U.S. patent application number 10/074595 was filed with the patent office on 2003-05-08 for alpha-aryl-n-alkylnitrones and pharmaceutical compositions containing the same.
Invention is credited to Dykman, Alina, Kelleher, Judith A., Levell, Julian, Maples, Kirk R., Wilcox, Allan L., Zhang, Yong-Kang.
Application Number | 20030087957 10/074595 |
Document ID | / |
Family ID | 27370256 |
Filed Date | 2003-05-08 |
United States Patent
Application |
20030087957 |
Kind Code |
A1 |
Kelleher, Judith A. ; et
al. |
May 8, 2003 |
Alpha-aryl-N-alkylnitrones and pharmaceutical compositions
containing the same
Abstract
Disclosed are novel .alpha.-aryl-N-alkylnitrone compounds and
pharmaceutical compositions containing such compounds. The
disclosed compositions are useful as therapeutics for preventing
and/or treating neurodegenerative, autoimmune and inflammatory
conditions in mammals and as analytical reagents for detecting free
radicals.
Inventors: |
Kelleher, Judith A.;
(Fremont, CA) ; Maples, Kirk R.; (San Jose,
CA) ; Dykman, Alina; (San Francisco, CA) ;
Zhang, Yong-Kang; (Santa Clara, CA) ; Wilcox, Allan
L.; (Mountain View, CA) ; Levell, Julian;
(Collegeville, PA) |
Correspondence
Address: |
BURNS, DOANE, SWECKER & MATHIS, L.L.P.
P.O. Box 1404
Alexandria
VA
22313-1404
US
|
Family ID: |
27370256 |
Appl. No.: |
10/074595 |
Filed: |
February 11, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10074595 |
Feb 11, 2002 |
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09500650 |
Feb 9, 2000 |
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09500650 |
Feb 9, 2000 |
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09172763 |
Oct 15, 1998 |
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6046232 |
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60062324 |
Oct 17, 1997 |
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60063736 |
Oct 29, 1997 |
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60090475 |
Jun 24, 1998 |
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Current U.S.
Class: |
514/466 ;
514/640; 549/440; 564/253 |
Current CPC
Class: |
A61P 11/00 20180101;
A61P 27/02 20180101; C07C 291/04 20130101; C07C 2603/74 20170501;
A61P 25/00 20180101; A61K 31/36 20130101; C07C 2601/18 20170501;
A61P 21/00 20180101; C07C 2601/08 20170501; C07C 2601/04 20170501;
A61P 19/02 20180101; A61P 29/00 20180101; C07C 2601/14 20170501;
A61P 1/04 20180101; A61K 31/04 20130101; A61P 37/06 20180101 |
Class at
Publication: |
514/466 ;
514/640; 564/253; 549/440 |
International
Class: |
A61K 031/36; A61K
031/15; C07C 251/48 |
Claims
What is claimed is:
1. A compound of formula I: 7wherein R.sup.1 is selected from the
group consisting of alkoxy, alkaryloxy, alkcycloalkoxy, aryloxy,
and cycloalkoxy; R.sup.2 is selected from the group consisting of
hydrogen, alkoxy, alkcycloalkoxy, cycloalkoxy and halogen, or when
R.sup.1 and R.sup.2 are attached to adjacent carbon atoms, R.sup.1
and R.sup.2 may be joined together to form an alkylenedioxy group;
R.sup.3 is selected from the group consisting of hydrogen, alkoxy,
alkcycloalkoxy, cycloalkoxy and halogen; R.sup.4 is selected from
the group consisting of hydrogen and alkyl; R.sup.5 is selected
from the group consisting of alkyl having at least 3 carbon atoms,
substituted alkyl having at least 3 carbon atoms and cycloalkyl;
provided that: (i) when R.sup.2 and R.sup.3 are independently
hydrogen or methoxy, R.sup.1 is not methoxy; (ii) when R.sup.2,
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-n-butoxy, 4-n-pentyloxy or 4-n-hexyloxy; (iii)
when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is
isopropyl, then R.sup.1 is not 4-ethoxy; (iv) when R.sup.1 and
R.sup.2 are joined together to form a 3,4-methylenedioxy group and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not isopropyl or
tert-butyl; (v) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and
R.sup.5 is 1-hydroxy-2-methylprop-2-- yl, then R.sup.1 is not
2-ethoxy; (vi) when R.sup.1 is 4-methoxy, R.sup.2 is 3-ethoxy, and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not
2,2-dimethylbut-3-yl or 1-hydroxy-2-methylprop-2-yl; and (vii) when
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-methoxy when R.sup.2 is 2-fluoro, and R.sup.1 is
not 2-methoxy when R.sup.2 is 4-fluoro.
2. The compound according to claim 1 wherein R.sup.4 is
hydrogen.
3. The compound according to claim 2 wherein R.sup.3 is selected
from the group consisting of hydrogen and alkoxy.
4. The compound according to claim 3 wherein R.sup.2 is selected
from the group consisting of hydrogen, alkoxy and fluoro.
5. The compound according to claim 4 wherein R.sup.1 is selected
from the group consisting of alkoxy, alkaryloxy and
cycloalkoxy.
6. The compound according to claim 4 wherein R.sup.1 and R.sup.2
are joined together to form an alkylenedioxy group.
7. The compound according to claim 5 or 6 wherein R.sup.5 is
selected from the group consisting of alkyl having 3 to about 8
carbon atoms and cycloalkyl having 3 to about 10 carbon atoms.
8. The compound according to claim 7 wherein R.sup.5 is selected
from the group consisting of n-propyl, isopropyl,
1-methoxy2-methylproo-2-yl, n-butyl, but-2-yl, tert-butyl,
2-methylbut-2-yl, 3-methylbut-1-yl, 3,3-dimethylbut-2-yl,
4-methylpent-2-yl, 2,4-dimethyl-2-pentyl,
2,2,4,4-tetramethylpent-3-yl, cyclopropyl, cyclobutyl, tert-octyl,
cyclopentyl, cyclohexyl, cyclooctyl, 1-adamantyl, 2-adamantyl,
3,5-dimethyl-1-adamantyl and benzyl.
9. A compound of formula II: 8wherein R.sup.6 is selected from the
group consisting of alkoxy having 1 to 8 carbon atoms, alkaryloxy
having 7 to 10 carbon atoms and aryloxy having 6 to 10 carbon
atoms; R.sup.7 is selected from the group consisting of alkoxy
having 1 to 8 carbon atoms and fluoro, or when R.sup.6 and R.sup.7
are attached to adjacent carbon atoms, R.sup.6 and R.sup.7 may be
joined together to form an alkylenedioxy group having 1 to about 6
carbon atoms; R.sup.8 is selected from the group consisting of
hydrogen and alkoxy having 1 to 8 carbon atoms; and R.sup.9 is
selected from the group consisting of alkyl having 3 to about 8
carbon atoms, substituted alkyl having 3 to about 8 carbon atoms
and cycloalkyl having 3 to about 10 carbon atoms; provided that:
(i) when R.sup.7 is methoxy and R.sup.8 is hydrogen or methoxy,
R.sup.6 is not methoxy; (ii) when R.sup.6 and R.sup.7 are joined
together to form a 3,4-methylenedioxy group and R.sup.8 is
hydrogen, then R.sup.9 is not isopropyl or tert-butyl; and (iii)
when R.sup.6 is 4-methoxy, R.sup.7 is 3-ethoxy and R.sup.8 is
hydrogen, then R.sup.9 is not 2,2-dimethylbut-3-yl or
1-hydroxy-2-methylprop-2-yl.
10. The compound according to claim 9 wherein R.sup.6 is alkoxy
having 1 to 8 carbon atoms, R.sup.7 is alkoxy having 2 to 8 carbon
atoms and R.sup.8 is hydrogen.
11. The compound according to claim 10 wherein R.sup.6 is methoxy,
R.sup.7 is ethoxy and R.sup.8 is hydrogen.
12. The compound according to claim 9 wherein R.sup.6 is ethoxy;
and R.sup.7 and R.sup.8 are hydrogen.
13. The compound according to claim 9 wherein R.sup.6 is benzyloxy,
R.sup.7 is alkoxy having 1 to 8 carbon atoms, and R.sup.8 is
hydrogen.
14. The compound according to claim 9 wherein R.sup.6 is benzyloxy;
and R.sup.7 and R.sup.8 are hydrogen.
15. The compound according to claim 9 wherein R.sup.6 is alkoxy
having 1 to 8 carbon atoms, R.sup.7 is fluoro and R.sup.8 is
hydrogen.
16. The compound according to claim 9 wherein R.sup.6 and R.sup.7
are joined together to form a methylenedioxy or ethylenedioxy group
and R.sup.8 is hydrogen.
17. The compound according to claim 9 wherein R.sup.6, R.sup.7 and
R.sup.8 are each independently alkoxy having 2 to 8 carbon
atoms.
18. A compound selected from the group consisting of:
.alpha.-(4-heptyloxyphenyl)-N-tert-butylnitrone
.alpha.-(4-hexyloxyphenyl- )-N-n-propylnitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-tert-butylnitrone
.alpha.-(4-ethoxyphenyl)-N-tert-butylnitrone
.alpha.-(4-benzyloxy-3-metho- xyphenyl)-N-tert-butylnitrone
.alpha.-[3-(4-methoxyphenoxy)phenyl]-N-tert-- butylnitrone
.alpha.-(2-ethoxyphenyl)-N-tert-butylnitrone
.alpha.-(3,4-ethylenedioxyphenyl)-N-tert-butylnitrone
.alpha.-(3,4-methylenedioxyphenyl)-N-tert-butylnitrone
.alpha.-(4-ethoxyphenyl)-N-cyclohexylnitrone
.alpha.-(4-benzyloxy-3-metho- xyphenyl)-N-cyclohexylnitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclohe- xylnitrone
.alpha.-(3,4-ethylenedioxyphenyl)-N-cyclohexylnitrone
.alpha.-(4-ethoxy-3-methoxyphenyl)-N-cyclohexylnitrone
.alpha.-(3,4-ethylenedioxyphenyl)-N-isopropylnitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-isopropylnitrone
.alpha.-(2-ethoxyphenyl)-N-isopropylnitrone
.alpha.-(2-ethoxyphenyl)-N-cy- clohexylnitrone
.alpha.-(4-benzyloxy-3-methoxyphenyl)-N-isopropylnitrone
.alpha.-(4-ethoxy-3-methoxyphenyl)-N-isopropylnitrone
.alpha.-(3-ethoxy-4-hexyloxyphenyl)-N-cyclohexylnitrone
.alpha.-(4-benzyloxy-3-methoxyphenyl)-N-n-butylnitrone
.alpha.-(4-ethoxy-3-methoxyphenyl)-N-n-butylnitrone
.alpha.-(2-ethoxyphenyl)-N-n-butylnitrone
.alpha.-(3-ethoxy-4-methoxyphen- yl)-N-n-butylnitrone
.alpha.-(3-ethoxy-4-hexyloxyphenyl)-N-isopropylnitron- e
.alpha.-(3-ethoxy-4-hexyloxyphenyl)-N-tert-butylnitrone
.alpha.-(2-fluoro-4-octyloxyphenyl)-N-tert-butylnitrone
.alpha.-(2,4,6-triethoxyphenyl)-N-tert-butylnitrone
.alpha.-(2,4,6-triethoxyphenyl)-N-cyclohexylnitrone
.alpha.-(2-n-butoxyphenyl)-N-tert-butyylnitrone
.alpha.-(3,4-diethoxyphen- yl)-N-tert-butylnitrone
.alpha.-(2-fluoro-4-heptyloxyphenyl)-N-tert-butyln- itrone
.alpha.-(2-fluoro-4-ethoxyphenyl)-N-tert-butylnitrone
.alpha.-(2-fluoro-4-ethoxyphenyl)-N-cyclohexylnitrone
.alpha.-(2-ethoxyphenyl)-N-adamantylnitrone
.alpha.-(3-ethoxy-4-methoxyph- enyl)-N-adamantylnitrone
.alpha.-(4-ethoxyphenyl)-N-cyclopentylnitrone
.alpha.-(4-ethoxyphenyl)-N-tert-octylnitrone
.alpha.-(4-benzyloxyphenyl)-- N-tert-butylnitrone
.alpha.-(4-benzyloxyphenyl)-N-cyclopentylnitrone
.alpha.-(4-benzyloxyphenyl)-N-cyclohexylnitrone
.alpha.-(2-ethoxyphenyl)-- N-cyclopentylnitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-tert-octylnitron- e
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(2,4-dimethyl-2-pentyl)nitrone
.alpha.-(4-ethoxyphenyl)-N-n-butylnitrone
.alpha.-(2-ethoxyphenyl)-N-benz- ylnitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(2,2,4,4-tetramethylpent-3--
yl)nitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(4-methylpent-2-yl)nitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-2-methylbut-2-yl)nitrone
.alpha.-(2-ethoxyphenyl)-N-but-2-ylnitrone
.alpha.-[4-(4-fluorobenzyloxy)- phenyl]-N-tert-butylnitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclopent- ylnitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-n-propylnitrone
.alpha.-(4-benzyloxyphenyl)-N-n-propylnitrone
.alpha.-(4-benzyloxyphenyl)- -N-isopropylnitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(2-methylbut-2-yl- )nitrone
.alpha.-(2-ethoxyphenyl)-N-(2-methylbut-2-yl)nitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclooctylnitrone
.alpha.-(2-ethoxyphenyl)-N-cyclobutylnitrone
.alpha.-(3-ethoxy-4-methoxyp- henyl)-N-cyclobutylnitrone
.alpha.-(4-benzyloxyphenyl)-N-cyclobutylnitrone
.alpha.-(4-benzyloxyphenyl)-N-tert-octylnitrone
.alpha.-[4-(4-fluorobenzy- loxy)phenyl]-N-cyclohexylnitrone
.alpha.-(2-ethoxyphenyl)-N-tert-octylnitr- one
.alpha.-[4-(4-fluorobenzyloxy)phenyl]-N-isopropylnitrone
.alpha.-(2-ethoxyphenyl)-N-cycloctylnitrone
.alpha.-(4-benzyloxyphenyl)-N- -cyclopropylnitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclopropylnitron- e
.alpha.-(4-benzyloxyphenyl)-N-cyclooctylnitrone
.alpha.-(3-ethoxy-4-meth-
oxyphenyl)-N-(3,5-dimethyl-1-adamantyl)nitrone
.alpha.-(4-benzyloxyphenyl)- -N-1-adamantylnitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(1-methoxy-2-me-
thylprop-2-yl)nitrone
.alpha.-(4-benzyloxyphenyl)-N-2-adamantylnitrone.
.alpha.-(4-ethoxyphenyl)-N-cyclooctylnitrone
.alpha.-(4-ethoxyphenyl)-N-1- -adamantylnitrone
.alpha.-[4-(4-methoxybenzyloxy)phenyl]-N-tert-butylnitro- ne
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(3-methylbut-1-yl)nitrone
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclooctylnitrone, and
.alpha.-[4-(4-fluorobenzyloxy)phenyl]-N-cyclopentylnitrone.
19. .alpha.-(2-Ethoxyphenyl)-N-tert-butylnitrone.
20. .alpha.-(2-Ethoxyphenyl)-N-cyclohexylnitrone.
21. .alpha.-(4-Ethoxyphenyl)-N-cyclohexylnitrone.
22. .alpha.-(4-Benzyloxyphenyl)-N-tert-butylnitrone.
23. .alpha.-(4-Benzyloxyphenyl)-N-cyclopentylnitrone.
24. .alpha.-(3-Ethoxy-4-methoxyphenyl)-N-adamantylnitrone.
25. .alpha.-(3-Ethoxy-4-methoxyphenyl)-N-tert-octylnitrone.
26. A pharmaceutical composition comprising a pharmaceutically
acceptable carrier and a pharmaceutically effective amount of a
compound of formula I: 9wherein R.sup.1 is selected from the group
consisting of alkoxy, alkaryloxy, alkcycloalkoxy, aryloxy, and
cycloalkoxy; R.sup.2 is selected from the group consisting of
hydrogen, alkoxy, alkcycloalkoxy, cycloalkoxy and halogen, or when
R.sup.1 and R.sup.2 are attached to adjacent carbon atoms, R.sup.1
and R.sup.2 may be joined together to form an alkylenedioxy group;
R.sup.3 is selected from the group consisting of hydrogen, alkoxy,
alkcycloalkoxy, cycloalkoxy and halogen; R.sup.4 is selected from
the group consisting of hydrogen and alkyl; R.sup.5 is selected
from the group consisting of alkyl having at least 3 carbon atoms,
alkcycloalkyl and cycloalkyl; provided that: (i) when R.sup.2 and
R.sup.3 are independently hydrogen or methoxy, R.sup.1 is not
methoxy; (ii) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and
R.sup.5 is tert-butyl, then R.sup.1 is not 4-n-butoxy,
4-n-pentyloxy or 4-n-hexyloxy; (iii) when R.sup.2, R.sup.3 and
R.sup.4 are hydrogen and R.sup.5 is isopropyl, then R.sup.1 is not
4-ethoxy; (iv) when R.sup.1 and R.sup.2 are joined together to form
a 3,4-methylenedioxy group and R.sup.3 and R.sup.4 are hydrogen,
then R.sup.5 is not isopropyl or tert-butyl; (v) when R.sup.2,
R.sup.3 and R.sup.4 are hydrogen and R is
1-hydroxy-2-methylprop-2-yl, then R.sup.1 is not 2-ethoxy; (vi)
when R.sup.1 is 4-methoxy, R.sup.2 is 3-ethoxy, and R.sup.3 and
R.sup.4 are hydrogen, then R.sup.5 is not 2,2-dimethylbut-3-yl or
1-hydroxy-2-methylprop-2-yl; and (vii) when R.sup.3 and R.sup.4 are
hydrogen and R.sup.5 is tert-butyl, then R.sup.1 is not 4-methoxy
when R.sup.2 is 2-fluoro, and R.sup.1 is not 2-methoxy when R.sup.2
is 4-fluoro.
27. The pharmaceutical composition according to claim 26 wherein
R.sup.4 is hydrogen.
28. The pharmaceutical composition according to claim 27 wherein
R.sup.3 is selected from the group consisting of hydrogen and
alkoxy.
29. The pharmaceutical composition according to claim 28 wherein
R.sup.2 is selected from the group consisting of hydrogen, alkoxy
and fluoro.
30. The pharmaceutical composition according to claim 29 wherein
R.sup.1 is selected from the group consisting of alkoxy, alkaryloxy
and cycloalkoxy.
31. The pharmaceutical composition according to claim 29 wherein
R.sup.1 and R.sup.2 are joined together to form an alkylenedioxy
group.
32. The pharmaceutical composition according to claim 30 or 31
wherein R.sup.5 is selected from the group consisting of alkyl
having 3 to about 8 carbon atoms and cycloalkyl having 3 to about 8
carbon atoms.
33. The pharmaceutical composition according to claim 32 wherein
R.sup.5 is selected from the group consisting of n-propyl,
isopropyl, 1-methoxy2-methylproo-2-yl, n-butyl, but-2-yl,
tert-butyl, 2-methylbut-2-yl, 3-methylbut-1-yl,
3,3-dimethylbut-2-yl, 4-methylpent-2-yl, 2,4-dimethyl-2-pentyl,
2,2,4,4-tetramethylpent-3-yl, cyclopropyl, cyclobutyl, tert-octyl,
cyclopentyl, cyclohexyl, cyclooctyl, 1-adamantyl, 2-adamantyl,
3,5-dimethyl-1-adamantyl and benzyl.
34. A pharmaceutical composition comprising a pharmaceutically
acceptable carrier and a pharmaceutically effective amount of
formula II: 10wherein R.sup.6 is selected from the group consisting
of alkoxy having 1 to 8 carbon atoms, alkaryloxy having 7 to 10
carbon atoms and aryloxy having 6 to 10 carbon atoms; R.sup.7 is
selected from the group consisting of alkoxy having 1 to 8 carbon
atoms and fluoro, or when R.sup.6 and R.sup.7 are attached to
adjacent carbon atoms, R.sup.6 and R.sup.7 may be joined together
to form an alkylenedioxy group having 1 to about 6 carbon atoms;
R.sup.8 is selected from the group consisting of hydrogen and
alkoxy having 1 to 8 carbon atoms; and R.sup.9 is selected from the
group consisting of alkyl having 3 to about 8 carbon atoms,
substituted alkyl having 3 to about 8 carbon atoms and cycloalkyl
having 3 to about 10 carbon atoms; provided that: (i) when R.sup.7
is methoxy and R.sup.8 is hydrogen or methoxy, R.sup.6 is not
methoxy; (ii) when R.sup.6 and R.sup.7 are joined together to form
a 3,4-methylenedioxy group and R.sup.8 is hydrogen, then R.sup.9 is
not isopropyl or tert-butyl; and (iii) when R.sup.6 is 4-methoxy,
R.sup.7 is 3-ethoxy and R.sup.8 is hydrogen, then R.sup.9 is not
2,2-dimethylbut-3-yl or 1-hydroxy-2-methylprop-2-yl.
35. The pharmaceutical composition according to claim 34 wherein
R.sup.6 is alkoxy having 1 to 8 carbon atoms, R.sup.7 is alkoxy
having 2 to 8 carbon atoms and R.sup.8 is hydrogen.
36. The pharmaceutical composition according to claim 35 wherein
R.sup.6 is methoxy, R.sup.7 is ethoxy and R.sup.8 is hydrogen.
37. The pharmaceutical composition according to claim 34 wherein
R.sup.6 is benzyloxy, 4-fluorobenzyloxy or 4-methoxybenzyloxy and
R.sup.7 and R.sup.8 are hydrogen.
38. The pharmaceutical composition according to claim 34 wherein
R.sup.6 is ethoxy and R.sup.7 and R.sup.8 are hydrogen.
39. The pharmaceutical composition according to claim 34 wherein
R.sup.6 is alkoxy having 1 to 8 carbon atoms, R.sup.7 is fluoro and
R.sup.8 is hydrogen.
40. The pharmaceutical composition according to claim 34 wherein
R.sup.6 and R.sup.7 are joined together to form a methylenedioxy or
ethylenedioxy group and R.sup.8 is hydrogen.
41. The pharmaceutical composition according to claim 34 wherein
R.sup.6, R.sup.7 and R.sup.8 are each independently alkoxy having 2
to 8 carbon atoms.
42. The pharmaceutical composition according to claim 26 or 34
wherein the carrier is an oral carrier.
43. The pharmaceutical composition according to claim 26 or 34
wherein the carrier is an injectable carrier.
44. A method for treating a patient with a neurodegenerative
disease which method comprises administering to said patient a
pharmaceutical composition comprising a pharmaceutically acceptable
carrier and an effective neurodegenerative disease-treating amount
of a compound of formula I: 11wherein R.sup.1 is selected from the
group consisting of alkoxy, alkaryloxy, alkcycloalkoxy, aryloxy,
and cycloalkoxy; R.sup.2 is selected from the group consisting of
hydrogen, alkoxy, alkcycloalkoxy, cycloalkoxy and halogen, or when
R.sup.1 and R.sup.2 are attached to adjacent carbon atoms, R.sup.1
and R.sup.2 may be joined together to form an alkylenedioxy group;
R.sup.3 is selected from the group consisting of hydrogen, alkoxy,
alkcycloalkoxy, cycloalkoxy and halogen; R.sup.4 is selected from
the group consisting of hydrogen and alkyl; R.sup.5 is selected
from the group consisting of alkyl having at least 3 carbon atoms,
substitututed alkyl having at least 3 carbon atoms and cycloalkyl;
provided that: (i) when R.sup.2 and R.sup.3 are independently
hydrogen or methoxy, R.sup.1 is not methoxy; (ii) when R.sup.2,
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-n-butoxy, 4-n-pentyloxy or 4-n-hexyloxy; (iii)
when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is
isopropyl, then R.sup.1 is not 4-ethoxy; (iv) when R.sup.1 and
R.sup.2 are joined together to form a 3,4-methylenedioxy group and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not isopropyl or
tert-butyl; (v) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and
R.sup.5 is 1-hydroxy-2-methylprop-2-yl, then R.sup.1 is not
2-ethoxy; (vi) when R.sup.1 is 4-methoxy, R.sup.2 is 3-ethoxy, and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not
2,2-dimethylbut-3-yl or 1-hydroxy-2-methylprop-2-yl; and (vii) when
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-methoxy when R.sup.2 is 2-fluoro, and R.sup.1 is
not 2-methoxy when R.sup.2 is 4-fluoro.
45. A method for preventing the onset of a neurodegenerative
disease in a patient at risk for developing the neurodegenerative
disease which method comprises administering to said patient a
pharmaceutical composition comprising a pharmaceutically acceptable
carrier and an effective neurodegenerative disease-preventing
amount of a compound of formula I: 12wherein R.sup.1 is selected
from the group consisting of alkoxy, alkaryloxy, alkcycloalkoxy,
aryloxy, and cycloalkoxy; R.sup.2 is selected from the group
consisting of hydrogen, alkoxy, alkcycloalkoxy, cycloalkoxy and
halogen, or when R.sup.1 and R.sup.2 are attached to adjacent
carbon atoms, R.sup.1 and R.sup.2 may be joined together to form an
alkylenedioxy group; R.sup.3 is selected from the group consisting
of hydrogen, alkoxy, alkcycloalkoxy, cycloalkoxy and halogen;
R.sup.4 is selected from the group consisting of hydrogen and
alkyl; R.sup.5 is selected from the group consisting of alkyl
having at least 3 carbon atoms, substitututed alkyl having at least
3 carbon atoms and cycloalkyl; provided that: (i) when R.sup.2 and
R.sup.3 are independently hydrogen or methoxy, R.sup.1 is not
methoxy; (ii) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and
R.sup.5 is tert-butyl, then R.sup.1 is not 4-n-butoxy,
4-n-pentyloxy or 4-n-hexyloxy; (iii) when R.sup.2, R.sup.3 and
R.sup.4 are hydrogen and R.sup.5 is isopropyl, then R.sup.1 is not
4-ethoxy; (iv) when R.sup.1 and R.sup.2 are joined together to form
a 3,4-methylenedioxy group and R.sup.3 and R.sup.4 are hydrogen,
then R.sup.5 is not isopropyl or tert-butyl; (v) when R.sup.2,
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is
1-hydroxy-2-methylprop-2-yl, then R.sup.1 is not 2-ethoxy; (vi)
when R.sup.1 is 4-methoxy, R.sup.2 is 3-ethoxy, and R.sup.3 and
R.sup.4 are hydrogen, then R.sup.5 is not 2,2-dimethylbut-3-yl or
1-hydroxy-2-methylprop-2-yl; and (vii) when R.sup.3 and R.sup.4 are
hydrogen and R.sup.5 is tert-butyl, then R.sup.5 is not 4-methoxy
when R.sup.2 is 2-fluoro, and R.sup.1 is not 2-methoxy when R.sup.2
is 4-fluoro.
46. The method according to claim 44 or 45 wherein the
neurodegenerative disease is Alzheimer's disease.
47. The method according to claim 44 or 45 wherein the
neurodegenerative disease is Parkinson's disease.
48. The method according to claim 44 or 45 wherein the
neurodegenerative disease is HIV dementia.
49. A method for treating a patient with an autoimmune disease
which method comprises administering to said patient a
pharmaceutical composition comprising a pharmaceutically acceptable
carrier and an effective autoimmune disease-treating amount of a
compound of formula I: 13wherein R.sup.1 is selected from the group
consisting of alkoxy, alkaryloxy, alkcycloalkoxy, aryloxy, and
cycloalkoxy; R.sup.2 is selected from the group consisting of
hydrogen, alkoxy, alkcycloalkoxy, cycloalkoxy and halogen, or when
R.sup.1 and R.sup.2 are attached to adjacent carbon atoms, R.sup.1
and R.sup.2 may be joined together to form an alkylenedioxy group;
R.sup.3 is selected from the group consisting of hydrogen, alkoxy,
alkcycloalkoxy, cycloalkoxy and halogen; R.sup.4 is selected from
the group consisting of hydrogen and alkyl; R.sup.5 is selected
from the group consisting of alkyl having at least 3 carbon atoms,
substitututed alkyl having at least 3 carbon atoms and cycloalkyl;
provided that: (i) when R.sup.2 and R.sup.3 are independently
hydrogen or methoxy, R.sup.1 is not methoxy; (ii) when R.sup.2,
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-n-butoxy, 4-n-pentyloxy or 4-n-hexyloxy; (iii)
when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is
isopropyl, then R.sup.1 is not 4-ethoxy; (iv) when R.sup.1 and
R.sup.2 are joined together to form a 3,4-methylenedioxy group and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not isopropyl or
tert-butyl; (v) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and
R.sup.5 is 1-hydroxy-2-methylprop-2-yl, then R.sup.1 is not
2-ethoxy; (vi) when R.sup.1 is 4-methoxy, R.sup.2 is 3-ethoxy, and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not
2,2-dimethylbut-3-yl or 1-hydroxy-2-methylprop-2-yl; and (vii) when
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-methoxy when R.sup.2 is 2-fluoro, and R.sup.1 is
not 2-methoxy when R.sup.2 is 4-fluoro.
50. A method for preventing the onset of an autoimmune disease in a
patient at risk for developing the autoimmune disease which method
comprises administering to said patient a pharmaceutical
composition comprising a pharmaceutically acceptable carrier and an
effective autoimmune disease-preventing amount of a compound of
formula I: 14wherein R.sup.1 is selected from the group consisting
of alkoxy, alkaryloxy, alkcycloalkoxy, aryloxy, and cycloalkoxy;
R.sup.2 is selected from the group consisting of hydrogen, alkoxy,
alkcycloalkoxy, cycloalkoxy and halogen, or when R.sup.1 and
R.sup.2 are attached to adjacent carbon atoms, R.sup.1 and R.sup.2
may be joined together to form an alkylenedioxy group; R.sup.3 is
selected from the group consisting of hydrogen, alkoxy,
alkcycloalkoxy, cycloalkoxy and halogen; R.sup.4 is selected from
the group consisting of hydrogen and alkyl; R.sup.5 is selected
from the group consisting of alkyl having at least 3 carbon atoms,
substitututed alkyl having at least 3 carbon atoms and cycloalkyl;
provided that: (i) when R.sup.2 and R.sup.3 are independently
hydrogen or methoxy, R.sup.1 is not methoxy; (ii) when R.sup.2,
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-n-butoxy, 4-n-pentyloxy or 4-n-hexyloxy; (iii)
when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is
isopropyl, then R.sup.1 is not 4-ethoxy; (iv) when R.sup.1 and
R.sup.2 are joined together to form a 3,4-methylenedioxy group and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not isopropyl or
tert-butyl; (v) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and
R.sup.5 is 1-hydroxy-2-methylprop-2-yl, then R.sup.1 is not
2-ethoxy; (vi) when R.sup.1 is 4-methoxy, R.sup.2 is 3-ethoxy, and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not
2,2-dimethylbut-3-yl or 1-hydroxy-2-methylprop-2-yl; and (vii) when
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-methoxy when R.sup.2 is 2-fluoro, and R.sup.1 is
not 2-methoxy when R.sup.2 is 4-fluoro.
51. The method according to claim 49 or 50 wherein the autoimmune
disease is systemic lupus.
52. The method according to claim 49 or 50 wherein the autoimmune
disease is multiple sclerosis.
53. A method for treating a patient with an inflammatory disease
which method comprises administering to said patient a
pharmaceutical composition comprising a pharmaceutically acceptable
carrier and an effective inflammatory disease-treating amount of a
compound of formula I: 15wherein R.sup.1 is selected from the group
consisting of alkoxy, alkaryloxy, alkcycloalkoxy, aryloxy, and
cycloalkoxy; R.sup.2 is selected from the group consisting of
hydrogen, alkoxy, alkcycloalkoxy, cycloalkoxy and halogen, or when
R.sup.1 and R.sup.2 are attached to adjacent carbon atoms, R.sup.1
and R.sup.2 may be joined together to form an alkylenedioxy group;
R.sup.3 is selected from the group consisting of hydrogen, alkoxy,
alkcycloalkoxy, cycloalkoxy and halogen; R.sup.4 is selected from
the group consisting of hydrogen and alkyl; R.sup.5 is selected
from the group consisting of alkyl having at least 3 carbon atoms,
substitututed alkyl having at least 3 carbon atoms and cycloalkyl;
provided that: (i) when R.sup.2 and R.sup.3 are independently
hydrogen or methoxy, R.sup.1 is not methoxy; (ii) when R.sup.2,
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-n-butoxy, 4-n-pentyloxy or 4-n-hexyloxy; (iii)
when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is
isopropyl, then R.sup.1 is not 4-ethoxy; (iv) when R.sup.1 and
R.sup.2 are joined together to form a 3,4-methylenedioxy group and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not isopropyl
or-tert-butyl; (v) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen
and R.sup.5 is 1-hydroxy-2-methylprop-2-yl, then R.sup.1 is not
2-ethoxy; (vi) when R.sup.3 is 4-methoxy, R.sup.2 is 3-ethoxy, and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not
2,2-dimethylbut-3-yl or 1-hydroxy-2-methylprop-2-yl; and (vii) when
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-methoxy when R.sup.2 is 2-fluoro, and R.sup.1 is
not 2-methoxy when R.sup.2 is 4-fluoro.
54. A method for preventing the onset of an inflammatory disease in
a patient at risk for developing the inflammatory disease which
method comprises administering to said patient a pharmaceutical
composition comprising a pharmaceutically acceptable carrier and an
effective inflammatory disease-preventing amount of a compound of
formula I: 16wherein R.sup.1 is selected from the group consisting
of alkoxy, alkaryloxy, alkcycloalkoxy, aryloxy, and cycloalkoxy;
R.sup.2 is selected from the group consisting of hydrogen, alkoxy,
alkcycloalkoxy, cycloalkoxy and halogen, or when R.sup.1 and
R.sup.2 are attached to adjacent carbon atoms, R.sup.1 and R.sup.2
may be joined together to form an alkylenedioxy group; R.sup.3 is
selected from the group consisting of hydrogen, alkoxy,
alkcycloalkoxy, cycloalkoxy and halogen; R.sup.4 is selected from
the group consisting of hydrogen and alkyl; R.sup.5 is selected
from the group consisting-of alkyl having at least 3 carbon atoms,
substitututed alkyl having at least 3 carbon atoms and cycloalkyl;
provided that: (i) when R.sup.2 and R.sup.3 are independently
hydrogen or methoxy, R.sup.1 is not methoxy; (ii) when R.sup.2,
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-n-butoxy, 4-n-pentyloxy or 4-n-hexyloxy; (iii)
when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is
isopropyl, then R.sup.1 is not 4-ethoxy; (iv) when R.sup.1 and
R.sup.2 are joined together to form a 3,4-methylenedioxy group and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not isopropyl or
tert-butyl; (v) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and
R.sup.5 is 1-hydroxy-2-methylprop-2-yl, then R.sup.1 is not
2-ethoxy; (vi) when R.sup.1 is 4-methoxy, R.sup.2 is 3-ethoxy, and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not
2,2-dimethylbut-3-yl or 1-hydroxy-2-methylprop-2-yl; and (vii) when
R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is tert-butyl, then
R.sup.1 is not 4-methoxy when R.sup.2 is 2-fluoro, and R.sup.1 is
not 2-methoxy when R.sup.2 is 4-fluoro.
55. The method according to claim 53 or 54 wherein the inflammatory
disease is rheumatoid arthritis.
56. The method according to claim 53 or 54 wherein the inflammatory
disease is septic shock.
57. The method according to claim 53 or 54 wherein the inflammatory
disease is erythema nodosum leprosy.
58. The method according to claim 53 or 54 wherein the inflammatory
disease is septicemia.
59. The method according to claim 53 or 54 wherein the inflammatory
disease is uveitis.
60. The method according to claim 53 or 54 wherein the inflammatory
disease is adult respiratory distress syndrome.
61. The method according to claim 53 or 54 wherein the inflammatory
disease is inflammatory bowel disease.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/062,324, filed Oct. 17, 1997; U.S. Provisional
Application No. 60/063,736, filed Oct. 29, 1997; and U.S.
Provisional Application No. 60/090,475, filed Jun. 24, 1998. These
applications are incorporated herein by reference in their
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to novel .alpha.-aryl-N-alkylnitrones
and their use as therapeutic agents and analytical reagents. More
particularly, this invention concerns novel
.alpha.-aryl-N-alkylnitrones and their use as therapeutics for
treating and/or preventing neurological, autoimmune and
inflammatory conditions in mammals and as analytical reagents for
detecting free radicals.
[0004] 2. State of the Art
[0005] Alzheimer's disease is a neurodegenerative condition in
which nerve cells in the brain are systematically destroyed
resulting in progressive memory loss, mental confusion and
ultimately death. The National Institute on Aging (NIA) has
recently estimated that about 4 million people in the United States
are currently afflicted with Alzheimer's disease. At present, there
is no treatment that effectively prevents the disease or reverses
its symptoms.
[0006] In recent years, significant progress has been made in
understanding the pathogenesis of Alzheimer's disease. For example,
it is now known that patients with Alzheimer's disease develop
amyloid plaque deposits around and between the nerve cells of their
brain. These plaque deposits are made up of fibrillar aggregates of
a small peptide called amyloid .beta.-peptide or A.beta.. The
plaque deposits initially form in the hippocampus and cortical
regions of the brain (areas associated with memory and cognition)
and then spread to other areas as the disease progresses. The
deposition of fibrils and plaques is also followed by inflammation
of the surrounding support cells, called glia, which may lead to
further loss of neurons. Eventually, the nerve cells in the brains
of most Alzheimer's patients develop tangles of a
microtubule-associated protein, called tau, which are believed to
be a response by the nerve cells to damage.
[0007] Progress in understanding the underlying mechanisms of
Alzheimer's disease has led to the development of various in vitro
and in vivo models to identify compounds effective for preventing
and/or treating Alzheimer's disease and other neurodegenerative
conditions. In one such in vitro model, compounds are evaluated for
their ability to intervene in A.beta.(1-40) or A.beta.(1-42)
beta-pleated sheet formation. Since the deposition of amyloid
.beta.-peptide is associated with the development of Alzheimer's
disease, compounds which effectively disrupt the formation of
A.beta.(1-40) beta-pleated sheets are potentially useful for
preventing and/or reversing Alzheimer's disease-related amyloid
deposits.
[0008] In another in vitro model, compounds are evaluated for their
ability to protect against A.beta.(25-35)-induced neuronal cell
loss in rat embryonic hippocampal neuronal/astrocyte cultures. As
discussed above, patients with Alzheimer's disease suffer a
progressive loss of neuronal cells. Accordingly, compounds which
are effective in this in vitro test are potentially useful for
reducing or preventing neuronal cell loss in patients afflicted
with Alzheimer's disease or other neurodegenerative conditions.
[0009] A third in vitro Alzheimer's disease model is based on the
observation that .beta.-amyloid increases the release of cytokines,
such as interleukin-1.beta. (IL-1.beta.), interleukin-6 (IL-6) and
tumor necrosis factor-.alpha. (TNF.alpha.), in human monocyte cells
induced with lipopolysaccharide (LPS). IL-1.beta., IL-6 and
TNF.alpha. are proteins associated with inflammatory and immune
responses. As previously mentioned, the deposition of fibrils in
the brains of Alzheimer's patients is associated with inflammation
of the surrounding support cells. See, S. D. Yan et al., Proc.
Natl. Acad. Sci. USA, 94, 5296 (1997). Thus, compounds effective in
this in vitro test are potentially useful for reducing and/or
preventing the inflammation associated with Alzheimer's
disease.
[0010] Additionally, elevated levels of IL-1.beta., IL-6,
TNF.alpha. and other cytokines are associated with a wide variety
of inflammatory and autoimmune conditions, including septic shock,
rheumatoid arthritis, erythema nodosum leprosy, meningococcal
meningitis, multiple sclerosis, systemic lupus and the like. See,
L. Sekut et al., Drug News Perspect. 1196, 9, 261; and A. Waage et
al., J. Exp. Med. 1989, 170, 1859-1867. Accordingly, compounds
which inhibit the production of such cytokines are potentially
useful for treating such inflammatory and autoimmune
conditions.
[0011] Similarly, various in vivo disease models are available for
identifying compounds useful for preventing and/or treating
neurodegenerative, autoimmune and inflammatory conditions. One such
in vivo disease model is based on the observation that mammals
suffer cognitive impairment when A.beta.(25-35) and ibotenate are
injected into the hippocampus of their brain. Since amyloid
.beta.-peptide deposits are associated with Alzheimer's disease,
compounds which effectively reduce the cognitive impairment caused
by A.beta.(25-35)/ibotenate are potentially useful for the
prevention and/or treatment of Alzheimer's disease and other
neurodegenerative conditions. Another in vivo disease model is
based on the observation that certain strains of autoimmune mice
develop cognitive deficits as they mature. See, for example,
Forster et al., Behav. Neural Biology 1988, 49, 139-151. Thus,
compounds which prevent or reduce such cognitive deficits are
potentially useful for preventing and/or treating neurodegenerative
and autoimmune conditions.
[0012] It has now been discovered that certain novel
.alpha.-aryl-N-alkylnitrone compounds effectively inhibit the
formation of A.beta.(1-42) beta-pleated sheets and/or protect
against neuronal cell loss and/or inhibit the release of cytokines,
such as IL-1.beta. and TNF.alpha.. Additionally, in in vivo tests,
these compounds have been found to reduce the cognitive impairment
caused by A.beta.(25-35)/ibotenate and to reduce the cognitive
deficits that develop in certain strains of autoimmune mice.
Accordingly, such compounds are useful for the prevention and/or
treatment of neurodegenerative, autoimmune and inflammatory
conditions in mammals.
[0013] The .alpha.-aryl-N-alkylnitrone compounds of this invention
are also useful as analytical reagents for detecting free radicals.
In this regard, the compounds of this invention function as "spin
traps" by reacting with unstable free radicals to form relatively
stable free radical spin adducts which are observable by electron
spin resonance (ESR) spectroscopy. Accordingly, when used as spin
traps, the compounds of this invention allow free radicals to be
identified and studied using ESR and related techniques.
SUMMARY OF THE INVENTION
[0014] This invention provides novel .alpha.-aryl-N-alkylnitrone
compounds which are useful as therapeutics for treating and/or
preventing neurological, autoimmune and inflammatory conditions in
mammals and as analytical reagents for detecting free radicals. In
particular, the compounds of this invention are useful for
preventing and/or treating Alzheimer's disease.
[0015] Accordingly, in one of its composition aspects, this
invention is directed to compounds of formula I: 1
[0016] wherein
[0017] R.sup.1 is selected from the group consisting of alkoxy,
alkaryloxy, alkcycloalkoxy, aryloxy, and cycloalkoxy;
[0018] R.sup.2 is selected from the group consisting of hydrogen,
alkoxy, alkcycloalkoxy, cycloalkoxy and halogen, or when R.sup.1
and R.sup.2 are attached to adjacent carbon atoms, R.sup.1 and
R.sup.2 may be joined together to form an alkylenedioxy group;
[0019] R.sup.3 is selected from the group consisting of hydrogen,
alkoxy, alkcycloalkoxy, cycloalkoxy and halogen;
[0020] R.sup.4 is selected from the group consisting of hydrogen
and alkyl;
[0021] R.sup.5 is selected from the group consisting of alkyl
having at least 3 carbon atoms, substituted alkyl having at least 3
carbon atoms and cycloalkyl;
[0022] provided that:
[0023] (i) when R.sup.2 and R.sup.3 are independently hydrogen or
methoxy, R.sup.1 is not methoxy;
[0024] (ii) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and
R.sup.5 is tert-butyl, then R.sup.1 is not 4-n-butoxy,
4-n-pentyloxy or 4-n-hexyloxy;
[0025] (iii) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and
R.sup.5 is isopropyl, then R.sup.1 is not 4-ethoxy;
[0026] (iv) when R.sup.1 and R.sup.2 are joined together to form a
3,4-methylenedioxy group and R.sup.3 and R.sup.4 are hydrogen, then
R.sup.5 is not isopropyl or tert-butyl;
[0027] (v) when R.sup.2, R.sup.3 and R.sup.4 are hydrogen and
R.sup.5 is 1-hydroxy-2-methylprop-2-yl, then R.sup.1 is not
2-ethoxy;
[0028] (vi) when R.sup.1 is 4-methoxy, R.sup.2 is 3-ethoxy, and
R.sup.3 and R.sup.4 are hydrogen, then R.sup.5 is not
2,2-dimethylbut-3-yl or 1-hydroxy-2-methylprop-2-yl; and
[0029] (vii) when R.sup.3 and R.sup.4 are hydrogen and R.sup.5 is
tert-butyl, then R.sup.1 is not 4-methoxy when R.sup.2 is 2-fluoro,
and R.sup.1 is not 2-methoxy when R.sup.2 is 4-fluoro.
[0030] Preferably, in the compounds of formula I above, R.sup.1 is
selected from the group consisting of alkoxy, alkaryloxy and
cycloalkoxy. More preferably, R.sup.1 is alkoxy having 1 to about 8
carbon atoms or alkaryloxy having 7 to about 10 carbon atoms.
Particularly preferred R.sup.1 groups include methoxy, ethoxy,
butoxy, pentyloxy, hexyloxy, cyclohexyloxy, heptyloxy, octyloxy,
benzyloxy, 4-fluorobenzyloxy and 4-methoxybenzyloxy.
[0031] R.sup.2 is preferably selected from the group consisting of
hydrogen, alkoxy and fluoro. More preferably, R.sup.2 is hydrogen,
alkoxy having 2 to about 8 carbon atoms, or fluoro. Particularly
preferred R.sup.2 groups include hydrogen, ethoxy and fluoro.
[0032] When R.sup.1 and R.sup.2 are attached to adjacent carbon
atoms, R.sup.1 and R.sup.2 are also preferably joined together to
form an alkylenedioxy group having 1 to about 6 carbon atoms.
Particularly preferred alkylenedioxy groups include methylenedioxy
and ethylenedioxy, provided that when R.sup.1 and R.sup.2 are
joined together to form a 3,4-methylenedioxy group and R.sup.3 and
R.sup.4 are hydrogen, then R.sup.5 is not isopropyl or
tert-butyl.
[0033] Preferably, R.sup.3 is hydrogen or alkoxy. More preferably,
R.sup.3 is hydrogen or alkoxy having 2 to 8 carbon atoms.
Particularly preferred R.sup.3 groups include hydrogen and
ethoxy.
[0034] R.sup.4 is preferably hydrogen or lower alkyl. More
preferably, R.sup.4 is hydrogen or alkyl having 1 to 4 carbon
atoms. Still more preferably, R.sup.4 is hydrogen.
[0035] R.sup.5 is preferably selected from the group consisting of
alkyl having 3 to about 8 carbon atoms, substituted alkyl having 3
to 8 carbon atoms and cycloalkyl having 3 to about 10 carbon atoms.
More preferably, R.sup.5 is alkyl having 3 to 6 carbon atoms or
cycloalkyl having 5 to 6 carbon atoms.
[0036] Particularly preferred R.sup.5 groups include n-propyl,
isopropyl, 1-methoxy2-methylproo-2-yl, n-butyl, but-2-yl,
tert-butyl, 2-methylbut-2-yl, 3-methylbut-1-yl,
3,3-dimethylbut-2-yl, 4-methylpent-2-yl, 2,4-dimethyl-2-pentyl,
2,2,4,4-tetramethylpent-3-yl, cyclopropyl, cyclobutyl, tert-octyl
(2,4,4-trimethylpent-2-yl), cyclopentyl, cyclohexyl, cyclooctyl,
1-adamantyl, 2-adamantyl, 3,5-dimethyl-1-adamantyl and benzyl. When
R.sup.5 is adamantyl, 1-adamantyl is preferred.
[0037] Other suitable R.sup.5 groups include, by way of example,
1-phenylethyl, 1-phenylprop-2-yl, 2-phenylprop-2-yl,
2-benzylprop-2-yl, 2-(methoxycarbonyl)-prop-2-yl,
1,3-dihydroxy-2-(hydroxymethyl)prop-2-yl,
1-sulfo-2-methylprop-2-yl, 4-fluorobenzyl, 3,4-dimethoxybenzyl,
3-thiomethoxybut-1-yl and 3-thiomethoxyprop-1-yl.
[0038] An especially preferred group of compounds of formula I are
those in which R.sup.1 is a 2-ethoxy group; R.sup.2, R.sup.3 and
R.sup.4 are each hydrogen; and R.sup.5 is as defined above.
[0039] Another especially preferred-group of compounds of formula I
are those in which R.sup.1 is a 4-ethoxy group; R.sup.2, R.sup.3
and R.sup.4 are each hydrogen; and R.sup.5 is as defined above.
[0040] Still another especially preferred group of compounds of
formula I are those in which R.sup.1 is a 4-benzyloxy group;
R.sup.2, R.sup.3 and R.sup.4 are each hydrogen; and R.sup.5 is as
defined above.
[0041] Yet another especially preferred group of compounds of
formula I are those in which R.sup.1 is a 3-ethoxy group; R.sup.2
is a 4-methoxy group; R.sup.3 and R.sup.4 are each hydrogen; and
R.sup.5 is as defined above.
[0042] In a preferred embodiment, this invention is directed to a
compound of formula II: 2
[0043] wherein
[0044] R.sup.6 is selected from the group consisting of alkoxy
having 1 to 8 carbon atoms, alkaryloxy having 7 to 10 carbon atoms,
aryloxy having 6 to 10 carbon atoms and cycloalkoxy having 3 to 10
carbon atoms;
[0045] R.sup.7 is selected from the group consisting of alkoxy
having 1 to 8 carbon atoms and fluoro, or when R.sup.6 and R.sup.7
are attached to adjacent carbon atoms, R.sup.6 and R.sup.7 may be
joined together to form an alkylenedioxy group having 1 to about 6
carbon atoms;
[0046] R.sup.8 is selected from the group consisting of hydrogen
and alkoxy having 1 to 8 carbon atoms; and
[0047] R.sup.9 is selected from the group consisting of alkyl
having 3 to about 8 carbon atoms, substituted alkyl having 3 to
about 8 carbon atoms and cycloalkyl having 3 to about 10 carbon
atoms;
[0048] provided that:
[0049] (i) when R.sup.7 is methoxy and R.sup.8 is hydrogen or
methoxy, R.sup.6 is not methoxy;
[0050] (ii) when R.sup.6 and R.sup.7 are joined together to form a
3,4-methylenedioxy group and R.sup.8 is hydrogen, then R.sup.9 is
not isopropyl or tert-butyl; and
[0051] (iii) when R.sup.6 is 4-methoxy, R.sup.7 is 3-ethoxy and
R.sup.8 is hydrogen, then R.sup.9 is not 2,2-dimethylbut-3-yl or
1-hydroxy-2-methylprop-2-yl.
[0052] In a preferred embodiment, R.sup.6 is alkoxy having 1 to 8
carbon atoms, R.sup.7 is alkoxy having 2 to 8 carbon atoms and
R.sup.8 is hydrogen. In this embodiment, particularly preferred
R.sup.6 groups include methoxy, ethoxy, butoxy, pentyloxy,
hexyloxy, heptyloxy and octyloxy, and particularly preferred
R.sup.7 groups include ethoxy. More preferably, R.sup.6 is methoxy
and R.sup.7 is ethoxy.
[0053] In another preferred embodiment, R.sup.6 is ethoxy; and
R.sup.7 and R.sup.8 are hydrogen.
[0054] In yet another preferred embodiment, R.sup.6 is benzyloxy,
R.sup.7 is alkoxy having 1 to 8 carbon atoms, and R.sup.8 is
hydrogen. In this embodiment, particularly preferred R.sup.7 groups
include methoxy, ethoxy, butoxy, pentyloxy, hexyloxy, heptyloxy and
octyloxy. In another preferred embodiment, R.sup.6 is benzyloxy;
and R.sup.7 and R.sup.8 are hydrogen.
[0055] In still another preferred embodiment, R.sup.6 is alkoxy
having 1 to 8 carbon atoms, R.sup.7 is fluoro and R.sup.8 is
hydrogen. In this embodiment, particularly preferred R.sup.6 groups
include methoxy, ethoxy, butoxy, pentyloxy, hexyloxy, heptyloxy and
octyloxy.
[0056] In yet another preferred embodiment, R.sup.6 and R.sup.7 are
joined together to form a methylenedioxy or ethylenedioxy group and
R.sup.8 is hydrogen, provided that when R.sup.6 and R.sup.7 are
joined together to form a 3,4-methylenedioxy group and R.sup.8 is
hydrogen, then R.sup.9 is not isopropyl or tert-butyl.
[0057] In the above embodiments, R.sup.9 is preferably alkyl having
3 to 6 carbon atoms or cycloalkyl having 5 to 10 carbon atoms.
Particularly preferred R.sup.9 groups include n-propyl, isopropyl,
1-methoxy2-methylproo-2-yl, n-butyl, but-2-yl, tert-butyl,
2-methylbut-2-yl, 3-methylbut-1-yl, 3,3-dimethylbut-2-yl,
4-methylpent-2-yl, 2,4-dimethyl-2-pentyl,
2,2,4,4-tetramethylpent-3-yl, cyclopropyl, cyclobutyl, tert-octyl
(2,4,4-trimethylpent-2-yl), cyclopentyl, cyclohexyl, cyclooctyl,
1-adamantyl, 2-adamantyl, 3,5-dimethyl-1-adamantyl, benzyl. When
R.sup.9 is adamantyl, 1-admantyl is preferred. Especially preferred
R.sup.9 groups are isopropyl, tert-butyl, 2,4-dimethyl-2-pentyl,
tert-octyl, 1-adamantyl, cyclopropyl and cyclohexyl.
[0058] In another of its composition aspects, this invention is
directed to each of the individual compounds:
[0059] .alpha.-(4-heptyloxyphenyl)-N-tert-butylnitrone
[0060] .alpha.-(4-hexyloxyphenyl)-N-n-propylnitrone
[0061] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-tert-butylnitrone
[0062] .alpha.-(4-ethoxyphenyl)-N-tert-butylnitrone
[0063]
.alpha.-(4-benzyloxy-3-methoxyphenyl)-N-tert-butylnitrone
[0064] .alpha.-[3-(4-methoxyphenoxy)phenyl]-N-tert-butylnitrone
[0065] .alpha.(2-ethoxyphenyl)-N-tert-butylnitrone
[0066] .alpha.-(3,4-ethylenedioxyphenyl)-N-tert-butylnitrone
[0067] .alpha.-(4-ethoxyphenyl)-N-cyclohexylnitrone
[0068]
.alpha.-(4-benzyloxy-3-methoxyphenyl)-N-cyclohexylnitrone
[0069] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclohexylnitrone
[0070] .alpha.-(3,4-ethylenedioxyphenyl)-N-cyclohexylnitrone
[0071] .alpha.-(4-ethoxy-3-methoxyphenyl)-N-cyclohexylnitrone
[0072] .alpha.-(3,4-ethylenedioxyphenyl)-N-isopropylnitrone
[0073] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-isopropylnitrone
[0074] .alpha.-(2-ethoxyphenyl)-N-isopropylnitrone
[0075] .alpha.-(2-ethoxyphenyl)-N-cyclohexylnitrone
[0076] .alpha.-(4-benzyloxy-3-methoxyphenyl)-N-isopropylnitrone
[0077] .alpha.-(4-ethoxy-3-methoxyphenyl)-N-isopropylnitrone
[0078] .alpha.-(3-ethoxy-4-hexyloxyphenyl)-N-cyclohexylnitrone
[0079] .alpha.-(4-benzyloxy-3-methoxyphenyl)-N-n-butylnitrone
[0080] .alpha.-(4-ethoxy-3-methoxyphenyl)-N-n-butylnitrone
[0081] .alpha.-(2-ethoxyphenyl)-N-n-butylnitrone
[0082] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-n-butylnitrone
[0083] .alpha.-(3-ethoxy-4-hexyloxyphenyl)-N-isopropylnitrone
[0084] .alpha.-(3-ethoxy-4-hexyloxyphenyl)-N-tert-butylnitrone
[0085] .alpha.-(2-fluoro-4-octyloxyphenyl)-N-tert-butylnitrone
[0086] .alpha.-(2,4,6-triethoxyphenyl)-N-tert-butylnitrone
[0087] .alpha.-(2,4,6-triethoxyphenyl)-N-cyclohexylnitrone
[0088] .alpha.-(2-n-butoxyphenyl)-N-tert-butylnitrone
[0089] .alpha.-(3,4-diethoxyphenyl)-N-tert-butylnitrone
[0090] .alpha.-(2-fluoro-4-heptyloxyphenyl)-N-tert-butylnitrone
[0091] .alpha.-(2-fluoro-4ethoxyphenyl)-N-tert-butylnitrone
[0092] .alpha.-(2-fluoro-4-ethoxyphenyl)-N-cyclohexylnitrone
[0093] .alpha.-(2-ethoxyphenyl)-N-1-adamantylnitrone
[0094] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-1-adamantylnitrone
[0095] .alpha.-(4-ethoxyphenyl)-N-cyclopentylnitrone
[0096] .alpha.-(4-ethoxyphenyl)-N-tert-octylnitrone
[0097] .alpha.-(4-benzyloxypheny)-N-tert-butylnitrone
[0098] .alpha.-(4-benzyloxyphenyl)-N-cyclopentylnitrone
[0099] .alpha.-(4-benzyloxyphenyl)-N-cyclohexynitrone
[0100] .alpha.-(2-ethoxyphenyl)-N-cyclopentylnitrone
[0101] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-tert-octylnitrone
[0102]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(2,4-dimethyl-2-pentyl)nitrone
[0103] .alpha.-(4-ethoxyphenyl)-N-n-butylnitrone
[0104] .alpha.-(2-ethoxyphenyl)-N-benzylnitrone
[0105]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(2,2,4,4-tetramethylpent-3-yl)-
nitrone
[0106]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(4-methylpent-2-yl)nitrone
[0107] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-but-2-ylnitrone
[0108] .alpha.-(2-ethoxyphenyl)-N-but-2-ylnitrone
[0109]
.alpha.-[4-(4-fluorobenzyloxy)phenyl]-N-tert-butylnitrone
[0110] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclopentylnitrone
[0111] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-n-propylnitrone
[0112] .alpha.-(4-benzyloxyphenyl)-N-n-propylnitrone
[0113] .alpha.-(4-benzyloxyphenyl)-N-isopropylnitrone
[0114]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(2-methylbut-2-yl)nitrone
[0115] .alpha.-(2-ethoxyphenyl)-N-(2-methylbut-2-yl)nitrone
[0116] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclooctylnitrone
[0117] .alpha.-(2-ethoxyphenyl)-N-cyclobutylnitrone
[0118] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclobutylnitrone
[0119] .alpha.-(4-benzyloxyphenyl)-N-cyclobutylnitrone
[0120] .alpha.-(4-benzyloxyphenyl)-N-tert-octylnitrone
[0121]
.alpha.-[4-(4-fluorobenzyloxy)phenyl]-N-cyclohexylnitrone
[0122] .alpha.-(2-ethoxyphenyl)-N-tert-octylnitrone
[0123] .alpha.-[4-(4-fluorobenzyloxy)phenyl]-N-isopropylnitrone
[0124] .alpha.-(2-ethoxyphenyl)-N-cyclooctylnitrone
[0125] .alpha.-(4-benzyloxyphenyl)-N-cyclopropylnitrone
[0126] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclopropylnitrone
[0127] .alpha.-(4-benzyloxyphenyl)-N-cyclooctylnitrone
[0128]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(3,5-dimethyl-1-adamantyl)nitr-
one
[0129] .alpha.-(4-benzyloxyphenyl)-N-1-adamantylnitrone
[0130]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(1-methoxy-2-methylprop-2-yl)n-
itrone
[0131] .alpha.-(4-benzyloxyphenyl)-N-2-adamantylnitrone
[0132] .alpha.-(4-ethoxyphenyl)-N-cyclooctylnitrone
[0133] .alpha.-(4-ethoxyphenyl)-N-1-adamantylnitrone
[0134]
.alpha.-[4-(4-methoxybenzyloxy)phenyl]-N-tert-butylnitrone
[0135]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(3-methylbut-1-yl)nitrone
[0136] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclooctylnitrone,
and
[0137]
.alpha.-[4-(4-fluorobenzyloxy)phenyl]-N-cyclopentylnitrone.
[0138] Particularly preferred compounds include:
[0139] .alpha.-(2-ethoxyphenyl)-N-tert-butylnitrone
[0140] .alpha.-(2-ethoxyphenyl)-N-cyclohexylnitrone
[0141] .alpha.-(4-ethoxyphenyl)-N-cyclohexylnitrone
[0142] .alpha.-(4-benzyloxyphenyl)-N-tert-butylnitrone
[0143] .alpha.-(4-benzyloxyphenyl)-N-cyclopentylnitrone
[0144] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-adamantylnitrone,
and
[0145] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-tert-octylnitrone.
[0146] In another of its composition aspects, this invention is
directed to pharmaceutical compositions comprising a
pharmaceutically acceptable carrier and a pharmaceutically
effective amount of a compound of formula I: 3
[0147] wherein R.sup.1-R.sup.5 are as defined above.
[0148] In additional composition aspects, this invention is
directed to pharmaceutical compositions comprising a
pharmaceutically acceptable carrier and a pharmaceutically
effective amount of a compound of formula II above.
[0149] As previously mentioned, the .alpha.-aryl-N-alkylnitrone
compounds of this invention have been discovered to inhibit the
formation of A.beta.(1-42) beta-pleated sheets and/or to protect
against A.beta.(25-35)-induced neuronal cell loss and/or to reduce
.beta.-amyloid-induced release of cytokines, such as IL-1.beta. and
TNF.alpha., in human monocyte cells. Such compounds have also been
found to reduce the cognitive defects caused by
A.beta.(25-35)/ibotenate as well as those which develop in certain
strains of autoimmune mice. Compounds having such properties are
useful for preventing and/or treating neurodegenerative, autoimmune
and inflammatory conditions.
[0150] Accordingly, in one of its method aspects, this invention is
directed to a method for treating a patient with a
neurodegenerative disease which method comprises administering to
said patient a pharmaceutical composition comprising a
pharmaceutically acceptable carrier and an effective
neurodegenerative disease-treating treating amount of a compound of
formula I or formula II above.
[0151] In another of its method aspects, this invention is directed
to a method for preventing the onset of a neurodegenerative disease
in a patient at risk for developing the neurodegenerative disease
which method comprises administering to said patient a
pharmaceutical composition comprising a pharmaceutically acceptable
carrier and an effective neurodegenerative disease-preventing
amount of a compound of formula I or formula II above.
[0152] In preferred embodiments of this invention, the
neurodegenerative disease treated and/or prevented in the above
methods is Alzheimer's disease, Parkinson's disease, HIV dementia
and the like.
[0153] In still another of its method aspects, this invention is
directed to a method for treating a patient with an autoimmune
disease which method comprises administering to said patient a
pharmaceutical composition comprising a pharmaceutically acceptable
carrier and an effective autoimmune disease-treating amount of a
compound of formula I or formula II above.
[0154] In yet another of its method aspects, this invention is
directed to a method for preventing the onset of an autoimmune
disease in a patient at risk for developing the autoimmune disease
which method comprises administering to said patient a
pharmaceutical composition comprising a pharmaceutically acceptable
carrier and an effective autoimmune disease-preventing amount of a
compound of formula I or formula II above.
[0155] In preferred embodiments of this invention, the autoimmune
disease treated and/or prevented in the above methods is systemic
lupus, multiple sclerosis and the like.
[0156] In still another of its method aspects, this invention is
directed to a method for treating a patient with an inflammatory
disease which method comprises administering to said patient a
pharmaceutical composition comprising a pharmaceutically acceptable
carrier and an effective inflammatory disease-treating amount of a
compound of formula I or formula II above.
[0157] In yet another of its method aspects, this invention is
directed to a method for preventing the onset of an inflammatory
disease in a patient at risk for developing the inflammatory
disease which method comprises administering to said patient a
pharmaceutical composition comprising a pharmaceutically acceptable
carrier and an effective inflammatory disease-preventing amount of
a compound of formula I or formula II above.
[0158] In preferred embodiments of this invention, the inflammatory
disease treated and/or prevented in the above methods is rheumatoid
arthritis, septic shock, erythema nodosum leprosy, septicemia,
adult respiratory distress syndrome (ARDS), inflammatory bowel
disease (IBD), uveitis and the like.
[0159] In another of its aspects, this invention is directed to the
use of a compound of formula I or formula II above in the
manufacture of a formulation or medicament for a medicinal
treatment. Preferably, the medical treatment is the therapeutic or
prophylactic treatment of a neurodegenerative disease, an
autoimmune disease or an inflammatory disease.
[0160] Particularly preferred compounds include those represented
in Tables I and II below.
1TABLE I 4 R.sup.a R.sup.b R.sup.c R.sup.d H-- H--
CH.sub.3(CH.sub.2).sub.6--O-- (CH.sub.3).sub.3C-- H-- H--
CH.sub.3(CH.sub.2).sub.5--O-- CH.sub.3CH.sub.2CH.sub.2-- H--
CH.sub.3CH.sub.2--O-- CH.sub.3--O-- (CH.sub.3).sub.3C-- H-- H--
CH.sub.3CH.sub.2--O-- (CH.sub.3).sub.3C-- H-- CH.sub.3--O--
PhCH.sub.2--O-- (CH.sub.3).sub.3C-- H-- 4-(CH.sub.3--O)--Ph-O-- H--
(CH.sub.3).sub.3C-- CH.sub.3CH.sub.2--O-- H-- H--
(CH.sub.3).sub.3C-- H-- --O--CH.sub.2CH.sub.2--O--
(CH.sub.3).sub.3C-- H-- H-- CH.sub.3CH.sub.2--O-- cyclohexyl- H--
CH.sub.3--O-- PhCH.sub.2--O-- cyclohexyl- H-- CH.sub.3CH.sub.2--O--
CH.sub.3--O-- cyclohexyl- H-- --O--CH.sub.2CH.sub.2--O--
cyclohexyl- H-- CH.sub.3--O-- CH.sub.3CH.sub.2--O-- cyclohexyl- H--
--O--CH.sub.2CH.sub.2--O-- (CH.sub.3).sub.2CH-- H--
CH.sub.3CH.sub.2--O-- CH.sub.3--O-- (CH.sub.3).sub.2CH--
CH.sub.3CH.sub.2--O-- H-- H-- (CH.sub.3).sub.2CH--
CH.sub.3CH.sub.2--O-- H-- H-- cyclohexyl- H-- CH.sub.3--O--
PhCH.sub.2--O-- (CH.sub.3).sub.2CH-- H-- CH.sub.3--O--
CH.sub.3CH.sub.2--O-- (CH.sub.3).sub.2CH-- H--
CH.sub.3CH.sub.2--O-- CH.sub.3(CH.sub.2).sub.5--O-- cyclohexyl- H--
CH.sub.3--O-- PhCH.sub.2--O-- CH.sub.3(CH.sub.2).sub.3-- H--
CH.sub.3--O-- CH.sub.3CH.sub.2--O-- CH.sub.3(CH.sub.2).sub.3--
CH.sub.3CH.sub.2--O-- H-- H-- CH.sub.3(CH.sub.2).sub.3-- H--
CH.sub.3CH.sub.2--O-- CH.sub.3--O-- CH.sub.3(CH.sub.2).sub.3-- H--
CH.sub.3CH.sub.2--O-- CH.sub.3(CH.sub.2).sub.5--O--
(CH.sub.3).sub.2CH-- H-- CH.sub.3CH.sub.2--O--
CH.sub.3(CH.sub.2).sub.5--O-- (CH.sub.3).sub.3C-- F-- H--
CH.sub.3(CH.sub.2).sub.7--O-- (CH.sub.3).sub.3C--
CH.sub.3(CH.sub.2).sub.3--O-- H-- H-- (CH.sub.3).sub.3C-- H--
CH.sub.3CH.sub.2--O-- CH.sub.3CH.sub.2--O-- (CH.sub.3).sub.3C-- F--
H-- CH.sub.3(CH.sub.2).sub.5--O-- (CH.sub.3).sub.3C-- F-- H--
CH.sub.3CH.sub.2--O-- (CH.sub.3).sub.3C-- F-- H--
CH.sub.3CH.sub.2--O-- cyclohexyl- CH.sub.3CH.sub.2--O-- H-- H--
1-adamantyl- H-- CH.sub.3CH.sub.2--O-- CH.sub.3--O-- 1-adamantyl-
H-- H-- CH.sub.3CH.sub.2--O-- cyclopentyl- H-- H--
CH.sub.3CH.sub.2--O-- (CH.sub.3).sub.3CCH.sub.2--
(CH.sub.3).sub.2C-- H-- H-- PhCH.sub.2--O-- (CH.sub.3).sub.3C-- H--
H-- PhCH.sub.2--O-- cyclopentyl- H-- H-- PhCH.sub.2--O--
cyclohexyl- CH.sub.3CH.sub.2--O-- H-- H-- cyclopentyl- H--
CH.sub.3CH.sub.2--O-- CH.sub.3--O-- (CH.sub.3).sub.3CCH.sub.2--
(CH.sub.3).sub.2C-- H-- CH.sub.3CH.sub.2--O-- CH.sub.3--O--
(CH.sub.3).sub.2CHCH.sub.2-- (CH.sub.3).sub.2C-- H-- H--
CH.sub.3CH.sub.2--O-- CH.sub.3(CH.sub.2).sub.3--
CH.sub.3CH.sub.2--O-- H-- H-- PhCH.sub.2-- H--
CH.sub.3CH.sub.2--O-- CH.sub.3--O-- [(CH.sub.3).sub.3C].sub.2CH--
H-- CH.sub.3CH.sub.2--O-- CH.sub.3--O--
(CH.sub.3).sub.2CHCH.sub.2-- (CH.sub.3)CH-- H--
CH.sub.3CH.sub.2--O-- CH.sub.3--O-- CH.sub.3CH.sub.2(CH.sub.3)--
CH-- CH.sub.3CH.sub.2--O-- H-- H-- CH.sub.3CH.sub.2(CH.sub.3)--
CH-- H-- H-- 4-F--PhCH.sub.2--O-- (CH.sub.3).sub.3C-- H--
CH.sub.3CH.sub.2--O-- CH.sub.3--O-- cyclopentyl- H--
CH.sub.3CH.sub.2--O-- CH.sub.3--O-- CH.sub.3CH.sub.2CH.sub.2-- H--
H-- PhCH.sub.2--O-- CH.sub.3CH.sub.2CH.sub.2-- H-- H--
PhCH.sub.2--O-- (CH.sub.3).sub.2CH-- H-- CH.sub.3CH.sub.2--O--
CH.sub.3--O-- CH.sub.3CH.sub.2(CH.sub.3).sub.2C--
CH.sub.3CH.sub.2--O-- H-- H-- CH.sub.3CH.sub.2(CH.sub.3).sub.2C--
H-- CH.sub.3CH.sub.2--O-- CH.sub.3--O-- cyclooctyl-
CH.sub.3CH.sub.2--O-- H-- H-- cyclobutyl- H-- CH.sub.3CH.sub.2--O--
CH.sub.3--O-- cyclobutyl- H-- H-- PhCH.sub.2--O-- cyclobutyl- H--
H-- PhCH.sub.2--O-- (CH.sub.3).sub.3CCH.sub.2-- (CH.sub.3).sub.2C--
H-- H-- 4-F--PhCH.sub.2--O-- cyclohexyl- CH.sub.3CH.sub.2--O-- H--
H-- (CH.sub.3).sub.3CCH.sub.2-- (CH.sub.3).sub.2C-- H-- H--
4-F--PhCH.sub.2--O-- (CH.sub.3).sub.2CH-- CH.sub.3CH.sub.2--O-- H--
H-- cyclooctyl- H-- H-- PhCH.sub.2--O-- cyclopropyl- H--
CH.sub.3CH.sub.2--O-- CH.sub.3--O-- 2-adamantyl- H--
CH.sub.3CH.sub.2--O-- CH.sub.3--O-- cyclopropyl- H-- H--
PhCH.sub.2--O-- cyclooctyl- H-- CH.sub.3CH.sub.2--O-- CH.sub.3--O--
3,5-di(CH.sub.3)-1- adamantyl- H-- H-- PhCH.sub.2--O-- 1-adamantyl-
H-- CH.sub.3CH.sub.2--O-- CH.sub.3--O-- CH.sub.3OCH.sub.2--
(CH.sub.3).sub.2C-- H-- H-- PhCH.sub.2--O-- 2-adamantyl- H-- H--
CH.sub.3CH.sub.2--O-- cyclooctyl- H-- H-- CH.sub.3CH.sub.2--O--
1-adamantyl- H-- H-- 4-CH.sub.3O--PhCH.sub.2O-- (CH.sub.3).sub.3C--
H-- CH.sub.3CH.sub.2--O-- CH.sub.3--O--
(CH.sub.3).sub.2CHCH.sub.2-- CH.sub.2-- H-- CH.sub.3CH.sub.2--O--
CH.sub.3--O-- cyclooctyl- H-- H-- 4-F--PhCH.sub.2--O--
cyclopentyl-
[0161]
2TABLE II 5 R.sup.e R.sup.f R.sup.g R.sup.h CH.sub.3CH.sub.2--O--
CH.sub.3CH.sub.2--O-- CH.sub.3CH.sub.2--O-- (CH.sub.3).sub.3C--
CH.sub.3CH.sub.2--O-- CH.sub.3CH.sub.2--O-- CH.sub.3CH.sub.2--O--
cyclohexyl-
BRIEF DESCRIPTION OF THE DRAWING
[0162] FIG. 1 is an electron spin resonance (ESR) spectra of the
radical adduct of .alpha.-(2-ethoxyphenyl)-N-tert-butylnitrone and
a methyl radical.
DETAILED DESCRIPTION OF THE INVENTION
[0163] Definitions
[0164] When describing the .alpha.-aryl-N-alkylnitrones,
pharmaceutical compositions and methods of this invention, the
following terms have the following meanings:
[0165] The term ".beta.-amyloid peptide" refers to a 39-43 amino
acid peptide having a molecular weight of about 4.2 kD, which
peptide is substantially homologous to the form of the protein
described by Glenner, et al., Biochem. Biophys. Res. Commun.,
120:885-890 (1984), including mutations and post-translational
translational modifications of the normal .beta.-amyloid
peptide.
[0166] The term "cytokines" refers to peptide protein mediators
that are produced by immune cells to modulate cellular functions.
Examples of cytokines include, interleukin-1.beta. (IL-1.beta.),
interleukin-6 (IL-6) and tumor necrosis factor-.alpha.
(TNF.alpha.).
[0167] "Acyl" refers to the group --OC(O)R where R is alkyl or
aryl.
[0168] "Alkyl" refers to monovalent alkyl groups preferably having
from 1 to about 10 carbon atoms, more preferably 1 to 8 carbon
atoms and still more preferably 1 to 6 carbon atoms. This term is
exemplified by groups such as methyl, ethyl, n-propyl, isopropyl,
n-butyl, isobutyl, tert-butyl, n-hexyl, n-octyl, tert-octyl and the
like. The term "lower alkyl" refers to alkyl groups having 1 to 6
carbon atoms.
[0169] "Substituted alkyl" refers to an alkyl group, preferably of
from 1 to 10 carbon atoms, having from 1 to 5 substituents, and
preferably 1 to 3 substituents, selected from the group consisting
of alkoxy, cycloalkyl, cycloalkoxy, acyl, aminoacyl, amino,
aminocarbonyl, cyano, halogen, hydroxyl, carboxyl, keto, thioketo,
alkoxycarbonyl, thiol, thioalkoxy, aryl, aryloxy, nitro,
--OSO.sub.3H and pharmaceutically acceptable salts thereof,
--SO-alkyl, --SO-substituted alkyl, --SO-aryl, --SO.sub.2-alkyl,
--SO.sub.2-substituted alkyl, --SO.sub.2-aryl, and mono- and
di-alkylamino, mono- and di-arylamino, and unsymmetric
di-substituted amines having different substituents selected from
alkyl, substituted alkyl and aryl.
[0170] "Alkylene" refers to divalent alkylene groups preferably
having from 1 to 10 carbon atoms and more preferably 1 to 6 carbon
atoms which can be straight chain or branched. This term is
exemplified by groups such as methylene (--CH.sub.2--), ethylene
(--CH.sub.2CH.sub.2--), the propylene isomers (e.g.,
--CH.sub.2CH.sub.2CH.sub.2-- and --CH(CH.sub.3)CH.sub.2--) and the
like.
[0171] "Alkylenedioxy" refers to --O-alkylene-O-- groups preferably
having from 1 to 10 carbon atoms and more preferably 1 to 6 carbon
atoms which can be straight chain or branched. This term is
exemplified by groups such as methylenedioxy (--OCH.sub.2O--),
ethylenedioxy (--OCH.sub.2CH.sub.2O--) and the like.
[0172] "Alkenylene" refers to divalent alkenylene groups preferably
having from 2 to 10 carbon atoms and more preferably 2 to 6 carbon
atoms which can be straight chain or branched and having at least 1
and preferably from 1-2 sites of alkenyl unsaturation. This term is
exemplified by groups such as ethenylene (--CH.dbd.CH--), the
propenylene isomers (e.g., --CH.dbd.CHCH.sub.2-- and
--C(CH.sub.3).dbd.CH-- and --CH.dbd.C(CH.sub.3)--) and the
like.
[0173] "Alkaryl" refers to -alkylene-aryl groups preferably having
from 1 to 10 carbon atoms in the alkylene moiety and from 6 to 14
carbon atoms in the aryl moiety. Such alkaryl groups are
exemplified by benzyl, phenethyl, and the like.
[0174] "Alkaryloxy" refers to --O-alkylene-aryl groups preferably
having from 1 to 10 carbon atoms in the alkylene moiety and from 6
to 14 carbon atoms in the aryl moiety. Such alkaryl groups are
exemplified by benzyloxy, 4-fluorobenzyloxy, phenethyloxy, and the
like.
[0175] "Alkcycloalkyl" refers to -alkylene-cycloalkyl groups
preferably having from 1 to 10 carbon atoms in the alkylene moiety
and from 3 to 8 carbon atoms in the cycloalkyl moiety. Such
alkcycloalkyl groups are exemplified by --CH.sub.2-cyclopropyl,
--CH.sub.2-cyclopentyl, --CH.sub.2CH.sub.2-cyclohexyl, and the
like.
[0176] "Alkcycloalkoxy" refers to --O-alkylene-cycloalkyl groups
preferably having from 1 to 10 carbon atoms in the alkylene moiety
and from 3 to 8 carbon atoms in the cycloalkyl moiety. Such
alkcycloalkoxy groups are exemplified by --OCH.sub.2-cyclopropyl,
--OCH.sub.2-cyclopentyl, --OCH.sub.2CH.sub.2-cyclohexyl, and the
like.
[0177] "Alkoxy" refers to the group "alkyl-O--". Preferred alkoxy
groups include, by way of example, methoxy, ethoxy, n-propoxy,
isopropoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentyloxy,
n-hexyloxy, 1,2-dimethylbutoxy, and the like.
[0178] "Alkoxycarbonyl" refers to the group --C(O)OR where R is
alkyl.
[0179] "Alkenyl" refers to alkenyl groups preferably having from 2
to 10 carbon atoms and more preferably 2 to 6 carbon atoms and
having at least 1 and preferably from 1-2 sites of alkenyl
unsaturation. Preferred alkenyl groups include ethenyl
(--CH.dbd.CH.sub.2), n-propenyl (--CH.sub.2CH.dbd.CH.sub.2),
isopropenyl (--C(CH.sub.3).dbd.CH.sub.2), and the like.
[0180] "Alkynyl" refers to alkynyl groups preferably having from 2
to 10 carbon atoms and more preferably 2 to 6 carbon atoms and
having at least 1 and preferably from 1-2 sites of alkynyl
unsaturation. Preferred alkynyl groups include ethynyl
(--C.ident.CH), propargyl (--CH.sub.2C.ident.CH), and the like.
[0181] "Aminocarbonyl" refers to the group --C(O)NRR where each R
is independently hydrogen or alkyl.
[0182] "Aminoacyl" refers to the group --NRC(O)R where each R is
independently hydrogen or alkyl.
[0183] "Aryl" refers to an unsaturated aromatic carbocyclic group
of from 6 to 14 carbon atoms having a single ring (e.g., phenyl) or
multiple condensed rings (e.g., naphthyl or anthryl). Preferred
aryls include phenyl, naphthyl and the like. Unless otherwise
constrained by the definition for the individual substituent, such
aryl groups can optionally be substituted with from 1 to 3
substituents selected from the group consisting of alkyl, alkoxy,
alkaryloxy, alkenyl, alkynyl, amino, aminoacyl, aminocarbonyl,
alkoxycarbonyl, aryl, carboxyl, cycloalkoxy, cyano, halo, hydroxy,
nitro, trihalomethyl, thioalkoxy, and the like.
[0184] "Aryloxy" refers to --O-aryl groups wherein "aryl" is as
defined above.
[0185] "Carboxyl" refers to the group --C(O)OH.
[0186] "Cyano" refers to the group --CN.
[0187] "Cycloalkyl" refers to cyclic alkyl groups of from 3 to 10
carbon atoms having a single cyclic ring or multiple condensed
rings, including fused and bridged ring systems, which can be
optionally substituted with from 1 to 3 alkyl groups. Such
cycloalkyl groups include, by way of example, single ring
structures such as cyclopropyl, cyclobutyl, cyclopentyl,
cyclooctyl, 1-methylcyclopropyl, 2-methylcyclopentyl,
2-methylcyclooctyl, and the like, or multiple ring structures such
as adamantanyl, and the like.
[0188] "Cycloalkoxy" refers to --O-cycloalkyl groups. Such
cycloalkoxy groups include, by way of example, cyclopentyloxy,
cyclohexyloxy and the like.
[0189] "Cycloalkenyl" refers to cyclic alkenyl groups of from 4 to
10 carbon atoms having a single cyclic ring and at least one point
of internal unsaturation which can be optionally substituted with
from 1 to 3 alkyl groups. Examples of suitable cycloalkenyl groups
include, for instance, cyclopent-3-enyl, cyclohex-2-enyl,
cyclooct-3-enyl and the like.
[0190] "Halo" or "halogen" refers to fluoro, chloro, bromo and
iodo. Preferred halo groups are either fluoro or chloro.
[0191] "Keto" or "oxo" refers to the group .dbd.O.
[0192] "Nitro" refers to the group --NO.sub.2.
[0193] "tert-Octyl" refers to a 2,4,4-trimethyl-2-pentyl group.
[0194] "Thiol" refers to the group --SH.
[0195] "Thioalkoxy" refers to the group --S-alkyl.
[0196] "Thioketo" refers to the group .dbd.S.
[0197] "Pharmaceutically acceptable salt" refers to
pharmaceutically acceptable salts which are derived from a variety
of organic and inorganic counter-ions well known in the art and
include, by way of example only, sodium, potassium, calcium,
magnesium, ammonium, tetraalkylammonium, and the like; and when the
molecule contains a basic functionality, salts of organic or
inorganic acids, such as hydrochloride, hydrobromide, tartrate,
mesylate, acetate, maleate, oxalate and the like. The term
"pharmaceutically acceptable cation" refers to a pharmaceutically
acceptable cationic counter-ion of an acidic functional group. Such
cations are exemplified by sodium, potassium, calcium, magnesium,
ammonium, tetraalkylammonium cations, and the like.
[0198] General Synthetic Procedures
[0199] The .alpha.-aryl-N-alkylnitrones of this invention can be
prepared from readily available starting materials using the
following general methods and procedures. It will be appreciated
that where typical or preferred process conditions (i.e., reaction
temperatures, times, mole ratios of reactants, solvents, pressures,
etc.) are given, other process conditions can also be used unless
otherwise stated. Optimum reaction conditions may vary with the
particular reactants or solvent used, but such conditions can be
determined by one skilled in the art by routine optimization
procedures.
[0200] Additionally, as will be apparent to those skilled in the
art, conventional protecting groups may be necessary to prevent
certain functional groups from undergoing undesired reactions. The
choice of a suitable protecting group for a particular functional
group as well as suitable conditions for protection and
deprotection are well known in the art. For example, numerous
protecting groups, and their introduction and removal, are
described in T. W. Greene and G. M. Wuts, Protecting Groups in
Organic Synthesis, Second Edition, Wiley, New York, 1991, and
references cited therein.
[0201] In a preferred method of synthesis, the
.alpha.-aryl-N-alkylnitrone compounds of this invention are
prepared by coupling an aryl carbonyl compound of formula III:
6
[0202] wherein R.sup.1-R.sup.4 are as defined above, with a
hydroxylamine of formula IV:
HO--NH--R.sup.5 IV
[0203] wherein R.sup.5 is as defined above, under conventional
reaction conditions.
[0204] The coupling reaction is typically conducted by contacting
the aryl carbonyl compound III with at least one equivalent,
preferably about 1.1 to about 2 equivalents, of hydroxylamine IV in
an inert polar solvent such as methanol, ethanol, 1,4-dioxane,
tetrahydrofuran, dimethyl sulfoxide, dimethylformamide and the
like. This reaction is preferably conducted at a temperature of
from about 0.degree. C. to about 100.degree. C. for about 1 to
about 48 hours. Optionally, a catalytic amount of an acid, such as
hydrochloric acid, acetic acid, p-toluenesulfonic acid and the
like, may be employed in this reaction. Upon completion of the
reaction, the .alpha.-aryl-N-alkylnitrone of formula I is recovered
by conventional methods including precipitation, chromatography,
filtration, distillation and the like.
[0205] The aryl carbonyl compounds of formula III employed in the
coupling reaction are either known compounds or compounds that can
be prepared from known compounds by conventional procedures. For
example, such compounds are readily prepared by acylation of the
corresponding aryl compound with the appropriate acyl halide under
Friedel-Crafts acylation reaction conditions. Additionally, the
formyl compounds, i.e. those compounds where R.sup.4 is hydrogen,
can be prepared by formylation of the corresponding aryl compound
using, for example, a disubstituted formamides, such as
N-methyl-N-phenylformamide, and phosphorous oxychloride (the
Vilsmeier-Haack reaction), or using Zn(CN).sub.2 followed by water
(the Gatterman reaction). Numerous other methods are known in the
art for preparing such aryl carbonyl compounds. Such methods are
described, for example, in I. T. Harrison and S. Harrison,
Compendium of Organic Synthetic Methods, Wiley, New York, 1971, and
references cited therein.
[0206] Certain aryl carbonyl compounds of formula III can also be
prepared by alkylation of the corresponding aryl hydroxy compound
(e.g., 4-hydroxybenzaldehyde and the like). This reaction is
typically conducted by contacting the aryl hydroxy compound with a
suitable base, such as an alkali or alkaline earth metal hydroxide,
fluoride or carbonate, in a inert solvent, such as ethanol, DMF and
the like, to deprotonate the hydroxyl group. This reaction is
generally conducted at about 0.degree. C. to about 50.degree. C.
for about 0.25 to 2 hours. The resulting intermediate is then
reacted in situ with about 1.0 to about 2.0 equivalents of an alkyl
halide, preferably an alkyl bromide or iodide, at a temperature of
from about 25.degree. C. to about 100.degree. C. for about 0.25 to
about 3 days.
[0207] Additionally, various aryl aldehydes of formula III can be
prepared by reduction of the corresponding aryl nitrites. This
reaction is typically conducted by contacting the aryl nitrile with
about 1.0 to 1.5 equivalents of a hydride reducing agent, such as
LiAlH(OEt).sub.3, in an inert solvent such as diethyl ether, at a
temperature ranging from about -78.degree. to about 25.degree. C.
for about 1 to 6 hours. Standard work-up conditions using aqueous
acid then provides the corresponding aryl aldehyde.
[0208] Preferred aryl carbonyl compounds include, but are not
limited to, 2-ethoxybenzaldehyde, 4-ethoxybenzaldehyde,
2-butoxybenzaldehyde, 4-butoxybenzaldehyde,
4-pentyloxybenzaldehyde, 4-benzyloxybenzaldehyde,
4-(4-fluorobenzyloxy)benzaldehyde,
4-(4-methoxybenzyloxy)benzaldehyde, 4-hexyloxybenzaldehyde,
4-heptyloxybenzaldehyde, 3-ethoxy-4-methoxybenzal- dehyde,
4-ethoxy-3-methoxybenzaldehyde, 3,4-diethoxybenzaldehyde,
3-ethoxy-4-hexyloxybenzaldehyde, 2-fluoro-4-methoxybenzaldehyde,
2-fluoro-4-ethoxybenzaldehyde, 2-fluoro-4-heptyloxybenzaldehyde,
2-fluoro-4-octyloxybenzaldehyde, 4-benzyloxy-3-methoxybenzaldehyde,
4-phenoxy-3-methoxybenzaldehyde, 3,4-methylenedioxybenzaldehyde
(piperonal), 3,4-ethylenedioxybenzaldehyde,
2,4,6-triethoxybenzaldehyde, and the like.
[0209] The hydroxylamine compounds of formula V above are also
known compounds or compounds which can be prepared from known
compounds by conventional procedures. Typically, the hydroxylamine
compounds of formula V are prepared by reduction of the
corresponding nitro compound (i.e., R.sup.5--NO.sub.2, wherein
R.sup.5 is as defined above) using a suitable reducing agent such
as activated zinc/acetic acid, activated zinc/ammonium chloride or
an aluminum/mercury amalgam. This reaction is typically conducted
at a temperature ranging from about 15.degree. C. to about
100.degree. C. for about 0.5 to 12 hours, preferably about 2 to 6
hours, in an aqueous reaction media, such as an alcohol/water
mixture in the case of the zinc reagents or an ether/water mixture
in the case of the aluminum amalgams. Aliphatic nitro compounds (in
the form of their salts) can also be reduced to hydroxylamines
using borane in tetrahydrofuran. Since some hydroxylamines have
limited stability, such compounds are generally prepared
immediately prior to reaction with the aryl carbonyl compound of
formula III.
[0210] Preferred hydroxylamines for use in this invention include,
but are not limited to, N-cyclopentylhydroxyamine,
N-tert-octylhydroxyamine, N-tert-butylhydroxylamine,
N-isopropylhydroxylamine, N-n-propylhydroxylamine,
N-n-butylhydroxylamine, N-tert-butylhydroxylamin- e,
N-cyclohexylhydroxylamine, N-2,4-dimethyl-2-pentylhydroxylamine,
1-adamantylhydroxylamine and the like.
[0211] Pharmaceutical Compositions
[0212] When employed as pharmaceuticals, the
.alpha.-aryl-N-alkylnitrones of this invention are typically
administered in the form of a pharmaceutical composition. Such
compositions can be prepared in a manner well known in the
pharmaceutical art and comprise at least one active compound.
[0213] Generally, the compounds of this invention are administered
in a pharmaceutically effective amount. The amount of the compound
actually administered will typically be determined by a physician,
in the light of the relevant circumstances, including the condition
to be treated, the chosen route of administration, the actual
compound administered, the age, weight, and response of the
individual patient, the severity of the patient's symptoms, and the
like.
[0214] The pharmaceutical compositions of this invention can be
administered by a variety of routes including oral, rectal,
transdermal, subcutaneous, intravenous, intramuscular, and
intranasal. Depending on the intended route of delivery, the
compounds of this invention are preferably formulated as either
injectable or oral compositions.
[0215] The compositions for oral administration can take the form
of bulk liquid solutions or suspensions, or bulk powders. More
commonly, however, the compositions are presented in unit dosage
forms to facilitate accurate dosing. The term "unit dosage forms"
refers to physically discrete units suitable as unitary dosages for
human subjects and other mammals, each unit containing a
predetermined quantity of active material calculated to produce the
desired therapeutic effect, in association with a suitable
pharmaceutical excipient. Typical unit dosage forms include
prefilled, premeasured ampules or syringes of the liquid
compositions or pills, tablets, capsules or the like in the case of
solid compositions. In such compositions, the
.alpha.-aryl-N-alkylnitrone compound is usually a minor component
(from about 0.1 to about 50% by weight or preferably from about 1
to about 40% by weight) with the remainder being various vehicles
or carriers and processing aids helpful for forming the desired
dosing form.
[0216] Liquid forms suitable for oral administration may include a
suitable aqueous or nonaqueous vehicle with buffers, suspending and
dispensing agents, colorants, flavors and the like. Solid forms may
include, for example, any of the following ingredients, or
compounds of a similar nature: a binder such as microcrystalline
cellulose, gum tragacanth or gelatin; an excipient such as starch
or lactose, a disintegrating agent such as alginic acid, Primogel,
or corn starch; a lubricant such as magnesium stearate; a glidant
such as colloidal silicon dioxide; a sweetening agent such as
sucrose or saccharin; or a flavoring agent such as peppermint,
methyl salicylate, or orange flavoring.
[0217] Injectable compositions are typically based upon injectable
sterile saline or phosphate-buffered saline or other injectable
carriers known in the art. As before, the
.alpha.-aryl-N-alkylnitrone compound in such compositions is
typically a minor component, often being from about 0.05 to 10% by
weight with the remainder being the injectable carrier and the
like.
[0218] The above-described components for orally administrable or
injectable compositions are merely representative. Other materials
as well as processing techniques and the like are set forth in Part
8 of Remington's Pharmaceutical Sciences, 17th edition, 1985, Mack
Publishing Company, Easton, Pa., which is incorporated herein by
reference.
[0219] The compounds of this invention can also be administered in
sustained release forms or from sustained release drug delivery
systems. A description of representative sustained release
materials can be found in the incorporated materials in Remington's
Pharmaceutical Sciences.
[0220] The following formulation examples illustrate representative
pharmaceutical compositions of this invention. The present
invention, however, is not limited to the following pharmaceutical
compositions.
Formulation 1--Tablets
[0221] A compound of formula I is admixed as a dry powder with a
dry gelatin binder in an approximate 1:2 weight ratio. A minor
amount of magnesium stearate is added as a lubricant. The mixture
is formed into 240-270 mg tablets (80-90 mg of active
.alpha.-aryl-N-alkylnitrone compound per tablet) in a tablet
press.
Formulation 2--Capsules
[0222] A compound of formula I is admixed as a dry powder with a
starch diluent in an approximate 1:1 weight ratio. The mixture is
filled into 250 mg capsules (125 mg of active
.alpha.-aryl-N-alkylnitrone compound per capsule).
Formulation 3--Liquid
[0223] A compound of formula I (125 mg), sucrose (1.75 g) and
xanthan gum (4 mg) are blended, passed through a No. 10 mesh U.S.
sieve, and then mixed with a previously made solution of
microcrystalline cellulose and sodium carboxymethyl cellulose
(11:89, 50 mg) in water. Sodium benzoate (10 mg), flavor, and color
are diluted with water and added with stirring. Sufficient water is
then added to produce a total volume of 5 mL.
Formulation 4--Tablets
[0224] The compound of formula I is admixed as a dry powder with a
dry gelatin binder in an approximate 1:2 weight ratio. A minor
amount of magnesium stearate is added as a lubricant. The mixture
is formed into 450-900 mg tablets (150-300 mg of active
.alpha.-aryl-N-alkylnitrone compound) in a tablet press.
Formulation 5--Injection
[0225] The compound of formula I is dissolved in a buffered sterile
saline injectable aqueous medium to a concentration of
approximately 5 mg/ml.
[0226] Utility
[0227] The .alpha.-aryl-N-alkylnitrones of this invention have been
discovered to inhibit the formation of A.beta.(1-42) beta-pleated
sheets and/or protect against neuronal cell loss and/or inhibit the
release of cytokines, such as IL-1.beta. and TNF.alpha. and/or
protect against IL-1.beta./IFN.sub..gamma.-induced toxicity.
Additionally, such compounds have been found to reduce the
cognitive deficits caused by A.beta.(25-35)/ibotenate as well as
those developed by certain autoimmune strains of mice. As
previously discussed, the formation of A.beta.(1-42) beta-pleated
sheets, neuronal cell loss, beta amyloid-induced cognitive deficits
are associated with neurodegenerative conditions, such as
Alzheimer's disease, and/or autoimmune conditions. Additionally,
elevated levels of cytokines are associated with neurodegenerative,
autoimmune and/or inflammatory conditions. Accordingly, the
compounds and pharmaceutical compositions of this invention find
use as therapeutics for preventing and/or treating
neurodegenerative, autoimmune and inflammatory conditions in
mammals including humans.
[0228] Surprisingly, it has also been discovered that the dimethoxy
and trimethoxy analogs of the compounds of formula I (i.e.,
compounds in which R.sup.1 and R.sup.2 are methoxy and R.sup.3 is
hydrogen or R.sup.1, R.sup.2 and R.sup.3 are all methoxy) have
significantly higher toxicity than the .alpha.-aryl-N-alkylnitrone
compounds of formula I. Due to their toxicity, such di- and
trimethoxy compounds are not useful as therapeutic agents or as
analytical reagents for detecting free radicals in living
biological systems.
[0229] Among the conditions which may be treated and/or prevented
with the .alpha.-aryl-N-alkylnitrones of formula I are
neurodegenerative conditions, such as Alzheimer's disease,
Parkinson's disease, HIV-dementia and the like; autoimmune
conditions, such as systemic lupus, multiple sclerosis and the
like; and inflammatory conditions, such as inflammatory bowel
disease (IBD), rheumatoid arthritis, septic shock, erythema nodosum
leprosy, septicemia, uveitis, adult respiratory distress syndrome
(ARDS) and the like.
[0230] Additionally, since the .alpha.-aryl-N-alkylnitrones of this
invention have been discovered to effectively inhibit the release
of cytokines, such a IL-1.beta., IL-6 and TNF.alpha., such
compounds are useful for treating diseases characterized by an
overproduction or a dysregulated production of cytokines,
particularly IL-1.beta., IL-6 and TNF.alpha., including many
autoimmune and/or inflammatory conditions.
[0231] As discussed above, the compounds described herein are
suitable for use in a variety of drug delivery systems. Injection
dose levels for treating neurodegenerative, autoimmune and
inflammatory conditions range from about 0.1 mg/kg/hour to at least
10 mg/kg/hour, all for from about 1 to about 120 hours and
especially 24 to 96 hours. A preloading bolus of from about 0.1
mg/kg to about 10 mg/kg or more may also be administered to achieve
adequate steady state levels. The maximum total dose is not
expected to exceed about 2 g/day for a 40 to 80 kg human
patient.
[0232] For the prevention and/or treatment of long-term conditions,
such as neurodegenerative and autoimmune conditions, the regimen
for treatment usually stretches over many months or years so oral
dosing is preferred for patient convenience and tolerance. With
oral dosing, one to five and especially two to four and typically
three oral doses per day are representative regimens. Using these
dosing patterns, each dose provides from about 0.1 to about 20
mg/kg of the .alpha.-aryl-N-alkylnitrone, with preferred doses each
providing from about 0.1 to about 10 mg/kg and especially about 1
to about 5 mg/kg.
[0233] When used to prevent the onset of a neurodegenerative,
autoimmune or inflammatory condition, the
.alpha.-aryl-N-alkylnitrones of this invention will be administered
to a patient at risk for developing the condition, typically on the
advice and under the supervision of a physician, at the dosage
levels described above. Patients at risk for developing a
particular condition generally include those that have a family
history of the condition, or those who have been identified by
genetic testing or screening to be particularly susceptible to
developing the condition.
[0234] The compounds of this invention can be administered as the
sole active agent or they can be administered in combination with
other agents, including other active .alpha.-aryl-N-alkylnitrone
derivatives.
[0235] The novel .alpha.-aryl-N-alkylnitrones of this invention are
also useful as analytical reagents, i.e. as spin traps, for
detecting unstable free radicals using electron spin resonance
(ESR) spectroscopy and related techniques. When used as analytical
reagents, the nitrone compounds of this invention are typically
contacted with the radical to be studied in solution and an ESR
spectrum generated in a conventional manner. In particular, the
.alpha.-aryl-N-alkylnitrones of this invention may be used to
detect and identify free radicals in biological systems. Any ESR
spectrometer, such as a JEOL JES-FE3XG spectrometer, may be
employed in these experiments. Typically, the solution containing
the spin-trap will be deoxygenated by, for example, bubbling argon
or nitrogen through the solution before the ESR experiment is
conducted. Preferably, an excess of the .alpha.-aryl-N-alkylnitrone
is used in such ESR experiments.
[0236] The actual experimental procedures employed in the
spin-trapping experiment will depend on a number of factors, such
as the manner of radical production, the inertness of the solvent
and reagents with respect to the spin trap, the lifetime of the
spin adduct and the like: Spin trapping procedures are well known
in the art and the exact procedure employed can be determined by
those skilled in the art. Typical procedures and apparatus for
conducting spin trapping experiments are described, for example, in
C. A. Evans, "Spin Trapping", Aldrichimica Acta, (1979), 12(2),
23-29, and references cited therein.
[0237] The following synthetic and biological examples are offered
to illustrate this invention and are not to be construed in any way
as limiting the scope of this invention.
EXAMPLES
[0238] In the examples below, the following abbreviations have the
following meanings. Abbreviations not defined below have their
generally accepted meaning.
3 bd = broad doublet bs = broad singlet d = doublet dd = doublet of
doublets dec = decomposed dH.sub.2O = distilled water ELISA =
enzyme-linked immuno-sorbent assay EtOAc = ethyl acetate EtOH =
ethanol FBS = fetal bovine serum g = grams h = hours Hz = hertz
IL-1.beta.= interleukin-1.beta. IL-6 = interleukin-6 L = liter LPS
= lipopolysaccharide m = multiplet min = minutes M = molar MeOH =
methanol mg = milligram MHz = megahertz mL = milliliter mmol =
millimole m.p. = melting point N = normal q = quartet quint. =
quintet s = singlet t = triplet THF = tetrahydrofuran ThT =
thioflavin T tlc = thin layer chromatography TNF.alpha. = tumor
necrosis factor-.alpha. .mu.g = microgram .mu.L = microliter UV =
ultraviolet
[0239] In the examples below, all temperatures are in degrees
Celsius (unless otherwise indicated). Example A-C describe the
synthesis of intermediates useful for preparing
.alpha.-aryl-N-alkylnitrones. The remaining examples describe the
synthesis of .alpha.-aryl-N-alkylnitrones of this invention and
comparative .alpha.-aryl-N-alkylnitrones, and the ESR, in vitro and
in vivo testing of such compounds.
Example A
Synthesis of N-tert-Butylhydroxylamine
[0240] Zinc dust (648 g) was added in portions to a cooled mixture
of 2-methyl-2-nitropropane (503 g) and ammonium chloride (207 g) in
deionized water (6 L) at such a rate so as to maintain the
temperature below 18.degree. C. The reaction mixture was stirred
mechanically for 15 hours and then filtered. The solid was washed
with hot water (1.75 L). The combined filtrate was saturated with
potassium carbonate (4.6 Kg) and extracted with ethyl acetate
(2.times.1300 mL). The organic solution was dried over anhydrous
sodium sulfate, filtered and rotary evaporated to give the title
compound (329 g, 75.7% yield) as white crystals. This material was
used without further purification.
[0241] Spectroscopic data were as follows:
[0242] .sup.1H NMR (CDCl.sub.3, 270 MHz) .delta.=1.090 (s, 3
CH.sub.3).
Example B
Synthesis of N-Isopropylhydroxylamine
[0243] Using the procedure of Example A above and
1-methyl-1-nitroethane, the title compound was prepared. The crude
hydroxylamine product was used without further purification.
Example C
Synthesis of N-Cyclohexylhydroxylamine
[0244] Using the procedure of Example A above and
1-nitrocyclohexane, the title compound can be prepared.
Alternatively, N-cyclohexylhydroxylamine hydrochloride may be
purchased commercially from Aldrich Chemical Company, Inc.,
Milwaukee, Wis. USA and neutralized with a base, such as potassium
carbonate, to provide the title compound.
Example 1
Synthesis of .alpha.-(4-Heptyloxyphenyl)-N-tert-butylnitrone
[0245] The title compound was prepared according to the procedure
described in Example 2 using 4-hydroxybenzaldehyde, 1-iodoheptane
and 2-methyl-2-nitropropane. The title compound was isolated in 60%
overall yield as a solid, m.p. 68.5.degree. C.
[0246] Spectroscopic data were as follows:
[0247] IR (KBr, cm.sup.-1): 3076.8 (CH), 2972.3 (CH), 1601.9
(C.dbd.N), 1250.9 (C--O--C) and 1118.8 (N--O).
[0248] .sup.1H NMR (CDCl.sub.3, 270 MHz) .delta.=8.25 (2H, d, J=8.9
Hz, phenyl 2H), 7.44 (1H, s, nitronyl H), 6.90 (2H, d, J=8.9 Hz,
phenyl 2H), 3.98 (2H, t, J=6.7 Hz, CH.sub.2), 1.77 (2H, quintet,
J=6.7 Hz, CH.sub.2), 1.58 (9H, s, 3 CH.sub.3), 1.36(8H, m, 4
CH.sub.2) and 0.87 (3H, t, J=6.7 Hz, CH.sub.3).
[0249] .sup.13C NMR (CDCl.sub.3, 67.9 MHz) .delta.=160.9, 131.0,
129.8, 124.0, 114.4, 69.9, 68.0, 31.5, 28.9, 28.7, 28.0, 25.6, 22.3
and 13.7.
Example 2
Synthesis of .alpha.-(4-Hexyloxyphenyl)-N-n-propylnitrone
[0250] A solution of 4-hydroxybenzaldehyde (27.11 g, 0.222 moles)
in ethanol was refluxed with sodium hydroxide (8.88 g, 0.222 moles)
for 30 minutes. 1-Iodohexane (47.10 g, 0.222 moles) was added in
one portion and the solution refluxed for 68 hours. The ethanol was
removed by rotary evaporation and the residue was reacted with
1-nitropropane, ammonium chloride, and zinc dust in H.sub.2O/
ethanol (300:20, v:v) for 18 hours at room temperature. The
reaction mixture was filtered, the solvent removed by rotary
evaporation, and the residue purified by column chromatography
using ethyl acetate/hexane (1:1, v:v) as the eluant (R.sub.f=0.42
on a silica gel plate using ethyl acetate/hexane (1:1, v:v) as the
eluant). The title compound was isolated as a solid (1.63 g, 12.4%
overall yield), m.p. 45.degree. C.
[0251] Spectroscopic data was as follows:
[0252] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.22 (2H, d,
J=8.8 Hz, phenyl 2H), 7.28 (1H, s, nitronyl H), 6.92 (2H, d, J=8.8
Hz, phenyl 2H), 3.93 (4H, m, 2CH.sub.2), 2.07 (4H, m, CH.sub.2),
1.36 (6H, m, 3CH.sub.2), 1.00 (3H, t, CH.sub.3), 0.908 (3H, t,
CH.sub.3).
Examples 3-6
[0253] Using the procedures described herein, the following
compounds were prepared:
[0254] .alpha.-(3-Ethoxy-4-methoxyphenyl)-N-tert-butylnitrone
[0255] .alpha.-(4-Ethoxyphenyl)-N-tert-butylnitrone
[0256] .alpha.-(4-Benzyloxy-3-methoxyphenyl)-N-tert-butylnitrone,
and
[0257]
.alpha.-[3-(4-Methoxyphenoxy)phenyl]-N-tert-butylnitrone.
Example 7
Synthesis of .alpha.-(2-Ethoxyphenyl)-N-tert-butylnitrone
[0258] 2-Ethoxybenzaldehyde (12.0 g, 79.90 mmol) and
N-tert-butylhydroxylamine (10.69 g, 119.86 mmol) were mixed in
chloroform with molecular sieves (50 g, 4A) and silica gel (10 g).
The mixture was sealed under argon gas and stirred for 70 h at room
temperature. The mixture was then filtered and the solid washed
with ethyl acetate and the combined solution was rotary evaporated.
Pentane (50 mL) was added to the liquid residue and isolation of
the resulting solid afforded 13.79 g (78.0% yield) of the title
compound as white crystals, m.p. 58.3.degree. C. (R.sub.f=0.55 on a
silica gel plate using ethyl acetate as the eluant).
[0259] Spectroscopic data were as follows:
[0260] IR (KBr, cm.sup.-1): 2976.7 (CH), 2935 (CH), 1597.0
(C.dbd.N), 1567.1 (benzene ring) and 1123.6 (N--O).
[0261] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=9.322 (1H, dd,
J.sub.1=1.7 Hz, J.sub.2=7.9 Hz, phenyl H), 8.067 (1H, s, CH.dbd.N),
7.302 (1H, td, J.sub.t=7.9 Hz, J.sub.d=1.7 Hz, phenyl H), 6.979
(1H, td, J.sub.t=7.9 Hz, J.sub.d=0.5 Hz, phenyl H), 6.839 (1H, d,
J=7.9 Hz, phenyl H), 4.055 (2H, q, J=6.9 Hz, OCH.sub.2), 1.586 (9H,
s, 3 CH.sub.3) and 1.423 (3H, t, J=6.9 Hz, CH.sub.3).
[0262] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=156.948,
131.323, 128.836, 124.688, 120.813, 120.386, 110.868, 70.767,
63.842, 27.997 and 14.375.
Examples 8-10
[0263] Using the procedures described herein, the following
compounds were prepared:
[0264] .alpha.-(3,4-Ethylenedioxyphenyl)-N-tert-butylnitrone,
and
[0265] .alpha.-(3,4-Methylenedioxyphenyl)-N-tert-butylnitrone.
[0266] .alpha.-(4-ethoxyphenyl)-N-n-butylnitrone
Example 11
Synthesis of .alpha.-(4Ethoxyphenyl)-N-cyclohexylnitrone
[0267] A solution of 4-ethoxybenzaldehyde (6.62 g, 44.1 mmol) in
200 mL of benzene was refluxed with N-cyclohexylhydroxylamine (6.61
g, 57.4 mmol) in the presence of p-toluenesulfonic acid (0.8 g, 4
mmol) for 72 h. After rotary evaporation, the residue was purified
by recrystallization from hexanes and ethylene glycol dimethyl
ether (100 mL, 3:1, v:v) to give the title compound (9.2 g, 84%
yield) as a solid, m.p. 124.0.degree. C.
[0268] Spectroscopic data were as follows:
[0269] IR (KBr, cm.sup.-1): 2933.0, 2862 (CH), 1599.6 (C.dbd.N),
1297.0 (C--O--C) and 1149.4 (N--O).
[0270] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.20 (2H, d,
J=8.9 Hz, phenyl 2H), 7.32 (1H, s, nitronyl H), 6.88 (2H, d, J=8.9
Hz, phenyl 2H), 4.05 (2H, quartet, J=7.0 Hz, CH.sub.2), 3.75 (1H,
m, CH), 1.94 (6H, m, 6 CH), 1.68 (2H, m, 2 CH), 1.39 (2H, t, J=7.0
Hz, CH.sub.3) and 1.27 (2H, m, 2 CH).
[0271] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=160.6, 132.1,
130.7, 123.8, 114.4, 75.0, 63.4, 30.8, 24.7 and 14.3.
Example 12
Synthesis of
.alpha.-(4-Benzyloxy-3-methoxyphenyl)-N-cyclohexylnitrone
[0272] The title compound was prepared according to the procedure
described in Example 11 using 4-benzyloxy-3-methoxybenzaldehyde and
N-cyclohexylhydroxylamine. The title compound was isolated in 97.9%
yield as a solid, m.p. 154.1.degree. C.
[0273] Spectroscopic data were as follows:
[0274] IR (KBr, cm.sup.-1): 2935.3 (CH), 1595.4 (C.dbd.N), 1265.1
(C--O--C) and 1147.6 (N--O).
[0275] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.50 (1H, d,
J=2.0 Hz, phenyl H), 7.34 (7H, m, phenyl H & nitronyl H), 6.86
(1H, d, J=8.4 Hz, phenyl H), 5.19 (2H, s, CH.sub.2), 3.94 (3H, s,
CH.sub.3), 3.78 (1H, m, cyclohexyl H), 1.95 (6H, m, 6 cyclohexyl
H), 1.67 (2H, m, 2 CH) and 1.30 (2H, m, 2 CH).
[0276] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=150.0, 149.4,
137.0, 132.5, 128.8, 128.2, 127.4, 124.8, 122.9, 113.3, 111.6,
75.2, 70.7, 55.7, 30.8 and 24.7.
Example 13
Synthesis of
.alpha.-(3-Ethoxy-4-methoxyphenyl)-N-cyclohexylnitrone
[0277] The title compound was prepared according to the procedure
described in Example 11 using 3-ethoxy-4-methoxybenzaldehyde and
N-cyclohexylhydroxylamine. The title compound was isolated in 57%
yield as a solid, m.p. 113.5 .degree. C.
[0278] Spectroscopic data were as follows:
[0279] IR (KBr, cm.sup.-1): 2857.3 (CH), 1590.8 (C.dbd.N), 1265.0,
1239.0 (C--O--C) and 1126.1 (N--O).
[0280] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.42 (1H, d,
J=1.8 Hz, phenyl H), 7.39 (1H, dd, J=7.5 and 1.8 Hz, phenyl H),
7.32 (1H, s, nitronyl H), 6.84 (1H, d, J=7.5 Hz, phenyl H), 4.14
(2H, quartet, J=7.0 Hz, CH.sub.2), 3.88 (3H, s, CH.sub.3), 3.76
(1H, m, CH), 1.96 (6H, m, 6 CH), 1.68 (1H, m, CH), 1.44 (3H, t,
J=7.0 Hz, CH.sub.3) and 1.27 (3H, m, 3 CH).
[0281] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=150.95, 148.13,
132.47, 124.32, 122.93, 112.36, 110.91, 75.14, 64.10, 55.71, 30.80,
24.75 and 14.34.
Example 14
Synthesis of
.alpha.-(3,4-Ethylenedioxyphenyl)-N-cyclohexylnitrone
[0282] The title compound was prepared according to the procedure
described in Example 11 using 3,4-ethylenedioxybenzaldehyde and
N-cyclohexylhydroxylamine. The title compound was isolated in 74.5%
yield as a solid, m.p. 96.7.degree. C.
[0283] Spectroscopic data were as follows:
[0284] IR (KBr, cm.sup.-1): 2927.9 (CH), 1575.6 (C.dbd.N), 1319.5
(C--O--C) and 1133.9 (N--O).
[0285] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=7.98 (1H, d,
J=2.0 Hz, phenyl H), 7.60 (1H, dd, J=7.4 & 2.0 Hz, phenyl H),
7.27 (1H, s, nitronyl H), 6.83 (1H, d, J=7.4 Hz, phenyl H), 4.24
(4H, m, 2 CH.sub.2), 3.75 (1H, m, CH), 1.94 (7H, m, 7 CH) and 1.28
(3H, m, 3 CH).
[0286] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=145.45, 143.45,
131.86, 124.75, 122.98, 117.76, 117.26, 75.16, 64.50, 63.98, 30.80
and 24.73.
Example 15
[0287] Using the procedures described herein, the following
compound was prepared:
[0288] .alpha.-(4-Ethoxy-3-methoxyphenyl)-N-cyclohexylnitrone.
Example 16
Synthesis of
.alpha.-(3,4-Ethylenedioxyphenyl)-N-isopropylnitrone
[0289] The title compound was prepared according to the procedure
described in Example 11 using 3,4-ethylenedioxybenzaldehyde and
N-isopropylhydroxylamine. The crude produce was purified by column
chromatography over silica gel using ethyl acetate as the eluant.
The title compound was isolated in 53% yield as a solid, m.p.
108.8.degree. C. (R.sub.f=0.31 on a silica gel plate using EtOAc as
the eluant).
[0290] Spectroscopic data were as follows:
[0291] IR (KBr, cm.sup.-1): 2978.9 (CH), 1582.3 (C.dbd.N), 1297.0
(C--O--C) and 1063.8 (N--O).
[0292] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=7.99 (1H, d,
J=2.0 Hz, phenyl H), 7.61 (1H, dd, J=8.5 & 2.0 Hz, phenyl H),
7.28 (1H, s, nitronyl H), 6.84 (1H, d, J=8.5 Hz, phenyl H), 4.25
(4H, m, 2 CH.sub.2), 4.13 (1H, septet, J=6.7 Hz, CH) and 1.46 (6H,
d, J=6.7 Hz, 2 CH.sub.3).
[0293] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=145.5, 143.5,
131.6, 124.7, 123.0, 117.8, 117.3, 67.3, 64.5, 64.0 and 20.5.
Example 17
Synthesis of
.alpha.-(3-Ethoxy-4-methoxyphenyl)-N-isopropylnitrone
[0294] The title compound was prepared according to the procedures
described in Examples 11 using 3-ethoxy-4-methoxybenzaldehyde and
N-isopropylhydroxylamine. The title compound was isolated in 43.9%
yield as a solid, m.p. 80.8.degree. C. (R.sub.f=0.15 on a silica
gel plate using ethyl acetate as the eluant).
[0295] Spectroscopic data were as follows:
[0296] IR (KBr, cm.sup.-1): 2981.6 (CH), 1596.7 (C.dbd.N), 1443.7
(CH.sub.3), 1263.3 (C--O--C) and 1128.6 (N--O).
[0297] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.44 (1H, d,
J=1.9 Hz, phenyl H), 7.40 (1H, dd, J=8.5 & 1.9 Hz, phenyl H),
7.34 (1H, s, nitronyl CH), 6.87 (1H, d, J=8.5 Hz, phenyl H), 4.16
(3H, m, CH.sub.2 and CH), 3.89 (3H, s, CH.sub.3) and 1.48 (9H, m, 3
CH.sub.3).
[0298] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=151.0, 148.2,
132.2, 124.2, 123.0, 112.3, 110.9, 67.2, 64.1, 55.7, 20.5 and
14.4.
Example 18
Synthesis of .alpha.-(2-Ethoxyphenyl)-N-isopropylnitrone
[0299] The title compound was prepared according to the procedure
described in Example 11 using 2-ethoxybenzaldehyde and
N-isopropylhydroxylamine. The title compound was isolated in 48.8%
yield as a solid, m.p. 59.4.degree. C. (R.sub.f=0.48 on a silica
gel plate using ethyl acetate as the eluant).
[0300] Spectroscopic data were as follows:
[0301] IR (KBr, cm.sup.-1): 2978.8 (CH), 1593.6 (C.dbd.N), 1245.0
(C--O--C) and 1149.3 (N--O).
[0302] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=9.30 (1H, d,
J=7.7 Hz, phenyl H), 7.961 (1H, s, nitronyl H), 7.30 (1H, td, J=7.7
& 1.7 Hz, phenyl H), 6.98 (1H, td, J=7.7 &1.7 Hz, phenyl
H), 6.83 (1H, d, J=7.7 Hz, phenyl H), 4.23 (1H, m, CH), 4.03 (2H,
quartet, J=7.2 Hz, CH.sub.2) and 1.44 (9H, m, 3 CH.sub.3).
[0303] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=156.56, 131.38,
129.02, 126.76, 120.80, 120.04, 110.75, 67.95, 63.78, 20.55 and
14.39.
Example 19
Synthesis of .alpha.-(2-Ethoxyphenyl)-N-cyclohexylnitrone
[0304] The title compound was prepared according to the procedure
described in Example 11 using 2-ethoxybenzaldehyde and
N-cyclohexylhydroxylamine. The title compound was isolated in 89%
yield as a solid, m.p. 54.8.degree. C.
[0305] Spectroscopic data were as follows:
[0306] IR (KBr, cm.sup.-1): 2932.9 (CH), 1593.8 (C.dbd.N), 1244.9
(C--O--C) and 1144.8 (N--O).
[0307] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=9.32 (1H, d,
J=7.9 Hz, phenyl H), 7.89 (1H, s, nitronyl H), 7.29 (1H, t, J=7.9
Hz, phenyl H), 6.97 (1H, t, J=7.9 Hz, phenyl H), 6.84 (1H, d, J=7.9
Hz, phenyl H), 4.06 (2H, quartet, J=7.1 Hz, CH.sub.2), 3.84 (1H, m,
CH), 1.95 (6H, m, 2 CH.sub.2 & 2 CH), 1.67 (1H, m, CH), 1.66
(3H, t, J=7.1 Hz, CH.sub.3) and 1.25 (3H, m, 3 CH).
[0308] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=156.6, 131.3,
129.0, 127.1, 120.8, 120.1, 110.7, 75.8, 63.8, 30.8, 24.7 and
14.4.
Example 20
Synthesis of
.alpha.-(4-Benzyloxy-3-methoxyphenyl)-N-isopropylnitrone
[0309] The title compound was prepared according to the procedures
described in Examples 11 using 4-benzyloxy-3-methoxybenzaldehyde
and N-isopropylhydroxylamine. The title compound was isolated in
54.6% yield as a solid, m.p. 95.5.degree. C.
[0310] Spectroscopic data were as follows:
[0311] IR (KBr, cm.sup.-1): 2988.4 (CH), 2935.0 (CH), 1585.1
(C.dbd.N), 1461.0 (CH.sub.3), 1262.9 (C--O--C) and 1126.9
(N--O).
[0312] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.50 (1H, d,
J=1.7 Hz, phenyl H), 7.33 (7H, m, 6 phenyl H & nitronyl H),
6.86 (1H, d, J=8.4 Hz, phenyl H), 5.18 (2H, s, CH.sub.2), 4.13 (1H,
septet, J=6.4 Hz, CH), 3.93 (3H, s, CH.sub.3) and 1.47 (6H, d,
J=6.4 Hz, 2 CH.sub.3).
[0313] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=149.8, 149.4,
136.9, 132.2, 128.8, 128.2, 127.4, 124.6, 122.9, 113.2, 111.5,
70.7, 67.3, 55.7 and 20.5.
Example 21
[0314] Using the procedures described herein, the following
compound was prepared:
[0315] .alpha.-(4-Ethoxy-3-methoxyphenyl)-N-isopropylnitrone.
Example 22
Synthesis of
.alpha.-(3-Ethoxy-4-hexyloxyphenyl)-N-cyclohexylnitrone
[0316] The title compound was prepared according to the procedure
described in Example 28 using 3-ethoxy-4-hydroxybenzaldehyde,
1-iodohexane and N-cyclohexylhydroxylamine. The title compound was
isolated in 41.3% yield as a solid, m.p. 67.3.degree. C.
[0317] Spectroscopic data were as follows:
[0318] IR (KBr, cm.sup.-1): 2920.7 (CH), 1597.7 (C.dbd.N), 1341.2
(CH.sub.3), 1267.7 (C--O--C), and 1129.0 (N--O).
[0319] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.36 (1H, d,
J=1.9 Hz, phenyl H), 7.39 (1H, dd, J=8.6 & 1.9 Hz, phenyl H),
7.31 (1H, s, nitronyl H), 6.84 (1H, d, J=8.6 Hz, phenyl H), 4.12
(2H, quartet, J=7.0 Hz, CH.sub.2), 4.01 (2H, t, J=6.8 Hz,
CH.sub.2), 3.76 (1H, m, CH), 1.93 (10H, m, 5 CH.sub.2), 1.42 (3H,
t, J=7.0 Hz, CH.sub.3), 1.32 (8H, m, 4 CH.sub.2) and 0.88 (3H, t,
J=7.0 Hz, CH.sub.3).
[0320] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=150.8, 157.6,
132.6, 124.2, 123.0, 113.2, 112.6, 75.1, 69.0, 64.4, 31.3, 30.8,
28.7, 25.3, 24.8, 22.2, 14.4 and 13.6.
Example 23
Synthesis of
.alpha.-(4-Benzyloxy-3-methoxyphenyl)-N-n-butylnitrone
[0321] The title compound was prepared according to the procedures
described in Examples 11 using 4-benzyloxy-3-methoxybenzaldehyde
and N-n-butylhydroxylamine. The title compound was isolated in
41.7% yield as a solid, m.p. 81.2.degree. C.
[0322] Spectroscopic data were as follows:
[0323] IR (KBr, cm.sup.-1): 2925.1 (CH), 2856.9 (CH), 1593.2
(C.dbd.N), 1463.1 (CH.sub.3), 1263.1 (C--O--C) and 1156.1
(N--O).
[0324] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.42 (1H, d,
J=2.0 Hz, phenyl H), 7.34 (7H, m, 6 phenyl H & nitronyl H),
6.86 (1H, d, J=8.4 Hz, phenyl H), 5.18 (2H, s, CH.sub.2), 3.93 (3H,
s, CH.sub.3), 3.93 (2H, t, J=7.3 Hz, CH.sub.2), 1.96 (2H, quintet,
J=7.3 Hz, CH.sub.2), 1.39 (2H, sextet, J=7.3 Hz, CH.sub.2) and 0.95
(3H, t, J=7.3 Hz, CH.sub.3).
[0325] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=150.0, 149.4,
136.9, 134.3, 128.8, 128.2, 127.4, 124.4, 122.9, 113.2, 111.4,
70.7, 66.6, 55.8, 29.4, 19.4 and 13.2.
Example 24
[0326] Using the procedures described herein, the following
compound was prepared:
[0327] .alpha.-(4-Ethoxy-3-methoxyphenyl)-N-n-butylnitrone.
Example 25
Synthesis of .alpha.-(2-Ethoxyphenyl)-N-n-butylnitrone
[0328] The title compound was prepared according to the procedures
described in Examples 11 using 2-ethoxybenzaldehyde and
N-n-butylhydroxylamine. The title compound was isolated in 44.5%
yield as a liquid.
[0329] Spectroscopic data were as follows:
[0330] IR (NaCl, cm.sup.-1): 2959.6 (CH), 1594.9 (C.dbd.N), 1454.8
(CH.sub.3), 1245.1 (C--O--C) and 1163.5 (N--O).
[0331] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=9.24 (1H, d,
J=8.0 Hz, phenyl H), 7.80 (1H, s, nitronyl H), 7.28 (1H, t, J=8.0
Hz, phenyl H), 6.95 (1H, t, J=8.0 Hz, phenyl H), 6.81 (1H, d, J=8.0
Hz, phenyl H), 4.02 (2H, quartet, J=6.35 Hz, CH.sub.2), 3.90 (2H,
t, J=7.1 Hz, CH.sub.2), 1.93 (2H, quintet, J=7.3 Hz, CH.sub.2),
1.40 (5H, m, CH.sub.2 & CH.sub.3) and 0.93 (3H, t, J=7.4 Hz,
CH.sub.3).
[0332] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=156.6, 131.5,
129.0, 128.9, 120.7, 119.9, 110.8, 67.2, 63.8, 29.5, 19.3, 14.3 and
13.2.
Example 26
Synthesis of
.alpha.-(3-Ethoxy-4-methoxyphenyl)-N-n-butylnitrone
[0333] The title compound was prepared according to the procedures
described in Examples 11 using 3ethoxy-4-methoxybenzaldehyde and
N-n-butylhydroxylamine. The title compound was isolated in 41.1%
yield as a solid, m.p. 117.3.degree. C.
[0334] Spectroscopic data were as follows:
[0335] IR (KBr, cm.sup.-1): 2953.1 (CH), 1593.9 (C.dbd.N), 1265.4
(C--O--C) and 1129.3 (N--O).
[0336] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.35 (1H, d,
J=1.8 Hz, phenyl H), 7.42 (1H, dd, J=8.5 & 1.8 Hz, phenyl H),
7.27 (1H, s, nitronyl H), 6.86 (1H, d, J=8.5 Hz, phenyl H), 4.16
(2H, quartet, J=6.9 Hz, CH.sub.2), 3.87 (5H, m, CH.sub.2 and
CH.sub.3), 1.94 (2H, quintet, J=7.4 Hz, CH.sub.2), 1.45 (5H, m,
CH.sub.2 and CH.sub.3) and 0.95 (3H, t, J=7.4 Hz, CH.sub.2).
[0337] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=151.2, 148.2,
132.3, 124.1, 122.9, 112.3, 111.0, 66.6, 64.2, 55.7, 29.4, 19.4,
14.3 and 13.2.
Example 27
Synthesis of
.alpha.-(3-Ethoxy-4-hexyloxyphenyl)-N-isopropylnitrone
[0338] The title compound was prepared according to the procedure
described in Example 28 using 3-ethoxy-4-hydroxybenzaldehyde,
1-iodohexane and N-isopropylhydroxylamine. The title compound was
isolated in 47.1% overall yield as a solid, m.p. 69.0.degree.
C.
[0339] Spectroscopic data were as follows:
[0340] IR (KBr, cm.sup.-1): 2995.0 (CH), 1596.9 (C.dbd.N), 1393.8
(iPr), 1261.2 (C--O--C) and 1128.7 (N--O).
[0341] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.36 (1H, d,
J=2.0 Hz, phenyl H), 7.40 (1H, dd, J=8.4 & 2.0 Hz, phenyl H),
7.32 (1H, s, nitronyl H), 6.86 (1H, d, J=8.4 Hz, phenyl H), 4.13
(3H, m, CH.sub.2 and CH), 4.02 (2H, t, J=6.9 Hz, CH.sub.2), 1.82
(2H, quintet, J=7.4 Hz, CH.sub.2), 1.48 (6H, d, J=6.7 Hz, 2
CH.sub.3), 1.42 (3H, t, J=6.9 Hz, CH.sub.3), 1.31 (6H, m, 3
CH.sub.2) and 0.88 (3H, t, J=6.9 Hz, CH.sub.3).
[0342] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=150.8, 148.6,
132.2, 124.1, 123.1, 133.2, 112.6, 69.0, 67.2, 64.4, 31.3, 28.7,
25.3, 22.2, 20.5, 14.4 and 13.6.
Example 28
Synthesis of
.alpha.-(3-Ethoxy-4-hexyloxyphenyl)-N-tert-butylnitrone
[0343] A solution of 3-ethoxy-4-hydroxybenzaldehyde (13.28 g, 79.9
mmol) and sodium hydroxide (3.20 g, 79.9 mmol) in ethanol (120 mL)
was refluxed for 30 min. To the refluxing solution was added
1-iodohexane (18.6 g, 87.9 mmol) in one portion and reflux was
continued for 24 h. The solution was then cooled and the ethanol
removed on a rotary evaporator. The residue was dissolved in ethyl
acetate and this solution filtered and rotary evaporated. The
resulting residue was reacted with N-tert-butylhydroxylamine (6.94
g) in 200 mL of benzene in the presence of p-toluenesulfonic acid
(0.8 g) at refluxing temperature for 24 h. After evaporation, the
residue obtained was purified by recrystallization from hexanes to
give the title compound (11.02 g, 57.2% overall yield) as a solid,
m.p. 35.5.degree. C.
[0344] Spectroscopic data were as follows:
[0345] IR (KBr, cm.sup.-1): 2900 (CH), 1596.2 (C.dbd.N), 1361.1
(CH.sub.3), 1276.0 (C--O--C) and 1144.8 (N--O).
[0346] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.38 (1H, d,
J=1.7 Hz, phenyl H), 7.45 (1H, dd, J=8.5 & 1.7 Hz, phenyl H),
7.42 (1H, s, nitronyl H), 6.86 (1H, d, J=8.5 Hz, phenyl H), 4.13
(2H, quartet, J=7.0 Hz, CH.sub.2), 4.02 (2H, t, J=6.8 Hz,
CH.sub.2), 1.82 (2H, m, CH.sub.2), 1.65 (2H, m, CH.sub.2), 1.58
(9H, s, 3 CH.sub.3). 1.42 (3H, t, J=7.0 Hz, CH.sub.3), 1.31 (4H, m,
2 CH.sub.2) and 0.88 (3H, t, J=6.3 Hz, CH.sub.3).
[0347] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.150.8, 148.6,
130.1, 124.4, 123.4, 113.4, 112.6, 70.0, 69.0, 64.4, 31.3, 28.7,
28.0, 25.3, 22.2, 14.4 and 13.6.
Example 29
Synthesis of
.alpha.c-(2-Fluoro-4-octyloxyphenyl)-N-tert-butylnitrone
[0348] To dry dimethylformamide (200 mL) were added
2-fluoro-4-hydroxybenzonitrile (13.71 g, 100 mmol), 1-iodooctane
(28.82 g, 120 mmol) and potassium fluoride (11.6 g, 200 mmol). This
mixture was stirred at room temperature for 16 h, and then at
50.degree. C. for 2 h and then at 90.degree. C. for 2 h. The
mixture was then poured into wet-ice (400 g) and 37% HCl (10 mL).
The resulting solution was extracted with diethyl ether
(3.times.200 mL). The ether layer was washed with water
(2.times.200 mL) and dried over Na.sub.2SO.sub.4. After filtration,
rotary evaporation gave the crude desired intermediate
2-fluoro-4-n-octyloxybenzonitrile (27.83 g). This liquid
intermediate was then added, over a 5-10 min period at 3-13.degree.
C., to a flask containing LiAlH(OEt).sub.3 [which had been freshly
prepared from LiAlK (5.03 g, 0.1326 mol) and ethyl acetate (15.24
g, 0.1730 mol) at 3-8.degree. C. in diethyl ether (130 mL)]. The
reaction mixture was stirred at 5.degree. C. for 75 min and 5 N
H.sub.2SO.sub.4 aqueous solution (120 mL) was added dropwise with
cooling. After separation, the aqueous layer was extracted with
diethyl ether (2.times.100 mL) and the combination extracts were
washed with water (2.times.100 mL). Standard work-up procedures
afforded crude 2-fluoro-4-n-octyloxybenzaldehyde (26.07 g). The
crude material was then mixed with N-tert-butylhydroxylami- ne (8.6
g, 96.4 mmol), molecular sieves (50 g, 4A) and silica gel (10 g) in
chloroform (250 mL). The mixture was stirred at room temperature
for 23 h and refluxed for 3 h under argon gas. The mixture was then
filtered and rotary evaporated to give a residue which was purified
by column chromatography over silica gel eluted with hexanes/ethyl
acetate (4:1, v:v). The title compound (12.90 g) was obtained in
39.9% overall yield as a slightly yellowish solid, m.p.
35.6.degree. C. (R.sub.f=0.36 on a silica gel plate using
hexanes/EtOAc, 4:1, v:v, as the eluant).
[0349] Spectroscopic data were as follows:
[0350] IR (KBr, cm.sup.-1): 2928.1 (CH), 2855.1 (CH), 1617.8
(C.dbd.N), 1556.8 (benzene ring), 1287.0 (Ar--F), 1161.2 (Ar--O),
1129.4 (N--O) and 1105.4 (alkyl-O).
[0351] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=9.288 (1H, t,
J.sub.H=J.sub.F=8.9 Hz, aromatic H), 7.702 (1H, s, CH.dbd.N), 6.684
(1H, dd, J.sub.H=8.9 Hz, J.sub.H=2.5 Hz, aromatic H), 6.586 (1H,
dd, J.sub.F=13.7 Hz, J.sub.H=2.5 Hz, aromatic H), 3.937 (2H, t,
J=6.6 Hz, OCH.sub.2), 1.745 (2H, m, CH.sub.2), 1.568 (9H, s, 3
CH.sub.3), 1.408-1.251 (10H, m, (CH.sub.2).sub.5) and 0.851 (3H, t,
J=6.9 Hz, CH.sub.3).
[0352] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=161.959 (d,
J=11.4 Hz), 161.959 (d, J=253.9 Hz), 130.103, 122.232 (d, J=8.3
Hz), 112.363 (d, J=8.3 Hz), 109.892, 101.693 (d, J=25.9 Hz),
70.630, 68.372, 31.459, 28.958, 28.851, 28.683, 27.936, 25.587,
22.261 and 13.658.
Example 30
Synthesis of
[0353] .alpha.-(2,4,6-Triethoxyphenyl)-N-tert-butylnitrone
[0354] The title compound was prepared according to the procedure
described in Example 11 using 2,4,6-triethoxybenzaldehyde and
N-tert-butylhydroxylamine. The title compound was isolated in 92.3%
yield as a solid, m.p. 109.1.degree. C.
[0355] Spectroscopic data were as follows:
[0356] IR (KBr, cm.sup.-1): 2978.5 (CH), 1608.2 (C.dbd.N), 1438.6
(CH.sub.3), 1231.2 (C--O--C) and 1132.3 (N--O).
[0357] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=7.46 (1H, s,
nitronyl H), 6.07 (2H, s, 2 phenyl H), 3.98 (6H, m, 3 CH.sub.2),
1.56 (9H, s, 3 CH.sub.3) and 1.32 (9H, m, 3 CH.sub.3).
[0358] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=161.9, 159.3,
125.0, 92.3, 69.3, 63.9, 63.4, 28.1, 14.5 and 14.3.
Example 31
Synthesis of
.alpha.-(2,4,6-Triethoxyphenyl)-N-cyclohexylnitrone
[0359] The title compound was prepared according to the procedure
described in Example 11 using 2,4,6-triethoxybenzaldehyde and
N-cyclohexylhydroxylamine. The title compound was isolated in 87.4%
yield as a solid, m.p. 145.7.degree. C.
[0360] Spectroscopic data were as follows:
[0361] IR (KBr, cm.sup.-1): 2935 (CH), 1601 (C.dbd.N), 1391
(CH.sub.3), 1167 (C--O--C) and 1133 (N--O).
[0362] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=7.34 (1H, s,
nitronyl H), 6.06 (2H, s, 2 phenyl H), 3.99 (6H, m, 3 CH.sub.2),
3.80 (1H, m, CH), 1.94 (10H, m, 5 CH.sub.2) and 1.32 (9H, m, 3
CH.sub.3).
[0363] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=162.1, 159.4,
127.2, 102.0, 92.2, 74.1, 64.0, 63.4, 31.0, 29.6, 24.8, 14.5 and
14.4.
Example 32
Synthesis of .alpha.-(2-n-Butoxyphenyl)-N-tert-butylnitrone
[0364] The title compound was prepared according to the procedure
described in Example 28 using 2-hydroxybenzonitrile, 1-iodobutane
and N-tert-butylhydroxylamine. The title compound was isolated in
77.4% overall yield as a viscous oil.
[0365] Spectroscopic data were as follows:
[0366] IR (NaCl, cm.sup.-1): 3074 (Ar CH), 2962 (CH), 1594
(C.dbd.N), 1468 (CH.sub.3), 1244 (C--O--C) and 1132 (N--O).
[0367] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=9.29 (1H, dd,
J=7.9 & 1.7 Hz, phenyl H), 8.06 (1H, s, nitronyl H), 7.29 (1H,
td, J=7.9 & 1.7 Hz, phenyl H), 6.96 (1H, t, J=7.9 Hz, phenyl
H), 6.82 (1H, d, J=7.9 Hz, phenyl H), 3.98 (2H, t, J=6.3 Hz,
CH.sub.2), 1.75 (2H, quintet, J=6.9 Hz, CH.sub.2), 1.57 (9H, m, 3
CH.sub.3), 1.50 (2H, m, CH.sub.2) and 0.96 (3H, t, J=7.3 Hz,
CH.sub.3).
[0368] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=157.1, 131.4,
128.8, 124.7, 120.7, 120.4, 110.8, 70.7, 67.9, 30.9, 28.0, 19.0 and
13.4.
Example 33
Synthesis of .alpha.-(3,4-Diethoxyphenyl)-N-tert-butylnitrone
[0369] The title compound was prepared according to the procedure
described in Example 11 using 3,4-diethoxybenzaldehyde and
N-tert-butylhydroxylamine. The title compound was isolated in 93.7%
yield as a solid, m.p. 57.9.degree. C.
[0370] Spectroscopic data were as follows:
[0371] IR (KBr, cm.sup.-1): 2984 (CH), 1596 (C.dbd.N), 1272
(C--O--C) and 1146 (N--O).
[0372] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.41 (1H, d,
J=1.9 Hz, phenyl H), 7.46 (1H, dd, J=8.4 & 1.9 Hz, phenyl H),
7.43 (1H, s, nitronyl H), 6.86 (1H, d, J=8.4 Hz, phenyl H), 4.14
(2H, quartet, J=7.0 Hz, CH.sub.2), 4.13 (2H, quartet, J=7.0 Hz,
CH.sub.2), 1.58 (9H, s, 3 CH.sub.3), 1.45 (3H, t, J=7.0 Hz,
CH.sub.3) and 1.44 (3H, t, J=7.0 Hz, CH.sub.3).
[0373] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=150.5, 148.4,
130.2, 124.4, 123.4, 113.0, 112.3, 70.1, 64.3, 28.0, 14.4 and
14.3.
Example 34
Synthesis of
.alpha.-(2-Fluoro-4-heptyloxyphenyl)-N-tert-butylnitrone
[0374] The title compound was prepared according to the procedure
described in Example 28 using 2-fluoro-4-hydroxybenzonitrile,
1-iodoheptane and N-tert-butylhydroxylamine. The title compound was
isolated in 66.0% overall yield as a white solid, m.p. 38.8.degree.
C. (R.sub.f=0.21 on a silica gel plate using hexanes/ethyl acetate,
4:1, v:v, as the eluant).
[0375] Spectroscopic data were as follows:
[0376] IR (KBr, cm.sup.-1): 2930.1 (CH), 2857.5 (CH), 1618.6
(C.dbd.N), 1556.6 (benzene ring), 1286.8 (Ar--F), 1161.6 (Ar--O),
1129.4 (N--O) and 1105.4 (alkyl-O).
[0377] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=9.291 (1H, t,
J.sub.H=J.sub.F=8.9 Hz, aromatic H), 7.723 (1H, s, CH.dbd.N), 6.700
(1H, dd, J.sub.H=8.9 Hz, J.sub.H=2.6 Hz, aromatic H), 6.603 (1H,
dd, J.sub.F=13.1 Hz, J.sub.H=2.6 Hz, aromatic H), 3.954 (2H, t,
J=6.6 Hz, OCH.sub.2), 1.747 (2H, m, CH.sub.2), 1.585 (9H, s, 3
CH.sub.3), 1.445-1.286 (8 H, m, (CH.sub.2).sub.4) and 0.872 (3H, t,
J=6.8 Hz, CH.sub.3).
[0378] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=161.997 (d,
J=12.4 Hz), 161.990 (d, J=253.9 Hz), 130.133, 122.354 (d, J=8.3
Hz), 112.332 (d, J=8.3 Hz), 109.922, 101.716 (d, J=24.9 Hz),
70.645, 68.387, 31.429, 28.683, 27.951, 25.556, 22.216 and
13.658.
Example 35
Synthesis of
.alpha.-(2-Fluoro-4-ethoxyphenyl)-N-tert-butylnitrone
[0379] The title compound was prepared according to the procedure
described in Example 29 using 2-fluoro-4-hydroxybenzonitrile, ethyl
iodide and N-tert-butylhydroxylamine. The title compound was
isolated in 64.7% overall yield as slightly yellowish crystals,
m.p. 82.5.degree. C. (R.sub.f=0.16 on a silica gel plate using
hexanes/ethyl acetate, 4:1, v:v, as the eluant).
[0380] Spectroscopic data were as follows:
[0381] IR (KBr, cm.sup.-1): 2978.4 (CH), 2938.0 (CH), 1616.3
(C.dbd.N), 1560.7 (benzene ring), 1290.0 (Ar--O), 1128.7 (N--O),
1112.9 (Ar--F) and 1042.3 (alkyl-O).
[0382] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=9.300 (1H, t,
J=9.0 Hz, aromatic H), 7.716 (1H, s, nitronyl CH), 6.695 (1H, dd,
J=9.0 Hz, J=2.4 Hz, aromatic H), 6.597 (1H, dd, J=13.1 Hz, J=2.4
Hz, aromatic H), 4.035 (2H, q, J=6.9 Hz, OCH.sub.2), 1.581 (9H, s,
3 CH.sub.3) and 1.396 (3H, t, J=6.9 Hz, CH.sub.3).
[0383] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=161.952 (d,
J.sub.F=254.9 Hz): 161.738 (d, J.sub.F=12.4 Hz), 130.118, 122.285
(d, J.sub.F=9.3 Hz), 112.409 (d, J.sub.F=8.3 Hz), 109.846, 101.708
(d, J.sub.F=25.9 Hz), 70.660, 63.842, 27.936 and 14.177.
Example 36
Synthesis of
.alpha.-(2-Fluoro-4-ethoxyphenyl)-N-cyclohexylnitrone
[0384] The title compound was prepared according to the procedure
described in Example 29 using 2-fluoro-4-hydroxybenzonitrile, ethyl
iodide and N-cyclohexylhydroxylamine. The title compound was
isolated in 58.8% overall yield as slightly yellowish crystals,
m.p. 112.7.degree. C. (R.sub.f=0.17 on a silica gel plate using
hexanes/ethyl acetate, 4:1, v:v, as the eluant).
[0385] Spectroscopic data were as follows:
[0386] IR (KBr, cm.sup.-1): 2956.5 (CH), 2933.2 (CH), 1616.9 (C=N),
1558.7 (benzene ring), 1287.4 (Ar--O), 1158.7 (N--O), 1103.5
(Ar--F) and 1039.6 (alkyl-O).
[0387] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=9.245 (1H, t,
J=9.0 Hz, aromatic H), 7.580 (1H, s, nitronyl CH), 6.689 (1H, dd,
J=9.0 Hz, J=2.5 Hz, aromatic H), 6.580 (1H, dd, J=14.3 Hz, J=2.5
Hz, aromatic H), 4.022 (2H, q, J=6.9 Hz, OCH.sub.2), 3.805 (1H, tt,
J=11.3 Hz, J=4.1 Hz, N--CH), 2.069-1.990 (2H, m, cyclohexyl 2H),
1.958-1.862 (4H, m, cyclohexyl 4H), 1.694-1.651 (1H, m, cyclohexyl
H), 1.386 (3H, t, J=6.9 Hz, CH.sub.3) and 1.333-1.176 (3H, m,
cyclohexyl 3H).
[0388] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=161.734 (d,
J.sub.F=13.0 Hz), 161.639 (d, J.sub.F=253.9 Hz), 130.255, 124.703
(d, J.sub.F=8.3 Hz), 112.165 (d, J.sub.F=8.3 Hz), 109.953, 101.731
(d, J.sub.F=24.9 Hz), 75.587, 63.857, 30.819, 24.702 and
14.177.
Examples 37-38
[0389] Using the procedures described herein, the following
compounds were prepared:
[0390] .alpha.-(2-Ethoxyphenyl)-N-1-adamantylnitrone, and
[0391] .alpha.-(3-Ethoxy-4-methoxyphenyl)-N-1-adamantylnitrone.
Example 39
Synthesis of .alpha.-(4-Ethoxyphenyl)-N-cyclopentylnitrone
[0392] 4-Ethoxybenzaldehyde (22.0 g, 0.1467 mol) and
N-cyclopentylhydroxylamine (14.1 g, 0.1398 mol) were mixed into
toluene (200 mL) with p-toluenesulfonic acid monohydrate (1.0 g,
5.26 mmol). The mixture was refluxed for 3 hrs under argon
atmosphere with a Dean-Stark trap to remove generated water. The
solution was rotary evaporated to give a residue which was purified
by flash chromatography over silica gel with EtOAc as an eluant and
then recrystallization from a mixed solvent of hexanes and EtOAc.
The title compound was obtained as a solid (21.24 g 65.1% yield),
m.p. 95.120 C. (R.sub.f=0.18 on a silica gel plate using
hexanes:EtOAc, 2:1, v/v, as an eluant).
[0393] Spectroscopic data were as follows:
[0394] IR (KBr, cm.sup.-1): 2977 (CH), 2873 (CH), 1601 (C.dbd.N
& benzene ring), 1575 (benzene ring), 1251 (Ar--O) and 1169
(N--O).
[0395] .sup.1H NMR (CDCI.sub.3, 270 MHZ): .delta.=8.22 (2H, d,
J=9.0 Hz, aromatic 2H), 7.41 (1H, s, CH.dbd.N), 6.91 (2H,d, J=9.0
Hz, aromatic 2H), 4.40 (1H, tt, J=6.3 & 7.8 Hz, CH), 4.07 (2H,
q, J=7.0 Hz, OCH.sub.2), 2.33-2.20 (2H, m, cyclopentyl 2H),
2.04-1.86 (4H, m, cyclopentyl 4H), 1.70-154 (2H, m, cyclopentyl
2H), and 1.42 (3H, t, J=7.0 Hz, CH.sub.3) ppm.
[0396] .sup.13C NMR (CDCl.sub.3, 67.9 MHZ): .delta.=160.13, 132.45,
130.39, 125.56, 114.19, 75.72, 63.45, 31.25, 25.56 and 14.66
ppm.
Example 40
Synthesis of .alpha.-(4-Ethoxyphenyl)-N-tert-octylnitrone
[0397] The title compound was prepared by oxidation of
N-(4-ethoxyphenyl)-N-tert-octylamine with m-chloroperoxybenzoic
acid in methylene chloride. The amine was synthesized via
NaBH.sub.4 reduction from the corresponding imine which was
acquired by condensation of 4-ethoxybenzaldehyde and
tert-octylamine in methanol. The title compound was isolated in
65.0% overall yield as white crystals, m.p. 100.8.degree. C.
(R.sub.f=0.33 on silica gel plate using hexanes:EtOAc, 7:3, v/v, as
an eluant).
[0398] Spectroscopic data were as follows:
[0399] IR (Kbr, cm.sup.-1): 2978 & 2951 (CH), 1605 (C.dbd.N
& benzene ring), 1563 (benzene ring), 1263 (Ar--O) and 1114
(N--O).
[0400] .sup.1H NMR (CDCl.sub.3, 270 MHZ): .delta.=8.27 (2H, d,
J=9.0 Hz, aromatic 2H), 7.49 (1H, s, CH.dbd.N), 6.91 (2H,d, J=9.0
Hz, aromatic 2H), 4.08 (2H, q, J=7.0 Hz, OCH.sub.3), 1.97 (2H, s,
CH.sub.2), 1.64 (6H, s, 2 CH.sub.3), 1.42 (3H, t, J=7.0 Hz,
CH.sub.3) and 0.97, (9H, s, 3 CH.sub.3) ppm.
[0401] .sup.13C NMR (CDCl.sub.3, 67.9 MHZ): .delta.=160.12, 130.55,
130.17, 124.11, 114.20, 73.20, 63.49, 51.35, 31.61, 30.69, 28.82
and 14.72 ppm.
Example 41
Synthesis of .alpha.-(Benzyloxyphenyl)-N-tert-butylnitrone
[0402] A mixture of 4-benzyloxybenzaldehyde,
N-tert-butylhydroxylamine and catalytic amount of p-toluenesulfonic
acid monohydrate in benzene was refluxed under argon atmosphere
with a Dean-Stark trap to remove generated water. The mixture was
then rotary evaporated to give a residue which was purified by
recrystallization. The title compound was obtained in 89.3% yield
as a white powder, m.p. 111.0.degree. C. (R.sub.f=0.66 on a silica
gel plate using EtOAc as an eluant).
[0403] Spectroscopic data were as follows:
[0404] IR (KBr, cm.sup.-1): 2982 (CH), 1601 (C.dbd.N & benzene
ring), 1508 (benzene ring), 1242 (Ar--O), 1170 (N--O). and 1005
(benzyl-O)
[0405] .sup.1H NMR (CDCl.sub.3, 270 MHZ): .delta.=8.29 (2H, d,
J=9.2 Hz, aromatic 2H), 7.46 (1H, s, CH.dbd.N), 7.41-7.31 (5H, m,
aromatic 5H), 7.00 (2H, d, J=9.2 Hz, aromatic 2H), 5.10 (2H, s,
OCH.sub.2), and 1.60 (9H, s, 3 CH.sub.3) ppm.
[0406] .sup.13C NMR (CDCl.sub.3, 67.9 MHZ): .delta.=159.89, 136.47,
130.64, 129.35, 128.52, 128.00, 127.42, 124.23, 114.58, 70.05,
69.91 and 28.25 ppm
Example 42
Synthesis of .alpha.-(4-Benzyloxyphenyl)-N-cyclopentylnitrone
[0407] A mixture of 4-benzyloxybenzaldehyde (20 g, 94.23 mmol),
N-cyclopentylhydroxylamine (14.3 g, 141.34 mmol), molecular sieves
(60 g, 4A) and silica gel (15 g) in chloroform (300 mL) was stirred
at room temperature under argon atmosphere for 48 hrs and then was
refluxed for an additional 3 hrs. The mixture was filtered and
rotary evaporated to give crystals which were recrystallized from
hexanes and EtOAc to provide the title compound as white crystals,
23.7 g, 85.1% yield), m.p. 115.1.degree. C. (R.sub.f=0.35 on a
silica gel plate using hexanes:EtOAc, 1:1, v:v, as an eluant).
[0408] Spectroscopic data were as follows:
[0409] IR (KBr, cm.sup.-1): 2953 (CH), 2867 (CH), 1601 (C.dbd.N
& benzene ring), 1505 (benzene ring), 1251 (Ar--O), 1139
(N--O). and 1009 (benzyl-O).
[0410] .sup.1H NMR (CDCl.sub.3, 270 MHZ): .delta.=8.23 (2H, d,
J=9.2 Hz, aromatic 2H), 7.40 (1H, s, CH.dbd.N), 7.43-7.27 (5H, m,
aromatic 5H), 6.98 (2H, d, J=9.2 Hz, aromatic 2H), 5.08 (2H, s,
OCH.sub.2), 4.36 (1H, tt, J=7.7 & 6.1 Hz, CH), 2.33-2.20 (2H,
m, cyclopentyl 2H), 2.04-1.86 (4H, m, cyclopentyl 4H), 1.70-1.54
(2H, m, cyclopentyl 2H) ppm.
[0411] .sup.13C NMR (CDCl.sub.3, 67.9 MHZ): .delta.=159.79, 136.39,
132.21, 130.30, 128.47, 127.94, 127.36, 123.96, 114.56, 75.71,
69.85, 31.21 and 25.50 ppm
Example 43
Synthesis of .alpha.-(4-Benzyloxyphenyl)-N-cyclohexylnitrone
[0412] The title compound was prepared according to the procedure
described in Example 42 using 4-benzyloxybenzaldehyde and
N-cyclohexylhydroxylamine. The title compound was obtained in 81.2%
yield as slightly yellowish solid, m.p. 129.0.degree. C.
(R.sub.f=0.30 on a silica gel plate using hexanes:EOAc, 1:1, v:v,
as an eluant).
[0413] Spectroscopic data were as follows:
[0414] IR (KBr, cm.sup.-1): 2993 (CH), 2854 (CH), 1603 (C.dbd.N
& benzene ring), 1507 (benzene ring), 1251 (Ar--O), 1138
(N--O). and 1012 (benzyl-O)
[0415] .sup.1H NMR (CDCl.sub.3, 270 MHZ): .delta.=8.24 (2H, d,
J=8.9 Hz, aromatic 2H), 7.35 (1H, s, CH.dbd.N), 7.44-7.32 (5H, m,
aromatic 5H), 7.00 (2H, d, J=8.9 Hz, aromatic 2H), 5.11 (2H, s,
OCH.sub.2), 3.79 (1H, m, CH), 2.10-1.89 (6H, m, cyclopentyl 6H),
1.70 (1H, m, cyclopentyl 1H), and 1.22-1.45 (3H, m, cyclopentyl 3H)
ppm.
[0416] .sup.13C NMR (CDCl.sub.3, 67.9 MHZ): .delta.=159.90, 136.51,
131.70, 130.44, 128.58, 128.05, 127.45, 124.05, 114.68, 75.14,
69.97, 31.12 and 25.09 ppm.
Example 44
Synthesis of .alpha.-(2-Ethoxyphenyl)-N-cyclopentylnitrone
[0417] The title compound was prepared according to the procedure
described in Example 42 using 2-ethoxybenzaldehyde and
N-cyclopentylhydroxylamine. The title compound was obtained in
72.6% yield as white crystals, m.p. 87.3.degree. C. (R.sub.f=0.43
on a silica gel plate using hexanes:EtOAc, 2:1, v:v, as an
eluant).
[0418] Spectroscopic data were as follows:
[0419] IR (KBr, cm.sup.-1): 2976 (CH), 2957 (CH), 1636 (C.dbd.N),
1597 & 1564 (benzene ring), 1251 (Ar--O), 1165 (N--O). and 1043
(Et--O).
[0420] .sup.1H NMR (CDCl.sub.3, 270 MHZ): .delta.=9.33 (1H, dd,
J=7.8 & 1.7 Hz, aromatic 1H), 7.98 (1H, s, CH.dbd.N), 7.32 (1H,
ddd, J=8.2, 7.5 & 1.7 Hz, aromatic 1H), 6.99 (1H, td, J=6.1
& 7.8 Hz, CH), 4.07 (2H, q, J=7.0 Hz, OCH.sub.2), 2.35-2.22
(2H, m, cyclopentyl 2H), 2.07-1.88 (4H, m, cyclopentyl 4H),
1.72-1.57 (2H, m, cyclopentyl 2H) and 1.45 (3H, t, J=7.0 Hz,
CH.sub.3) ppm.
[0421] .sup.13C NMR (CDCl.sub.3, 67.9 MHZ): .delta.=156.11, 131.00,
128.64, 127.31, 120.50, 119.88, 110.57, 76.64, 63.85, 31.38, 25.55
and 14.74 ppm.
Example 45
Synthesis of
.alpha.-(3-Ethoxy-4-methoxyphenyl)-N-tert-octylnitrone
[0422] A solution of 3-ethoxy-4methoxybenzaldehyde,
N-tert-octylhydroxylamine and catalytic amount of HCl in methanol
was refluxed for 90 hrs with molecular sieves in a soxhlet for
waster removal. The title compound was obtained in 60.0% yield as
white powder, m.p. 77.5.degree. C. (R.sub.f=0.40 on a silica gel
plate using hexanes:EtOAc, 3:2, v:v, as an eluant).
[0423] Spectroscopic data were as follows:
[0424] IR (KBr, cm.sup.-1): 2975 (CH), 1636 (C.dbd.N), 1597 &
1575 (benzene ring), 1279 (Ar--O), 1145 (N--O). and 1039 & 1026
(alkyl-O).
[0425] .sup.1H NMR (CDCl.sub.3, 270 MHZ): .delta.=8.44 (1H, d,
J=2.0 Hz, aromatic 1H), 7.50 (1H, dd, J=8.3 & 2.0 Hz, aromatic
1H), 7.48 (1H, s, CH.dbd.N), 6.90 (1H, d, J=8.3 HZ aromatic 1H),
4.20 (2H, q, J=7.0 Hz, OCH.sub.2), 3.91 (3H, s, CH.sub.3), 1.97
(2H, s, CH.sub.2), 1.64 (6H, s, 2CH.sub.3), 1.48 (3H, t, J=7.0 Hz,
CH.sub.3), 0.98 (9H, s, 3CH.sub.3), ppm.
[0426] .sup.13C NMR (CDCl.sub.3, 67.9 MHZ): .delta.=150.44, 147.71,
130.41, 124.56, 122.85, 112.22, 110.67, 73.36, 64.23, 55.87, 51.43,
31.63, 30.68, 28.78 and 14.72 ppm.
Example 46
Synthesis of
.alpha.-(3-Ethoxy-4-methoxyphenyl)-N-(2,4,-dimethyl-2-pentyl)-
nitrone
[0427] The title compound can be prepared according to the
procedure described in Example 45 using
3-ethoxy-4-methoxybenzaldehyde and
N-2,4,-dimethyl-2-pentylhydroxylamine.
Example 47
Synthesis of
.alpha.-[4-(4-Fluorobenzyloxy)phenyl]-N-tert-butylnitrone
[0428] The title compound was prepared by refluxing a benzene
solution of 4-(4-fluorobenzyloxy)benzaldehyde and
N-tert-butylhydroxylamine for 21 hours with p-toluenesulfonic acid
as a catalyst. The title compound was obtained as a solid in 98.5%
yield, m.p. 180.3.degree. C. (R.sub.f=0.16 on a silica gel plate
using hexanes: EtOAc, 1:1, v/v, as an eluant).
[0429] Spectroscopic data were as follows:
[0430] IR (KBr, cm.sup.-1): 2984 (CH), 1607 (C.dbd.N & benzene
ring), 1509 (benzene ring), 1218 (Ar--O) and 1121 (N--O).
[0431] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.29 (2H, d,
J=9.0 Hz, aromatic 2H), 7.47 (2H, s, CH.dbd.N), 7.40 (2H, dd, J=8.7
& 5.3 Hz, aromatic 2H), 7.07 (2H, t, J=8.7 Hz, aromatic 2H),
6.99 (2H, d, J=9.0 Hz, aromatic 2H), 5.07 (2H, s, CH.sub.2O) and
1.61 (9H, s, C(CH.sub.3).sub.3) ppm.
[0432] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=162.49 (d,
J.sub.F=246.5 Hz), 159.69, 132.26, 130.66, 129.37, 129.27, 124.39,
115.47 (d, J.sub.F=21.3 Hz), 114.55, 70.12, 69.25, 28.27 ppm.
Example 48
Synthesis of
.alpha.-(3-Ethoxy-4-methoxyphenyl)-N-cyclobutylnitrone
[0433] A solution of 3-ethoxy-4-methoxybenzaldehyde,
cyclobutylamine hydrochloride salt, molecular sieves and silica gel
in chloroform was refluxed for 20 hours. Filtration and rotary
evaporation gave the corresponding imine intermediate which was
reduced with NaBH.sub.4 in ethanol to give
N-cyclobutyl-N-(3-ethoxy-4-methoxybenzyl)amine. This amine
intermediate was oxidized with H.sub.2O.sub.2/Na.sub.2WO.sub.4 in
acetone/water to afford the nitrone product. The title compound was
obtained in 19.9% overall yield as cream-colored crystals, m.p.
112.7.degree. C. (R.sub.f=0.30 on a silica gel plate using EtOAc as
an eluant).
[0434] Spectroscopic data were as follows:
[0435] IR (KBr, cm.sup.-1): 2980 (CH), 2935 (CH), 1634 (C.dbd.N),
1597 and 1586 (benzene ring), 1265 (Ar--O), 1134 (N--O) and 1047
and 1021 (alkyl-O).
[0436] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.48 (1H, d,
J=2.0 Hz, aromatic 1H), 7.42 (1H, dd, J=8.5 and 2.0 Hz, aromatic
1H), 7.30 (1H, s, CH.dbd.N), 6.89 (1H, d, J=8.5 Hz, aromatic 1H),
4.53 (1H, quintet, J=8.1 Hz, cyclobutyl CH), 4.19 (2H, q, J=7.0 Hz,
OCH.sub.2) 3.91 (3H, s, CH.sub.3), 2.84-2.68 (2H, m, cyclobutyl
2H), 2.36-2.25 (2H, m, cyclobutyl 2H), 1.91-1.75 (2H, m, cyclobutyl
2H), 1.48 (3H, t, J=7.0, CH.sub.3) ppm.
[0437] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=150.68, 147.73,
132.30, 123.77, 122.86, 112.11, 110.71, 67.45, 64.18, 55.83, 26.97,
14.69 and 14.15 ppm.
Example 49
Synthesis of
.alpha.-(3-Ethoxy-4-methoxyphenyl)-N-(4-methylpent-2-yl)nitro-
ne
[0438] 3-Ethoxy-4-methoxybenzaldehyde (12.0 g, 0.0666 mol) and
N-(4-methylpent-2-yl)hydroxylamine (9.36 g, 0.0799 mol) were mixed
into benzene (200 mL) with p-toluenesulfonic acid monohydrate (1.0
g, 5.26 mol.). The mixture was refluxed for 16 hours under an argon
atmosphere with a Dean-Stark trap to remove the generated water.
The solution was rotary evaporated, dissolved in ethyl acetate,
washed with 5% aqueous sodium hydroxide solution, dried over
magnesium sulfate, filtered and concentrated. The title compound
was obtained as a white solid (17.07 g, 91.8% yield), m.p.
87.2.degree. C. (R.sub.f=0.31 on a silica gel plate using
hexanes;EtOAc, 1:1, v/v, as an eluant). The
N-(4-methyl-2-pentyl)hy- droxylamine precursor was obtained by
sodium cyanoborohydride reduction of 4-methyl-2-pentanone oxime in
methanol, with hydrochloric acid catalysis.
[0439] Spectroscopic data were as follows:
[0440] IR (KBr, cm.sup.-1): 2962 (CH), 1632 (C.dbd.N and benzene
ring), 1588 (benzene ring), 1265 (Ar--O) and 1129 (N--O).
[0441] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.44 (1H, d,
J=2.0 HZ, aromatic H), 7.45 (1H, dd, J=8.5 and 2.0 Hz, aromatic H),
7.33 (1H, s, CH.dbd.N), 6.89 (H, d, J=8.5 Hz, aromatic H), 4.19
(2H, q, J=7.0 Hz, OCH.sub.2), 4.07 (1H, m, N(O)CH), 3.91 (3H, s,
OCH.sub.3), 2.09-1.99 (1H, m, pentyl C.sup.4H), 1.66-1.34 (8H, m,
CH.sub.3 of EtO, pentyl C.sup.1H.sub.3, and pentyl C.sup.3H.sub.2),
0.95 (3H, d, J=8.4 Hz, pentyl C.sup.5H.sub.3), and 0.94 (3H, d,
J=8.6 Hz, 4-methyl of pentyl) ppm.
[0442] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=150.55, 117.75,
132.59, 123.88, 122.64, 112.12, 110.69, 69.93, 64.19, 55.83, 43.09,
24.74, 22.80, 22.10, 19.64, 14.67 ppm.
Example 50
Synthesis of .alpha.-(4-Benzyloxyphenyl)-N-cyclooctylnitrone
[0443] A solution of 4-benzyloxybenzaldehyde (12.7 g, 0.060 mol),
N-cyclooctylhydroxylamine (10.0 g, 0.070 mol) and a catalytic
amount of HCl in methanol (300 mL) was refluxed for 56 hours with
molecular sieves in a soxhlet for water removal. The reaction
mixture was concentrated and dry flash columned on silica with
hexanes/ethyl acetate to give the title compound as a pale yellow
powder, (9.53 g, 47.0% yield), m.p. 107.5.degree. C. (R.sub.f=0.46
on a silica gel plate using hexanes: EtOAc, 1:1, v:v, as an
eluant). The N-cyclooctylhydroxylamine precursor was obtained by
sodium cyanoborohydride reduction of cyclooctanone oxime in acetic
acid/tetrahydrofuran.
[0444] Spectroscopic data were as follows:
[0445] IR (KBr, cm.sup.-1): 3061 (CH), 2967 (CH), 1648 (C.dbd.N),
1603 (benzene ring), 1579 (benzene ring), 1251 (Ar--O) and 1147
(N--O).
[0446] .sup.1H NMR (CDCl.sub.3, 67.9 MHz): .delta.=8.22 (2H, d,
J=9.0 Hz, aromatic 2H), 7.47-7.29 (6H, m, aromatic 5H &
CH.dbd.N), 6.99 (2H, d, J=9.0 Hz, aromatic 2H), 5.10 (2H, s, benzyl
CH.sub.2), 4.08-3.97 (1H, m, N(O)CH), 2.31-2.15 (2H, m,
cyclooctyl), 2.10-1.97 (2H, m, cyclooctyl), 1.94-1.76 (2H, m,
cyclooctyl), 1.76-1.40 (8H, m, cyclooctyl) ppm.
[0447] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=159.80, 136.47,
131.27, 130.34, 128.56, 128.02, 127.44, 124.07, 114.64, 76.73,
69.93, 31.96, 26.54, 26.01, 24.70 ppm.
Examples 51-80
[0448] Using the procedures described herein and the appropriate
starting materials, the following additional compounds were
prepared:
[0449] .alpha.-(2-ethoxyphenyl)-N-benzylnitrone
[0450]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(2,2,4,4-tetramethylpent-3-yl)-
nitrone
[0451] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-but-2-ylnitrone
[0452] .alpha.-(2-ethoxyphenyl)-N-but-2-ylnitrone
[0453] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclopentylnitrone
[0454] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-n-propylnitrone
[0455] .alpha.-(4-benzyloxyphenyl)-N-n-propylnitrone
[0456] .alpha.-(4-benzyloxyphenyl)-N-isopropylnitrone
[0457]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(2-methylbut-2-yl)nitrone
[0458] .alpha.-(2-ethoxyphenyl)-N-(2-methylbut-2-yl)nitrone
[0459] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclooctylnitrone
[0460] .alpha.-(2-ethoxyphenyl)-N-cyclobutylnitrone
[0461] .alpha.-(4-benzyloxyphenyl)-N-cyclobutylnitrone
[0462] .alpha.-(4-benzyloxyphenyl)-N-tert-octylnitrone
[0463]
.alpha.-[4-(4-fluorobenzyloxy)phenyl]-N-cyclohexylnitrone
[0464] .alpha.-(2-ethoxyphenyl)-N-tert-octylnitrone
[0465] .alpha.-[4-(4-fluorobenzyloxy)phenyl]-N-isopropylnitrone
[0466] .alpha.-(2-ethoxyphenyl)-N-cyclooctylnitrone
[0467] .alpha.-(4-benzyloxyphenyl)-N-cyclopropylnitrone
[0468] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclopropylnitrone
[0469]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(3,5-dimethyl-1-adamantyl)nitr-
one
[0470] .alpha.-(4-benzyloxyphenyl)-N-1-adamantylnitrone
[0471]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(1-methoxy-2-methylprop-2-yl)n-
itrone
[0472] .alpha.-(4-benzyloxyphenyl)-N-2-adamantylnitrone
[0473] .alpha.-(4-ethoxyphenyl)-N-cyclooctylnitrone
[0474] .alpha.-(4-ethoxyphenyl)-N-1-adamantylnitrone
[0475]
.alpha.-[4-(4-methoxybenzyloxy)phenyl]-N-tert-butylnitrone
[0476]
.alpha.-(3-ethoxy-4-methoxyphenyl)-N-(3-methylbut-1-yl)nitrone
[0477] .alpha.-(3-ethoxy-4-methoxyphenyl)-N-cyclooctylnitrone,
and
[0478]
.alpha.-[4-(4-fluorobenzyloxy)phenyl]-N-cyclopentylnitrone.
Comparative Example 1
Synthesis of .alpha.-(2-Methoxyphenyl)-N-tert-butylnitrone
[0479] The title compound was prepared according to the procedure
described in Example 7 using 2-methoxybenzaldehyde and
N-tert-butylhydroxylamine. The title compound was isolated in 82.9%
overall yield as white crystals, m.p. 109.1.degree. C.
(R.sub.f=0.53 on a silica gel plate using ethyl acetate as the
eluant).
[0480] Spectroscopic data were as follows:
[0481] IR (KBr, cm.sup.-1): 3004.0 (aromatic CH), 2966.0 (CH),
1593.4 (C.dbd.N), 1556.1 (benzene ring), 1235.4 (Ar--O), 1125.5
(N--O), and 1017.3 (alkyl-O).
[0482] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=9.343 (1H, dd,
J=7.9 Hz, J=1.7 Hz, aromatic H), 8.025 (1H, s, nitronyl CH), 7.329
(1H, td, J=7.9 Hz, J=1.7 Hz, aromatic H), 6.993 (1H, t, J=7.7 Hz,
aromatic H), 6.856 (1H, d, J=8.4 Hz, aromatic H), 3.841 (3H, s,
OCH.sub.3) and 1.587 (9H, s, 3 CH.sub.3).
[0483] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=157.452,
131.353, 128.836, 124.535, 120.890, 120.234, 109.739, 70.843,
55.392 and 28.058.
Comparative Example 2
Synthesis of .alpha.-(3-Methoxyphenyl)-N-tert-butylnitrone
[0484] The title compound was prepared according to the procedure
described in Example 11 using 3-methoxybenzaldehyde and
N-tert-butylhydroxylamine. The title compound was isolated in 56.5%
overall yield as a crystalline solid, m.p. 93.4.degree. C.
[0485] Spectroscopic data were as follows:
[0486] IR (KBr, cm.sup.-1): 2977 (CH), 1589 (C.dbd.N), 1110 (N--O)
and 1035 (C--O).
[0487] .sup.1H NMR (DMSO-d.sub.6, 270 MHz): .delta.=8.20 (1H, m,
phenyl H), 7.84 (1H, s, nitronyl H), 7.78 (1H, d, J=8.0 Hz, phenyl
H), 7.33 (1H, t, J=8.0 Hz, phenyl H), 6.98 (1H, dd, J=8.1, 2.5 Hz,
phenyl H), 3.77 (3H, s, CH.sub.3) and 1.51 (9H, s, 3 CH.sub.3).
[0488] .sup.13C NMR (DMSO-d.sub.6, 67.9 MHz): .delta.=159.76,
133.55, 129.80, 129.40, 121.96, 116.41, 113.34, 70.89, 55.35 and
28.04.
Comparative Example 3
Synthesis of .alpha.-(4-Ethoxyphenyl)-N-isopropylnitrone
[0489] The title compound was prepared according to the procedure
described in Example 11 using 4-ethoxybenzaldehyde and
N-isopropylhydroxylamine. The title compound was isolated in 41.2%
yield as a solid, m.p. 115.1.degree. C.
[0490] Spectroscopic data were as follows:
[0491] IR (KBr, cm.sup.-1): 2979.6 (CH), 1597.5 (C.dbd.N), 1302.4
(CH.sub.3), 1259.2 (C--O--C) and 1169.4 (N--O).
[0492] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.20 (2H, d,
J=9.0 Hz, phenyl 2CH), 7.33 (1H, s, nitronyl CH), 6.88 (2H, d,
J=9.0 Hz, phenyl 2CH), 4.06 (3H, m, CH.sub.2 and CH), 1.46 (6H, m,
2 CH.sub.3) and 1.40 (3H, m, CH.sub.3).
[0493] .sup.13C NMR (CDCl.sub.3, 67.9 MHz): .delta.=160.6, 131.8,
130.7, 123.8, 114.4, 67.1, 63.4, 20.5 and 14.3.
Comparative Example 4
Synthesis of .alpha.-(4-Butoxyphenyl)-N-tert-butylnitrone
[0494] The title compound was prepared according to the procedure
described in Example 11 using 4-butoxybenzaldehyde and
N-tert-butylhydroxylamine. The title compound was isolated in 96%
yield (7.18 g) as a solid, m.p. 68.5.degree. C. Spectroscopic data
were as follows:
[0495] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.27 (2H, d,
J=8.8, phenyl 2H), 7.45 (1H, s, nitronyl H), 6.91 (2H, d, J=8.8 Hz,
phenyl 2H), 4.00 (2 H, t, CH.sub.2), 1.60 (9H, s, tert-butyl H),
1.50 (4H, m, 2CH.sub.2), 0.97 (3H, t, J=6.7 Hz, CH.sub.3).
Comparative Example 5
Synthesis of .alpha.-(4-Pentloxyphenyl)-N-tert-butylnitrone
[0496] The title compound was prepared according to the procedure
described in Example 2 using 4-hydroxybenzaldehyde, 1-iodopentane
and 2-methyl-2-nitropropane. The title compound was isolated in 75%
overall yield as a solid, m.p. 43.2.degree. C.
[0497] Spectroscopic data were as follows:
[0498] IR (KBr, cm.sup.-1): 3092.7 (CH), 2972.1 (CH), 1604.9
(C.dbd.N), 1362.9 (CH.sub.3), 1258.8 (C--O--C) and 1117.3
(N--O).
[0499] .sup.1H NMR (CDCl.sub.3, 270 MHz): .delta.=8.24 (2H, d,
J=9.1 Hz, phenyl 2H), 7.43 (1H, s, nitronyl H), 6.69 (2H, s, J=9.1
Hz, phenyl 2H), 3.97 (2H, t, J=6.4 Hz, CH.sub.2), 1.76 (2H, m,
CH.sub.2), 1.57 (9H, s, 3 CH.sub.3), 1.39 (4H, m, 2, CH.sub.2) and
0.90.(3H, t, J=6.9 Hz, CH.sub.3).
[0500] .sup.13C NMR (CDCl.sub.3, 67.9 MHz) .delta.=160.8, 130.9,
129.7, 124.0, 114.4, 69.9, 68.0, 28.5, 28.0, 27.8, 22.1 and
13.6.
Comparative Example 6
Synthesis of .alpha.-(4-Hexyloxyphenyl)-N-tert-butylnitrone
[0501] A solution of 4-hexyloxybenzaldehyde (3.83 g, 18.6 mmol) in
120 mL of benzene was refluxed with N-tert-butylhydroxylamine (3.32
g, 37.2 mmol) for 18 hours. The reaction mixture was then
concentrated by rotary evaporation and the resulting residue was
purified by silica gel column chromatography using 50:50 ethyl
acetate/hexane to afford the title compound (2.88 g, 55.8% yield)
as a solid, m.p. 69.0.degree. C.
[0502] Spectroscopic data were as follows:
[0503] .sup.1H NMR (CDCl.sub.3, 270 MHz) .delta.=8.27 (2H, d, J=8.8
Hz, phenyl 2H), 7.45 (1H, s, nitronyl H), 6.91 (2H, d, J=8.8 Hz,
phenyl 2H), 4.00 (2H, t, J=6.4 Hz, O--CH.sub.2), 1.60 (9H, singlet,
tert-butyl H), 1.36 (8H, m, 4 CH.sub.2) and 0.90 (3H, t,
CH.sub.3).
Example I
Electron Spin Resonance (ESR) Study
[0504] In this experiment, the ability of
.alpha.-aryl-N-alkylnitrones of formula I above to trap free
radicals is demonstrated using ESR spin trapping techniques. See,
for example, K. R. Maples et al., "In Vivo Detection of Free
Radical Metabolites", Free Radicals in Synthesis and Biology (F.
Minisci, ed.) pp. 423-436 (Kluwer Academic Publishers, Boston,
1989); and J. A. DeGray et al., "Biological Spin Trapping",
Electron Spin Resonance 14:246-300 (1994). A t-butyl
hydroperoxide/ferrous iron free radical generating system was used
in this experiment. This free radical generating system produces
t-butyl-alkoxyl radicals, t-butyl-peroxyl radicals, and methyl
radicals. If the .alpha.-aryl-N-alkylnitrones of this invention are
capable of trapping any of these radicals to form a stable radical
adduct, such radical adducts should be detectable by ESR
spectroscopy.
[0505] To 490 .mu.l of a 100 mM solution of
.alpha.-(2-ethoxyphenyl)-N-ter- t-butylnitrone in water was added 5
.mu.l of 100 mM ferrous sulfate. The reaction was initiated by the
addition of 5 .mu.l of 100 mM t-butyl hydroperoxide. The final
concentrations of reagents are 1 mM ferrous iron, 1 mM t-butyl
hydroperoxide and 98 mM of the nitrone compound in water. Once
mixed, the solution was quickly transferred into a quartz flat cell
and this cell was placed in the cavity of a Bruker ESP 300 ESR
spectrometer, and scanned within 5 minutes of mixing. ESR
spectrometer settings were: 3480 G center field, 200 G field width,
480 seconds sweep time, 9.76 GHz frequency, 10 dB power,
1.6.times.10.sup.5 receiver gain, 0.200 G modulation amplitude,
0.320 second time constant, and 270.degree. phase. The resulting
ESR spectrum, as shown in FIG. 1, consisted of primarily one
species, characterized as a 16.8 G (1:1:1) triplet of 4.3 G (1:1)
doublets, representing a.sub.N and a.sub.H, respectively. This
species is believed to be the methyl radical adduct of
.alpha.-(2-ethoxyphenyl)-N-tert-butylnitrone. Thus, the ESR
spectrum shown in FIG. 1 demonstrates that the
.alpha.-aryl-N-alkylnitrones of formula I are effective at trapping
free radicals and that such compounds can be used as analytical
reagents for ESR applications.
Example II
Inhibition of A.beta. Beta-pleated Sheet Formation
[0506] The deposition of amyloid .beta.-peptide (A.beta.) is
associated with the development of Alzheimer's disease. See, for
example, G. G. Glenner et al. (1984) Biochem. Biophys. Res.
Commun., 120:885-890; and R. E. Tanzi (1989) Ann. Med., 21:91-94.
Accordingly, compounds which effectively disrupt the formation of
A.beta.(1-40) or A.beta.(1-42) beta-pleated sheets are potentially
useful for preventing and/or reversing such amyloid deposits.
Thioflavin T (ThT) is known to rapidly associate with beta-pleated
sheets, particularly the aggregated fibrils of synthetic
A.beta.(1-42). This association gives rise to an excitation maximum
at 440 nm and to an emission at 490 nm. In this experiment, the
ability of certain .alpha.-aryl-N-alkylnitrones of formula I above
to inhibit the association of ThT with synthetic A.beta.(1-42) is
demonstrated by measuring changes in fluorescence.
[0507] The experiments were performed using a CytoFluor II
fluorescence plate reader having the following parameters:
4 Filters: Excitation 440 nm/20 Emission 490 nm/40 Gain: 75 Cycle
to Cycle Time: 30 min Run Time: 720 min (24 cycles) or dependent on
experimental design Plate: 96 well
[0508] Into each well was aliquoted 95 .mu.l of ThT (3 .mu.M)
prepared in PBS (pH 6.0), 2 .mu.L of the compound to be tested (10
.mu.M) prepared with 0.05% of methylcellulose in PBS (pH 6.0), and
3 .mu.L of A.beta.(1-42)(3 .mu.g) prepared with dH.sub.2O. The
fluorescence measurement began when the A.beta.(1-42) was added and
continued for a total of 12 hours. The percent inhibition of
beta-pleated sheet formation was calculated from the relative
fluorescence unit difference between aggregation in the presence
and in the absence of the test compounds. Inhibition of
A.beta.(1-42) beta-pleated sheet formation by at least 30% compared
to the controls is considered significant in this test. The results
of these in vitro tests are described below.
Example III
Protection Against A.beta.(25-35)-Induced Neuronal Cell Loss
[0509] Patients with Alzheimer's disease are known to suffer a
progressive loss of neuronal cells. See, for example, P. J.
Whitehause et al., (1982) Science, 215:1237-1239. In this
experiment, the ability of certain .alpha.-aryl-N-alkylnitrones of
formula I above to protect against A.beta.(25-35)-induced neuronal
cell loss is demonstrated. Sprague Dawley rat hippocampus of
18-day-gestation embryos was excised and then dissociated by
trituration to prepare primary neuronal cultures. Cells
(3.times.10.sup.5) were plated on 35 mm poly-D-lysine-coated plates
containing Eagle's minimum essential medium supplemented with 10%
fetal bovine serum. After 3-5 hours, the original medium was
removed and replaced with 1 mL of fresh medium. Cultures were
maintained at 37.degree. C. in a 5% CO.sub.2/95% air humidified
incubator. Glial growth is observed as a monolayer under
neurons.
[0510] To the cells (7 DIV) was added 30 .mu.M of A.beta.(25-35)
dissolved in dH.sub.2O (stored at -20.degree. C.) and 100 .mu.M of
the test compound in 1% methylcellulose. Controls were also
conducted without the test compound. The percentage of
morphologically viable neurons was determined by counting the
number of viable neurons after 96 hours treatment (three
regions/well, n=6 wells). Inhibition of A.beta.(25-35)-induced
neuronal cell loss by at least 30% compared to the controls is
considered significant in this test. The results of these in vitro
tests are described below.
Example IV
Reduction of .beta.-Amyloid-Induced Increased Release of
Interleukin-1.beta. and Tumor Necrosis Factor-.alpha.
[0511] In this experiment, the ability of certain
.alpha.-aryl-N-alkylnitr- ones of formula I above to reduce the
.beta.-amyloid-induced increased release over LPS alone of
interleukin-1.beta. (IL-1.beta.) and tumor necrosis factor-.alpha.
(TNF.alpha.) is demonstrated. THP-1 cells, a human monocyte cell
line from American Type Culture Collection, were grown in RPMI-1640
medium plus 10% fetal bovine serum (FBS, not heat-inactivated) in
T-flasks. The medium was changed every two days by spinning down
the cells (800 rpm, 5 minutes) and adding the same fresh medium.
Alternatively, the cultures were maintained by supplementation with
fresh medium. The cultures were maintained at a cell concentration
ranging from between 1.times.10.sup.5 and 1.times.10.sup.6
cells/mL. Because sera may contain unknown factors which can affect
macrophage/monocyte IL-1 production, the FBS was reduced to 5% for
24 hours. The FBS was further reduced to 2% over two days prior to
starting each experiment. The cells were collected by
centrifugation and resuspended in media containing 2% FBS. Cell
numbers were calculated and cells were plated on 24-well plates
(3.times.10.sup.5 cells/0.6 mL/well). Cells were then treated with
LPS (0.5 .mu.g/ml or 0-10 .mu.g/ml for LPS dose-response
experiments) alone or in combination with AP peptides (5 .mu.M or
0.05-5 .mu.M for dose-response experiments). When determining the
effect of the test compounds on IL-1.beta. and TNF.alpha. release,
100 .mu.M of the test compound was added with the LPS and
A.beta.(25-35) and this mixture was incubated for 48 hours prior to
performing ELISA.
[0512] IL-1.beta. and TNF.alpha. secretions into medium by
LPS-stimulated THP-1 cells, in the presence or absence of amyloid
peptides and a test compound, were assayed with a commercially
available ELISA kit (R & D Systems). Briefly, a microtiter
plate coated with a murine monoclonal antibody to human IL-1.beta.
or TNF.alpha. was supplied by the manufacturer. Standards and
samples were pipetted into the wells and any IL-1.beta. or
TNF.alpha. present was bound by the immobilized antibody. Unbound
proteins were washed away and a horseradish peroxidase-linked
polyclonal antibody specific for IL-1.beta. or TNF.alpha. was added
to the wells to "sandwich" the IL-1.beta. and TNF.alpha. bound in
the initial step. After washing to remove any unbound
antibody-enzyme reagent, a substrate solution (1:1 hydrogen
peroxide:tetramethylbenzidine- , v/v) was added to the wells and
color developed in proportion to the amount of IL-1.beta. or
TNF.alpha. bound in the initial step. Color development was stopped
with 2 N sulfuric acid and the optical density of the standard and
the test samples was measured at 450 nm. The amounts of IL-1.beta.
or TNF.alpha. present in the samples were calculated based upon a
standard curve. Assays were run in quadruplicate wells. Inhibition
of .beta.-amyloid-induced increase release of interleukin-1.beta.
or tumor necrosis factor by at least 30% compared to controls is
considered significant in these tests. The results of these in
vitro tests are described below.
Example V
Protection Against IL-1.beta. and IFN.gamma.-Induced Toxicity
[0513] In this experiment, the ability of certain
.alpha.-aryl-N-alkylnitr- ones of formula I above to reduce the
IL-1.beta. and IFN.gamma.-induced neuronal toxicity in mixed rat
hippocampal neuronal cultures is demonstrated. Rat hippocampus of
18-day-gestation embryos were dissected free and incubated in HBSS
containing 0.1% trypsin at 37.degree. C. for 30 minutes. Tissue was
then suspended in plating medium consisting of Eagle's minimum
essential medium supplemented with 2 mM L-glutamine, 14.75 mM KCl,
1 mM pyruvic acid, 10% fetal bovine serum and 100 units/mL
penicillin/100 .mu.g/mL streptomycin. After trituration through a
flame-polished Pasteur pipette, cells were diluted in additional
plating medium, counted and seeded at a density of
3.5.times.10.sup.5/mL/well on Falcon 6-well plates which were
precoated with 20 .mu.g/mL poly-D-lysine for 2-3 hours at room
temperature, and washed twice with HBSS. After 3-5 hours, the
original medium was removed and replaced with 1 mL of fresh medium.
Cultures were maintained at 37.degree. C. in a 5% CO.sub.2/95% air
humidified incubator for 12 days.
[0514] 12 DIV hippocampal cultures which contain neurons and
astrocytes were used to perform the experiment. In each well was
added 200 U/mL of recombinant mouse IL-1.beta. (Genzyme) and 1,000
U/mL of IFN.gamma. (Genzyme). 10 .mu.L of the test compound (100
.mu.M final concentration) in 1% methyl cellulose was added
immediately to each well. To control wells were added only 1%
methyl cellulose. Dexamethasone (30 .mu.M) was used as a positive
control. Cultures were incubated at 37.degree. C. in a humidified
atmosphere containing 5% CO.sub.2 for 48 or 96 hours. Neuronal
injury was estimated in all experiments by examination of cultures
with phase-contrast microscopy and was quantified by measurement of
cytosolic lactate dehydrogenase (LDH) release into the culture
medium.
[0515] Release of LDH into the bathing medium was estimated from
the conversion of NAD to NADH, after lactate addition, and was
measured spectrophotometrically from the rate of decrease in 340 nm
absorbance. LDH activity is defined as that amount of enzyme that
catalyzed the formation of one micromole of NADH per minute under
the conditions of the assay procedure. To a 96-well plate, 0.05 mL
medium collected from each sample was added to and then mixed with
0.10 mL reagent from LD-L 20 kit (Sigma). The plate was immediately
placed into the SpectraMax 340 plate reader to read at 340 nm
wavelength at 25.degree. C. for 3 minutes at 30 second intervals.
Reduction of neuronal injury by at least 30% compared to controls
is considered significant in this test. The results of this in
vitro test are described below.
[0516] In vitro Test Results:
[0517] Certain of the compounds prepared in the above examples were
tested in at least one of the above described in vitro tests. The
compounds of this invention either inhibited A.beta.(1-42)
beta-pleated sheet formation and/or A.beta.(25-35)-induced neuronal
cell loss and/or .beta.-amyloid-induced increase release of
interleukin-1.beta. and/or tumor necrosis factor and/or
IL-1.beta./IFN.sub..gamma.-induced toxicity by at least 30%
compared to the controls or are expected to be effective in at
least one of these in vitro assays upon further testing. In
contrast, the compounds of Comparative Examples 1-6 failed to
inhibit A.beta.(1-42) beta-pleated sheet formation and/or
A.beta.(25-35)-induced neuronal cell loss and/or
.beta.-amyloid-induced increase release of interleukin-1.beta.
and/or tumor necrosis factor and/or
IL-1.beta./IFN.sub..gamma.-induced toxicity by at least 30%
compared to the controls.
Example VI
Reduction of Cognitive Defects Due to A.beta.-Peptide/Ibotenate
[0518] In this experiment, the ability of certain
.alpha.-aryl-N-alkylnitr- ones of formula I above to reduce the in
vivo impairment of animals treated with ibotenate and
A.beta.(25-35) is demonstrated. The procedures employed in this
example are similar to those described in Dornan et al.,
NeuroReport 5, 165-168 (1993). Male Sprague-Dawley rats (200-300 g)
were weighed and given 10 mg/kg of
.alpha.-(2-ethoxyphenyl)-N-tert-butylnitron- e or 1%
methylcellulose by oral gavage. One hour later, the rats were
stereotaxically injected into the CA1 region of their hippocampus
with 8 nmol of A.beta.(25-35) and 6 nmol of ibotenate per side
(coordinates from bregma -3.6=AP, .+-.2.2=ML, -3.0=DV from the top
of the dura). Controls were injected with PBS (pH 7.4). All
injections were 1.5 .mu.L in volume. The animals receiving PBS were
orally dosed with 1% methylcellulose. Oral dosing continued daily
until the end of the Morris water maze testing.
[0519] Nine to eleven days following injection, animals were tested
in a Morris water maze task to measure spatial memory and learning.
Animals were given three days of testing with four to six trials
per day. The last trial on the fourth day was a probe trial where
the platform was removed and time in quadrant and annulae crossings
were determined. Following the behavioral testing, animals were
perfused with 10% neutral formalin. The brain was post-fixed for 1
week in 10% formalin and then sliced for histological evaluation.
Image analysis of cresyl violet staining was used to compare the
neuronal loss -(lesion volume) in the hippocampus between groups.
The data show that .alpha.-(2-ethoxyphenyl)-N- -tert-butylnitrone
reduced the A.beta. peptide/ibotenate-induced learning deficit.
Example VII
Reduction of Cognitive Deficits in Autoimmune Mice
[0520] In this experiment, the ability of certain
.alpha.-aryl-N-alkylnitr- ones of formula I above to reduce
cognitive deficits in autoimmune strains of mice is demonstrated.
MRL/MpJfas.sup.Ipr ("mutant mice" or "Fas.sup.Ipr") strains of mice
have been described as useful models of Lupus due to their
autoimmune lymphoproliferative pathology. In particular, the mutant
mice show a cognitive deficit at approximately four months of age,
which is not observed at two months of age. See, for example,
Forster et al., 1988, Behav. Neural Biology, 49, 139-151.
[0521] In the experiment, male MRL/MpJ Fas.sup.Ipr and normal
MRL/MpJ++ mice of 8 weeks of age were weighed and administered 100
mg/kg of the test compound (either
.alpha.-(2-ethoxyphenyl)-N-tert-butylnitrone or
.alpha.-(4-ethoxyphenyl)-N-cyclohexylnitrone) or 1% methylcellulose
vehicle by oral gavage daily for 8 to 9 weeks. At 4 months of age,
the mice were tested for avoidance, discrimination, session
criteria and acquisition in a one day T-maze task with a maximum of
25 trials. Criteria was met with four of five trials correct with
the last two correct trials being consecutive in avoidance and
discrimination. The Fas.sup.Ipr mice showed a deficit in both
avoidance and acquisition compared to the normal mice which
received the 1% methylcellulose. In contrast, the Fas.sup.Ipr mice
treated with the test compounds of this invention had reduced
acquisition values and acquired avoidance skills earlier than
untreated mutant mice (i.e., similar to the normal controls). These
results demonstrate that .alpha.-aryl-N-alkylnitrones of formula I
above reduced the cognitive deficits of the autoimmune strains of
mice.
Example VIII
Prevention of MBP-Induced Experimental Allergic
Encephalomyelitis
[0522] Multiple sclerosis (MS) is a chronic inflammatory CNS
disorder caused by demyelination in the brain and spinal cord. The
disease is characterized by progressive CNS dysfunction, including
muscular weakness, tremor, incontinence, ocular disturbances, and
mental dysfunction, with remissions and exacerbations.
[0523] Experimental allergic encephalomyelitis (EAE) induced by
injection of guinea pig myelin basic protein (MBP) or MBP peptide
fragments is reported to be a useful model for MS. See, for
example, D. E. McFarlin et al., "Recurrent Experimental Allergic
Encephalomyelitis in the Lewis Rat," The Journal of Immunology,
113(2): 712-715 (1974). In this experiment, the ability of certain
.alpha.-aryl-N-alkylnitrones of formula I above to prevent
MBP-induced EAE is demonstrated.
[0524] Female, Lewis rats of 8 weeks of age (180-250 g) were
weighed and then given two intradermal injections (0.1 mL each) of
0.4 mg of M. tuberculin in 0.1 mL incomplete Freunds adjuvant and
50 mg of myelin basic protein in 0.1 mL of saline into the base of
the tail. Animals were weighed daily and given a clinical score
beginning on Day 8, post inoculation, according to the following
criteria:
[0525] 0.0=No illness
[0526] 0.5=Tip of tail flaccid
[0527] 1.0=Entire tail flaccid
[0528] 1.5=Hind limb weakness
[0529] 2.0=Hind limb paralysis
[0530] 2.5=Hind limb paralysis and front limb weakness
[0531] 3.0=Hind and front limb paralysis
[0532] 4.0=Moribund state or death
[0533] On day 3, post-inoculation animals were administered b.i.d
either a test compound (100 mg/kg) or 1% methylcellulose vehicle by
oral gavage up to and including day 16. The results demonstrate
that the compounds of Examples 3, 11, 17, 22, 41, 42 and 45 reduced
the CNS inflammatory deficit in acute EAE animals. At the dosages
tested, the compounds of Examples 4, 5, 7, 10, 15 and 29 did not
significantly reduce the CNS inflammatory deficit.
[0534] From the foregoing description, various modifications and
changes in the compositions and methods of this invention will
occur to those skilled in the art. All such modifications coming
within the scope of the appended claims are intended to be included
therein.
* * * * *