U.S. patent application number 09/304720 was filed with the patent office on 2001-07-26 for novel analgesic and immunomodulatory cannabinoids.
Invention is credited to KHANOLKAR, ATMARAM, LU, DAI, MAKRIYANNIS, ALEXANDROS, MENG, ZHAOXING.
Application Number | 20010009965 09/304720 |
Document ID | / |
Family ID | 22182164 |
Filed Date | 2001-07-26 |
United States Patent
Application |
20010009965 |
Kind Code |
A1 |
MAKRIYANNIS, ALEXANDROS ; et
al. |
July 26, 2001 |
NOVEL ANALGESIC AND IMMUNOMODULATORY CANNABINOIDS
Abstract
Disclosed are novel compounds represented by the following
structural formula: R--X--Y; and physiologically acceptable salts
thereof. R is a tricyclic core of a cannabinoid or substituted
cannabinoid. X is a covalent bond, --CH2-- or --CHR.sub.1--,
wherein R.sub.1 a C1 to C3 substituted or unsubstituted alkyl
group. Y is a heterocyclic ring, a substituted heterocyclic ring, a
carbocyclic ring, a substituted carbocyclic ring, a fused bicyclic
ring system, a substituted fused bicyclic ring system, a bridged
bicyclic ring system, a substituted bridged bicyclic ring system, a
bridged tricyclic ring system or a substituted bridged tricyclic
ring system. Also disclosed is a method of stimulating a CB1 and/or
CB2 receptor in a subject. The method comprises administering to
the subject a therapeutically effective amount of R--X--Y.
Inventors: |
MAKRIYANNIS, ALEXANDROS;
(WILLIMANTIC, CT) ; LU, DAI; (STORRS, CT) ;
KHANOLKAR, ATMARAM; (STORRS, CT) ; MENG,
ZHAOXING; (MIDDLETOWN, CT) |
Correspondence
Address: |
ALIX YALE & RISTAS LLP
750 MAIN STREET
SUITE 600
HARTFORD
CT
06103
|
Family ID: |
22182164 |
Appl. No.: |
09/304720 |
Filed: |
May 4, 1999 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60084008 |
May 4, 1998 |
|
|
|
Current U.S.
Class: |
549/359 ;
549/263; 549/280 |
Current CPC
Class: |
C07D 407/04 20130101;
C07D 409/04 20130101; C07D 311/80 20130101 |
Class at
Publication: |
549/359 ;
549/263; 549/280 |
International
Class: |
C07D 311/78 |
Goverment Interests
[0002] The invention was supported, in whole or in part, by grants
DA3801 and DA9158 from the National Institute of Drug Abuse (NIDA).
The Government has certain rights in the invention.
Claims
What is claimed is:
1. A compound represented by the following structural formula:
R--X--Y; and physiologically acceptable salts thereof, wherein: R
is a tricyclic core of a cannabinoid or substituted cannabinoid; X
is a covalent bond, --CH-- or --CHR.sub.1--, wherein R.sub.1 a C1
to C3 substituted or unsubstituted alkyl group; and Y is a
heterocyclic ring, a substituted heterocyclic ring, a carbocyclic
ring, a substituted carbocyclic ring, a fused bicyclic ring system,
a substituted fused bicyclic ring system, a bridged bicyclic ring
system, a substituted bridged bicyclic ring system, a bridged
tricyclic ring system or a substituted bridged tricyclic ring
system.
2. The compound of claim 1 wherein R is represented by the
following structural formula: 11wherein Ring A has zero to three
endocyclic double bonds; Z is >C(CH.sub.3).sub.2 or --C=O; and
R.sub.2 is --H, --OH, --OCH.sub.3, --OCH.sub.2CH.sub.3, halogen,
--CN, --NO.sub.2, --CH.sub.3, --C(halogen).sub.3, --CH.sub.2OH,
--CH.sub.2OCH.sub.3, --CH.sub.2OCH.sub.2CH.sub.3,
--CH.sub.2(halogen), --CH.sub.2CN, --CH.sub.2NO.sub.2,
--CH.sub.2CH.sub.3 or --CH.sub.2C(halogen).sub.3,
--CH.sub.2NH.sub.2, --CH.sub.2NHCH.sub.3 or
--CH.sub.2N(CH.sub.3).sub.2.
3. The compound of claim 2 wherein R is represented by the
following structural formula: 12wherein R.sub.2 is --CH.sub.3 or
--CH.sub.2OH.
4. The compound of claim 3 wherein the compound is represented by
the following structural formula: wherein X is a covalent bond and
Y is a C5-C7 carbocyclic ring, a substituted C5-C7 carbocyclic
ring, a C5-C7 heterocyclic ring or a C5-C7 substituted heterocyclic
ring.
5. The compound of claim 4 wherein X is represented by the
following structural formula: 13wherein: R.sub.3 is --H or
--CH.sub.3; R.sub.4 and R.sub.5 are independently --H or a C1 to C8
substituted or unsubstituted straight chained alkyl group and
wherein at least one of R.sub.4 and R.sub.5 is --H.
6. The compound of claim 4 wherein X is a covalent bond and Y is
represented by a structural formula selected from: 14wherein: Z'
and Z" are independently --S--, --O-- or --N(R.sub.7)--; R.sub.6 is
a substituted or unsubstituted C1 to about C12 straight chained
alkyl group; and R.sub.7 is --H or --CH.sub.3.
7. The compound of claim 6 wherein Z' and Z" are each --O-- or
--S-- and R.sub.6 is a C4 to C10 alkyl group.
8. The compound of claim 4 wherein X is a covalent bond and Y is
represented by the following structural formula: 15wherein: R.sub.8
is --H or --CH.sub.3; and R.sub.9 is --H, a substituted or
unsubstituted C1-C4 alkyl group.
9. The compound of claim 3 wherein X is a covalent bond and Y is a
bridged bicyclic ring system, a substituted bridged bicyclic ring
system, a bridged tricyclic ring system or a substituted bridged
tricyclic ring system.
10. The compound of claim 9 wherein Y is a substituted or
unsubstituted 0,1,1,1,1,1-tricyclic nine-membered ring system,
1,3,3-bicyclic nine-membered ring system, 1,2,3-bicyclic
eight-membered ring system, 1,1,1,1,1,1-tricyclic ten-membered ring
system, 1,1,3-bicyclic nine-membered ring system or 1,3-bicyclic
six-membered ring system.
11. The compound of claim 3 wherein the X is a covalent bond and Y
is a substituted or unsubstituted norbornyl ring system.
12. The compound of claim 11 wherein the norbornyl ring system is
represented by the following structural formula: 16wherein
R.sub.10-R.sub.12 are independently --H, C1-C3 alkyl group or C1-C3
substituted alkyl group.
13. The compound of claim 12 wherein R.sub.10-R.sub.12 are
independently --H or --CH.sub.3.
14. The compound of claim 3 wherein X is a covalent bond and Y is a
substituted or unsubstituted adamantyl ring system which contains
zero, one or two heteroatoms.
15. The compound of claim 14 wherein Y is represented by the
structural formula: 17wherein: R.sub.13, R.sub.14, R.sub.15 and
R.sub.16 are independently --H, C1-C3 alkyl group or C1 to C3
substituted alkyl group; and X.sub.1 and X.sub.2 independently are
>N-- or >CH--.
16. The compound of claim 15 wherein R.sub.14-R.sub.16 are each
--H, R.sub.13 is --CH.sub.3 and X.sub.1 and X.sub.2 are
>CH--.
17. A method of stimulating a CB1 or CB2 receptor in a subject,
comprising administering to the subject a therapeutically effective
amount of a compound represented by the following structural
formula: R--X--Y; and physiologically acceptable salts thereof;
wherein: R is a tricyclic core of a cannabinoid or substituted
cannabinoid; X is a covalent bond, --CH.sub.2-- or --CHR.sub.1--,
wherein R.sub.1 a C1 to C3 substituted or unsubstituted lower alkyl
group; and Y is a heterocyclic ring, a substituted heterocyclic
ring, a carbocyclic ring, a substituted carbocyclic ring, a fused
bicyclic ring system, a substituted fused bicyclic ring system, a
bridged bicyclic ring system, a substituted bridged bicyclic ring
system, a bridged tricyclic ring system or a substituted bridged
tricyclic ring system.
18. The method of claim 17 wherein R is represented by the
following structural formula: 18wherein Ring A has zero to three
endocyclic double bonds; Z is >C(CH.sub.3).sub.2 or --C=O; and
R.sub.2 is --H, --OH, --OCH.sub.3, --OCH.sub.2CH.sub.3, halogen,
--CN, --NO.sub.2, --CH.sub.3, --C(halogen).sub.3, --CH.sub.2OH,
--CH.sub.2OCH.sub.3, --CH.sub.2OCH.sub.2CH.sub.3,
--CH.sub.2(halogen), --CH.sub.2CN, --CH.sub.2NO.sub.2,
--CH.sub.2CH.sub.3, CH.sub.2NH.sub.2, --CH.sub.2NHCH.sub.3,
--CH.sub.2N (CH.sub.3).sub.2 or --CH.sub.2C(halogen).sub.3.
19. The method of claim 17 wherein R is represented by the
following structural formula: 19wherein R.sub.2 is --CH.sub.3 or
-CH.sub.2OH.
20. The method of claim 19 wherein X is a covalent bond and Y is a
substituted or unsubstituted norbornyl ring system.
21. The method of claim 20 wherein the norbornyl ring system is
represented by the following structural formula: 20wherein
R.sub.10-R.sub.12 are independently --H, C1-C3 alkyl or C1-C3
substituted alkyl.
22. The method of claim 21 wherein R.sub.10-R.sub.12 are
independently --H or --CH.sub.3.
23. A substituted or unsubstituted cannabinoid having substituted
at C-3 with a heterocyclic ring, a substituted heterocyclic ring, a
carbocyclic ring, a substituted carbocyclic ring, a fused bicyclic
ring, a substituted fused bicyclic ring, a bridged bicyclic ring, a
substituted bridged bicyclic ring, a bridged tricyclic ring or a
substituted bridged tricyclic ring, and physiologically acceptable
salts thereof.
Description
RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/084,008, filed May 4, 1998, the contents of
which are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
[0003] .DELTA..sup.8-Tetrahydrocannabinol, the pyschoactive
marijuana derived cannabinoid, binds to the CB1 receptor in the
brain and to the CB2 receptor in the spleen. Compounds which
stimulate the CB1 receptor have been shown to induce analgesia and
sedation, to cause mood elevation, to control nausea and appetite
and to lower intraocular pressure (Mechoulam, Cannabinoids as
Therapeutic Agents, CRC Press, Boca Raton, Fla. (1986), Fride and
Mechoulam, Eur. J. Pharmacol. 231:313 (1993), Crawley et al.,
Pharmacol. Biochem. Behav. 46:967 (1993) and Smith et al., J.
Pharm. Exp. Therap. 270:219 (1994)). Compounds which stimulate the
CB2 receptor have been shown to suppress the immune system
(Mechoulam, Cannabinoids as Therapeutic Agents, CRC Press, Boca
Raton, Fla. (1986), Fride and Mechoulam, Eur. J. Pharmacol. 231:313
(1993), Crawley et al., Pharmacol. Behav. 46:967 (1993) and Smith
et al., J. Pharm. Exp. Therap. 270:219 (1994)).
SUMMARY OF THE INVENTION
[0004] Disclosed herein is the discovery that cannabinoids with a
monocyclic, a fused bicyclic, a bridged bicyclic or a bridged
tricyclic side chain at the C-3 position show improved binding
affinities for the CB1 and/or CB2 receptor compared with known
cannabinoids, which typically have a linear side chain at the C-3
position. For example, the cannabinoids AMG3 and AMG14 have a
K.sub.i for the CB1 receptor of less than 1.0 nM and AM731 and
AM732 have a K.sub.i for the CB2 receptor of less than 10.0 nM
(Example 2). In contrast, the K.sub.i of
.DELTA..sup.8-tetrahydrocannabinol for the CB1 and CB2 receptors is
only 45 nM and 14 nM, respectively. The structures of these
compounds are shown below. 1
[0005] Based on these results, novel cannabinoids with increased
binding affinity for the CB1 and CB2 receptors are disclosed. Also
disclosed are methods of stimulating a CB1 and/or CB2 receptor in a
subject.
[0006] One embodiment of the present invention is a compound
represented by Structural Formula (I):
R--X--Y; (I)
[0007] and physiologically acceptable salts thereof.
[0008] R is a tricyclic core of a cannabinoid or substituted
cannabinoid.
[0009] X is covalent bond, --CH-- or --CHR.sub.1--, wherein R.sub.1
is a C1 to C3 substituted or unsubstituted alkyl group.
[0010] Y is a heterocyclic ring, a substituted heterocyclic ring, a
carbocyclic ring, a substituted carbocyclic ring, a fused bicyclic
ring system, a substituted fused bicyclic ring system, a bridged
bicyclic ring system, a substituted bridged bicyclic ring system, a
bridged tricyclic ring system or a substituted bridged tricyclic
ring system.
[0011] Another embodiment of the present invention is a method of
stimulating a CB1 and/or CB2 receptor in a subject. The method
comprises administering to the subject a therapeutically effective
amount of a compound represented by Structural Formula (I).
[0012] The novel compounds of the present invention can be used to
stimulate the CB1 or CB2 receptors in a subject at lower doses and
higher selectivity than other known CB1 or CB2 receptor agonists.
Thus, they are expected to produce fewer side-effects than known
CB1 or CB2 receptor agonists when used for treatment, for example,
in treating glaucoma, treating autoimmune disease (e.g., lupus
erythematosus, rheumatoid arthritis, psoriasis, multiple sclerosis
and inflammatory bowel disease such as ulcerative colitis and
Crohn's disease), preventing tissue rejection in organ transplant
patients, controlling nausea in patients undergoing chemotherapy
and enhancing appetite and controlling pain in individuals with
AIDS Wasting Syndrome. In addition, some of these compounds are
selective agonists for either the CB1 (e.g., AM411) or CB2 receptor
(e.g., AM731 and AM732).
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIGS. 1A, 1B and 1C show the structure of a number of
examples of novel compounds included in the present invention.
[0014] FIGS. 2A and 2B show the structure of a number of novel
cannabinoid side chains which can be found in the compounds of the
present invention.
[0015] FIG. 3 is a schematic showing a general procedure for the
preparation of .DELTA..sup.8-tetrahydrocannabinol analogs and 2-
and 4- substituted deoxy-.DELTA..sup.8-tetrahydrocannabinols.
[0016] FIG. 4 is a schematic of the synthesis of cannabinol analogs
with noncyclic side chains.
[0017] FIGS. 5A and 5B are schematics showing the preparation of
the rescorinol starting materials used in the syntheses shown in
FIGS. 3 and 4.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Cannabinoids have a core tricyclic ring system in which a
monohydroxylated phenyl ring and a six membered ring are each fused
to a central pyran ring or to a central six-membered lactone ring
(preferably to a pyran ring). In addition, cannabinoids are able to
induce characteristic physiological effects in mammals, including
euphoria, delerium, drowsiness, halluncinations, weakness and/or
hyporeflexia. The tricyclic core ring system of many cannabinoids
is shown in Structural Formula (II). Other cannabinoids have the
tricyclic core shown in Structural Formula (II), modified to
include one or more double bonds in Ring A, for example, a double
bond between carbons 8 and 9, between carbons 9 and 10 or between
carbons 9 and 11. Yet other cannabinoids have the core structures
described above, modified so that the methyl group bonded to carbon
11 has been replaced, for example, with a hydrogen, hydroxyl,
hydroxymethyl, halogen (e.g., chloro, bromo, iodo and fluoro),
methoxy, ethoxy, nitrile, nitro, halogenated methyl, halogenated
ethyl, methoxymethyl, ethoxymethyl, nitromethyl, ethyl or
--CH.sub.2CN group. In other cannabinoids, the hydroxyl group at
position 1 of the core structure is replaced with --H, --OCH.sub.3,
--NH.sub.2 or --NHCH.sub.3. The term "cannabinoid", as it is used
herein, also refers to other compounds which: 1) induce one or more
of the physiological effects described above which are
characteristic of the cannabinoids and 2) have core structures
which are related to Structural Formula (II). Also shown in
Structural Formula (II) is a numbering system for the atoms in the
core tricylic structure. 2
[0019] Cannabinoids also generally have a linear alkyl side chain
at position C-3 of the cannabinoid core. In the cannabinoids of the
present invention, the linear alkyl side chain is replaced with a
heterocyclic ring, a substituted heterocyclic ring, a carbocyclic
ring, a substituted carbocyclic ring, a fused bicyclic ring system,
a substituted fused bicyclic ring system, a bridged bicyclic ring
system, a substituted bridged bicyclic ring system, a bridged
tricyclic ring system or a substituted bridged tricyclic ring
system.
[0020] Suitable substituents for a cannabinoid include groups which
do not significantly diminish the ability of a cannabinoid to
activate a cannabinoid receptor. Substitutions can occur at
positions 2, 4, 6a-10a or at the three methyl groups. Substitutions
at more than one position are possible. Substituents which do no
significantly diminish the biological activity of cannabinoids are
generally small, pharmacophoric groups. Examples include --H, --OH,
--OCH.sub.3, --OCH.sub.2CH.sub.3, halogen (e.g., chloro, bromo,
iodo and fluoro), --CN, azido, isocyanate, isothiocyanate,
--NO.sub.2O, --CH.sub.3, --C(halogen).sub.3, --CH.sub.2OH,
--CH.sub.2OCH.sub.3, --CH.sub.2OCH.sub.2CH.sub.3,
--CH.sub.2(halogen), --CH.sub.2CN, --CH.sub.2NO.sub.2,
--CH.sub.2CH.sub.3, --CH.sub.2C(halogen).sub.3, --CH.sub.2NH.sub.2,
--CH.sub.2NHCH.sub.3 or --CH.sub.2N(CH.sub.3).sub.2. Suitable
substituents can be identified by testing modified cannabinoids in
the in vitro CB1 or CB2 assays described in Example 2. Cannabinoids
with other substituents can be prepared by modification of the
synthetic procedures described in Example 1, e.g., by replacing
alcohol (A) in the synthesis shown in FIG. 3 or by replacing the
ester/ketone starting material in FIG. 4 with suitably substituted
analogs.
[0021] Preferably, the tricyclic cannabinoid core is represented by
Structural Formula (III): 3
[0022] Ring A has from zero to three endocyclic double bonds.
Examples include wherein Ring A is completely saturated, wherein
Ring A has three double bonds and wherein Ring A has one endocyclic
double bond which connects carbons 9 and 10 or 9 and 11.
Preferably, Ring A has one endocyclic double bond which connects
carbons 8 and 9. As used herein, a double bond between two ring
atoms is an "endocyclic" double bond.
[0023] Z is >C(CH.sub.3).sub.2 or --C=O. Z is preferably
>C(CH.sub.3).sub.2.
[0024] R.sub.2 is --H, --OH, --OCH.sub.3, --OCH.sub.2CH.sub.3,
halogen (e.g., chloro, bromo, iodo and fluoro), --CN, --NO.sub.2,
--CH.sub.3, --C(halogen).sub.3, --CH.sub.2OH, --CH.sub.2OCH.sub.3,
--CH.sub.2OCH.sub.2CH.sub.3, --CH.sub.2(halogen), --CH.sub.2CN,
--CH.sub.2NO.sub.2, --CH.sub.2CH.sub.3, --CH.sub.2C(halogen).sub.3,
--CH.sub.2NH.sub.2, --CH.sub.2NHCH.sub.3 or
--CH.sub.2N(CH.sub.3).sub.2. Preferably, R.sub.2 is --CH.sub.3 or
--CH.sub.2OH.
[0025] When the tricyclic cannabinoid core is represented by
Structural Formula (III), X and Y, taken together, are a C5-C7
carbocyclic ring, a substituted C5-C7 carbocyclic ring, a C5-C7
heterocyclic ring or a C5-C7 substituted heterocyclic ring.
[0026] Carbocyclic rings are non-aromatic rings which have only
carbon as the ring atoms. Preferably, carbocyclic rings include
from about five to about seven ring carbons and are substituted or
unsubstituted. Examples include substituted and unsubstituted
cyclopentane, cyclopentene, cyclohexane, cyclohexene, cycloheptane
and cycloheptene. A preferred example is a substituted cyclohexane
shown below in Structural Formula (IV): 4
[0027] R.sub.3 is --H or --CH.sub.3.
[0028] R.sub.4 and R.sub.5 are independently --H, a C1-C8 straight
chained alkyl group or a C1-C8 substituted straight chained alkyl
group. Preferably, at least one of R.sub.4 and R.sub.5 is --H.
[0029] Heterocyclic rings are non-aromatic rings with carbon and
one or more heteroatoms such oxygen, nitrogen and/or sulfur as ring
atoms. Preferably, heterocyclic rings contain from about five to
about seven ring atoms and are substituted or unsubstituted.
Preferred examples of heterocyclic rings are shown below in
Structural Formulas (V) and (VI): 5
[0030] Z' and Z" are independently --S--, --O--, --S(O)-- or
--N(R.sub.7)--. Preferably, Z' and Z" are each --O-- or --S--.
[0031] R.sub.6 is a C1 to about C12 straight chained alkyl or
substituted alkyl group. Preferably, R.sub.6 is a C4 to C10 alkyl
group.
[0032] R.sub.7 is --H or --CH.sub.3.
[0033] Other examples of hetetocyclic rings include substituted and
unsubstituted 1,3-dioxane, 1,4-dioxane, 1,3-dithiane, 1,4-dithiane,
diazetane, tetrahydrofuran, tetrahyrothiophene, morpholine,
thiomorpholine, pyrrolidine, piperazine, piperidine and
thiazolidine.
[0034] A fused bicyclic ring comprises two rings which share two
ring atoms. Examples include systems such as decalin and tetralin.
A preferred example of a fused bicyclic ring system is represented
by Structural Formula (VII): 6
[0035] R.sub.8 is --H or --CH.sub.3; and
[0036] R.sub.9 is --H, a C1-C4 alkyl group or a C1-C4 substituted
or unsubstituted alkyl group.
[0037] A "bridged bicyclic ring" has two rings in which more than
two ring atoms are shared by the two rings. Optionally, a bicyclic
ring can have one or more ring heteroatoms such as oxygen, sulfur
or nitrogen. A preferred bridged bicyclic ring is a substituted or
unsubstituted 2.2.1 seven membered system also referred to as a
"norbornyl group". Examples of norbornyl groups are represented by
Structural Formula (VIII) and (IX); 7
[0038] R.sub.10-R12 are independently --H, C1-C3 alkyl group or
C1-C3 substituted alkyl group. Preferably, R.sub.10-R.sub.12 are
independently --H or --CH.sub.3.
[0039] Other examples of suitable bridged bicyclic structures
include a 3.2.1 eight-membered bicyclic structure, a 3.3.1
nine-membered bicyclic structure and a 2.2.2 eight-membered
structure and a 3.3.2 nine-membered structure. The structures of a
3.2.1 eight-membered bicyclic system, a 3.3.1 nine-membered
bicyclic system, a 2.2.2 eight-membered bicyclic system and a 3.3.2
nine-membered bicyclic system are provided by Structural Formulas
(X)-(XIII): 8
[0040] In one example, the bridged bicyclic structures represented
by Structural Formulas (X)-(XIII) are substituted by one or more
methyl groups.
[0041] The nomenclature for bridged bicyclic and tricyclic ring
systems indicates the number of ring atoms between bridgeheads. A
"bridgehead" is an atom shared by both rings. For example, bicyclo
2.2.1. heptane, shown in Structural Formula (VIII), has two (C-2
and C-3), two (C-5 and C-6) and one (C-7) carbons between the
bridgeheads (C-1 and C-4). The numbering scheme for the ring atoms
in 2.2.1 heptane is also shown in Structural Formula (VIII).
[0042] Bridged tricyclic ring systems comprise three rings, each of
which shares two or more ring atoms with each of the other two
rings. optionally, a bridged tricyclic ring can have one or more
heteroatoms such as oxygen, nitrogen or sulfur. A preferred example
is a substituted or unsubstituted 1,1,1,1,1,1-tricyclic
ten-membered ring system, also referred to as an "adamantyl" group.
Examples of adamantyl groups are represented by Structural Formula
(XIV)-(XVII): 9
[0043] R.sub.13, R.sub.14, R.sub.15 and R.sub.16 are independently
--H, a C1-C3 alkyl group or a C1 to C3 substituted alkyl group.
Preferably, R.sub.13 is --CH.sub.3.
[0044] X.sub.1 and X.sub.2 independently are >N-- or >CH--.
Preferably, X.sub.1 and X.sub.2 are >CH--.
[0045] In another preferred embodiment, the novel cannabinoid
analogs of the present invention are represented by Formula (III),
modified so that the hydroxyl group attached to the phenyl ring is
replaced with an --H and/or modified so that the side chain is
attached to position four of the tricyclic cannabinoid core.
[0046] Another example of suitable bridged tricyclic system is a
substituted or unsubstituted 0,1,1,1,1,1-tricyclic nine-membered
ring system.
[0047] Suitable substituents for a carbocyclic ring, a heterocyclic
ring, a fused bicyclic ring, a bridged bicyclic ring and a bridged
tricyclic ring are generally C1-C8 alkyl groups, substituted C1-C8
alkyl groups and small, pharmacophoric groups. Examples of small,
pharmacophoric groups include, but are not limited to, --H, --OH,
--OCH.sub.3, --OCH.sub.2CH.sub.3, halogen (e.g., chloro, bromo,
iodo and fluoro), --CN, azido, isocyanate, isothiocyanate,
--NO.sub.2, --CH.sub.3, --C(halogen).sub.3, --CH.sub.2OH,
--CH.sub.2OCH.sub.3, --CH.sub.2OCH.sub.2CH.sub.3,
--CH.sub.2(halogen), --CH.sub.2CN, --CH.sub.2NO.sub.2,
--CH.sub.2CH.sub.3, --CH.sub.2C(halogen).sub.3, --CH.sub.2NH.sub.2,
--CH.sub.2NHCH.sub.3 or --CH.sub.2N(CH.sub.3).sub.2. Alkyl groups
can be straight chained or branched. Suitable substituents for an
alkyl group include small, pharmacophoric groups, as described
above.
[0048] Specific examples of the compounds of the present invention
are shown in FIGS. 1 and 2.
[0049] In the structural formulas depicted herein, the single or
double bond by which a chemical group or moiety is connected to the
remainder of the molecule or compound is indicated by the following
symbol: 10
[0050] For example, the corresponding symbol in Structural Formula
(VIII) indicates that the norbornyl group, which is represented in
Structural Formula (I) by Y, is connected to R or X in Structural
Formula (I) by a single covalent bond with between carbon three of
the norbornyl group and R or X.
[0051] A "therapeutically effective amount" is the quantity of
compound which results in a desired therapeutic effect in a
subject, e.g., immune system suppression, decreased nausea in
patients undergoing chemotherapy, increased appetite and/or
decreased pain in individuals with AIDS Wasting Syndrome or
intraocular pressure in individuals with glaucoma. The specific
dosage level of active ingredient will depend upon a number of
factors, including, for example, biological activity of the
particular preparation, age, body weight, sex and general health of
the subject being treated. Typically, a "therapeutically effective
amount" of the compound ranges from about 10 mg/day to about 1000
mg/day, preferably from about 50 mg/day to about 500 mg/day.
[0052] As used herein, a "subject" refers to a human. An "animal"
refers to veterinary animals, such as dogs, cats, horses, and the
like, and farm animals, such as cows, pigs, guinea pigs and the
like.
[0053] The compounds of the present invention can be administered
by a variety of known methods, including orally, rectally, or by
parenteral routes (e.g., intramuscular, intravenous, subcutaneous,
nasal or topical). The form in which the compounds are administered
will be determined by the route of administration. Such forms
include, but are not limited to capsular and tablet formulations
(for oral and rectal administration), liquid formulations (for
oral, intravenous, intramuscular or subcutaneous administration)
and slow releasing microcarriers (for rectal, intramuscular or
intravenous administration). The formulations can also contain a
physiologically acceptable vehicle and optional adjuvants,
flavorings, colorants and preservatives. Suitable physiologically
acceptable vehicles may include saline, sterile water, Ringer's
solution, and isotonic sodium chloride solutions.
[0054] The compounds of the present invention can be prepared by
the syntheses shown in FIGS. 3-5. Specific conditions for reactions
shown in FIGS. 3-5 are provided in Example 1.
[0055] Also included in the present invention are physiologically
acceptable salts of the novel compounds disclosed herein. Salts of
compounds containing a phenolic group or other acidic functional
group can be prepared by reacting with a suitable base, for
example, a hydroxide base or amine base. Salts of acidic functional
groups contain a countercation such as sodium, potassium, ammonium
and the like. Salts of compounds containing an amine or other basic
group can be obtained, for example, by reacting with a suitable
organic or inorganic acid, such as hydrogen chloride, hydrogen
bromide, acetic acid, perchloric acid and the like. Compounds with
quaternary ammonium group also contain a counteranion such as
chloride, bromide, iodide, acetate, perchlorate and the like.
[0056] The novel compounds of the present invention have utilities
other than immunomodulation. For example, the disclosed
cannabinoids can be used to screen for cells which express
cannabinoid receptors (CB1 or CB2). The cells are contacted with a
radiolabelled cannabinoid, washed to remove unbound compound and
then counted to assess retained radioactivity. Cells which retain
radioactivity bind cannabinoids and are there likely to express a
cannabinoid receptor. Preferably, the cannabinoid is a CB1 or CB2
selective cannabinoid and therefore identifies cells which express
the CB1 or CB2 receptor, respectively.
[0057] The disclosed cannabinoids can also be used to identify
other compounds which bind to a cannabinoid receptor. For example,
radiolabelled cannabinoids can be used in place of CP-55,940 in the
CB1 or CB2 assay described in Example 1. Radiolabeled cannabinoids
can be prepared by, for example, by reducing the ketones used in
Method II of FIG. 5 with a suitable radiolabeled reducing agent
such a tritiated sodium borohydride and oxidizing back to the
ketone with a suitable oxidizing agent such as pyridinium chloro
chromate (PCC). Preferably, the cannabinoid is selective for the
CB1 or CB2 receptor.
[0058] The invention is illustrated by the following examples which
are not intended to be limiting in any way.
EXEMPLIFICATION
Example 1
[0059] Preparation of the compound of the present invention
[0060] Resorcinol synthesis
[0061] (I). Resorcinols synthesized by method I in FIG. 5
[0062] A procedure for preparing resorcinols is described in
Dominiami, et al., J. Org. Chem. 42:344 (1977). The crude
resorcinols obtained by this method were purified by silica gel
column chromatography eluted with a 2:1 mixture of petroleum ether
and acetone.
[0063] (II). Resorcinols synthesized by method II
[0064] Preparation of 5-Bromo-3, 5-Dimethoxy Benzene. 100 mmol of
3,5-dimethoxyaniline were mixed with 75 ml of 48% hydrobromic acid.
150 mmol of sodium nitrite powder were added portionally over 20
minutes with rigorous stirring. The reaction was monitored by
iodine-starch test paper until the paper turned blue. The resulting
diazonium salt solution was added to a pre-prepared boiling
solution of 50 mmol copper (I) bromide in 7 ml of 48% hydrobromic
acid. The addition was complete after 20 minutes. The reaction
mixture was then heated for 30 minutes with rigorous stirring.
Steam distillation of the reaction mixture provided a white solid
product with a yield of 40%.
[0065] Preparation of 1'-hydroxy-1-alkyl-3,5-dimethoxybenzene. 1
mmol of 3,5-dimethoxyphenylmagnesium bromide was prepared in 8 ml
of anhydrous THF according to procedures disclosed in Harvill and
Herbst, J. Org. Chem., 9:21 (1944), the entire teachings of which
are incorporated herein by reference. A solution of 1.1 mmol of a
suitable ketone in 2 ml of anhydrous THF was added dropwise to the
Grignard reagent solution. The mixture was refluxed for 2 to 3
hours and then quenched with the addition of saturated ammonium
chloride solution. After work up and purification by column
chromatography, product was collected in a yield of 95%.
[0066] Preparation of 1-alkyl-3,5-dimethoxybenzene. This compound
was synthesized through lithium ammonia reduction of
1'-hydroxy-l-alkyl-3,5-d- imethoxybenzene by the method described
in Gray et al., J. Org. Chem., Vol.40:3151 (1975), the entire
teachings of which are incorporated herein by reference.
[0067] Preparation of 5-alkyl-resorcinol. This resorcinol was
perpetrated by demethylation of 1-alkyl-3,5-dimethoxybenzene
through the method described in Dominiami, et al., J. Org. Chem.
42:344 (1977), the entire teachings of which are incorporated
herein by reference.
[0068] (III) Resorcinols synthesized by method III in FIG. 5
[0069] Preparation of 1-alkyl-3,5-dimethoxybenzene. A ethereal 10
mmol of 3,5-dimethoxybenzylmagnesium bromide was prepared in the
usual manner with 40 ml of anhydrous ether according to procedures
disclosed in Harvill and Herbst, J. Org. Chem., 9:21 (1944). The
solution of Grignard reagent was concentrated to 15 ml and
transferred into an Ace pressure tube containing a 10 ml ethereal
solution of 10 mmol of a suitable tertiary alkyl bromide. The
mixture was sealed and heated in a 100.degree. C. oil bath with
stirring for 30 minutes, as described in Osama, et al., J. Org.
Chem., 36:205 (1971), Ohno, et al., J. Org. Chem., 53:729 (1988)
and Love, et al., J. Med. Chem., 16:1200 (1973), the entire
teachings of which are incorporated herein by reference. The crude
product was purified through column chromatoghraphy with a yield
about 25%.
[0070] Preparation of 5-alkyl-resorcinol. This resorcinol was
prepared by demethylation of 1-alkyl-3,5-dimethoxybenzene by
methods described in Dominiami, et al., J. Org. Chem., 42:344
(1977), the entire teachings of which are incorporated herein by
reference.
[0071] (IV). Resorcinols synthesized by method IV in FIG. 5
[0072] The procedure for the preparation of these resorcinols is
the same as described in (III), except that the Grignard reagent
was prepared using tetrahydrofuran.
[0073] (V). Resorcinols synthesized by method V in FIG. 5
[0074] A mixture of 100 mmol resorcinol and 100 mmol tertiary
alcohol in 200 ml of 70% methanesulfonic acid was stirred at
0.degree. C. for 12 hours for the preparation of linear side chain
resorcinols, and stirred for 3 to 4 hours at room temperature for
preparation of cyclic side chain resorcinols. The reaction was
quenched by addition of an excess of water. The crude product was
purified by column chromatography. The column was eluted with 2:1
mixture of petroleum ether and acetone. Yield was about 70%.
[0075] Synthesis of .DELTA..sup.8-Tetrahydrocannabinol Analogs Via
the Method of Scheme 1 of FIG. 3.
[0076] A mixture of 1 mmol of the resorcinol, 1 mmol
trans-p-mentha-2, 8-dien-1-ol and 18 mg of p-toluenesulfonic acid
monohydrate in 10 ml of chloroform was stirred and heated in a
70.degree. C. oil bath for 2 to 4 hours. Then the reaction
temperature was lowered to room temperature and quenched by
addition of 5 ml of saturated sodium bicarbonate solution. After
separation, the aqueous layer was extracted twice with methylene
chloride. The combined organic layer was washed with brine and
dried over sodium sulfate. Removal of solvent by vacuum evaporation
provides a yellow oil crude product. The product was purified by
column chromatography. By eluting with 20:1 mixture of petroleum
ether and ethyl acetate. The yield was generally about 65%. For
some stereoisomers, HPLC purification was performed with a chiral
column. The mobil phase was a mixture of hexane and
isopropanol.
[0077] Synthesis of 1-Deoxy-.DELTA..sup.8-Tetrahydrocannabinol Via
the Method of Scheme 2 in FIG. 3
[0078] A mixture of 1 mmol of the phenol, 3 mmol trans-p-mentha-2,
8-dien-1-01 and 35 mg of p-toluenesulfonic acid monohydrate in 10
ml of chloroform was stirred and heated in a 70.degree. C. oil bath
for 4 to 8 hours. Then the reaction temperature was lowered to room
temperature. The reaction was quenched by addition of 5 ml of
saturated sodium bicarbonate solution. After separation, the
aqueous layer was extracted twice by methylene chloride. The
combined organic layer was washed by brine and dried over sodium
sulfate. Removal of solvent by vacuum evaporation provided a yellow
oil crude product. The product was purified by column
chromatography, eluting with 20:1 mixture of petroleum ether and
ethyl acetate. The yield was generally about 15% to 20%.
[0079] Synthesis of Cannabinol and 1-Deoxy-Cannabinol Analogs Via
the Method of Scheme 3 of FIG. 4
[0080] The experimental procedures are as described in Love, et
al., J. Med. Chem., 16:1200 (1973), Meltzer, et al., Synthsis,
1981, 985, and Gareau, et al., Bioorg. Med. Chem. Lett., 6:189
(1996), the entire teachings of which are incorporated herein by
reference.
Example 2
[0081] Compounds of the present invention bind to the CB1 and/or
CB2 receptor
RADIOLIGAND BINDING ASSAY
[0082] The binding affinities of the novel compounds described in
this invention for the central cannabinoid receptor was assessed
using rat forebrain membranes as a source of CB1. Membranes were
prepared as described by the method of Dodd et al., Brain Res.
226:107 (1981), the entire teachings of which are incorporated
herein by reference. Rat whole brains minus the cerebral cortex
were diced with a razor blade and homogenized in 0.32 M sucrose, pH
7.4. The resulting suspension was spun at 400.times.g at 4.degree.
C. The supernatant was decanted and layered over 1.2 M sucrose in
TME buffer (25 mM Tris base, 5 mM MgCl.sub.2 1 mMEDTA, pH 7.4) and
spun at 109,000.times.g. The interface containing plasma membrane
protein was collected, pooled and layered over 0.8 M sucrose in
TME, pH 7.4. The pellet was carefully resuspended in TME, pH 7.4
and the total protein content was assayed by the method of Markwell
et al., Anal. Biochem. 87:206 (1978), the entire teachings of which
are incorporated herein by reference. Protein was aliquotted,
frozen under liquid nitrogen and stored at -80.degree. C. until
use.
[0083] Approximately 30 .mu.g of tissue was incubated in silanized
96 well microtiter plate with TME containing 0.1% essentially fatty
acid free bovine serum albumin (BSA), 0.8 nM [H.sup.3]CP-55,940 and
various concentrations of the test compound in a final volume of
200 .mu.L. Assays were incubated at 30.degree. C. for 1 hour. The
samples were filtered using Packard Filtermate 196 and Whatman GF/C
Filterplates and washed with wash buffer (TME) containing 0.5% BSA.
Radioactivity was detected using MicroScint 20 scintillation
cocktail added directly to the dried filterplates, and the
filterplates were counted using a Packard Instruments Top-Count.
Nonspecific binding was assessed using 100 nM CP-55,940. Data
collected from three independent experiments performed with
duplicate determinations were normalized between 100% and 0%
specific binding for [H.sup.3]CP-55,940, determined using buffer
and 100 nM CP-55,940. The normalized data was analyzed using a 4
parameter nonlinear logistic equation to yield IC.sub.50 values.
Data from at least two independent experiments performed in
duplicate were used to calculate IC.sub.50 values which were
convered to K.sub.i values using the assumptions of Cheng and
Prusoff, Biochem. Pharmacol., 22:3099 (1973), the entire teachings
of which are incorporated herein by reference.
[0084] Mouse spleen was used a source of CB2 receptors to assess
binding affinity of analogs described in this invention. The CB2
binding assay was conducted in the same manner as for CB1.
Silanized centrifuge tubes were used throughout to minimize
receptor loss due to adsorption.
[0085] The K.sub.is (nanomolar) for a number of the compounds of
the present invention are shown in the Table below:
1 TABLE K.sub.i in nM for the K.sub.i in nM for the Compound CB1
Receptor CB2 Receptor AM405 19.1 AM406 14.5 AM410 25.8 22.3 AM409
75.3 AM407 9.1 AM408 18.3 AM412 182.9 85.0 AMG3 0.32 1.7 AMG9 3.6
AMG14 0.2 AM411 6.9 52.0 AM722 78.2 40.3 AM729 29.3 26.9 AM723
382.6 2845.0 AM728 30.7 32.8 AM731 60.6 6.1 AM732 20.1 2.0
[0086] While this invention has been particularly shown and
described with references to preferred embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made therein without departing from the
spirit and scope of the invention as defined by the appended
claims.
* * * * *