U.S. patent application number 11/171181 was filed with the patent office on 2005-10-27 for novel nucleosides and related processes, pharmaceutical compositions and methods.
This patent application is currently assigned to YALE UNIVERSITY. Invention is credited to Cheng, Yung-Chi, Liu, Mao-Chin, Sartorelli, Alan C..
Application Number | 20050239726 11/171181 |
Document ID | / |
Family ID | 32507046 |
Filed Date | 2005-10-27 |
United States Patent
Application |
20050239726 |
Kind Code |
A1 |
Sartorelli, Alan C. ; et
al. |
October 27, 2005 |
Novel nucleosides and related processes, pharmaceutical
compositions and methods
Abstract
The invention provides novel nucleosides and related processes,
pharmaceutical compositions, and methods. The novel nucleosides are
useful in a wide variety of antiviral, antineoplastic, and
antibacterial applications. Preferred embodiments of the instant
invention include novel 2 halogen-substituted, 3
halogen-substituted, and 2',3'dihalogen-substituted analogues of
3-deazaadenosine, and novel 3 halogen-substituted analogues of
3-deazaguanosine. Compounds of the instant invention, including
4-Amino-6-fluoro-1-(.beta.-D-ribofuranosyl)i- midazo[4,5-c]pyridine
and 6-Amino-7-bromo-1,5-dihydro-1-.beta.-D-ribofuran-
osylimidazo[4,5-c]pyridin-4-one, have exhibited potent antiviral
and anticancer activity in vitro. The compounds are also useful in
the concomitant treatment of bacterial infections associated with
viral infections such as AIDS.
Inventors: |
Sartorelli, Alan C.;
(Woodbridge, CT) ; Cheng, Yung-Chi; (Woodbridge,
CT) ; Liu, Mao-Chin; (North Haven, CT) |
Correspondence
Address: |
COLEMAN SUDOL SAPONE, P.C.
714 COLORADO AVENUE
BRIDGE PORT
CT
06605-1601
US
|
Assignee: |
YALE UNIVERSITY
New Haven
CT
|
Family ID: |
32507046 |
Appl. No.: |
11/171181 |
Filed: |
June 30, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11171181 |
Jun 30, 2005 |
|
|
|
10321133 |
Dec 17, 2002 |
|
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|
Current U.S.
Class: |
514/43 ;
536/27.1 |
Current CPC
Class: |
C07H 19/22 20130101 |
Class at
Publication: |
514/043 ;
536/027.1 |
International
Class: |
A61K 031/7056; C07H
019/22 |
Claims
1-59. (canceled)
60. A method of treating tuberculosis in a patient in need thereof
comprising administering to said patient an effective amount of a
compound according to the formula: 11or its pharmaceutically
acceptable salt, optionally in combination with a pharmaceutically
acceptable carrier additive or excipient.
Description
FIELD OF THE INVENTION
[0001] The invention provides novel nucleosides and related
processes, pharmaceutical compositions, and methods. The novel
nucleosides are useful in a wide variety of antiviral,
antineoplastic, and antibacterial applications. Preferred
embodiments of the instant invention include novel 2
halogen-substituted, 3 halogen-substituted, and 2',
3'dihalogen-substituted analogues of 3-deazaadenosine, and novel 3
halogen-substituted analogues of 3-deazaguanosine. Compounds of the
instant invention, including
4-Amino-6-fluoro-1-(.beta.-D-ribofuranosyl)i- midazo[4,5-c]pyridine
and 6-Amino-7-bromo-1,5-dihydro-1-.beta.-D-ribofuran-
osylimidazo[4,5-c]pyridin-4-one, have exhibited potent antiviral
and anticancer activity in vitro. The compounds are also useful in
the concomitant treatment of bacterial infections associated with
viral infections such as AIDS.
BACKGROUND OF THE INVENTION
[0002] Considerable progress has been made in developing
nucleosides with anticancer and/or antiviral activity by modifying
the base portion of a nucleoside. For example, 3-deazaadenosine, a
potent inhibitor of adenosylhomocysteine hydrolase, has been shown
to have significant activity against herpes simplex virus type-1,
human immunodeficiency virus and oncogenic DNA viruses. Bodner, A.
J.; Cantoni, G. L.; Chiang, P. K. Biochem. Biophys. Res. Commun.
1981 98,476-481. Flexner, C. W.; Hildreth, J. E.; Kuncl, R. W.;
Drachman, D. B. Lancet 1992 339, 438. Bader, J. P.; Brown, N. R.;
Chiang, P. K.; Cantoni, G. L. Virology 1978 89, 494-505. Chiang, P.
K.; Cantoni, G. L.; Bader, J. P.; Shannon, W. M.; Thomas, H. J.;
Montgomery, J. A. Biochem. Biophys. Res. Commun. 1978 82 417-423.
3-Deazaguanosine has been reported to possess broad spectrum
antiviral activity against a variety of DNA and RNA viruses, as
well as antitumor activity against the L1210 leukemia and several
mammary adenocarcinomas in mice. Allen, L. B.; Huffman, J. H.;
Cook, P. D.; Meyer, R. B., Jr.; Robins, R. K.; Sidwell, R. W.
Antimicrob. Agents Chemother. 1977 12, 114-119. Saunders, P. P.;
Chao, L. Y.; Loo, T. L.; Robins, R. K. Biochem. Pharmacol. 1981 30,
2374-2376. Revankar, G. R.; Gupta, P. K.; Adams, A. D.; Dalley, N.
K.; McKernan, P. A.; Cook, P. D.; Canonico, P. G.; Robins, R. K. J.
Med. Chem., 1984 27, 1389-1396.
[0003] Certain 2-halogen-substituted purine nucleosides have
exhibited cytotoxicity in vitro and anticancer activity in vivo.
Carson, D. A.; Wasson, D. B.; Kaye, J.; Ullman, B.; Martin, D. W.,
Jr.; Robins, R. K.; Montgomery, J. A. Proc. Natl. Acad. Sci. USA
1980 77, 6865-6869. Hutton, J. J.; Von Hoff, D. D.; Kuhn, J.;
Phillips, J.; Hersh, M.; Clark, G. Cancer Res. 1984 44, 4183-4186.
Secrist, J. A., III; Shortnacy, A. T.; Montgomery, J. A. J. Med.
Chem. 1988 31, 405-410. Montgomery, J. A.; Shortnacy-Fowler, A. T.;
Clayton, S. D.; Riordan, J. M.; Secrist, J. A., III. J. Med. Chem.
1992 35, 397-401. Among these analogues, Fludarabine phosphate
(9-.beta.-D-arabinofuranosyl-2-fluoroadenine 5'-O-phosphate) and
Cladribine (2-chloro-2'-deoxy-.beta.-D-adenosine) are currently
used as anticancer agents.
[0004] However, notwithstanding the progress that has been made in
identifying nucleosides having anticancer and/or antiviral
activity, the need exists for biologically-active nucleosides that
exhibit a wide range of antiviral and/or anticancer properties and
that may be employed in antiviral and anticancer pharmaceutical
compositions. Such nucleosides must be safe and well-tolerated and
be suitable for use in numerous pharmaceutical dosage forms and
routes of administration. Preferably, such nucleosides would
exhibit both antineoplastic and antiviral activity upon
administration to a patient in need, and would also be useful in
treating bacterial infections such as tuberculosis and associated
viral infections such as AIDS.
OBJECTS OF THE INVENTION
[0005] It is an object of the instant invention to provide novel,
biologically-active nucleosides useful in a wide range of
antiviral, antineoplastic, and antibacterial applications.
[0006] It is a further object of the instant invention to provide
novel, biologically-active nucleosides that may be employed in
antiviral and anticancer pharmaceutical compositions and which are
also effective against bacterial infections and bacterial
infections associated with viral infections such as AIDS.
[0007] It is a further object of the instant invention to provide
novel, biologically-active nucleosides that are safe and
well-tolerated.
[0008] It is a further object of the instant invention to provide
methods of using novel, biologically-active nucleosides to treat
viral, bacterial and neoplastic conditions.
[0009] It is a further object of the instant invention to provide
novel processes for making novel, biologically-active
nucleosides.
SUMMARY OF THE INVENTION
[0010] In accordance with the above stated objects, the instant
invention provides novel nucleosides of the formula (I): 1
[0011] and anomers, pharmaceutically acceptable salts, solvates, or
polymorphs thereof where R.sup.1, R.sup.2 and R.sup.3 are selected
from OH, SH, NRR' or a halogen group (F, Cl, Br or I); R.sup.4 and
R.sup.5 are selected from H, OH, a halogen group or together form
an unsaturated double bond between the 2' and 3' positions (i.e.,
the carbons to which R.sup.4 and R.sup.5 are attached); and R and
R' are independently selected from H or a C.sub.1-C.sub.3 alkyl
group. The invention also provides antiviral, bacterial and
antineoplastic (including anticancer) pharmaceutical compositions
comprising the novel nucleosides, methods of using these
pharmaceutical compositions to treat a wide variety of viral,
bacterial and neoplastic conditions, and processes for making the
novel nucleosides.
[0012] The beta-anomer of compounds of formula (1) is preferred,
and that anomer is illustrated below in formula (II): 2
[0013] Preferred nucleosides of the instant invention include
compounds of the following formulae (III) through (X): 3
[0014] where X is a halogen group (F, Cl, Br or I); 4
[0015] where X is a halogen group (F, Cl, Br or I) and A is an
alkyl group; 5
[0016] where X is a halogen group (F, Cl, Br or I); 6
[0017] where X is a halogen group (F, Cl, Br or I); 7
[0018] where X is a halogen group (F, Cl, Br or I); 8
[0019] where X and Y are the same or different and are a halogen
group (F, Cl, Br or I); 9
[0020] where X and Y are the same or different and are a halogen
group (F, Cl, Br or I); and 10
[0021] where X is a halogen group (F, Cl, Br or I).
[0022] Preferred nucleosides of the instant invention therefore
include:
[0023]
4-Amino-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine;
[0024]
6-Fluoro-4-methylamino-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyri-
dine;
[0025]
4-Amino-6-fluoro-1-.beta.-D-arabinofuranosylimidazo[4,5-c]pyridine;
[0026]
4-Amino-6-fluoro-1-.alpha.-D-arabinofuranosylimidazo[4,5-c]pyridine-
;
[0027]
4-Amino-7-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine;
[0028]
4-Amino-7-chloro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine;
[0029]
4-Amino-6,7-difluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridi-
ne;
[0030]
4-Amino-6,7-difluoro-3-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridi-
ne;
[0031]
4-Amino-7-chloro-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]p-
yridine;
[0032]
4-Amino-7-chloro-6-fluoro-3-(.beta.-D-ribofuranosyl)imidazo[4,5-c]p-
yridine;
[0033]
6-Amino-7-chloro-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,5-c]-
pyridin-4-one; and
[0034]
6-Amino-7-bromo-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,5-c]p-
yridin-4-one.
[0035] Particularly preferred nucleosides of the instant invention
include:
[0036]
4-Amino-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine;
[0037]
4-Amino-7-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine;
[0038]
4-Amino-6,7-difluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridi-
ne;
[0039]
4-Amino-6,7-difluoro-3-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridi-
ne;
[0040]
4-Amino-7-chloro-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]p-
yridine;
[0041]
6-Amino-7-chloro-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,5-c]-
pyridin-4-one; and
[0042]
6-Amino-7-bromo-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,5-c]p-
yridin-4-one.
[0043] Of these seven nucleosides of the instant invention,
4-Amino-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine
and
6-Amino-7-bromo-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,5-c]pyridin-
-4-one are especially preferred.
[0044] The novel nucleosides of the instant invention have a broad
spectrum of antiviral and antineoplastic (including anticancer)
activity. As defined further hereinafter, an antineoplastic agent
is an agent that is antagonistic to the growth of a neoplasm. For
example, as disclosed in detail hereinafter,
4-Amino-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,-
5-c]pyridine,
4-Amino-7-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyr-
idine,
4-Amino-6,7-difluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridi-
ne, and
4-Amino-7-chloro-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]-
pyridine have proven active in vitro against some or all of the
following neoplastic cell lines: L1210 and P388 leukemias, the
CCRF-CEM lymphoblastic leukemia, and the B.sub.16F.sub.10 melanoma
cell lines. The novel 3 halogen substituted analogues of
3-deazaguanosine of the instant invention,
6-Amino-7-chloro-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4-
,5-c]pyridin-4-one and
6-Amino-7-bromo-1,5-dihydro-1-.beta.-D-ribofuranosy-
limidazo[4,5-c]pyridin-4-one have also proven active in vitro
against these neoplastic cell lines.
[0045] The present invention also relates to methods for inhibiting
the growth, replication or elaboration of a virus population and
for treating a variety of virus infections, including, for example,
human immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2), human
T-cell leukemia viruses 1 and 2 (HTLV-1 and HTLV-2), respiratory
syncytial virus (RSV), human papilloma virus (HPV), adenovirus,
hepatitis B virus (HBV), hepatitis C virus (HCV), Epstein-Barr
virus (EBV), varicella zoster virus (VZV), cytomegalovirus (CMV),
herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), human herpes
virus 8 (HHV-8, also known as Kaposi's sarcoma-associated virus)
and flaviviruses, including Yellow Fever virus, Dengue virus,
Japanese Encephalitis and West Nile viruses, said method comprising
administering an antiviral effective amount of a composition
according to the present invention to a patient in need thereof to
treat, prevent or reduce the likelihood of contracting a viral
infection.
[0046] The invention provides methods of use relating to treatment
of infections caused by viruses, including, for example, human
immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2), human T-cell
leukemia viruses 1 and 2 (HTLV-1 and HTLV-2), respiratory syncytial
virus (RSV), human papilloma virus (HPV), adenovirus, hepatitis B
virus (HBV), hepatitis C virus (HCV), Epstein-Barr virus (EBV),
varicella zoster virus (VZV), cytomegalovirus (CMV), herpes simplex
viruses 1 and 2 (HSV-1 and HSV-2), human herpes virus 8 (HHV-8,
also known as Kaposi's sarcoma-associated virus) and flaviviruses,
including Yellow Fever virus, Dengue virus, Japanese Encephalitis
and West Nile viruses. For example, the novel compounds
4-Amino-7-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,-
5-c]pyridine,
4-Amino-6,7-difluoro-3-(.beta.-D-ribofuranosyl)imidazo[4,5-c-
]pyridine, and
4-Amino-7-chloro-6-fluoro-1-(1-D-ribofuranosyl)imidazo[4,5--
c]pyridine showed particular activity in vitro against Hepatitis B
virus.
[0047] The invention also provides a method of making
2-halogen-substituted analogues of 3-deazaadenosine by reacting
halogen-substituted imidazo[4,5-c]pyridines with excess
hexamethyldisilazane and a catalytic amount of ammonium sulfate to
yield a trimethylsilyl derivative, which is reacted with
l-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose in an organic solvent
such as 1,2-dichloroethane using a Lewis acid such as
trimethylsilyl trifluoromethanesulfonate (TMSOTf) as a catalyst at
around room temperature to give a tribenzoyl-protected nucleoside
derivative. This derivative is reacted with either saturated
ethanolic ammonia or 40% methylamine to yield the
2-halogen-substituted analogue of 3-deazaadenosine. For example,
the invention provides a method of making
4-Amino-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine
by reacting 4,6-Difluoroimidazo[4,5-c]pyridine with excess
hexamethyldisilazane and a catalytic amount of ammonium sulfate to
yield a trimethylsilyl derivative, which is reacted with
1-O-acetyl-2,3,5-tri-O-benzoyl-.beta.-D-ribofuranose in
1,2-dichloroethane using TMSOTf as a catalyst at room temperature
to give a tribenzoyl-protected nucleoside derivative, which in turn
is reacted with either saturated ethanolic ammonia or 40%
methylamine to yield
4-Amino-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine.
[0048] The invention also provides a method of making
2-halogen-substituted analogues of 3-deazaadenosine by reacting
halogen-substituted imidazo[4,5-c]pyridines with excess
hexamethyldisilazane to yield a trimethylsilyl derivative, which is
treated with
2,3,5-tri-O-benzyl-1-O-(4-nitro-benzoyl)-.beta.-D-arabinofur- anose
in 1,2-dichloroethane using TMSOTf as a catalyst at room
temperature under nitrogen to yield a mixture of .alpha.- and
.beta.-nucleosides. The mixture of .alpha.- and .beta.-nucleosides
is treated with ammonia saturated ethanol to yield a 4-amino
derivative. The 4-amino derivative undergoes debenzylation with
palladium (II) oxide hydrate and cyclohexene in ethanol to yield
the 2-halogen-substituted analogues of 3-deazaadenosine. For
example, the invention provides a method of making
4-Amino-6-fluoro-1-.beta.-D-arabinofuranosylimidazo[4,5-c]pyridine
and
4-Amino-6-fluoro-1-.alpha.-D-arabinofuranosylimidazo[4,5-c]pyridine
by reacting 4,6-Difluoroimidazo[4,5-c]pyridine with excess
hexamethyldisilazane to yield the trimethylsilyl derivative, which
is treated with
2,3,5-tri-O-benzyl-1-O-(4-nitro-benzoyl)-D-arabinofuranose in
1,2-dichloroethane using TMSOTf as a catalyst at room temperature
under nitrogen to yield a mixture of .alpha.- and
.beta.-nucleosides. The .alpha.- and .beta.-nucleosides are treated
with ammonia saturated ethanol to yield the 4-amino derivatives,
which undergo debenzylation with palladium (II) oxide hydrate and
cyclohexene in ethanol to yield
4-Amino-6-fluoro-1-.beta.-D-arabinofuranosylimidazo[4,5-c]pyridine
and
4-Amino-6-fluoro-1-.alpha.-D-arabinofuranosylimidazo[4,5-c]pyridine.
[0049] The invention also provides a method of making
3-halogen-substituted analogues of 3-deazaadenosine by condensing
silylated 4,7 dihaloimidazo[4,5-c]pyridines with
1-O-acetyl-2,3,5-tri-O-b- enzoyl-.beta.-D-ribofuranose in an
organic solvent such as 1,2-dichloroethane and in the presence of
TMSOTf to yield 3-deaza-3-halogen-substituted purine nucleosides,
which are deblocked with sodium methoxide in methanol to yield
corresponding nucleoside derivatives. These derivatives are treated
with anhydrous hydrazine, and the reaction product is catalytically
hydrogenated to yield 3-halogen-substituted analogues of
3-deazaadenosine. For example, the invention provides a method of
making 4-Amino-7-fluoro-1-(.beta.-D-ribofu-
ranosyl)imidazo[4,5-c]pyridine and
4-Amino-7-chloro-1-(.beta.-D-ribofurano- syl)imidazo[4,5-c]pyridine
by condensation of silylated
4-chloro-7-fluoroimidazo[4,5-c]pyridine and silylated
4,7-dichloroimidazo[4,5-c]pyridine with
1-O-acetyl-2,3,5-tri-O-benzoyl-.b- eta.-D-ribofuranose in
1,2-dichloroethane in the presence of TMSOTf to yield
3-deaza-3-halogen-substituted purine nucleosides. The nucleosides
are deblocked with sodium methoxide in methanol to yield the
corresponding nucleoside derivatives. These derivatives are treated
with anhydrous hydrazine, and the reaction product is catalytically
hydrogenated to yield either
4-Amino-7-fluoro-1-(.beta.-D-ribofuranosyl)i- midazo[4,5-c]pyridine
or 4-Amino-7-chloro-1-(.beta.-D-ribofuranosyl)imidaz-
o[4,5-c]pyridine.
[0050] The invention also provides a method of making
6,7-dihalogen-substituted analogues of 3-deazaadenosine by
condensation of a silylated 4,6,7-trihaloimidazo[4,5-c]pyridine or
a silylated 7-halo-4,6-dihaloimidazo[4,5-c]pyridine with
1-O-acetyl-2,3,5-tri-O-benzo- yl-.beta.-D-ribofuranose in an
organic solvent such as 1,2-dichloroethane and in the presence of a
Lewis acid such as TMSOTf to yield the corresponding protected
1-ribosides and 3-ribosides. Treatment of these ribosides with
ammonia saturated ethanol yields the 6,7-dihalogen-substituted
analogues of 3-deazaadenosine. For example, the invention provides
a method of making 4-Amino-6,7-difluoro-1-(.beta.-D-ri-
bofuranosyl)imidazo[4,5-c]pyridine and
4-Amino-7-chloro-6-fluoro-1-(.beta.-
-ribofuranosyl)imidazo[4,5-c]pyridine by condensing silylated
4,6,7-trifluoroimidazo[4,5-c]pyridine and silylated
7-chloro-4,6-difluoroimidazo[4,5-c]pyridine with
1-O-acetyl-2,3,5-tri-O-b- enzoyl-.beta.-D-ribofuranose in
1,2-dichloroethane and in the presence of TMSOTf to yield the
corresponding protected 1-ribosides and 3-ribosides. Treatment of
these ribosides with ammonia saturated ethanol yielded
4-Amino-6,7-difluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine
or
4-Amino-7-chloro-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridin-
e.
4-Amino-6,7-difluoro-3-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine
and
4-Amino-7-chloro-6-fluoro-3-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyr-
idine can be made in the same way.
[0051] The invention also provides a method of making
3-halogen-substituted analogues of 3-deazaguanosine by halogenation
of 3-deazaguanosine. For example, the invention provides a method
of making
6-Amino-7-chloro-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,5-c]pyridi-
n-4-one and
6-Amino-7-bromo-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,-
5-c]pyridin-4-one by halogenation of 3-deazaguanosine.
[0052] Synthesis of the novel compounds of the instant invention,
and methods of making and using the compounds in a broad ranges of
pharmaceutical compositions and uses, are illustrated further in
the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] FIG. 1 illustrates the synthesis of various
halogen-substituted 4-aminopyridines useful as intermediates in
making novel nucleosides of the instant invention.
[0054] FIG. 2 illustrates the synthesis of various
halogen-substituted imidazo[4,5c]pyridines useful as intermediates
in making novel nucleosides of the instant invention.
[0055] FIG. 3 illustrates the synthesis of the novel nucleosides
4-Amino-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine;
6-Fluoro-4-methylamino-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine;
4-Amino-6-fluoro-1-.beta.-D-arabinofuranosylimidazo[4,5-c]pyridine;
and
4-Amino-6-fluoro-1-.alpha.-D-arabinofuranosylimidazo[4,5-c]pyridine.
[0056] FIG. 4 illustrates the synthesis of the novel nucleosides
4-Amino-7-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine
and
4-Amino-7-chloro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine.
[0057] FIG. 5 illustrates the synthesis of the novel nucleosides
4-Amino-6,7-difluorol-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine;
4-Amino-6,7-difluoro-3-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine;
4-Amino-7-chloro-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridin-
e; and
4-Amino-7-chloro-6-fluoro-3-(.beta.-D-ribofuranosyl)imidazo[4,5-c]p-
yridine.
[0058] FIG. 6 illustrates the synthesis of the novel nucleosides
6-Amino-7-chloro-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,5-c]pyridi-
n-4-one and
6-Amino-7-bromo-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,-
5-c]pyridin-4-one.
DETAILED DESCRIPTION OF THE INVENTION
[0059] As used herein, the following terms have the following
respective meanings.
[0060] The term "alkyl" as used herein, unless otherwise indicated,
includes saturated and monovalent C.sub.1 to C.sub.6, preferably,
C.sub.1 to C.sub.6 hydrocarbon radicals having straight, branched,
or cyclic moieties or combinations thereof.
[0061] The term "anomer" as used herein means one of a pair of
isomers of a cyclic carbohydrate resulting from creation of a new
point of symmetry when a rearrangement of atoms occurs at an
aldehyde or ketone position.
[0062] The term "one or more substituents" as used herein refers to
a number of substituents that equals from one to the maximum number
of substituents possible based on the number of available bonding
sites.
[0063] "2' and 3' positions" mean the carbons to which R.sup.4 and
R.sup.5 are attached, e.g., in formulae (I) and (II) above.
[0064] The term "halogen group" as used herein means F, Cl, Br or
I.
[0065] The term "patient" is used throughout the specification to
describe an animal, preferably a human, to whom treatment,
including prophylactic treatment, with the compositions according
to the present invention is provided. For treatment of those
infections, conditions or disease states which are specific for a
specific animal such as a human patient, the term patient refers to
that specific animal.
[0066] The term "neoplasia" is used to describe the pathological
process that results in the formation and growth of a neoplasm,
i.e., an abnormal tissue that grows by cellular proliferation more
rapidly than normal tissue and continues to grow after the stimuli
that initated the new growth cease. Neoplasia exhibits partial or
complete lack of structural organization and functional
coordination with the normal tissue, and usually forms a distinct
mass of tissue which may be benign (benign tumor) or malignant
(carcinoma). The term "cancer" is used as a general term to
describe any of various types of malignant neoplasms, most of which
invade surrounding tissues, may metastasize to several sites and
are likely to recur after attempted removal and to cause death of
the patient unless adequately treated. As used herein, the term
cancer is subsumed under the term neoplasia.
[0067] The term "virus" shall be used to describe all types of
viruses, the growth or replication of which may be inhibited or
disease states of which may be treated using one or more methods
according to the present invention. Viruses which may be treated
according to the present invention include, for example, human
immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2), human T-cell
leukemia viruses 1 and 2 (HTLV-1 and HTLV-2), respiratory syncytial
virus (RSV), human papilloma virus (HPV), adenovirus, hepatitis B
virus (HBV), hepatitis C virus (HCV), Epstein-Barr virus (EBV),
varicella zoster virus (VZV), cytomegalovirus (CMV), herpes simplex
viruses 1 and 2 (HSV-1 and HSV-2), human herpes virus 8 (HHV-8,
also known as Kaposi's sarcoma-associated virus) and flaviviruses,
including Yellow Fever virus, Dengue virus, Japanese Encephalitis
and West Nile viruses, among numerous others.
[0068] The term "human immunodeficiency virus" shall be used to
describe human immunodeficiency virus (HIV) and its infections,
which term shall be used to embrace both human immunodeficieny
virus 1 (HIV-1) and human immunodeficiency virus 2 (HIV-2).
[0069] The term "human T-cell leukemia virus" shall be used to
describe human T-cell leukemia virus and its infections, which term
shall be used to embrace both human T-cell leukemia virus 1
(HTLV-1) and human T-cell leukemia virus 2 (HTLV-2).
[0070] The term "Hepatitis B Virus (HBV)" is used to describe the
virus (serum hepatitis virus) which produces viral heptatis type B
in humans. This is a viral disease with a long incubation period
(about 50 to 160 days) in contrast to Hepatitis A virus (infectious
hepatitis virus) which has a short incubation period. The virus is
usually tramsmitted by injection of infected blood or blood
derivatives or merely by use of contaminated needles, lancets or
other instruments. Clinically and pathologically, the disease is
similar to viral hepatitis type A; however, there is no
cross-protective immunity. Viral antigen (HBAg) is found in the
serum after infection.
[0071] The term "Hepatitis C Virus (HCV)" is used throughout the
specification to describe the hepatitis virus which is the
causative agent of non-A, non-B hepatitis. The disease in the acute
stage is, in general, milder than hepatitis B, but a greater
proportion of such infections become chronic.
[0072] The term "Epstein-Barr virus (EBV)" is used throughout the
specification to describe a herpetovirus found in cell cultures of
Burkitts lymphoma. EBV is the causative agent in infectious
mononucleosis, as well as in a number of other related
conditions/disease states, including EBV-associated lymphomas.
[0073] The term "Varicella-Zoster virus (VZV)" is used to describe
Herpes virus varicellae, also known as chicken pox or herpes
zoster. Varicella results from a primary infection with the virus;
herpes zoster results from secondary invasion by the same or by
reactivation of infection which in many instances may have been
latent for a number of years. Both the primary and secondary
infections of VZV may be treated using compositions according to
the present invention.
[0074] The term "respiratory syncytial virus (RSV)" is used
throughout the specification to describe an RNA-containing virus of
the genus Pneumovirus that causes minor respiratory infection with
rhinitis and cough in adults, but is capable of causing bronchitis
and bronchopneumonia in young children. The virus is named for the
tendency to form syncytia in tissue culture.
[0075] The term "adenovirus" is used throughout the specification
to describe a virus of the family adenoviridae which are
double-stranded DNA-containing viruses, which infect mammals and
birds. The virion is 70 to 90 nm in diameter and is naked (has no
envelope). The virus develops in nuclei of infected cells;
isolation requires tissue cultures since laboratory animals are not
susceptible to apparent infection. The family includes two genera,
Mastadenovirus and Acviadenovirus.
[0076] The term "Human Herpes Virus 8 (HHV-8)" is used throughout
the specification to describe a herpetovirus which is believed to
be the causative agent of Kaposis sarcoma in AIDS patients.
[0077] The term "Human Papilloma Virus (HPV)" is used throughout
the specification to describe a virus which causes genital warts.
Also known as infectious warts virus, HPV is a universal, common,
often recurrent viral infection with a large number of serotypes.
HPV infection can lead to the formation of genital warts which can,
in turn, lead to genital and/or cervical cancer. Genital warts
caused by HPV types 1, 2, 6, 11, 16 and 18 are generally
transmitted sexually and are often associated with cervical and/or
genital cancer. HPV may mature to produce a papillary tumor or
wart, which is a circumscribed benign epithelial tumor projecting
from the surrounding surface. It is generally a benign epithelial
neoplasm consisting of villous or arborescent outgrowths of
fibrovascular stroma covered by neoplastic cells.
[0078] The term "flavivirus" is used throughout the specification
to describe viruses belonging to the genus Flavivirus of the family
Togaviridae. According to virus taxonomy, about 50 viruses
including Hepatitis C virus (HCV), Yellow Fever virus, Dengue
Virus, Japanese Encephalitis virus, West Nile virus and related
flaviviruses are members of this genus. The viruses belonging to
the genus Flavivirus are simply called flaviviruses. These viruses
were formerly classified as group B arboviruses. The flaviviruses
are agents of infectious disease and predominate in East, Southeast
and South Asia and Africa, although they may be found in other
parts of the world as well.
[0079] The term "Yellow Fever virus" is used to describe the
flavivirus which is the causative agent of yellow fever. Yellow
fever is a tropical mosquito-borne viral hepatitis, due to Yellow
Fever virus (YFV), with an urban form transmitted by Aedes aegypti,
and a rural, jungle or sylvatic form from tree-dwelling mammals by
various mosquitos of the Haemagogus species complex. Yellow fever
is characterized clinically by fever, slow pulse, albuminuria,
jaundice, congesion of the face and hemorrhages, especially
hematemesis (black vomit). It is fatal in about 5-10% of the
cases.
[0080] The term "Dengue virus" is used throughout the specification
to descibe the flavivirus which is the causative agent(s) of dengue
fever/dengue hemorrhagic fever. Dengue is a disease of tropical and
subtropical regions occurring epidemically and caused by Dengue
virus, one of a group of arboviruses which causes the hemorrhagic
fever syndrome. Four grades of severity are recognized: grade I:
fever and constitutional symptoms, grade II: grade I plus
spontaneous bleeding (of skin, gums or gastrointestinal tract),
grade III: grade II plus agitation and circulatory failure and
grade IV: profound shock. The disease is transmitted by a mosquito
of the genus Aedes (generally A. aegyptil, but frequently, A.
albopictus). Also called Aden, bouquet, breakbone, dandy, date,
dengue (hemorrhagic) or polka, solar fever, stiffneck fever,
scarlatina rheumatica or exanthesis arthorosia. Hemorrhagic dengue
is a more pathogenic epidemic form of dengue which has erupted in a
number of epidemic outbreaks in the Pacific region in recent
years.
[0081] The term "Mycobacterium spp." refers to a genus of aerobic,
nonmotile bacteria containing Gram-positive, acid-fast, slender,
straight or slightly curbed rods. A number of Mycobacterium
associated diseases are associated with immunocompromised patients,
especially those with AIDS. Mycobacterium tuberculosis refers to
the causative agent of tuberculosis, which may affect any tissue or
organ of the body, the most common location of the disease being
found in the lungs. The present invention also relates to the
treatment of tuberculosis in patients in need of therapy.
[0082] The term "West Nile virus" is used to describe the
flavivirus which is the causative agent of West Nile fever, a
disease characterized by headache, fever, masculopapular rash,
myalgia, lymphadenopathy and leukopenia. The virus is spread by
Culex mosquitoes from a reservoir in birds. Although in the past,
West Nile virus infections had been considered virtually
nonexistent in the United States, recent developments have
suggested that West Nile and other flavivirus infections will
appear with greater regulatory in the future in the United
States.
[0083] The term "pharmaceutically acceptable salt" is used
throughout the specification to describe a salt form of one or more
of the compositions (and in particularly preferred aspects
according to the present invention, phosphate salts) herein which
are presented to increase the solubility of the compound in saline
for parenteral delivery or in the gastric juices of the patient's
gastrointestinal tract in order to promote dissolution and the
bioavailability of the compounds. Pharmaceutically acceptable salts
include those derived from pharmaceutically acceptable inorganic or
organic bases and acids. Suitable salts include those derived from
alkali metals such as potassium and sodium, alkaline earth metals
such as calcium, magnesium and ammonium salts, among numerous other
acids well known in the pharmaceutical art. Sodium and potassium
salts are particularly preferred as neutralization salts of
carboxylic acids and free acid phosphate containing compositions
according to the present invention. The term "salt" shall mean any
salt consistent with the use of the compounds according to the
present invention. In the case where the compounds are used in
pharmaceutical indications, including the treatment of neoplasia,
including cancer, the term "salt" shall mean a pharmaceutically
acceptable salt, consistent with the use of the compounds as
pharmaceutical agents.
[0084] The term "inhibitory effective concentration" or "inhibitory
effective amount" is used throughout the specification to describe
concentrations or amounts of compounds according to the present
invention which substantially or significantly inhibit the growth
or replication of susceptible viruses, especially including human
immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2), human T-cell
leukemia viruses 1 and 2 (HTLV-1 and HTLV-2), respiratory syncytial
virus (RSV), human papilloma virus (HPV), adenovirus, hepatitis B
virus (HBV), hepatitis C virus (HCV), Epstein-Barr virus (EBV),
varicella zoster virus (VZV), cytomegalovirus (CMV), herpes simplex
viruses 1 and 2 (HSV-1 and HSV-2), human herpes virus 8 (HHV-8,
also known as Kaposi's sarcoma-associated virus) and flaviviruses,
including Yellow Fever virus, Dengue virus, Japanese Encephalitis
and West Nile viruses, among numerous others.
[0085] The terms "an effective amount", "therapeutic effective
amount", or "therapeutically effective amount" shall mean an amount
or concentration of a compound according to the present invention
which is effective within the context of its administration or use,
including, for example, the treatment or prevention of viral
infections. Thus, the term "effective amount" is used throughout
the specification to describe concentrations or amounts of
compounds according to the present invention which may be used to
produce a favorable change in the disease or condition treated,
whether that change is a remission, a decrease in growth or size of
cancer or a tumor, a favorable physiological result, a reduction in
the growth or elaboration of a microbe, or the like, depending upon
the disease or condition treated.
[0086] The term "preventing effective amount" is used throughout
the specification to describe concentrations or amounts of
compounds according to the present invention which are
prophylactically effective in preventing, reducing the likelihood
of infection or delaying the onset of infections in patients caused
by human immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2), human
T-cell leukemia viruses 1 and 2 (HTLV-1 and HTLV-2), respiratory
syncytial virus (RSV), human papilloma virus (HPV), adenovirus,
hepatitis B virus (HBV), hepatitis C virus (HCV), Epstein-Barr
virus (EBV), varicella zoster virus (VZV), cytomegalovirus (CMV),
herpes simplex viruses 1 and 2 (HSV-1 and HSV-2), human herpes
virus 8 (HHV-8, also known as Kaposi's sarcoma-associated virus)
and flaviviruses, including Yellow Fever virus, Dengue virus,
Japanese Encephalitis and West Nile viruses, among numerous
others.
[0087] The term "coadministration" or "combination therapy" is used
to describe a therapy in which at least two active compounds in
effective amounts are used to treat a viral or fungal infection at
the same time. Although the term coadministration preferably
includes the administration of two active compounds to the patient
at the same time, it is not necessary that the compounds be
administered to the patient at the same time, although effective
amounts of the individual compounds will be present in the patient
at the same time.
[0088] The term "organic solvent" includes but not is limited to
1,2-dichloroethane, dimethoxyethane, diethylene glycol dimethyl
ether, tetrahydrofuran, dioxane or diisopropyl ether, hydrocarbons
such as hexane, heptane, cyclohexane, toluene or xylene, alcohols
such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol,
2-butanol, tert-butanol or ethylene glycol, ketones such as methyl
ethyl ketone or isobutyl methyl ketone, amides such as
dimethylformamide, dimethylacetamide or N-methylpyrrolidone,
dimethoxyethane, tetrahydrofuran, dioxane, cyclohexane, toluene,
xylene, alcohols, e.g. ethanol, 1-propanol, 2-propanol, 1-butanol,
tert-butanol and mixtures thereof. 1,2-Dichloroethane is a
preferred organic solvent.
[0089] "Lewis acids" include but are not limited to trimethylsilyl
trifluoromethanesulfonate (TMSOTf), titanium chloride, tin
chloride, zinc chloride, zinc bromide, zinc iodide, magnesium
chloride, titanium alkoxide, boron bromide, boron chloride, boron
fluoride, boron trifluoride-diethyl ether complex, aluminum
chloride, aluminum bromide, thionyl chloride, phosphorus
oxychloride, phosphorus chloride, trimethylsilyl chloride, and
trimethylsilyl iodide. TMSOTf is a preferred Lewis acid.
[0090] Compounds according to the present invention may be used in
pharmaceutical compositions having biological/pharmacological
activity for the treatment of, for example, neoplasia, including
cancer, as well as a number of other conditions and/or disease
states, as intermediates in the synthesis of compounds exhibiting
biological activity as well as standards for determining the
biological activity of the present compounds as well as other
biologically active compounds. In some applications, the present
compounds may be used for treating microbial infections, especially
including viral infections. These compositions comprise an
effective amount of any one or more of the compounds disclosed
hereinabove, optionally in combination with a pharmaceutically
acceptable additive, carrier or excipient.
[0091] A further aspect of the present invention relates to the
treatment of neoplasia, including cancer, comprising administering
to a patient in need thereof an effective amount of a compound as
described hereinabove, optionally in combination with a
pharmaceutically acceptable additive, carrier or excipient. The
present invention also relates to methods for inhibiting the growth
of neoplasia, including a malignant tumor or cancer comprising
exposing the neoplasia to an inhibitory or therapeutically
effective amount or concentration of at least one of the disclosed
compounds. This method may be used therapeutically, in the
treatment of neoplasia, including cancer or in comparison tests
such as assays for determining the activities of related analogs as
well as for determining the susceptibility of a patient's cancer to
one or more of the compounds according to the present invention.
Primary utility resides in the treatment of neoplasia, including
cancer, especially including lung cancer, breast cancer and
prostate cancer, among others.
[0092] A preferred therapeutic aspect according to the present
invention relates to methods for treating neoplasia, including
benign and malignant tumors and cancer in animal or human patients,
and in preferred embodiments, cancers which have developed drug
resistance, including, for example, multiple drug resistant breast
cancer comprising administering therapeutically effective amounts
or concentrations of one or more of the compounds according to the
present invention to inhibit the growth or spread of or to actually
shrink the neoplasm in the animal or human patient being
treated.
[0093] Cancers which may be treated using compositions according to
the present invention include, for example, stomach, colon, rectal,
liver, pancreatic, lung, breast, cervix uteri, corpus uteri, ovary,
prostate, testis, bladder, renal, brain/cns, head and neck, throat,
Hodgkins disease, non-Hodgkins leukemia, multiple myeloma
leukemias, skin melanoma, acute lymphocytic leukemia, acute
mylogenous leukemia, Ewings Sarcoma, small cell lung cancer,
choriocarcinoma, rhabdomyosarcoma, Wilms Tumor, neuroblastoma,
hairy cell leukemia, mouth/pharynx, oesophagus, larynx, melanoma,
kidney and lymphoma, among others. Compounds according to the
present invention are particularly useful in the treatment of lung
cancer, breast cancer and prostate cancer.
[0094] In the present methods, in certain preferred embodiments, it
has been found advantageous to coadminister at least one additional
anti-neoplastia agent for the treatment of neoplasia, including
cancer. In these aspects according to the present invention, an
effective amount of one or more of the compounds according to the
present invention is co-administered along with an effective amount
of at least one additional antineoplastia/anticancer agent such as,
for example cyclophosphamide.
[0095] The compositions of the present invention may be formulated
in a conventional manner using one or more pharmaceutically
acceptable carriers. Pharmaceutically acceptable carriers that may
be used in these pharmaceutical compositions include, but are not
limited to, ion exchangers, alumina, aluminum stearate, lecithin,
serum proteins, such as human serum albumin, buffer substances such
as phosphates, glycine, sorbic acid, potassium sorbate, partial
glyceride mixtures of saturated vegetable fatty acids, water, salts
or electrolytes, such as prolamine sulfate, disodium hydrogen
phosphate, potassium hydrogen phosphate, sodium chloride, zinc
salts, colloidal silica, magnesium trisilicate, polyvinyl
pyrrolidone, cellulose-based substances, polyethylene glycol,
sodium carboxymethylcellulose, polyacrylates, waxes,
polyethylene-polyoxypropylene-block polymers, polyethylene glycol
and wool fat.
[0096] The compositions of the present invention may be
administered orally, parenterally, by inhalation spray, topically,
rectally, nasally, buccally, vaginally or via an implanted
reservoir. The term "parenteral" as used herein includes
subcutaneous, intravenous, intramuscular, intra-articular,
intra-synovial, intrasternal, intrathecal, intrahepatic,
intralesional and intracranial injection or infusion techniques.
Preferably, the compositions are administered orally,
intraperitoneally, or intravenously.
[0097] Sterile injectable forms of the compositions of this
invention may be aqueous or oleaginous suspension. These
suspensions may be formulated according to techniques known in the
art using suitable dispersing or wetting agents and suspending
agents. The sterile injectable preparation may also be a sterile
injectable solution or suspension in a non-toxic
parenterally-acceptable diluent or solvent, for example as a
solution in 1,3-butanediol. Among the acceptable vehicles and
solvents that may be employed are water, Ringer's solution and
isotonic sodium chloride solution. In addition, sterile, fixed oils
are conventionally employed as a solvent or suspending medium. For
this purpose, any bland fixed oil may be employed including
synthetic mono- or di-glycerides. Fatty acids, such as oleic acid
and its glyceride derivatives are useful in the preparation of
injectables, as are natural pharmaceutically-acceptable oils, such
as olive oil or castor oil, especially in their polyoxyethylated
versions. These oil solutions or suspensions may also contain a
long-chain alcohol diluent or dispersant, such as Ph. Helv or
similar alcohol.
[0098] The pharmaceutical compositions of this invention may be
orally administered in any orally acceptable dosage form including,
but not limited to, capsules, tablets, aqueous suspensions or
solutions. In the case of tablets for oral use, carriers which are
commonly used include lactose and corn starch. Lubricating agents,
such as magnesium stearate, are also typically added. For oral
administration in a capsule form, useful diluents include lactose
and dried corn starch. When aqueous suspensions are required for
oral use, the active ingredient is combined with emulsifying and
suspending agents. If desired, certain sweetening, flavoring or
coloring agents may also be added.
[0099] Alternatively, the pharmaceutical compositions of this
invention may be administered in the form of suppositories for
rectal administration. These can be prepared by mixing the agent
with a suitable non-irritating excipient which is solid at room
temperature but liquid at rectal temperature and therefore will
melt in the rectum to release the drug. Such materials include
cocoa butter, beeswax and polyethylene glycols.
[0100] The pharmaceutical compositions of this invention may also
be administered topically, especially when the target of treatment
includes areas or organs readily accessible by topical application,
including diseases of the eye, the skin, or the lower intestinal
tract. Suitable topical formulations are readily prepared for each
of these areas or organs.
[0101] Topical application for the lower intestinal tract can be
effected in a rectal suppository formulation (see above) or in a
suitable enema formulation. Topically-transdermal patches may also
be used.
[0102] For topical applications, the pharmaceutical compositions
may be formulated in a suitable ointment containing the active
component suspended or dissolved in one or more carriers. Carriers
for topical administration of the compounds of this invention
include, but are not limited to, mineral oil, liquid petrolatum,
white petrolatum, propylene glycol, polyoxyethylene,
polyoxypropylene compound, emulsifying wax and water.
Alternatively, the pharmaceutical compositions can be formulated in
a suitable lotion or cream containing the active components
suspended or dissolved in one or more pharmaceutically acceptable
carriers. Suitable carriers include, but are not limited to,
mineral oil, sorbitan monostearate, polysorbate 60, cetyl esters
wax, cetearyl alcohol, 2-octyldodecanol, benzyl alcohol and
water.
[0103] For ophthalmic use, the pharmaceutical compositions may be
formulated as micronized suspensions in isotonic, pH adjusted
sterile saline, or, preferably, as solutions in isotonic, pH
adjusted sterile saline, either with or without a preservative such
as benzylalkonium chloride. Alternatively, for ophthalmic uses, the
pharmaceutical compositions may be formulated in an ointment such
as petrolatum.
[0104] The pharmaceutical compositions of this invention may also
be administered by nasal aerosol or inhalation. Such compositions
are prepared according to techniques well-known in the art of
pharmaceutical formulation and may be prepared as solutions in
saline, employing benzyl alcohol or other suitable preservatives,
absorption promoters to enhance bioavailability, fluorocarbons,
and/or other conventional solubilizing or dispersing agents.
[0105] The amount of novel nucleoside of the instant invention that
may be combined with the carrier materials to produce a single
dosage form will vary depending upon the host treated, the
particular mode of administration. Preferably, the compositions
should be formulated so that a dosage of between about 20 and 80
mg/m.sup.2/day of the novel nucleoside can be administered to a
patient receiving these compositions.
[0106] It should also be understood that a specific dosage and
treatment regimen for any particular patient will depend upon a
variety of factors, including the activity of the specific compound
employed, the age, body weight, general health, sex, diet, time of
administration, rate of excretion, drug combination, and the
judgment of the treating physician and the severity of the
particular disease or condition being treated.
[0107] Chemistry
[0108] The novel compounds of the instant invention were generally
prepared in the following manner.
[0109] Referring to FIG. 1, Scheme 1, halogen-substituted
4-aminopyridines useful as intermediates in making the novel
nucleosides of the instant invention were synthesized as follows.
Treatment of commercially available 3-chlorotetrafluoropyridine (1)
and 3,5-dichlorotrifluoropyridi- ne (4) with ammonium hydroxide at
room temperature gave almost quantitatively
4-amino-3-chloro-2,5,6-trifluoropyridine (2) and
4-amino-3,5-dichloro-2,6-difluoropyridine (5), respectively.
Chambers, R. D.; Hutchinson, J.; Musgrave, W. K R. J. Chem. Soc.
1964, 5634-5640. Catalytic hydrogenation of 2 afforded
4-amino-2,3,6-trifluoropyridine (3) in high yield. Catalytic
hydrogenation of 5 was reported to give
4-amino-2,6-difluoropyridine (7); McNamara, D. J.; Cook, P. D. J.
Med. Chem. 1987 30, 340-347; however, when the reaction was stopped
at an early stage, a mixture of
4-amino-3-chloro-2,6-difluoropyridine (6) and 7 were produced,
which was easily separated by flash silica gel column
chromatography.
[0110] 2-Chloro-5-fluoropyridine (9), a highly volatile substance,
was synthesized from thermolysis of 2-chloro-5-pyridinediazonium
tetrafluoroborate (8). Hand, E. S.; Baker, D. C. Synthesis 1989,
905-908. The isolation of 9 by the literature procedure was very
complicated, in that it included repeated extractions, repeated
distillations, treatment with sulfuric acid and sodium hydroxide,
and steam distillation. In our hands, the reported yield of 70% was
difficult to obtain after these operations. To improve upon these
complicated procedures, following the thermolysis of compound 8,
the reaction mixture was directly treated with 50% hydrogen
peroxide and trifluoroacetic acid to give
2-chloro-5-fluoropyridine-N-oxide (10), which was easily isolated,
with a total yield of 73%. Nitration of 10, followed by catalytic
hydrogenation of the resulting
2-chloro-5-fluoro-4-nitropyridine-1-oxide (11) removed the N-oxide
function, as well as reduced the nitro group to give the desired
4-amino-2-chloro-5-fluoropyridine (12). N-Oxidation of commercially
available 2,5-dichloropyridine (13), followed by nitration and
reduction yielded 4-amino-2,5-dichloropyridine (16).
[0111] Various halogen-substituted imidazo[4,5-c]pyridines (32-36)
were synthesized from the corresponding halogen-substituted
4-pyridinamines for the synthesis of
4,6-dichloroimidazo[4,5-c]pyridine, in accordance with Scheme 2
illustrated in FIG. 2. This scheme is a variation of that used in
Rousseau, R. J.; Robins, R. J. J. Heterocycl. Chem. 1965 2,
196-201. Nitration of compounds 3, 6, 7, 12 and 16 with potassium
nitrate in sulfuric acid gave the respective 4-nitraminopyridines
(17-21). Rearrangement of compounds 17-21 in concentrated sulfuric
acid produced the respective 4-amino-3-nitropyridine derivatives
22-26. Catalytic hydrogenation of 22-26 in the presence of Raney
nickel afforded the corresponding 3,4-diaminopyridine derivatives
27-31. Ring closure of compounds 27-31 by reaction with
diethoxymethyl acetate gave the desired halogen-substituted
imidazo[4,5c]pyridines 32-36, Kroon, C.; van den Brink, A. M.;
Vlietstra, E. J.; Salernink, C. A. Rec. Trav. Chim. 1976 95,
127-156 and N-1 substituted compounds 32a-36a which were separated
by silica gel column chromatography; these by-products were easily
converted back to compounds 32-36 by reaction with trimethylsilyl
trifluoromethanesulfonate. The synthesis of
4,6-difluoroimidazo[4,5-c]pyr- idine (34) has been previous
reported by a different synthetic route; however, this method was
rather lengthy and the overall yield was quite low. Kroon, C.; van
den Brink, A. M.; Vlietstra, E. J.; Salernink, C. A. Rec. Trav.
Chim. 1976 95, 127-156.
[0112] Treatment of 4,6-difluoroimidazo[4,5-c]pyridine (34) with
excess hexamethyldisilazane and a catalytic amount of ammonium
sulfate gave the trimethylsilyl derivative, which was treated with
1-O-acetyl-2,3,5-tri-O-- benzoyl-.beta.-D-ribofuranose in
1,2-dichloroethane using trimethylsilyl trifluoromethanesulfonate
(TMSOTf) as a catalyst at room temperature to give the
tribenzoyl-protected nucleoside derivative 37 as illustrated in
Scheme 3 shown in FIG. 3. Treatment of 37 with either saturated
ethanolic ammonia or 40% methylamine removed the protecting groups
and displaced the 4-fluoro group in one step to produce the
respective target nucleosides 38 and 39. Refluxing of silylated 34
with 2,3,5-tri-O-benzyl-1-O-(4-nitro-benzoyl)-D-arabinofuranose in
1,2-dichloroethane in the presence of TMSOTf under nitrogen
afforded a mixture of .alpha.- and .beta.-nucleosides 40. Treatment
of 40 with ammonia saturated ethanol gave the
4-amino-6-fluoro-1-(2,3,5-tri-O-benzyl-
-.beta.-D-arabinofuranosyl)imidazo[4,5-c]pyridine (41) and its a
analogue 42, which were separated by silica gel chromatography.
Debenzylation of 41 and 42 with palladium (II) oxide hydrate and
cyclohexene in ethanol afforded the target compound 43 and its a
analogue 44.
[0113] The assignment of the anomeric configurations of these
nucleosides (41-44) was made on the basis of the characteristics of
the proton NMR spectra in Table 1. The 4'-H protons of the a
anomers appear at a lower field than those of the .beta. anomers.
Conversely, the 5'-H protons of the .alpha.-anomers appear at a
higher field than those of the O-anomers. These shifts are
attributed to the fact that protons at the syn-position relative to
the base are more deshielded than those in the anti-position
relative to the base. The 4'-H protons of the .alpha.-anomers and
the bases are on the same side of the sugar ring and those of
.beta.-anomers are on the opposite side. In contrast, the 5'-H
protons of the .alpha.-anomers and the bases are on the opposite
side of the sugar ring and those of .beta.-anomers are on the same
side. The findings are consistent with reports by others with both
pyrimidine and purine nucleosides. Okabe, M.; Sun, R. C.; Tam, S.
Y. K; Todaro, L. J.; Coffen, D. L. J. Org. Chem., 1988 53,
47804786. Chu, C. K.; Ullas, G. V.; Jeong, L. S.; Ahn, S. K;
Doboszewski, B.; Lin, Z. X.; Beach, J. W.; Schinazi, R. F. J. Med.
Chem. 1990 33, 1553-1561. Tiwari, K. N.; Montgomery, J. A.;
Secrist, J. A., III Nucleosides & Nucleotides 1993 12,
841-846.
1TABLE 1 Proton NMR chemical shifts .delta. (ppm) Compd 4'-H.sup.a
.DELTA. .delta. 5'-H.sup.a .DELTA. .delta. 41 (.beta.).sup.b 4.10
(anti) 0.15 3.70 (syn) 0.12 42 (.alpha.).sup.b 4.25 (syn) 3.58
(anti) 43 (.beta.).sup.c 3.73 (anti) 0.29 3.65 (syn) 0.13 44
(.alpha.).sup.c 4.02 (syn) 3.52 (anti) .sup.aStereochemistry
relative to the base. .sup.bSpectra were recorded in CDCl.sub.3;
.sup.cin DMSO-d.sub.6.
[0114] The synthesis of 3-halogen-substituted 3-deazaadenosine
analogues 51 and 52 is shown in Scheme 4 illustrated in FIG. 4.
Condensation of silylated 4-chloro-7-fluoroimidazo[4,5-c]pyridine
(35) and silylated 4,7-dichloroimidazo[4,5-c]pyridine (36) with
1-O-acetyl-2,3,5-tri-O-benzo- yl-.beta.-D-ribofuranose in
1,2-dichloroethane in the presence of TMSOTf gave the
3-deaza-3-halogen-substituted purine nucleosides 45 and 46,
respectively. Deblocking of 45 and 46 with sodium methoxide in
methanol yielded the corresponding nucleoside derivatives 47 and
48. Attempts at conversion of the 4-chloro substituents on 45 and
46 to the corresponding amino functions by either ammonia saturated
ethanol or liquid ammonia at various temperatures were unsuccessful
and resulted in either a decomposed by-product or recovery of the
starting material. However, treatment of 47 and 48 with anhydrous
hydrazine, Secrist, J. A., III; Comber, R. N.; Gray, R. J.; Gilroy,
R. B.; Montgomery, J. A. J. Med. Chem. 1993 36, 2102-2106, followed
by catalytic hydrogenation of compounds 49 and 50 with Raney nickel
furnished 51 and 52.
[0115] The synthesis of 2,3-dihalogen-substituted 3-deazaadenosine
analogues 5740 is depicted in Scheme 5 shown in FIG. 5.
Condensation of silylated 4,6,7-trifluoroimidazo[4,5-c]pyridine
(32) and silylated 7-chloro-4,6-difluoroimidazo[4,5-c]pyridine (33)
with 1-O-acetyl-2,3,5-tri-O-benzoyl-.beta.-D-ribofuranose in
1,2-dichloroethane in the presence of TMSOTf gave the corresponding
protected 1-ribosides 53 and 55, and 3-ribosides 54 and 56.
Treatment of compounds 53-56, with ammonia saturated ethanol
afforded the respective target compounds 57-60. The assignment of
the N-glycosidic linkage of the N.sup.1- and N.sup.3-isomers of
compounds 57-60 was based upon the UV spectra of these derivatives.
The UV spectra of the N.sup.1-3-deazapurine nucleoside isomers
showed a maximum peak at 274 nm (57 and 59), while the
N.sup.3-isomers showed a maximum peak at 292 nm (58 and 60).
Furthermore, the NMR spectra of the 2-H protons of the
N.sup.3-isomers were downfield from those of the corresponding
N.sup.1-isomers. For example, the chemical shifts of the 2-H
protons of the N.sup.3-isomers 58 and 60 appeared at 8.54 and 8.55
ppm and for the N.sup.1-isomers 57 and 59 at 8.43 and 8.51 ppm,
respectively. These results are similar to those obtained with
other 3-deazapurine nucleosides. Montgomery, J. A.; Shortnacy, A.
T.; Clayton, S. D. J. Heterocycl. Chem. 1977 14, 195-197. Poonian,
M. S.; McComas, W. W. J. Med. Chem. 1979 22, 958-962.
[0116] The synthesis of 3-deaza-3-halogen-substituted
3-deazaguanosine analogues is illustrated in Scheme 6 shown in FIG.
6. Halogenation of 3-deazaguanosine, which was synthesized by a
known procedure with N-chlorosuccinimide in water and
bromine-water, respectively, gave the corresponding
3-deaza-3-chloroguanosine (61) and 3-deaza-3-bromoguanosine (62).
Revankar, G. R.; Gupta, P. K.; Adams, A. D.; Dalley, N. K.;
McKernan, P. A.; Cook, P. D.; Canonico, P. G.; Robins, R. K. J.
Med. Chem., 1984 27, 1389-1396; Cook, P. D.; Rousseau, R. J.; Mian,
A. M.; Dea, P.; Meyer, R. B., Jr.; Robins, R. K. J. Amer. Chem.
Soc. 1976 98, 1492-1498.
[0117] Biology
[0118] The synthesized compounds were evaluated in vitro for their
cytotoxicity against the L1210 and P388 leukemias, the CCRF-CEM
lymphoblastic leukemia, and the B.sub.16F.sub.10 melanoma cell
lines and the results are shown in Table 2. Among these compounds,
3-deaza-3-chloroguanosine (61) showed activity with IC.sub.50
values of 12, 40, 30 and 35 .mu.M and 3-deaza-3-bromoguanosine (62)
produced IC.sub.50 values of 3, 7, 9 and 7 .mu.M against L1210,
P388, CCRF-CEM and B.sub.16F.sub.10 cells, respectively. The
halogen-substituted 3-deazaadenosine derivatives 38, 51, 57 and 59
showed moderate to weak activities, and the other compounds had
only slight or no activity in concentrations up to 100 .mu.M
against these neoplastic cell lines.
[0119] Antiviral assays were performed against hepatitis B virus
(HBV) and human immunodeficiency virus (HIV-IIIB) in vitro as
previously described. Lin, T. S.; Luo, M. Z.; Liu, M. C.; Pai, S.
B.; Dutschman, G. E.; Cheng, Y. C., J. Med. Chem. 1994 37, 798-803.
Among these compounds, 3-deaza-3-chloro-2-fluoroadenosine (59),
3-deaza-3-fluoroadenosine (51) and
4-amino-6,7-difluoro-3-(.beta.-D-ribfuranosyl)imidazo[4,5c]pyridine
(58) showed moderate activity against HBV with EC.sub.50 values of
7.5, 9.2 and 10 .mu.M, respectively. The remaining compounds showed
little or no activity against HBV and HIV-IIIB up to their maximum
tested concentrations of 10 and 100 .mu.M, respectively.
2TABLE 2 Evaluation of the cytotoxicity of halogen-substituted
3-deazaadenosine and 3-deazaguanosine analogues against L1210,
P388, CCRF-CEM, and B.sub.16F.sub.10 cell lines in vitro IC.sub.50
(.mu.M).sup.a Compd L1210 P388 CCRF-CEM B.sub.16F.sub.10 38 35 50
100 40 39 >100 >100 100 >100 43 >100 >100 >100
>100 44 >100 >100 >100 >100 51 15 100 60 45 52
>100 >100 >100 >100 57 90 90 40 100 58 >100 >100
>100 >100 59 55 90 60 100 60 >100 >100 >100 >100
61 12 40 30 35 62 3 7 9 7 .sup.aIC.sub.50 values represent the drug
concentration (.mu.M) required to inhibit cancer cell replication
by 50%. The compounds were tested up to a concentration of 100
.mu.M.
[0120] The invention is described further in the following
examples, which are illustrative only and are in no way
limiting.
EXAMPLE 1
[0121] The following examples describe syntheses employed in making
the compounds of the instant invention in accordance with the
aforementioned Schemes 1 through 6 illustrated in FIGS. 1 through
6.
[0122] Experimental Section
[0123] Melting points for each of the examples described
hereinafter were determined with a Thomas-Hoover Unimelt apparatus
and are uncorrected. .sup.1H NMR spectra were recorded on a Varian
EM-390 (90 MHz) or Gemini-300 (300 MHz) NMR spectrometer with
Me.sub.4Si as the internal reference. The UV spectra were recorded
on a Beckman-25 spectrophotometer. Mass spectra were recorded on a
VG-ZAB-SE mass spectrometer in the fast bombardment (FAB) mode
(glycerol matrix). Column chromatography was conducted with Merck
silica gel 60, 230-400 mesh. TLC was performed on EM precoated
silica gel sheets containing a fluorescent indicator. Elemental
analyses were carried out by the Baron Consulting Co., Orange,
Conn., USA.
EXAMPLE 2
[0124] Scheme 1
[0125] 4-Amino-3-chloro-2,5,6-trifluoropyridine (2). This compound
was prepared by a modification of the procedure of Chambers et al.,
J. Chem. Soc. 1964, 5634-5640. A mixture of
3-chloro-2,4,5,6-tetrafluoropyridine (1, 37.4 g, 201 mmol) and 150
mL of 28% ammonium hydroxide was stirred at room temperature for 5
h. The resulting white crystals were collected and carefully washed
with ice water to give 2 as a white solid (35 g). The combined
filtrate and washings were extracted with ether. The ether extract
was dried (MgSO.sub.4), filtered and evaporated in vacuo to give
additional 2 (1.3 g); total yield: 26.3 g (99%). The product was
used directly for the next step in the reaction. A small sample was
purified by silica gel column chromatography: mp 118-120.degree. C.
(Lit., Chambers et al., J. Chem. Soc. 1964, 5634-5640, mp
117-118.degree. C.).
[0126] 4-Amino-3,5-dichloro-2,6-difluoropyridine (5). This compound
was prepared from 3,5-dichloro-2,4,6-trifluoropyridine (24.5 g) by
a procedure similar to that described for compound 2: yield, 23.7 g
(98%); mp 110.degree. C. (Lit., Chambers et al., J. Chem. Soc.
1964, 5634-5640 mp 112-113.degree. C.).
[0127] 4-Amino-2,3,6-trifluoropyridine (3). A suspension of
4-amino-3-chloro-2,5,6-trifluoropyridine (2, 19.7 g, 108 mmol), 10%
Pd/C (1.8 g) and triethylamine (20 mL, 140 mmol) in 150 mL of
anhydrous ethanol was hydrogenated at 50 psi in a Parr
hydrogenation apparatus until TLC showed the reaction was completed
(about 18 hours). The catalyst was removed by filtration and
carefully washed with ethanol. The combined filtrate and washings
were evaporated to dryness in vacuo. The residue was stirred with
80 mL of water for 1 h, filtered, and washed with water to give 3
(14 g) as a white solid. The filtrate and washings were combined
and extracted with ether. The combined ether layers were then dried
(MgSO.sub.4) and concentrated to give an additional 1.3 g of 3
(total yield: 15.3 g, 96%). A small analytical sample was purified
by silica gel column chromatography (R.sub.f 0.47,
CH.sub.2Cl.sub.2): mp 94-96.degree. C.; .sup.1H NMR (CDCl.sub.3)
.delta. 4.78 (br s, 2H, 4-NH.sub.2, D.sub.2O exchangeable), 6.20
(d, 1H, 5-H). Analysis calculated for C.sub.5H.sub.3F.sub.3N.sub.2:
C, 40.55; H, 2.04; N, 18.92. Found: C, 40.60; H, 2.16; N,
18.67.
[0128] 4-Amino-3-chloro-2,6-difluoropyridine (6) and
4-amino-2,6-difluoropyridine (7). A suspension of 19.9 g (100 mmol)
of 5, 2.2 g of 10% Pd/C and 27 mL (190 mmol) of triethylamine in
100 mL of anhydrous ethanol was hydrogenated at 50 psi in a Parr
hydrogenation apparatus overnight (about 18 h). The catalyst was
filtered and carefully washed with ethanol. The combined filtrate
and washings were evaporated to dryness in vacuo. The residue was
partitioned between ether and water, and the water layer was
extracted with ether. The combined ether layers were dried
(MgSO.sub.4) and concentrated to dryness. The residue was dissolved
in ethanol and the solution was treated with 50 g of silica gel.
The solvent was removed in vacuo to give a powder, which was
purified by silica gel column chromatography, eluted with
CH.sub.2Cl.sub.2 to afford 9.4 g (57%) of 6 and 4.3 g (33%) of
7.
[0129] Compound 6 was isolated as a white solid: mp 84-85.degree.
C.; TLC, R.sub.f 0.55 (CH.sub.2Cl.sub.2); .sup.1H NMR (CDCl.sub.3)
.delta. 5.15 (br s, 2H, NH.sub.2, D.sub.2O exchangeable), 6.20 (s,
1H, 5-H). Analysis calculated for C.sub.5H.sub.3ClF.sub.2N.sub.2:
C, 36.49; H, 1.84; N, 17.02. Found: C, 36.78; H, 2.09; N,
16.89.
[0130] Compound 7 was isolated as a white solid: mp 126-128.degree.
C. (Lit., Secrist, et al., J. Med. Chem. 1988 31, 405-410 mp
125-127.degree. C.); TLC, R.sub.f 0.37 (CH.sub.2Cl.sub.2); .sup.1H
NMR (DMSO-d.sub.6) .delta. 6.00 (s, 2H, 3- and 5-H), 6.70 (br s,
2H, NH.sub.2, D.sub.2O exchangeable). Analysis calculated for
C.sub.5H.sub.4F.sub.2N.sub.2: C, 46.16; H, 3.10; N, 21.54. Found:
C, 46.01; H, 3.39; N, 21.29.
[0131] 2-Chloro-5-fluoropyridine-1-oxide (10). Hand, E. S.; Baker,
D. C. Synthesis 1989, 905-908. A suspension of
2-chloro-5-pyridinediazonium tetrafluoroborate (8, 7.6 g, 33.4
mmol) in dry heptane (50 mL) was heated to 105.degree. C. (oil bath
temperature) for 2 h. A rapid evolution of nitrogen was observed
after 10-15 min, which lasted for about 30 min. The reaction
mixture formed two layers: the clear upper heptane layer and the
blackened dark lower layer. The temperature was then lowered to
70.degree. C., and 100 mL of trifluoroacetic acid and 11 mL of 50%
hydrogen peroxide were subsequently added from the top of the
condenser. The reaction mixture was stirred at 70-75.degree. C.
until TLC showed that the reaction was complete (around 20 hours).
The lower dark layer gradually changed to a clear orange solution
during the reaction process. The two-layer mixture was evaporated
to dryness in vacuo and co-evaporated with toluene (50 mL). To the
residue were added 20 mL of water and 100 mL of methylene chloride,
and the mixture was neutralized by dropwise addition of 28%
ammonium hydroxide solution with stirring. The aqueous layer was
further extracted with methylene chloride and the combined organic
layer was dried, filtered and evaporated to give the crude product,
which was purified by silica gel column chromatography
(CH.sub.2Cl.sub.2/EtOAc, 1:1, v/v, R.sub.f 0.23) to give 3.6 g
(73%) of product as a white solid: mp 98-100.degree. C.; .sup.1H
NMR (CDCl.sub.3) .delta. 7.15 (m, 1H, 3-H), 7.60 (m, 1H, 4-H), 8.40
(dd, 1H, 6-H, J=2.0 Hz, 8.5 Hz). Analaysis calculated for
C.sub.5H.sub.3ClFNO.0.5H.sub.2O: C, 38.36; H, 2.56; N, 8.95. Found:
C, 38.13; H, 2.19; N, 8.65.
[0132] 2-Chloro-5-fluoro-4-nitropyridine-1-oxide (11).
2-Chloro-5-fluoropyridine-N-oxide (10, 3.5 g, 23.7 mmol) was
gradually added to 46 mL of concentrated sulfuric acid, followed by
10 g of potassium nitrate with stirring. The reaction mixture was
heated at 120.degree. C. for 2 h, cooled and poured onto 160 g of
crushed ice. The solution was neutralized by dropwise addition of
28% ammonium hydroxide with stirring, while the temperature was
maintained below 15.degree. C. with an ice bath. The light yellow
crystals which precipitated were collected by filtration, washed
with ice water, and dried to yield 2.7 g (59%) of product. A small
sample was purified by silica gel column chromatography
(CH.sub.2Cl.sub.2/EtOAc, 4:1, v/v, R.sub.f 0.71): mp
131-132.degree. C.; .sup.1H NMR (DMSO-d.sub.6) .delta. 8.70 (m, 1H,
3-H), 9.12 (m, 1H, 6-H). Analysis calculated for
C.sub.5H.sub.2ClFN.sub.2O.sub.- 3: C, 31.19; H, 1.05; N, 14.55.
Found: C, 31.36; H, 1.16; N, 14.75
[0133] 4-Amino-2-chloro-5-fluoropyridine (12). A mixture of
2-chloro-5-fluoro-4-nitropyridine-1-oxide (11, 1.3 g, 6.8 mmol) and
1.6 g of Raney nickel in 80 mL of anhydrous ethyl alcohol was
hydrogenated at 40 psi in a Parr hydrogenation apparatus for 3 h
when TLC showed that the starting material had disappeared and a
new spot was detected (CH.sub.2Cl.sub.2/EtOAc, 4:1, v/v, R.sub.f
0.78 and 0.71, for the starting material and the product,
respectively). The catalyst was removed by filtration and washed
carefully with ethyl alcohol. The filtrate and washings were
combined and evaporated in vacuo to give 0.9 g (91%) of product as
an off-white solid. A small analytical sample was purified by
recrystallization from hot water to afford white crystals: mp
110-111.degree. C.; .sup.1H NMR (CDCl.sub.3) .delta. 4.50 (br s,
2H, NH.sub.2, D.sub.2O exchangeable), 7.15 (d, 1H, 3-H, J=6 Hz),
7.95 (d, 1H, 6-H, J=2 Hz). Analysis calculated for
C.sub.5H.sub.4ClFN.sub.2: C, 40.97; H, 2.75; N, 19.12. Found: C,
41.18; H, 2.39; N, 18.89.
[0134] 2,5-Dichloropyridine-1-oxide (14). A mixture of
2,5-dichloropyridine (10 g, 67 mmol), 180 mL of trifluoroacetic
acid and 22 mL of 50% hydrogen peroxide was heated at 70-75.degree.
C. with stirring until TLC showed the reaction to be complete. The
reaction mixture was evaporated to dryness in vacuo and
co-evaporated with water twice. The residue was stirred with 40 mL
of water and 200 mL of methylene chloride and neutralized by
dropwise addition of 28% ammonium hydroxide solution. The aqueous
layer was further extracted with methylene chloride and the
combined organic layer was dried, filtered and evaporated to give
10 g (91%) of product, which was used directly for the next step. A
small sample was purified by silica gel column chromatography
(CH.sub.2Cl.sub.2/EtOAc, 10:1, v/v, R.sub.f 0.24): mp 73-75.degree.
C.; .sup.1H NMR (CDCl.sub.3) .delta. 7.13 (dd, 1H, 4-H, J=10 Hz, 2
Hz), 7.45 (d, 1H, 3-H, J=10 Hz), 8.35 (d, 1H, 6-H, J=2 Hz).
Analysis calculated for C.sub.5H.sub.3Cl.sub.2NO.0.5H.sub.2O: C,
36.62; H, 1.84; N, 8.54. Found: C, 36.43; H, 2.01; N, 8.25.
[0135] Compounds 15 and 16 were synthesized by methodology similar
to that described for compounds 11 and 12, respectively.
[0136] 2,5-Dichloro-4-nitropyridine-1-oxide (15). Compound 15 was
isolated as light yellow crystals (6.5 g, 50.5%): mp
137-139.degree. C.; .sup.1H NMR (DMSO-d.sub.6) 58.70 (s, 1H, 3-H),
9.05 (s, 1H, 6-H). Analysis calculated for
C.sub.5H.sub.2Cl.sub.2N.sub.2O.sub.3: C, 28.73; H, 0.96; N, 13.41.
Found: C, 28.39; H, 1.06; N, 13.55.
[0137] 2,5-Dichloro-4-aminopyridine (16). Compound 16 was isolated
as a white solid (4.0 g, 85%): mp 122-123.degree. C.; .sup.1H NMR
(CDCl.sub.3) .delta. 4.75 (br s, 2H, NH.sub.2, D.sub.2O
exchangeable), 6.63 (s, 1H, 3-H), 8.05 (s, 1H, 6-H). Analysis
calculated for C.sub.5H.sub.4Cl.sub.2N.- sub.2: C, 36.84; H, 2.47;
N, 17.19. Found: C, 36.58; H, 2.30; N, 16.88.
EXAMPLE 3
[0138] Scheme 2
[0139] 4-Nitramino-2,3,6-trifluoropyridine (17).
4-Amino-2,4,6-trifluoropy- ridine (3, 7 g, 47.3 mmol) was carefully
added to 75 mL of concentrated sulfuric acid at 0-5.degree. C.
(ice-bath) with stirring to form a solution. Potassium nitrate
(10.1 g, 100 mmol) was gradually added to the solution during a
period of 20 min while the internal temperature was maintained
below 5.degree. C. The reaction mixture was further stirred at
0-5.degree. C. for 1 h and at room temperature for 15 min, then
poured onto 300 g of crushed ice. The resulting acidic solution was
extracted with methylene chloride. The methylene chloride extracts
were combined, dried, filtered and concentrated to give 8 g (88%)
of product as a yellow solid. It was used directly for the next
step in the reaction without further purification. A small
analytical sample was purified by silica gel chromatography: mp
135-137.degree. C.; .sup.1H NMR (CDCl.sub.3) .delta. 7.55 (d, 1H,
3-H, J=2 Hz), 10.70 (br s, 1H, NH, D.sub.2O exchangeable). Analysis
calculated for C.sub.5H.sub.2F.sub.3N.sub.3O.sub.- 2: C, 31.10; H,
1.04; N, 21.76. Found: C, 31.23; H, 1.23; N, 21.60.
[0140] Compounds 18-21 were synthesized by methodology similar to
that described for compound 17.
3-Chloro-2,6-difluoro-4-nitraminopyridine (18). Compound 18 was
isolated as a light yellow solid (10.7 g, 76.4%): mp
100-102.degree. C.; .sup.1H NMR (CDCl.sub.3) .delta. 7.62 (d, 1H,
5-H, J=2 Hz), 10.48 (br s, 1H, NH, D.sub.2O exchangeable). Analysis
calculated for C.sub.5H.sub.2ClF.sub.2N.sub.3O.sub.2: C, 28.66; H,
0.96; N, 20.05. Found: C, 29.02; H, 1.25; N, 20.40.
[0141] 2,6-Difluoro-4-nitraminopyridine (19). Compound 19 was
isolated as an off-white solid (4.2s g, 76%): mp 140.degree. C.
(dec.); .sup.1H NMR (CDCl.sub.3) .delta. 6.96 (s, 2H, 3- and 5-H),
7.62 (br s, 1H, NH, D.sub.2O exchangeable). Analysis calculated for
C.sub.5H.sub.3F.sub.2N.su- b.3O.sub.2: C, 34.30; H, 1.73; N, 24.00.
Found: C, 34.42; H, 1.85; N, 24.05.
[0142] 2-Chloro-5-fluoro-4-nitraminopyridine (20). Compound 20 was
isolated as a light yellow solid (2.0 g, 83%): mp 160.degree. C.
(dec.); .sup.1H NMR (CDCl.sub.3) .delta. 7.90 (s, 1H, 3-H), 8.32
(d, 1H, 6-H, J=2 Hz), 12.70 (br s, 1H, NH, D.sub.2O exchangeable).
Analysis calculated for C.sub.5H.sub.3ClFN.sub.3O.sub.2: C, 37.17;
H, 3.12; N, 26.01. Found: C, 37.36; H, 3.16; N, 25.75.
[0143] 2,5-Dichloro-4-nitraminopyridine (21). Compound 21 was
isolated as a light yellow solid (1.2 g, 65%): mp 154.degree. C.
(dec.); .sup.1H NMR (DMSO-d.sub.6) .delta. 6.90 (br s, 1H, NH,
D.sub.2O exchangeable), 7.85 (s, 1H, 3-H), 8.45 (s, 1H, 6-H).
Analysis calculated for C.sub.5H.sub.3Cl.sub.2N.sub.3O.sub.2: C,
28.87; H, 1.45; N, 20.20. Found: C, 28.55; H, 1.26; N, 20.45.
[0144] 4-Amino-3-nitro-2,5,6-trifluoropyridine (22).
4-Nitramino-2,3,6-trifluoropyridine (17, 9.3 g, 48 mmol) was
carefully added to 70 mL of concentrated sulfuric acid. The mixture
was stirred at room temperature overnight (18 h), then poured onto
170 g of crushed ice with stirring. The resulting acidic solution
was mixed with 100 mL of methylene chloride and neutralized by
dropwise addition of 28% ammonium hydroxide with stirring while the
internal temperature was maintained below 5.degree. C. in a salted
ice bath. The organic layer was separated and the aqueous layer was
extracted with methylene chloride. The combined organic extracts
were dried, filtered, evaporated in vacuo to dryness and purified
by silica gel column chromatography (CH.sub.2Cl.sub.2/hexane, 1:1,
v/v) to give 3.7 g (40%) of off-white crystals: mp 99-100.degree.
C.; .sup.1H NMR (CDCl.sub.3) .delta. 6.80 (br s, 2H, 4-NH.sub.2,
D.sub.2O exchangeable). Analysis calculated for
C.sub.5H.sub.2F.sub.3N.sub.3O.sub.- 2: C, 31.10; H, 1.04; N, 21.76.
Found: C, 31.01; H, 1.34; N, 21.43.
[0145] Compounds 23-26 were synthesized by a procedure similar to
that described for compound 22.
[0146] 4-Amino-3-chloro-2,6-difluoro-5-nitropyridine (23). Compound
23 was isolated as an off-white solid (4.1 g, 82%): mp
84-85.degree. C.; .sup.1H NMR (CDCl.sub.3) .delta. 6.20 (br s, 2H,
4-NH.sub.2, D.sub.2O exchangeable). Analysis calculated for
C.sub.5H.sub.2ClF.sub.2N.sub.3O.su- b.2: C, 28.66; H, 0.96; N,
20.05. Found: C, 28.99; H, 0.78; N, 19.66.
[0147] 4-Amino-2,6-difluoro-5-nitropyridine (24). Compound 24 was
isolated as an off-white solid (1.7 g, 89%): mp 149-150.degree. C.
(lit..sup.20 147.degree. C.); .sup.1H NMR (DMSO-d.sub.6)
.delta.6.40 (s, 1H, 5-H), 8.20 (br s, 2H, 4-NH.sub.2, D.sub.2O
exchangeable).
[0148] 4-Amino-2-chloro-5-fluoro-3-nitropyridine (25). Compound 25
was isolated as an off-white solid (1.7 g, 90%): mp 154-155.degree.
C.; .sup.1H NMR (CDCl.sub.3) .delta. 6.70 (br s, 2H, 4-NH.sub.2,
D.sub.2O exchangeable), 8.00 (d, 1H, 6-H, J=2 Hz). Analysis
calculated for C.sub.5H.sub.3ClFN.sub.3O.sub.2: C, 31.35; H, 1.58;
N, 21.94. Found: C, 31.55; H, 1.60; N, 21.77.
[0149] 4-Amino-2,5-dichloro-3-nitropyridine (26). Compound 26 was
isolated as an off-white solid (1.8 g, 97%): mp 168-170.degree. C.;
.sup.1H NMR (DMSO-d.sub.6) .delta. 7.45 (br s, 2H, 4-NH.sub.2,
D.sub.2O exchangeable), 8.20 (s, 1H, 6-H). Analysis calculated for
C.sub.5H.sub.3Cl.sub.2N.sub.3O.sub.2: C, 28.87; H, 1.45; N, 20.20.
Found: C, 28.60; H, 1.31; N, 20.02.
[0150] 3,4-Diamino-2,5,6-trifluoropyridine (27). A mixture of
4-amino-3-nitro-2,5,6-trifluoropyridine (22, 1.08 g, 5.6 mmol) and
1.5 g of Raney nickel in 50 mL of anhydrous ethyl alcohol was
hydrogenated at 36 psi in a Parr hydrogenation apparatus for 2 h.
The catalyst was removed by filtration and washed carefully with
ethyl alcohol. The filtrate and washings were combined and
evaporated in vacuo to give 0.9 g (98%) of product as an off-white
solid. A small analytical sample was purified by silica gel
chromatography (CH.sub.2Cl.sub.2/EtOH, 20:1, v/v, R.sub.f 0.48) to
give white crystals: mp 116-117.degree. C.; .sup.1H NMR
(DMSO-d.sub.6) .delta. 3.35 (br s, 2H, NH.sub.2, D.sub.2O
exchangeable), 5.10 (br s, 2H, NH.sub.2, D.sub.2O exchangeable).
Analysis calculated for C.sub.5H.sub.4F.sub.3N.sub.3: C, 36.82; H,
2.47; N, 25.76. Found: C, 37.20; H, 2.59; N, 25.40.
[0151] Compounds 28-31 were synthesized by methodology similar to
that described for compound 27.
[0152] 5-Chloro-3,4-diamino-2,6-difluoropyridine (28). Compound 28
was isolated as a white solid (2.9 g, 92%): mp 178-179.degree. C.;
.sup.1H NMR (DMSO-d.sub.6) .delta. 3.00 (br s, 2H, NH.sub.2,
D.sub.2O exchangeable), 4.80 (br s, 2H, NH.sub.2, D.sub.2O
exchangeable). Analysis calculated for C.sub.5H.sub.4Cl
F.sub.2N.sub.3: C, 33.44; H, 2.24; N, 23.40. Found: C, 33.80; H,
2.45; N, 23.03.
[0153] 3,4-Diamino-2,6-difluoropyridine (29). Compound 29 was
isolated as a white solid (3.3 g, 92%): mp 135-136.degree. C. (lit.
McNamara, D. J.; Cook, P. D. J. Med. Chem. 1987 30, 340-347; mp
132.degree. C.); .sup.1H NMR (DMSO-d.sub.6) .delta. 4.23 (br s, 2H,
NH.sub.2, D.sub.2O exchangeable), 6.05 (s, 1H, 5-H), 6.20 (br s,
2H, NH.sub.2, D.sub.2O exchangeable). Analysis calculated for
C.sub.5H.sub.5F.sub.2N.sub.3: C, 41.38; H, 3.47; N, 28.96. Found:
C, 41.10; H, 3.68; N. 28.64.
[0154] 2-Chloro-3,4-diamino-5-fluoropyridine (30). Compound 30 was
isolated as an off-white solid (1.4 g, 94%): mp 178-179.degree. C.;
.sup.1H NMR (DMSO-d.sub.6) .delta. 4.95 (br s, 2H, NH.sub.2,
D.sub.2O exchangeable), 5.80 (br s, 2H, NH.sub.2, D.sub.2O
exchangeable), 7.42 (d, 1H, 6-H, J=2 Hz). Analysis calculated for
C.sub.5H.sub.5ClFN.sub.3: C, 37.17; H, 3.12; N, 26.01. Found: C,
37.36; H, 3.16; N, 25.75.
[0155] 3,4-Diamino-2,5-dichloropyridine (31). Compound 31 was
isolated as a white solid (1.9 g, 94%): mp 197-199.degree. C.;
.sup.1H NMR (DMSO-d.sub.6) .delta. 5.05 (br s, 2H, NH.sub.2,
D.sub.2O exchangeable), 5.95 (br s, 2H, NH.sub.2, D.sub.2O
exchangeable), 7.45 (s, 1H, 6-H). Analysis calculated for
C.sub.5H.sub.5Cl.sub.2N.sub.3: C, 33.73; H, 2.83; N, 23.60. Found:
C, 33.60; H, 3.11; N, 23.22.
[0156] 4,6,7-Trifluoroimidazo[4,5-c]pyridine (32) and
1-[(1-acetyloxy-1-ethoxy)methyl]-4,6,7-trifluoroissssmidazo[4,5-c]pyridin-
e (32a). A mixture of 3,4-diamino-2,5,6-trifluoropyridine (27, 0.9
g, 5.5 mmol) and 9 mL of diethoxymethyl acetate was heated at
100.degree. C. for 1 h with exclusion of moisture. The reaction
mixture was then evaporated to dryness in vacuo and the residue was
purified on a silica gel column, eluted with
CH.sub.2Cl.sub.2/EtOAc, first (10:1, v/v), then (1:1, v/v) to give
compounds 32 (0.45 g, 47%) and 32a (0.45 g, 28%).
[0157] Compound 32 was isolated as white crystals: TLC, R.sub.f
0.35 (CH.sub.2Cl.sub.2/EtOH, 20:1, v/v); mp 182-184.degree. C.;
.sup.1H NMR (DMSO-d.sub.6) .delta. 8.55 (s, 1H, 2-H), 10.60 (br s,
1H, NH, D.sub.2O exchangeable). Analysis calculated for
C.sub.6H.sub.2F.sub.3N.sub.3: C, 41.90; H, 1.16; N, 24.27. Found:
C, 42.00; H, 1.42; N, 23.87.
[0158] Compound 32a was isolated as a syrup: TLC, R.sub.f 0.77
(CH.sub.2Cl.sub.2/EtOAc, 10:1, v/v); .sup.1H NMR (CDCl.sub.3)
.delta. 1.42 (t, 3H, CH.sub.3), 2.25 (s, 3H, acetyl), 4.20 (m, 2H,
CH.sub.2), 7.62 (s, 1H, CH), 8.45 (d, 1H, 2-H); MS, m/e 290
(M.sup.++1). Compound 32a in methylene chloride (30 mL) was treated
with trimethylsilyl trifluoromethanesulfonate (1 mL). The mixture
was stirred at room temperature overnight, then neutralized with
10% sodium bicarbonate solution and co-evaporated with 5 g of
silica gel. The residue was purified by silica gel column
chromatography to give 0.25 g of 32. The total yield of 32 was 0.7
g (74%).
[0159] Compounds 33-36 were synthesized by methodology similar to
that described for compound 32.
[0160] 7-Chloro-4,6-difluoroimidazo[4,5-c]pyridine (33). Compound
33 was isolated as off-white crystals (2.0 g, 74%): TLC, R.sub.f
0.45 (CH.sub.2Cl.sub.2/EtOH, 20:1, v/v); mp 225-227.degree. C.;
.sup.1H NMR (DMSO-d.sub.6) 58.50 (s, 1H, 2-H), 10.45 (br s, 1H, NH,
D.sub.2O exchangeable). Analysis calculated for
C.sub.6H.sub.2ClF.sub.2N.sub.3: C, 38.02; H, 1.06; N, 22.17. Found:
C, 38.33; H, 1.08; N, 21.84.
[0161]
1-[(1-Acetyloxy-1-ethoxy)methyl]-7-chloro-4,6-difluoroimidazo[4,5-c-
]pyridine (33a). Compound 33a was isolated as a syrup: TLC, R.sub.f
0.77 (CH.sub.2Cl.sub.2/EtOAc, 10:1, v/v); .sup.1H NMR (CDCl.sub.3)
.delta. 1.40 (t, 3H, CH.sub.3), 2.23 (s, 3H, acetyl), 4.18 (m, 2H,
CH.sub.2), 7.58 (s, 1H, CH), 8.42 (d, 1H, 2-H); MS, m/e 307
(M.sup.++1).
[0162] 4,6-Difluoroimidazo[4,5-c]pyridine (34). Compound 34 was
isolated as a white solid (0.96 g, 90%): TLC, R.sub.f 0.35
(CH.sub.2Cl.sub.2/EtOH, 20:1, v/v); mp 170-171.degree. C. (lit.
Kroon, et al, Rec. Trav. Chim. 1976 95, 127-156; 169.degree. C.);
.sup.1H NMR (DMSO-d.sub.6) .delta. 7.15 (t, 1H, 2-H, J=1.5 Hz),
8.40 (s, 1H, 7-H), 12.60 (br s, 1H, NH, D.sub.2O exchangeable).
[0163]
1-[(1-Acetyloxy-1-ethoxy)methyl]-4,6-difluoroimidazo[4,5-c]pyridine
(34a). Compound 34a was isolated as a syrup: TLC, R.sub.f 0.84
(CH.sub.2Cl.sub.2/EtOH, 20:1, v/v); .sup.1H NMR (CDCl.sub.3)
.delta. 1.30 (t, 3H, CH.sub.3), 2.20 (s, 3H, acetyl), 3.90 (q, 2H,
CH.sub.2), 7.05 (d, 1H, 7H, J=2 Hz), 7.32 (s, 1H, CH), 8.21 (d, 1H,
2-H); MS, n/e 272 (M.sup.++1).
[0164] 4-Chloro-7-fluoroimidazo[4,5-c]pyridine (35). Compound 35
was isolated as white crystals (1.11 g, 80%): TLC, R.sub.f 0.19
(CH.sub.2Cl.sub.2/EtOAc, 1:1, v/v); mp 232-234.degree. C.; .sup.1H
NMR (DMSO-d.sub.6) .delta. 8.12 (d, 1H, 6-H, J=2 Hz), 8.56 (s, 1H,
2-H), 13.80 (br s, 1H, NH, D.sub.2O exchangeable). Analysis
calculated for C.sub.6H.sub.3ClFN.sub.3: C, 37.17; H, 3.12; N,
26.01. Found: C, 37.36; H, 3.16; N, 25.75.
[0165]
1-[(1-Acetyloxy-1-ethoxy)methyl]-4-chloro-7-fluoroimidazo[4,5-c]pyr-
idine (35a). Compound 35a was isolated as a syrup: TLC, R.sub.f
0.29 (CH.sub.2Cl.sub.2/EtOAc, 10:1, v/v); .sup.1H NMR (CDCl.sub.3)
.delta. 1.37 (t, 3H, CH.sub.3), 2.20 (s, 3H, acetyl), 3.95 (q, 2H,
CH.sub.2), 7.57 (s, 1H, CH), 8.15 (d, 1H, 6-H, J=2 Hz), 8.35 (s,
1H, 2-H); MS, m/e 289 (M.sup.++1).sss
[0166] 4,7-Dichloroimidazo[4,5-c]pyridine (36). Compound 36 was
isolated as a white solid (1.52 g, 80%): TLC, R.sub.f 0.0sss9
(CH.sub.2Cl.sub.2/EtOAc, 5:1, v/v); mp 270-272.degree. C.; .sup.1H
NMR (DMSO-d.sub.6) .delta. 8.25 (s, 1H, 6-H), 8.60 (s, 1H, 7-H),
13.60 (br s, 1H, NH, D.sub.2O exchangeable). Analysis calculated
for C.sub.6H.sub.3Cl.sub.2N.sub.3: C, 38.33; H, 1.61; N, 22.35.
Found: C, 38.52; H, 1.90; N, 22.17.
[0167]
1-[(1-Acetyloxy-1-ethoxy)methyl]-4,7-dichloroimidazo[4,5-c]pyridine
(36a). Compound 36a was isolated as a syrup: TLC, R.sub.f 0.58
(CH.sub.2Cl.sub.2/EtOAc, 5:1, v/v); .sup.1H NMR (CDCl.sub.3)
.delta. 1.32 (t, 3H, CH.sub.3), 2.15 (s, 3H, acetyl), 4.10 (m, 2H,
CH.sub.2), 7.95 (s, 1H, CH), 8.25 (s, 1H, 2-H), 8.44 (s, 1H, 6-H);
MS, m/e 304 (M.sup.++1).
EXAMPLE 4
[0168] Scheme 3
[0169]
4,6-Difluoro-1-(2,3,5-tri-O-benzoyl-.beta.-D-ribofuranosyl)imidazo[-
4,5-c]pyridine (37). A suspension of
4,6-difluoroimidazo[4,5-c]pyridine (34, 0.34 g, 2.2 mmol) in
hexamethyldisilazane (10 mL) and ammonium sulfate (a catalytic
amount) was refluxed for 2 h under anhydrous conditions. The
resulting clear solution was cooled and concentrated in vacuo to
yield the silylated base as a white solid, which was dissolved in
12 mL of dichloroethane. 1-O-Acetyl-2,3,5-O-benzoyl-D-ribofuranose
(1.2 g, 2.4 mmol) was added to the solution, followed by 1 mL of
TMSOTf and the reaction mixture was stirred at room temperature
under nitrogen overnight. The reaction mixture was quenched by
addition of a saturated sodium bicarbonate solution (10 mL) and
further stirred for 10 minutes at room temperature. The organic
layer was separated and the aqueous layer was extracted with
methylene chloride (30 mL.times.2). The combined organic layers
were washed with a saturated sodium bicarbonate solution, then
water and dried (anhydrous MgSO.sub.4). After filtration, the
filtrate was concentrated in vacuo and the residue was purified by
silica gel column chromatography (CH.sub.2Cl.sub.2/EtOAc, 30:1,
v/v) to yield 37 (1.0 g, 77%) as a foam: .sup.1H NMR (CDCl.sub.3)
.delta. 4.62-4.82 (m, 3H, 4'- and 5'-H), 5.85-5.92 (m, 2H, 2'- and
3'-H), 6.20 (d, 1H, 1'-H, J=5 Hz), 7.05 (d, 1H, 7-H, J=1.5 Hz),
7.20-7.90 (m, 15H, ArH), 8.15 (s, 1H, 2-H). Analysis calculated for
C.sub.32H.sub.23F.sub.2N.sub.3O.sub.7: C, 64.10; H, 3.87; N, 7.01.
Found: C, 64.28; H, 4.06; N, 6.93.
[0170]
4-Amino-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine
(38). A suspension of
4,6-difluoro-1-(2,3,5-tri-O-benzoyl-.beta.-D-ribofu-
ranosyl)imidazo[4,5-c]pyridine (37, 0.6 g, 1 mmol) in 50 mL of
saturated ethanolic ammonia solution was stirred in a pressure
bottle at room temperature for 4 days. The cooled reaction mixture
was evaporated to dryness and the residue was purified by silica
gel column chromatography (CH.sub.2Cl.sub.2/EtOH, 10:1, v/v) to
give 0.2 g (70%) of product as a white solid: mp 171-172.degree.
C.; UV (MeOH) .lambda..sub.max 274 nm (E 15,026), .lambda..sub.min
234 nm; UV (0.01 N HCl) .lambda..sub.max 276 nm (.epsilon. 11,863),
min 236 nm; UV (0.01 N NaOH) .lambda..sub.max 274 nm (.epsilon.
14,027), .lambda..sub.min 232 nm; .sup.1H NMR (DMSO-d.sub.6) 53.63
(m, 2H, 5'-H), 3.94 (m, 1H, 4'-H), 4.10 (m, 1H, 3'-H), 4.28 (m, 1H,
2'-H), 5.12 [t, 1H, 5'-OH, D.sub.2O exchangeable), 5.20 (d, 1H, OH,
D.sub.2O exchangeable), 5.45 (d, 1H, OH, D.sub.2O exchangeable),
5.71 (d, 1H, 1'-H, J=6.0 Hz), 6.55 (d, 1H, 7-H, J=1.5 Hz), 6.55 (br
s, 2H, 4-NH.sub.2, D.sub.2O exchangeable), 8.25 (s, 1H, 2-H).
Analysis calculated for C.sub.11H.sub.13FN.sub.4O.sub.4: C, 46.48;
H, 4.61; N, 19.70. Found: C, 46.12; H, 4.44; N, 19.39.
[0171]
6-Fluoro-4-methylamino-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyri-
dine (39). A mixture of
4,6-difluoro-1-(2,3,5-tri-O-benzoyl-.beta.-D-ribof-
uranosyl)imidazo[4,5-c]pyridine (37, 0.3 g, 0.5 mmol) and 10 mL of
40% methylamine was stirred at room temperature until TLC showed
the reaction to be complete (about 3 days). The reaction mixture
was evaporated to dryness and purified by silica gel column
chromatography (CH.sub.2Cl.sub.2/EtOH, 10:1, v/v) to give 0.12 g
(77%) of product as a white solid: mp 175-177.degree. C.; UV (MeOH)
.lambda..sub.max 280 nm (.epsilon. 19,306), .lambda..sub.min 238
nm; UV (0.01 N HCl) .lambda..sub.max 282 nm (.epsilon. 15,835),
.lambda..sub.min 242 nm; UV (0.01 N NaOH) .lambda..sub.max 280 nm
(e 18,221), 2 min 238 mm; .sup.1H NMR (DMSO-d.sub.6) .delta. 2.88
(d, 3H, CH.sub.3, J=4.5), 3.62 (m, 2H, 5'-H), 3.75 (m, 1H, 4'-H),
4.07 (m, 1H, 3'-H), 4.26 (m, 1H, 2'-H), 5.15 [t, 1H, 5'-OH,
D.sub.2O exchangeable), 5.20 (d, 1H, OH, D.sub.2O exchangeable),
5.44 (d, 1H, OH, D.sub.2O exchangeable), 5.71 (d, 1H, 1'-H, J=6.3
Hz), 6.55 (d, 1H, 7-H, J=1.5 Hz), 6.53 (br s, 1H, 4-NHCH.sub.3,
D.sub.2O exchangeable), 8.25 (s, 1H, 2-H). Analysis calculated for
C.sub.12H.sub.15FN.sub.4O.sub.4: C, 48.32; H, 5.07; N, 18.78.
Found: C, 47.94; H, 5.01; N, 18.39.
[0172]
4-Amino-6-fluoro-1-2,3,5-tri-O-benzyl-.beta.-D-arabinofuranosyl)imi-
dazo[4,5-c]pyridine (41) and
4-amino-6-fluoro-1-(2,3,5-tri-O-benzyl-.alpha-
.-D-arabinofuranosyl)imidazo[4,5-c]pyridine (42). A mixture of
4,6-difluoroimidazo[4,5-c]pyridine (34, 0.5 g, 3.2 mmol) and
ammonium sulfate (a catalytic amount) in hexamethyldisilazane (15
mL) was refluxed for 2 h. The resulting clear solution was cooled
and concentrated in vacuo under anhydrous conditions to dryness.
The residue was dissolved in 15 mL of dichloroethane, followed by
addition of 1-O-(4-nitrobenzoyl)-2,3-
,5-tri-O-benzyl-D-arabinofuranose (2 g, 3.6 mmol) and TMSOTf (1 mL)
and the reaction mixture was refluxed with stirring under nitrogen
for 2 h. The reaction mixture was cooled and stirred with saturated
sodium bicarbonate solution (15 mL) for 10 min at room temperature.
The organic layer was separated and the aqueous layer was extracted
with methylene chloride (30 mL.times.2). The combined organic layer
was washed with saturated sodium bicarbonate solution, then water
and dried (anhydrous MgSO.sub.4). After filtration, the filtrate
was concentrated in vacuo and the residue was purified by silica
gel column chromatography (CH.sub.2Cl.sub.2/EtOAc, 20:1, v/v) to
yield 40 (1.2 g, 67%) as a syrup. NMR showed it to be a mixture of
.alpha.- and .beta.-anomers. Compound 40 (1.1 g, 2.0 mmol) was
dissolved in 60 mL of ethanol, saturated with anhydrous ammonia and
heated in a stainless steel bomb at 100105.degree. C. overnight.
The reaction mixture was cooled, evaporated to dryness and
separated by silica gel column chromatography
(CH.sub.2Cl.sub.2/EtOH, 20:1, v/v) to yield 41 (0.30 g, 27%), 42
(0.34 g, 31%) and a mixture of 41 and 42 (0.17 g, 15%).
[0173] Compound 41 was isolated as a white foam: TLC, R.sub.f 0.63
(CH.sub.2Cl.sub.2/EtOH, 20:1, v/v); .sup.1H NMR (CDCl.sub.3)
.delta. 3.70 (m, 2H, 5'-H), 4.10 (m, 1H, 4'-H), 4.25 (m, 2H, 2'-
and 3'-H), 4.65 (s, 6H, ArCH.sub.2), 5.75 (br s, 2H, NH.sub.2,
D.sub.2O exchangeable), 5.96 (d, 1H, 1'-H, J=5 Hz), 6.14 (s, 1H,
7-H), 6.80-7.40 (m, 15H, ArH), 8.01 (s, 1H, 2-H). Analysis
calculated for C.sub.32H.sub.31FN.sub.4O.sub.4: C, 69.28; H, 5.63;
N, 10.10. Found: C, 69.10; H, 5.40; N, 9.96.
[0174] Compound 42 was isolated as a white foam: TLC, R.sub.f 0.53
(CH.sub.2Cl.sub.2/EtOH, 20:1, v/v); .sup.1H NMR (CDCl.sub.3)
.delta. 3.58 (m, 2H, 5'-H), 4.25 (m, 1H, 4'-H), 4.30 (m, 2H, 2'-
and 3'-H), 4.50 (s, 6H, ArCH.sub.2), 5.60 (br s, 2H, NH.sub.2,
D.sub.2O exchangeable), 5.85 (d, 1H, 1'-H, J=5.2 Hz), 6.20 (s, 1H,
7-H), 7.00-7.40 (m, 15H, ArH), 7.84 (s, 1H, 2-H). Analysis
calculated for C.sub.32H.sub.31FN.sub.4O.sub.4.0.0- 5EtOH: C,
69.01; H, 5.67; N, 10.06. Found: C, 68.87; H, 5.30; N, 9.98.
[0175]
4-Amino-6-fluoro-1-.beta.-D-arabinofuranosylimidazo[4,5-c]pyridine
(43). A mixture of
4-amino-6-fluoro-1-(2,3,5-tri-O-benzyl-.beta.-D-arabin-
ofuranosyl)imidazo[4,5-c]pyridine (41, 0.15 g, 0.27 mmol),
palladium (II) oxide hydrate (0.25 g), cyclohexene (20 mL) and
ethanol (20 mL) was refluxed overnight. The reaction mixture was
cooled, filtered and washed with ethanol. The combined filtrate and
washings were evaporated in vacuo and the residue was purified by
silica gel column chromatography (CH.sub.2Cl.sub.2/EtOH, 6:1, v/v)
to give 45 mg (58%) of product as white crystals: mp 215.degree. C.
(dec.); UV (MeOH) .lambda..sub.max 274 nm (.epsilon. 14,127),
.lambda..sub.min 234 nm; UV (0.01 N HCl) .lambda..sub.max 275 nm
(.epsilon. 9,701), .lambda..sub.min 235 mm; UV (0.01 N NaOH)
.lambda..sub.max 274 nm (E 12,595), .lambda..sub.min 234 nm;
.sup.1H NMR (DMSO-d.sub.6) 53.65 (m, 2H, 5'-H), 3.73 (m, 1H, 4'-H),
4.06 (m, 1H, 3'-H), 4.15 (m, 1H, 2'-H), 5.08 [t, 1H, 5'-OH,
D.sub.2O exchangeable), 5.05 (d, 1H, OH, D.sub.2O exchangeable),
5.50 (d, 1H, OH, D.sub.2O exchangeable), 6.08 (d, 1H, 1'-H, J=5.1
Hz), 6.42 (d, 1H, 7-H, J=1.2 Hz), 6.59 (br s, 2H, 4-NH.sub.2,
D.sub.2O exchangeable), 8.17 (s, 1H, 2-H). Analysis calculated for
C.sub.11H.sub.13FN.sub.4O.sub.4: C, 46.48; H, 4.61; N, 19.70.
Found: C, 46.70; H, 5.00; N, 19.35.
[0176]
4-Amino-6-fluoro-1-.alpha.-D-arabinofuranosylimidazo[4,5-c]pyridine
(44). This compound was synthesized by a procedure similar to that
described for compound 43. Compound 44 was isolated as white
crystals (60 mg, 65%): mp 198.degree. C. (dec.); UV (MeOH)
.lambda..sub.max 272 mm (.epsilon. 12,344), .lambda..sub.min 234
mm; UV (0.01 N HCl) .lambda..sub.max 274 mm (.epsilon. 10,232),
.lambda..sub.min 234 mm; UV (0.01 N NaOH) ?max 274 nm (.epsilon.
11,532), .lambda..sub.min 234 nm; .sup.1H NMR (DMSO-d.sub.6)
.delta.3.52 (m, 2H, 5'-H), 4.02 (m, 1H, 4'-H), 4.08 (m, 1H, 3'-H),
4.33 (m, 1H, 2'-H), 4.90 (t, 1H, 5'-OH, D.sub.2O exchangeable),
5.50 (d, 1 sH, OH, D.sub.2O exchangeable), 5.72 (d, 1H, 1'-H, J=5.4
Hz), 5.84 (d, 1H, OH, D.sub.2O exchangeable), 6.41 (d, 1H, 7-H,
J=1.5 Hz), 6.69 (br s, 2H, 4-NH.sub.2, D.sub.2O exchangeable), 8.20
(s, 1H, 2-H). Analysis calcssulated for
C.sub.11H.sub.13FN.sub.4O.sub.4: C, 46.48; H, 4.61; N, 19.71.
Found: C, 46.68; H, 4.87; N, 19.43.
EXAMPLE 5
[0177] Scheme 4
[0178] Compounds 45 and 46 were synthesized by methodology similar
to that described for compound 37.
[0179]
4-Chloro-7-fluoro-1-2,3,5-tri-O-benzoyl-.beta.-D-ribofuranosyl)imid-
azo[4,5-]pyridine (45). Compound 45 was isolated as a white foam
(0.77 g, 61%): .sup.1H NMR (CDCl.sub.3) .delta.4.82 (m, 2H, 5'-H),
4.92 (m, 1H, 4'-H), 5.94 (m, 2H, 2'- and 3'-H), 6.58 (d, 1H, 1'-H,
J=5 Hz), 7.30-8.10 (m, 15H, ArH), 8.13 (d, 1H, 7-H, J=1.5 Hz), 8.27
(s, 1H, 2-H). Analysis calculated for
C.sub.32H.sub.23ClFN.sub.3O.sub.7: C, 62.39; H, 3.76; N, 6.82.
Found: C, 62.12; H, 4.02; N, 6.63.
[0180]
4,7-Dichloro-1-(2,3,5-tri-O-benzoyl-.beta.-D-ribofuranosyl)imidazo[-
4,5-c]pyridine (46). Compound 46 was isolated as a foam (2.4 g,
47%): .sup.1H NMR (CDCl.sub.3) .delta.4.75 (m, 2H, 5'-H), 4.80 (m,
1H, 4'-H), 5.95 (m, 1H, 3'-H), 6.00 (m, 1H, 2'-H), 7.15 (d, 1H,
1'-H, J=6 Hz), 7.25-8.00 (m, 15H, ArH), 8.15 (s, 1H, 6-H), 8.40 (s,
1H, 2-H). Analysis calculated for
C.sub.32H.sub.23Cl.sub.2N.sub.3O.sub.7: C, 60.87; H, 3.67; N, 6.66.
Found: C, 61.10; H, 3.84; N, 6.30.
[0181]
4-Chloro-7-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine
(47). To a suspension of
4-chloro-7-fluoro-1-(2,3,5-tri-O-benzoyl-.beta.--
D-ribofuranosyl)imidazo[4,5-c]pyridine (45, 0.73 g, 1.2 mmol) in
dry methanol (50 mL) was added sodium methoxide until pH 10 was
reached. The reaction mixture was refluxed for 30 min, cooled,
neutralized with glacial acetic acid, and evaporated to dryness.
The residue was purified by silica gel column chromatography
(CH.sub.2Cl.sub.2/EtOH, 10:1, v/v) to give 0.29 g (78%) as a white
solid: mp 187-189.degree. C.; .sup.1H NMR (DMSO-d.sub.6) .delta.
3.58 (m, 1H, 5'-H.sub.A), 3.70 (m, 1H, 5'-H.sub.B), 3.99 (m, 1H,
4'-H), 4.13 (m, 1H, 3'-H), 4.36 (m, 1H, 2'-H), 5.16 (t, 1H, 5'-OH,
D.sub.2O exchangeable), 5.28 (d, 1H, OH, D.sub.2O exchangeable),
5.63 (d, 1H, OH, D.sub.2O exchangeable), 6.03 (d, 1H, 1'-H, J=5.1
Hz), 8.27 (d, 1H, 6-H, J=2.1 Hz), 8.88 (s, 1H, 2-H). Analysis
calculated for C.sub.11H.sub.11ClFN.sub.3O.sub.4: C, 43.50; H,
3.65; N, 13.84. Found: C, 43.43; H, 3.26; N, 13.81.
[0182]
4,7-Dichloro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine (48).
Compound 48 was synthesized by a procedure similar to that
described for compound 47 and was isolated as white crystals (0.2
g, 56%): mp 172-174.degree. C.; .sup.1H NMR (DMSO-d.sub.6) .delta.
3.53 (m, 1H, 5'-HA), 3.65 (m, 1H, 5'-H.sub.B), 4.15 (m, 1H, 4'-H),
4.28 (m, 1H, 3'-H), 4.45 (m, 1H, 2'-H), 4.94 (t, 1H, 5'-OH,
D.sub.2O exchangeable), 5.27 (d, 1H, OH, D.sub.2O exchangeable),
5.43 (d, 1H, OH, D.sub.2O exchangeable), 6.79 (d, 1H, 1'-H, J=5.1
Hz), 8.27 (s, 1H, 6-H), 8.72 (s, 1H, 2-H). Analysis calculated for
C.sub.11H.sub.11Cl.sub.2N.sub.3O.sub.4: C, 41.27; H, 3.46; N,
13.13. Found: C, 41.00; H, 3.57; N, 12.91.
[0183]
4-Amino-7-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine
(51). A suspension of
4-chloro-7-fluoro-1-(.beta.-D-ribofuranosyl)imidazo-
[4,5-c]pyridine (47, 0.51 g, 1.7 mmol) in 30 mL of anhydrous
hydrazine was refluxed for 1 h. The reaction mixture was evaporated
in vacuo to dryness and the residue was co-evaporated with ethanol
(30 mL) and deoxygenated water twice (2.times.30 mL). The residue
was dissolved in 40 mL of deoxygenated water containing 3.0 g (wet
weight) of Raney Nickel and was refluxed with stirring under
hydrogen (1 atm) for 8 h. The reaction mixture was filtered through
Celite while hot, and the catalyst was washed with hot deoxygenated
water. The combined filtrate and washings were evaporated in vacuo
to dryness. The residue was purified by silica gel column
chromatography (CH.sub.2Cl.sub.2/EtOH, 6:1, v/v) to give 0.26 g
(54%) of product as a white solid: mp 160-161.degree. C.; UV (MeOH)
.lambda..sub.max 270 nm (.epsilon. 7,145), .lambda..sub.min 238 nm;
UV (0.01 N HCl) .lambda..sub.max 268 nm (.epsilon. 8,077),
.lambda..sub.min 238 nm; UV (0.01 N NaOH) .lambda..sub.max 268 nm
(.epsilon. 7,445), .lambda..sub.min 238 nm; .sup.1H NMR
(DMSO-d.sub.6) .delta. 3.58 (m, 1H, 5'-H.sub.A), 3.62 (m, 1H,
5'-H.sub.B), 3.94 (m, 1H, 4'-H), 4.10 (m, 1H, 3'-H), 4.35 (m, 1H,
2'-H), 5.07 (t, 1H, 5'-OH, D.sub.2O exchangeable), 5.24 (d, 1H, OH,
D.sub.2O exchangeable), 5.54 (d, 1H, ssOH, D.sub.2O exchangeable),
5.91 (d, 1H, 1'-H, J=5.1 Hz), 6.22 (br s, 2H, NH.sub.2, D.sub.2O
exchangeable), 7.67 (d, 1H, 6-H, J=2.1 Hz), 8.48 (s, 1H, 2-H).
Analysis calculated for C.sub.11H.sub.13FN.sub.4O.sub.4: C, 46.48;
H, 4.61; N, 19.71. Found: C, 46.52; H, 4.50; N, 19.50.
[0184]
4-Amino-7-chloro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridine
(52). Compound 52 was synthesized by a procedure similar to that
described for compound 51 and was isolated as a white solid (0.14
g, 49%): mp 169.degree. C. (dec); UV (MeOH) .lambda..sub.max 271 nm
(.epsilon. 7,010), .lambda..sub.min 237 nm; UV (0.01 N HCl)
.lambda..sub.max 269 nm (.epsilon. 7,900), .lambda..sub.min 236 nm;
UV (0.01 N NaOH) .lambda..sub.max 269=n (.epsilon. 7,400),
.lambda..sub.min 236 nm; .sup.1H NMR (DMSO-d.sub.6) .delta. 3.45
(m, 1H, 5'-H.sub.A), 3.56 (m, 1H, 5'-H.sub.B), 4.12 (m, 1H, 4'-H),
4.20 (m, 1H, 3'-H), 4.34 (m, 1H, 2'-H), 4.92 (t, 1H, 5'-OH,
D.sub.2O exchangeable), 5.27 (d, 1H, OH, D.sub.2O exchangeable),
5.61 (d, 1H, OH, D.sub.2O exchangeable), 6.08 (br s, 2H, NH.sub.2,
D.sub.2O exchangeable), 6.41 (d, 1H, 1'-H, J=4.5 Hz), 7.72 (s, 1H,
6-H), 8.41 (s, 1H, 2-H). Analysis calculated for
C.sub.11H.sub.13ClN.sub.4O.sub.4: C, 43.93; H, 4.36; N, 18.63.
Found: C, 43.70; H, 4.32; N, 18.51.
EXAMPLE 6
[0185] Scheme 5
[0186] Compounds 53-56 were synthesized by methodology similar to
that described for compound-37.
[0187]
4,6,7-Trifluoro-1-(2,3,5-tri-O-benzoyl-.beta.-D-ribofuranosyl)imida-
zo[4,5-]pyridine (53). Compound 53 was isolated as a foam (0.76 g,
36%): TLC, R.sub.f 0.47 (CH.sub.2Cl.sub.2/EtOAc, 30:1, v/v);
.sup.1H NMR (CDCl.sub.3) .delta. 4.80-4.90 (m, 3H, 4'- and 5'-H),
5.94 (m, 2H, 2'- and 3'-H), 6.55 (d, 1H, 1'-H, J=5.2 Hz), 7.30-8.05
(m, 15H, ArH), 8.25 (s, 1H, 2-H). Analysis calculated for
C.sub.32H.sub.22F.sub.3N.sub.3O.sub- .7: C, 62.24; H. 3.59; N,
6.80. Found: C, 62.25; H, 3.49; N, 6.51.
[0188]
4,6,7-Trifluoro-3-(2,3,5-tri-O-benzoyl-.beta.s-D-ribofuranosyl)imid-
azo[4,5-c]pyridine (54). Compound 54 was isolated as a foam (0.53
g, 25%): TLC, R.sub.f 0.55 (CH.sub.2Cl.sub.2/EtOAc, 30:1, v/v);
.sup.1H NMR (CDCl.sub.3) .delta. 4.80-4.92 (m, 3H, 4'- and 5'-H),
5.95 (m, 2H, 2'- and 3'-H), 6.53 (d, 1H, 1'-H, J=5.5 Hz), 7.30-8.20
(m, 15H, ArH), 8.43 (s, 1H, 2-H). Analysis calculated for
C.sub.32H.sub.22F.sub.3N.sub.3O.sub- .7: C, 62.24; H, 3.59; N,
6.80. Found: C, 62.06; H, 3.31; N, 6.69.
[0189]
7-Chloro-4,6-difluoro-1,2,3,5-tri-O-benzoyl-.beta.-D-ribofuranosyl)-
imidazo[4,5-c]pyridine (55). Compound 55 was isolated as a foam
(0.57 g, 34%): TLC, R.sub.f 0.38 (CH.sub.2Cl.sub.2/EtOAc, 30:1,
v/v); .sup.1H NMR (CDCl.sub.3) .delta. 4.78-4.90 (m, 3H, 4'- and
5'-H), 5.97 (m, 2H, 2'- and 3'-H), 6.50 (d, 1H, 1'-H, J=5.1 Hz),
7.30-8.12 (m, 15H, ArH), 8.35 (s, 1H, 2-H). Analysis calculated for
C.sub.32H.sub.22ClF.sub.2N.sub.3O.s- ub.7: C, 60.62; H, 3.50; N,
6.63. Found: C, 60.46; H, 3.40; N, 6.49.
[0190] 7-Chloro-4,6-difluoro-3-(2,3,5-tri-O
benzoyl-.beta.-D-ribofuranosyl- )imidazo[4,5-]pyridine (56).
Compound 56 was isolated as a foam (0.50 g, 26%): TLC, R.sub.f 0.47
(CH.sub.2Cl.sub.2/EtOAc, 30:1, v/v); .sup.1H NMR (CDCl.sub.3)
.delta. 4.77-4.85 (m, 3H, 4'- and 5'-H), 5.92 (m, 2H, 2'- and
3'-H), 6.50 (d, 1H, 1'-H, J=5.2 Hz), 7.25-8.15 (m, 15H, ArH), 8.40
(s, 1H, 2-H). Analysis calculated for
C.sub.32H.sub.22ClF.sub.2N.sub.3O.s- ub.7: C, 60.62; H, 3.50; N,
6.63. Found: C, 60.87; H, 3.39; N, 6.52.
[0191] Compounds 57-60 were synthesized by methodology similar to
that described for compound 38.
[0192]
4-Amino-6,7-difluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridi-
ne (57). Compound 57 was isolated as a white solid (0.17 g, 77%):
mp 163-165.degree. C.; UV (MeOH) .lambda..sub.max 274 nm (E
13,510), .lambda..sub.min 232 nm; UV (0.01 N HCl) .lambda..sub.max
274 nm (.epsilon. 12,256), min 232 nm; UV (0.01 N NaOH)
.lambda..sub.max 274 nm (.epsilon. 11,421), .lambda..sub.min 232
nm; .sup.1H NMR (DMSO-d.sub.6) 63.65 (m, 1H, 5'-H.sub.A), 3.67 (m,
1H, 5'-H.sub.B), 3.93 (m, 1H, 4'-H), 4.02 (m, 1H, 3'-H), 4.32 (m,
1H, 2'-H), 5.07 (t, 1H, 5'-OH, D.sub.2O exchangeable), 5.22 (d, 1H,
OH, D.sub.2O exchangeable), 5.54 (d, 1H, OH, D.sub.2O
exchangeable), 5.87 (d, 1H, 1'-H, J=5.6 Hz), 6.65 (br s, 2H,
NH.sub.2, D.sub.2O exchangeable), 8.43 (s, 1H, 2-H). Analysis
calculated for C.sub.11H.sub.12F.sub.2N.sub.4O.sub.4: C, 43.71; H,
4.00; N, 18.54. Found: C, 43.92; H, 3.91; N, 18.59.
[0193]
4-Amino-6,7-difluoro-3-(.beta.-D-ribofuranosyl)imidazo[4,5-c]pyridi-
ne (58). Compound 58 was isolated as a white solid (0.14 g, 88%):
mp 155-157.degree. C.; UV (MeOH) .lambda..sub.max 292 nm (E 5,742),
.lambda..sub.min 264 nm; UV (0.01 N HCl) .lambda..sub.max 292 nm
(.epsilon.6,045), .lambda..sub.min 262 nm; UV (0.01 N NaOH)
.lambda..sub.max 292 nm (.epsilon. 5,440), .lambda..sub.min 262 nm;
.sup.1H NMR (DMSO-d.sub.6) .delta. 3.65 (m, 1H, 5'-H.sub.A), 3.68
(m, 1H, 5'-H.sub.B), 4.01 (m, 1H, 4'-H), 4.11 (m, 1H, 3'-H), 4.22
(m, 1H, 2'-H), 5.13 (t, 1H, 5'-OH, D.sub.2O exchangeable), 5.20 (d,
1H, OH, D.sub.2O exchangeable), 5.30 (d, 1H, OH, D.sub.2O
exchangeable), 5.90 (d, 1H, 1'-H, J=6.6 Hz), 6.34 (br s, 2H,
NH.sub.2, D.sub.2O exchangeable), 8.54 (s, 1H, 2-H). Analysis
calculated for C.sub.11H.sub.12F.sub.2N.sub.4O.sub- .4: C, 43.71;
H, 4.00; N, 18.54. Found: C, 43.90; H, 4.02; N, 18.16.
[0194]
4-Amino-7-chloro-6-fluoro-1-(.beta.-D-ribofuranosyl)imidazo[4,5-c]p-
yridine (59). Compound 59 was isolated as a white solid (0.10 g,
85%): mp 175-177.degree. C.; UV (MeOH) .lambda..sub.max 274 nm
(.epsilon. 14,503), .lambda..sub.min 234 nm; UV (0.01 N HCl)
.lambda..sub.max 274 nm (.epsilon. 12,997), .lambda..sub.min 236
nm; UV (0.01 N NaOH) .lambda..sub.max 274 nm (.epsilon. 15,367),
.lambda..sub.min 235 rum; .sup.1H NMR (DMSO-d.sub.6) .delta. 3.52
(m, 1H, 5'-H.sub.A), 3.62 (m, 1H, 5'-H.sub.B), 3.95 (m, 1H, 4'-H),
4.10 (m, 1H, 3'-H), 4.37 (m, 1H, 2'-H), 5.12 (t, 1H, 5'-OH,
D.sub.2O exchangeable), 5.22 (d, 1H, OH, D.sub.2O exchangeable),
5.58 (d, 1H, OH, D.sub.2O exchangeable), 6.34 (d, 1H, 1'-H, J=4.5
Hz), 6.94 (br s, 2H, NH.sub.2, D.sub.2O exchangeable), 8.51 (s, 1H,
2-H). Analysis calculated for C.sub.11H.sub.12ClFN.sub.4O.sub.4: C,
41.45; H, 3.80; N, 17.58. Found: C, 41.17; H, 4.00; N, 17.35.
[0195]
4-Amino-7-chloro-6-fluoro-3-(.beta.-D-ribofuranosyl)imidazo[4,5-c]p-
yridine (60). Compound 60 was isolated as a white solid (0.13 g,
53%): mp 166-168.degree. C.; UV (MeOH) .lambda..sub.max 292 nm
(.epsilon. 8,631), .lambda..sub.min 268 nm; UV (0.01 N HCl)
.lambda..sub.max 292 nm (.epsilon. 8,465), .lambda..sub.min 266 nm;
UV (0.01 N NaOH) .lambda..sub.max 292 nm (.epsilon. 7,967),
.lambda..sub.min 268 nm; .sup.1H NMR (DMSO-d.sub.6) .delta. 3.55
(m, 1H, 5'-H.sub.A), 3.65 (m, 1H, 5'-H.sub.B), 3.98 (m, 1H, 4'-H),
4.11 (m, 1H, 3'-H), 4.20 (m, 1H, 2'-H), 5.25 (t, 1H, 5'-OH,
D.sub.2O exchangeable), 5.35 (d, 1H, OH, D.sub.2O exchangeable),
5.65 (d, 1H, OH, D.sub.2O exchangeable), 5.87 (d, 1H, 1'-H, J=6.6
Hz), 6.63 (br s, 2H, NH.sub.2, D.sub.2O exchangeable), 8.55 (s, 1H,
2-H). Analysis calculated for C.sub.11H.sub.12ClFN.sub.4O.sub.4: C,
41.45; H, 3.80; N, 17.58. Found: C, 41.31; H, 4.10; N, 17.27.
EXAMPLE 7
[0196] Scheme 6
[0197]
6-Amino-7-chloro-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,5-c]-
pyridin-4-one (3-chloro-3-deazaguanosine, 61). To a stirred
suspension of 3-deazaguanosine (see, Chiang, et al., Biochem.
Biophys. Res. Commun. 1978 82,417-423 and Secrist, et al., J. Med.
Chem. 1993 36, 2102-2106 (0.25 g, 0.9 mmol) in 7 mL of water was
added N-chlorosuccimide (0.14 g, 1.0 mmol) at 0-5.degree. C. in an
ice-water bath. The reaction mixture was stirred at 0-5.degree. C.
for 1 h. The solid was collected, washed with cold water and then
cold acetone. Crystallization from water provided 0.12 g (42%) of
product: mp 195-196.degree. C. (dec.); UV (MeOH) .lambda..sub.max
273 nm (.epsilon. 11,000), .lambda..sub.min 238 nm; UV (0.01 N HCl)
.lambda..sub.max 285 nm (E 13,200), .lambda..sub.min 242 nm; UV
(0.01 N NaOH) .lambda..sub.max 274 nm (.epsilon. 11,200),
.lambda..sub.min 240 nm; .sup.1H NMR (DMSO-d.sub.6) 53.52 (m, 2H,
5'-H), 3.90 (m, 1H, 4'-H), 4.10 (m, 1H, 3'-H), 4.25 (m, 1H, 2'-H),
5.02 (d, 1H, OH, D.sub.2O exchangeable), 5.10 (t, 1H, OH, D.sub.2O
exchangeable), 5.40 (d, 1H, OH, D.sub.2O exchangeable), 5.70 (br s,
2H, NH.sub.2, D.sub.2O exchangeable), 6.25 (d, 1H, 1'-H, J=7.0 Hz),
8.10 (s, 1H, 2-H), 10.70 (br s, 1H, NH, D.sub.2O exchangeable).
Analysis calculated for C.sub.11H.sub.13ClN.sub.4O.sub.5: C, 41.71;
H, 4.14; N, 17.69. Found: C, 41.80; H, 4.00; N, 17.38.
[0198]
6-Amino-7-bromo-1,5-dihydro-1-.beta.-D-ribofuranosylimidazo[4,5-c]p-
yridin-4-one (3-bromo-3-deazaguanosine, 62). To a stirred
suspension of 3-deazaguanosine, prepared according to the method of
Chiang, et al. and Secrist, et al., supra, (0.5 g, 1.8 mmol) in 6
mL of water was added gradually 12 mL of saturated bromine-water at
such a rate that the yellow color of the reaction mixture
disappeared between each addition (about 5 min). The reaction
mixture was stirred for another 5 min and the solid was collected
by filtration, and washed with cold water and cold acetone. The
solid was crystallized from water to give 0.45 g (70%) of product:
mp 174.degree. C. (dec.); UV (MeOH) .lambda..sub.max 274 nm
(.epsilon. 11,200), .lambda..sub.min 240 nm; UV (0.01 N HCl)
.lambda..sub.max 284 nm (.epsilon. 13,200), .lambda..sub.min 238
nm; UV (0.01 N NaOH) .lambda..sub.max 274 nm (.epsilon. 11,600),
min 240 nm; .sup.1H NMR (DMSO-d.sub.6) 63.50 (m, 2H, 5'-H), 3.80
(m, 1H, 4'-H), 4.05 (m, 1H, 3'-H), 4.28 (m, 1H, 2'-H), 5.20-5.40
(br s, 2H, OH, D.sub.2O exchangeable), 5.40 (t, 1H, OH, D.sub.2O
exchangeable), 5.62 (br s, 2H, NH.sub.2, D.sub.2O exchangeable),
6.38 (d, 1H, 1'-H, J=6.8 Hz), 8.12 (s, 1H, 2-H), 10.62 (br s, 1H,
NH, D.sub.2O exchangeable). Analysis calculated for
C.sub.11H.sub.13BrN.sub.4O.sub.5: C, 36.58; H, 3.62; N, 15.51.
Found: C, 36.41; H, 3.43; N, 15.23.
* * * * *