl-phenyl)-5-methyl-1H-tetrazole (313 mg,
49%) as a white solid: mp 175-176.degree. C.; EI-HRMS m/e calcd for
C.sub.9H.sub.9BrN.sub.4O.sub.2S (M.sup.+) 315.9630, found
315.9630.
[0209] A mixture of lithium chloride (8.48 g, 200 mmol, predried at
130.degree. C. under high vacuum for 3 h) and copper cyanide (8.96
g, 100 mmol) in dry tetrahydrofuran (100 mL) was stirred at
25.degree. C. under argon for 10 min to obtain a clear solution.
The reaction mixture was then cooled to -70.degree. C. and then
slowly treated with a 2.0M solution of cyclopentylmagnesium
chloride in diethyl ether (55 mL, 110 mmol). After the addition,
the reaction mixture was allowed to warm to -30.degree. C. where it
was stirred for 5 min. The resulting reaction mixture was again
cooled back to -70.degree. C. and then slowly treated with methyl
propiolate (7.99 g, 95 mmol). The reaction mixture was stirred
overnight at -60.degree. C. to -50.degree. C. The reaction mixture
was then slowly treated with a solution of iodine (34.3 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (200 mL) and
ammonium hydroxide (50 mL), and the organic compound was extracted
into diethyl ether (3.times.100 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.300 mL) and a saturated aqueous
sodium chloride solution (1.times.300 mL). The organic layer was
then dried over anhydrous magnesium sulfate, filtered, and
concentrated in vacuo. Flash chromatography (Merck Silica gel 60,
230-400 mesh, 20/1 hexanes/diethyl ether) afforded
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (25.8 g, 97%) as
a yellow oil: EI-HRMS m/e calcd for C.sub.9H.sub.13IO.sub.2
(M.sup.+) 279.9960, found 279.9961.
[0210] A mixture of zinc dust (330 mg, 5 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (440 mg, 1.5
mmol) in dry tetrahydrofuran (1 mL). The resulting reaction mixture
was then stirred at 40-45.degree. C. for 1 h and then stirred
overnight at 25.degree. C. The reaction mixture was then diluted
with dry tetrahydrofuran (3 mL), and the stirring was stopped to
allow the excess zinc dust to settle down (.about.2 h). In a
separate reaction flask, bis(dibenzylideneacetone)palladium(0) (27
mg, 0.05 mmol) and triphenylphosphine (52 mg, 0.2 mmol) in dry
tetrahydrofuran (4 mL) was stirred at 25.degree. C. under argon for
10 min and then treated with
1-(4-bromo-2-methanesulfonyl-phenyl)-5-methyl-1H-tetrazole (297 mg,
0.94 mmol) and the freshly prepared zinc compound in
tetrahydrofuran. The resulting brick red solution was stirred at
40-45.degree. C. over the weekend. The reaction mixture was cooled
to 25.degree. C. and then poured into a saturated aqueous ammonium
chloride solution (30 mL), and the organic compound was extracted
into ethyl acetate (3.times.25 mL). The combined organic extracts
were washed with a saturated aqueous sodium chloride solution
(1.times.50 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40M,
Silica, 4/1 to 1/1 hexanes/ethyl acetate) afforded
(E)-3-cyclopentyl-2-[3-methanesulfonyl-4-(5-methyl-tetrazol-1-yl)-phenyl]-
-acrylic acid methyl ester (289 mg, 78%) as an amorphous yellow
solid: EI-HRMS m/e calcd for C.sub.18H.sub.22N.sub.4O.sub.4S
(M.sup.+) 390.1362, found 390.1363.
[0211] A solution of
(E)-3-cyclopentyl-2-[3-methanesulfonyl-4-(5-methyl-te-
trazol-1-yl)-phenyl]-acrylic acid methyl ester (273 mg, 0.7 mmol)
in ethanol (5 mL) was treated with a 1N aqueous sodium hydroxide
solution (1.5 mL). The solution was heated at 45-50.degree. C. for
15 h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was concentrated in vacuo to remove ethanol. The
residue was diluted with water (20 mL) and extracted with diethyl
ether (1.times.30 mL) to remove any neutral impurities. The aqueous
layer was then acidified with a 1N aqueous hydrochloric acid
solution, and the resulting acid was extracted into ethyl acetate
(2.times.30 mL). The combined organic layers were washed with a
saturated aqueous sodium chloride solution (1.times.50 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford
(E)-3-cyclopentyl-2-[3-methanesulfonyl-4-(5-methyl-tetraz-
ol-1-yl)-phenyl]-acrylic acid (262 mg, 100%) as a yellow solid:
EI-HRMS m/e calcd for C.sub.17H.sub.20N.sub.4O.sub.4S (M.sup.+)
376.1205, found 376.1204.
[0212] A solution of triphenylphosphine (262 mg, 1 mmol) in
methylene chloride (6 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (178 mg, 1 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with (E)-3-cyclopentyl-2-[3-meth-
anesulfonyl-4-(5-methyl-tetrazol-1-yl)-phenyl]-acrylic acid (190
mg, 0.5 mmol). The reaction mixture was stirred for 15 min at
0.degree. C. and then allowed to warm to 25.degree. C. where it was
stirred for 1.5 h. The reaction mixture was then treated with
2-aminothiazole (250 mg, 2.5 mmol), and the resulting suspension
was stirred for 2 d at 25.degree. C. The reaction mixture was then
concentrated in vacuo to remove methylene chloride, and the residue
was diluted with ethyl acetate (20 mL) and water (30 mL). The two
layers were separated, and the aqueous layer was extracted with
ethyl acetate (1.times.15 mL). The combined organic extracts were
successively washed with a saturated aqueous sodium bicarbonate
solution (1.times.50 mL) and a saturated aqueous sodium chloride
solution (1.times.50 mL), dried over anhydrous magnesium sulfate,
filtered, and concentrated in vacuo. Biotage chromatography (FLASH
40S, Silica, 3/1 hexanes/ethyl acetate) afforded
(E)-3-cyclopentyl-2-[3-methanesulfonyl-4-(5-methyl-tetrazol-1-yl)-phenyl]-
-N-thiazol-2-yl-acrylamide (42 mg, 18%) as an amorphous white
solid: EI-HRMS m/e calcd for C.sub.20H.sub.22N.sub.6O.sub.3S.sub.2
(M.sup.+) 458.1195, found 458.1192.
EXAMPLE 21
(E)-4-Cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]--
but-2-enoic acid thiazol-2-ylamide
[0213] 34
[0214] A solution of 2-(trifluoromethyl)-4-bromoaniline (4.8 g, 20
mmol) in dry tetrahydrofuran (20 mL) was cooled to 0.degree. C. and
then treated with acetic anhydride (8.2 g, 80 mmol). The reaction
mixture was stirred at 0.degree. C. for 10 min and then allowed to
warm to 25.degree. C. The reaction mixture was stirred at
25.degree. C. for 2 h, at which time, thin layer chromatography
analysis of the reaction mixture indicated the absence of starting
material. The reaction mixture was then concentrated in vacuo. The
crude residue precipitated from diethyl ether (50 mL) and hexanes
(50 mL). The solid was collected by filtrated and washed with
hexanes to afford N-(4-bromo-2-trifluoromethyl-phenyl)-acetam- ide
(5.07 g, 90%) as an amorphous white solid: EI-HRMS m/e calcd for
C.sub.9H.sub.7BrF.sub.3NO (M.sup.+) 281.8352, found 281.8348.
[0215] A suspension of
N-(4-bromo-2-trifluoromethyl-phenyl)-acetamide (2.41 g, 8.54 mmol)
in acetonitrile (40 mL) was treated with methylene chloride (5 mL)
to obtain a clear solution at 25.degree. C. The resulting solution
was treated with sodium azide (1.24 g, 19.1 mmol), and the reaction
mixture was then cooled to 0.degree. C. The reaction mixture was
then treated with trifluoromethanesulfonic anhydride (3.59 g, 12.7
mmol). The resulting reaction mixture was allowed to warm to
25.degree. C. where it was stirred overnight, at which time, thin
layer chromatography analysis of the reaction mixture indicated the
absence of starting material. The reaction mixture was then
concentrated in vacuo. The resulting residue was diluted with ethyl
acetate (50 mL) and water (50 mL). The two layers were separated,
and the aqueous layer was extracted with ethyl acetate (1.times.30
mL). The combined organic extracts were washed with a saturated
aqueous sodium chloride solution (1.times.100 mL), dried over
anhydrous magnesium sulfate, filtered, and concentrated in vacuo.
Biotage chromatography (FLASH 40M, Silica, 2/1 hexanes/ethyl
acetate) afforded
1-(4-bromo-2-trifluoromethyl-phenyl)-5-methyl-1H-tetraz- ole (1.85
g, 70%) as a white solid: EI-HRMS m/e calcd for
C.sub.9H.sub.6BrF.sub.3N.sub.4 (M.sup.+) 305.9728, found
305.9733.
[0216] A mixture of zinc dust (3.92 g, 60 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (4 mL) under argon was treated with
1,2-dibromoethane (0.56 g, 3 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (0.32 g, 3 mmol, and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
cyclopentylmethyl iodide (4.2 g, 20 mmol) in dry tetrahydrofuran (7
mL) over 5 min. During the addition, the temperature rose to
50.degree. C., and the reaction mixture was stirred overnight at
40-45.degree. C. The reaction mixture was then cooled to 25.degree.
C. and diluted with dry tetrahydrofuran (5 mL). The stirring was
stopped to allow the excess zinc dust to settle down (.about.2 h).
In a separate reaction flask, a mixture of lithium chloride (1.7 g,
40 mmol, predried at 130.degree. C. under high vacuum for 2 h) and
copper cyanide (1.79 g, 20 mmol) in dry tetrahydrofuran (20 mL) was
stirred for 10 min at 25.degree. C. to obtain a clear solution. The
reaction mixture was cooled to -70.degree. C. and then the slowly
treated with the freshly prepared zinc solution using a syringe.
After the addition, the reaction mixture was allowed to warm to
-30.degree. C., where it was stirred for 5 min. The reaction
mixture was again cooled back to -70.degree. C. and then slowly
treated with methyl propiolate (1.52 g, 18 mmol). The reaction
mixture was stirred for 4 h at -40.degree. C. to -30.degree. C. and
then slowly treated with a solution of iodine (6.85 g, 27 mmol) in
dry tetrahydrofuran (10 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After the addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 1 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (90 mL) and ammonium
hydroxide (10 mL), and the organic compound was extracted into
diethyl ether (3.times.50 mL). The combined ether extracts were
successively washed with a saturated aqueous sodium thiosulfate
solution (1.times.100 mL) and a saturated aqueous sodium chloride
solution (1.times.100 mL), dried over anhydrous magnesium sulfate,
filtrated, and concentrated in vacuo. Biotage chromatography (FLASH
40M, Silica, 9/1 hexanes/diethyl ether) afforded
(E)-4-cyclopentyl-2-iodo-but-2-enoic acid methyl ester (4.56 g,
86%) as a colorless oil: EI-HRMS m/e calcd for
C.sub.10H.sub.15IO.sub.2 (M.sup.+) 294.0116, found 294.0114.
[0217] A mixture of zinc dust (330 mg, 5 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-4-cyclopentyl-2-iodo-but-2-enoic acid methyl ester (590 mg, 2
mmol) in dry tetrahydrofuran (1 mL). After the addition, the
reaction mixture was stirred for 1 h at 40-45.degree. C. and then
stirred overnight at 25.degree. C. The reaction mixture was then
diluted with dry tetrahydrofuran (3 mL), and the stirring was
stopped to allow the excess zinc dust to settle down (.about.2 h).
In a separate reaction flask, bis(dibenzylideneacetone)palladium(0)
(38 mg, 0.07 mmol) and triphenylphosphine (73 mg, 0.28 mmol) in dry
tetrahydrofuran (7 mL) was stirred at 25.degree. C. under argon for
10 min and then treated with
1-(4-bromo-2-trifluoromethyl-phenyl)-5-methyl-1H-tetrazole (350 mg,
1.4 mmol) and the freshly prepared zinc compound in
tetrahydrofuran. The resulting brick red solution was heated at
45-50.degree. C. for 20 h. The reaction mixture was cooled to
25.degree. C. and then poured into a saturated aqueous ammonium
chloride solution (30 mL), and the organic compound was extracted
into ethyl acetate (3.times.25 mL). The combined organic extracts
were washed with a saturated aqueous sodium chloride solution
(1.times.50 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40M,
Silica, 4/1 to 1/1 hexanes/ethyl acetate) afforded
(E)-4-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-
-but-2-enoic acid methyl ester (360 mg, 65%) as an amorphous white
solid: EI-HRMS m/e calcd for C.sub.19H.sub.21F.sub.3N.sub.4O.sub.2
(M.sup.+) 394.1617, found 394.1621.
[0218] A solution of
(E)-4-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-tri-
fluoromethyl-phenyl]-but-2-enoic acid methyl ester (359 mg, 0.9
mmol) in ethanol (5 mL) was treated with a 1N aqueous sodium
hydroxide solution (3 mL). The solution was heated at 45-50.degree.
C. for 15 h, at which time, thin layer chromatography analysis of
the reaction mixture indicated the absence of starting material.
The reaction mixture was concentrated in vacuo to remove ethanol.
The residue was diluted with water (20 mL) and extracted with
diethyl ether (1.times.30 mL) to remove any neutral impurities. The
aqueous layer was then acidified with a 1N aqueous hydrochloric
acid solution, and the resulting acid was extracted into ethyl
acetate (2.times.30 mL). The combined organic layers were washed
with a saturated aqueous sodium chloride solution (1.times.50 mL),
dried over anhydrous magnesium sulfate, filtered, and concentrated
in vacuo to afford
(E)-4-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl--
phenyl]-but-2-enoic acid (340 mg, 98%) as a yellow solid: EI-HRMS
m/e calcd for C.sub.18H.sub.19F.sub.3N.sub.4O.sub.2 (M.sup.+)
380.1460, found 380.1460.
[0219] A solution of triphenylphosphine (450 mg, 1.72 mmol) in
methylene chloride (20 mL) was cooled to 0.degree. C. and then
treated with N-bromosuccinimide (306 mg, 1.72 mmol). The reaction
mixture was stirred at 0.degree. C. for 30 min and then treated
with a solution of the
(E)-4-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-
-but-2-enoic acid (326 mg, 0.86 mmol) in methylene chloride (5 mL).
The reaction mixture was stirred for 15 min at 0.degree. C. and
then allowed to warm to 25.degree. C. where it was stirred for 1.5
h. The reaction mixture was then treated with 2-aminothiazole (257
mg, 2.57 mmol), and the resulting suspension was stirred for 2 d at
25.degree. C. The reaction mixture was then concentrated in vacuo
to remove methylene chloride, and the residue was diluted with
ethyl acetate (20 mL) and water (30 mL). The two layers were
separated, and the aqueous layer was extracted with ethyl acetate
(1.times.15 mL). The combined organic extracts were successively
washed with a saturated aqueous sodium bicarbonate solution
(1.times.50 mL) and a saturated aqueous sodium chloride solution
(1.times.50 mL), dried over anhydrous magnesium sulfate, filtered,
and concentrated in vacuo. Biotage chromatography (FLASH 40S,
Silica, 3/1 hexanes/ethyl acetate) afforded
(E)-4-cyclopentyl-2-[4-(5-methyl-tetrazol-1-yl)-3-trifluoromethyl-phenyl]-
-but-2-enoic acid thiazol-2-ylamide (52 mg, 13%) as an amorphous
white solid: EI-HRMS m/e calcd for C.sub.21H.sub.21F.sub.3N.sub.6OS
(M.sup.+) 462.1450, found 462.1451.
EXAMPLE 22
(E)-1-{3-Cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-acrylo-
yl}-3-methyl-urea
[0220] 35
[0221] A solution of 2-fluoro-4-iodoaniline (4.74 g, 20 mmol) in
dry tetrahydrofuran (20 mL) was cooled to 0.degree. C. and then
treated with acetic anhydride (8.2 g, 80 mmol). The reaction
mixture was stirred for 10 min at 0.degree. C. and then was allowed
to warn to 25.degree. C. where it was stirred for 2 h. After this
time, thin layer chromatography analysis of the reaction mixture
indicated the absence of starting material. The reaction mixture
was then concentrated in vacuo to afford a crude residue. The
residue precipitated from diethyl ether (50 mL) and hexanes (50
mL). The solid was collected by filtration and washed with hexanes
to afford N-(2-fluoro-4-iodo-phenyl)-acetamide (5.12 g, 92%) as a
white crystalline solid: mp 152-154.degree. C.; EI-HRMS m/e calcd
for C.sub.8H.sub.7FINO (M.sup.+) 278.9556, found 278.9559.
[0222] A suspension of N-(2-fluoro-4-iodo-phenyl)-acetamide (5 g,
18.24 mmol) in acetonitrile (100 mL) was cooled to 0.degree. C. and
then treated with sodium azide (3.56 g, 54.7 mmol). The reaction
mixture was then treated with trifluoromethanesulfonic anhydride
(13.6 g, 48 mmol). The resulting reaction mixture was allowed to
warm to 25.degree. C. where it was stirred overnight, at which
time, thin layer chromatography analysis of the reaction mixture
indicated the absence of starting material. The reaction mixture
was then concentrated in vacuo. The resulting residue was diluted
with ethyl acetate (100 mL) and water (100 mL). The two layers were
separated, and the aqueous layer was extracted with ethyl acetate
(1.times.50 mL). The combined organic extracts were washed with a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo. Biotage chromatography (FLASH 40M, Silica, 4/1 hexanes/ethyl
acetate) afforded 1-(2-fluoro-4-iodo-phenyl)-5-methyl-1H-tetrazole
(3.45 g, 62%) as a white solid: mp 122-124.degree. C.; EI-HRMS m/e
calcd for C.sub.8H.sub.6FIN.sub.4 (M.sup.+) 303.9621, found
303.9615.
[0223] A mixture of lithium chloride (8.48 g, 200 mmol, predried at
130.degree. C. under high vacuum for 3 h) and copper cyanide (8.96
g, 100 mmol) in dry tetrahydrofuran (100 mL) was stirred at
25.degree. C. under argon for 10 min to obtain a clear solution.
The reaction mixture was then cooled to -70.degree. C. and then
slowly treated with a 2.0M solution of cyclopentylmagnesium
chloride in diethyl ether (55 mL, 110 mmol). After the addition,
the reaction mixture was allowed to warm to -30.degree. C. where it
was stirred for 5 min. The resulting reaction mixture was again
cooled back to -70.degree. C. and then slowly treated with methyl
propiolate (7.99 g, 95 mmol). The reaction mixture was stirred
overnight at -60.degree. C. to -50.degree. C. The reaction mixture
was then slowly treated with a solution of iodine (34.3 g, 135
mmol) in dry tetrahydrofuran (30 mL), with the temperature kept at
-70.degree. C. to -60.degree. C. After addition of the iodine
solution, the cooling bath was removed, and the reaction mixture
was allowed to warm to 25.degree. C. where it was stirred for 2 h.
The reaction mixture was then poured into a solution consisting of
a saturated aqueous ammonium chloride solution (200 mL) and
ammonium hydroxide (50 mL), and the organic compound was extracted
into diethyl ether (3.times.100 mL). The combined organic extracts
were successively washed with a saturated aqueous sodium
thiosulfate solution (1.times.300 mL) and a saturated aqueous
sodium chloride solution (1.times.300 mL). The organic layer was
then dried over anhydrous magnesium sulfate, filtered, and
concentrated in vacuo. Flash chromatography (Merck Silica gel 60,
230-400 mesh, 20/1 hexanes/diethyl ether) afforded
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (25.8 g, 97%) as
a yellow oil: EI-HRMS m/e calcd for C.sub.9H.sub.13IO.sub.2
(M.sup.+) 279.9960, found 279.9961.
[0224] A mixture of zinc dust (650 mg, 10 mmol, Aldrich, -325 mesh)
and dry tetrahydrofuran (1 mL) under argon was treated with
1,2-dibromoethane (187 mg, 1 mmol). The zinc suspension was then
heated with a heat gun to ebullition, allowed to cool, and heated
again. This process was repeated three times to make sure the zinc
dust was activated. The activated zinc dust suspension was then
treated with trimethylsilyl chloride (108 mg, 1 mmol), and the
suspension was stirred for 15 min at 25.degree. C. The reaction
mixture was then treated dropwise with a solution of
(E)-3-cyclopentyl-2-iodo-acrylic acid methyl ester (2.21 g, 7.5
mmol) in dry tetrahydrofuran (3 mL) over 3 min. The resulting
reaction mixture was then stirred at 40-45.degree. C. for 1 h and
then stirred overnight at 25.degree. C. The reaction mixture was
then diluted with dry tetrahydrofuran (5 mL), and the stirring was
stopped to allow the excess zinc dust to settle down (.about.2 h).
In a separate reaction flask, bis(dibenzylideneacetone)palladium(0)
(90 mg, 0.16 mmol) and triphenylphosphine (160 mg, 0.6 mmol) in dry
tetrahydrofuran (10 mL) was stirred at 25.degree. C. under argon
for 10 min and then treated with
1-(2-fluoro-4-iodo-phenyl)-5-methyl-1H-tetrazole (1.52 g, 5 mmol)
and the freshly prepared zinc compound in tetrahydrofuran. The
resulting brick red solution was stirred at 25.degree. C. over the
weekend and then heated at 40-45.degree. C. for 4 h. The reaction
mixture was cooled to 25.degree. C. and then poured into a
saturated aqueous ammonium chloride solution (50 mL), and the
organic compound was extracted into ethyl acetate (3.times.50 mL).
The combined organic extracts were washed with a saturated aqueous
sodium chloride solution (1.times.100 mL), dried over anhydrous
magnesium sulfate, filtered, and concentrated in vacuo. Flash
chromatography (Merck Silica gel 60, 230-400 mesh, 4/1 to 1/1
hexanes/ethyl acetate) afforded
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-
-tetrazol-1-yl)-phenyl]-acrylic acid methyl ester (1.14 g, 68%) as
a light yellow solid: mp 111-114.degree. C.; EI-HRMS m/e calcd for
C.sub.17H.sub.19FN.sub.4O.sub.2 (M.sup.+) 330.1492, found
330.1493.
[0225] A solution of
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1--
yl)-phenyl]-acrylic acid methyl ester (720 mg, 2.18 mmol) in
ethanol (15 mL) was treated with a 1N aqueous sodium hydroxide
solution (5 mL). The solution was heated at 45-50.degree. C. for 15
h, at which time, thin layer chromatography analysis of the
reaction mixture indicated the absence of starting material. The
reaction mixture was concentrated in vacuo to remove ethanol. The
residue was diluted with water (30 mL) and extracted with diethyl
ether (1.times.50 mL) to remove any neutral impurities. The aqueous
layer was then acidified with a 1N aqueous hydrochloric acid
solution, and the resulting acid was extracted into ethyl acetate
(2.times.50 mL). The combined organic layers were washed with a
saturated aqueous sodium chloride solution (1.times.100 mL), dried
over anhydrous magnesium sulfate, filtered, and concentrated in
vacuo to afford
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-a-
crylic acid (690 mg, 100%) as a white solid: mp 182-185.degree. C.;
EI-HRMS m/e calcd for C.sub.16H.sub.17FN.sub.4O.sub.2 (M.sup.+)
316.1336, found 316.1334.
[0226] A solution of
(E)-3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1--
yl)-phenyl]-acrylic acid (158 mg, 0.5 mmol) in fluorobenzene (1 mL)
and N,N-dimethylformamide (2 .mu.L) at 25.degree. C. was treated
dropwise with oxalyl chloride (54 .mu.L, 0.6 mmol) over 2-3 min.
The clear solution was stirred for 1 h at 25.degree. C. and then
treated with methyl urea (111 mg, 1.5 mmol). The resulting
suspension was heated at 70.degree. C. (bath temperature) for 10
min and then treated with pyridine (81 .mu.L, 1 mmol). The reaction
mixture was then stirred at 70.degree. C. for 20 h. The reaction
mixture was then cooled to 25.degree. C. and diluted with ethyl
acetate (30 mL) and a 3N aqueous hydrochloric acid solution (30
mL). The two layers were separated, and the aqueous layer was
extracted with ethyl acetate (1.times.20 mL). The combined organic
extracts were successively washed with a saturated aqueous sodium
bicarbonate solution (1.times.50 mL) and a saturated aqueous sodium
chloride solution (1.times.50 mL), dried over anhydrous magnesium
sulfate, filtered, and concentrated in vacuo. Biotage
chromatography (FLASH 40M, Silica, 1/1 hexanes/ethyl acetate)
afforded the
(E)-1-{3-cyclopentyl-2-[3-fluoro-4-(5-methyl-tetrazol-1-yl)-phenyl]-a-
cryloyl}-3-methyl-urea (41 mg, 22%) as a white solid: mp
186-192.degree. C.; EI-HRMS m/e calcd for
C.sub.18H.sub.21FN.sub.6O.sub.2 (M.sup.+) 372.1710, found
372.1708.
BIOLOGICAL ACTIVITY EXAMPLES
Example A
In Vitro Glucokinase Activity
[0227] Glucokinase Assay: Glucokinase (GK) was assayed by coupling
the production of glucose-6-phosphate to the generation of NADH
with glucose-6-phosphate dehydrogenase (G6PDH, 0.75-1 kunits/mg;
Boehringer Mannheim, Indianapolis, Ind.) from Leuconostoc
mesenteroides as the coupling enzyme (Scheme 2). Recombinant 36
[0228] Human liver GK1 was expressed in E. coli as a glutathione
S-transferase fusion protein (GST-GK) [Liang et al, 1995] and was
purified by chromatography over a glutathione-Sepharose 4B affinity
column using the procedure provided by the manufacturer (Amersham
Pharmacia Biotech, Piscataway, N.J.). Previous studies have
demonstrated that the enzymatic properties of native GK and GST-GK
are essentially identical (Liang et al, 1995; Neet et al.,
1990).
[0229] The assay was conducted at 25.degree. C. in a flat bottom
96-well tissue culture plate from Costar (Cambridge, Mass.) with a
final incubation volume of 120 .mu.l. The incubation mixture
contained: 25 mM Hepes buffer (pH, 7.1), 25 mM KCl, 5 mM D-glucose,
1 mM ATP, 1.8 mM NAD, 2 mM MgCl.sub.2, 1 .mu.M
sorbitol-6-phosphate, 1 mM dithiothreitol, test drug or 10% DMSO,
1.8 unit/ml G6PDH, and GK (see below). All organic reagents were
>98% pure and were from Boehringer Mannheim with the exceptions
of D-glucose and Hepes that were from Sigma Chemical Co, St Louis,
Mo. Test compounds were dissolved in DMSO and were added to the
incubation mixture minus GST-GK in a volume of 12 .mu.l to yield a
final DMSO concentration of 10%. This mix was preincubated in the
temperature controlled chamber of a SPECTRAmax 250 microplate
spectrophotometer (Molecular Devices Corporation, Sunnyvale,
Calif.) for 10 minutes to allow temperature equilibrium and then
the reaction was started by the addition of 20 .mu.l GST-GK.
[0230] After addition of enzyme, the increase in optical density
(OD) at 340 nm was monitored over a 10 minute incubation period -as
a measure of GK activity. Sufficient GST-GK was added to produce an
increase in OD.sub.340 of 0.08 to 0.1 units over the 10 minute
incubation period in wells containing 10% DMSO, but no test
compound. Preliminary experiments established that the GK reaction
was linear over this period of time even in the presence of
activators that produced a 5-fold increase in GK activity. The GK
activity in control wells was compared with the activity in wells
containing test GK activators, and the concentration of activator
that produced a 50% increase in the activity of GK, i.e., the
SC.sub.1.5, was calculated. All of the compounds of formula IA or
IB described in the Synthesis Examples had an SC.sub.1.5 less than
or equal to 30 .mu.M.
Example B
Glucokinase Activator in vivo Screen Protocol
[0231] C57BL/6J mice were orally dosed via gavage with Glucokinase
(GK) activator at 50 mg/kg body weight following a two hour fasting
period. Blood glucose determinations were made five times during
the six hour post-dose study period.
[0232] Mice (n=6) were weighed and fasted for a two hour period
prior to oral treatment GK activators were formulated at 6.76 mg/ml
in Gelucire vehicle. (Ethanol:Gelucire44/14:PEG400 q.s. 4:66:30
v/w/v. Mice were dosed orally with 7.5 .mu.L formulation per gram
of body weight to equal a 50 mg/kg dose. Immediately prior to
dosing, a pre dose (time zero) blood glucose reading is acquired by
snipping off a small portion of the animals tail (.about.1 mm) and
collecting 15 .mu.L blood into a heparinized capillary tube for
analysis. Following GK activator administration, additional blood
glucose readings were taken at 1, 2, 4, and 6 hours post dose from
the same tail wound. Results were interpreted by comparing the mean
blood glucose values of six vehicle treated mice with six GK
activator treated mice over the six hour study duration. Compounds
are considered active when they exhibit a statistically significant
(p.ltoreq.0.05) decrease in blood glucose compared to vehicle for
two consecutive assay time points.
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