U.S. patent application number 11/975463 was filed with the patent office on 2008-04-24 for oxadiazole ketone inhibitors of fatty acid amide hydrolase.
This patent application is currently assigned to The Scripps Research Institute. Invention is credited to Dale L. Boger.
Application Number | 20080096931 11/975463 |
Document ID | / |
Family ID | 36203291 |
Filed Date | 2008-04-24 |
United States Patent
Application |
20080096931 |
Kind Code |
A1 |
Boger; Dale L. |
April 24, 2008 |
Oxadiazole ketone inhibitors of fatty acid amide hydrolase
Abstract
Certain oxadiazole ketone compounds are useful as FAAH
inhibitors. Such compounds may be used in pharmaceutical
compositions and methods for the treatment of disease states,
disorders, and conditions mediated by fatty acid amide hydrolase
(FAAH) activity. Thus, the compounds may be administered to treat
anxiety, pain, inflammation, sleep disorders, eating disorders, or
movement disorders (such as MS).
Inventors: |
Boger; Dale L.; (La Jolla,
CA) |
Correspondence
Address: |
THE SCRIPPS RESEARCH INSTITUTE
OFFICE OF PATENT COUNSEL, TPC-8
10550 NORTH TORREY PINES ROAD
LA JOLLA
CA
92037
US
|
Assignee: |
The Scripps Research
Institute
10550 N. Torrey Pines Road
La Jolla
CA
92037
|
Family ID: |
36203291 |
Appl. No.: |
11/975463 |
Filed: |
October 19, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11251317 |
Oct 14, 2005 |
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11975463 |
Oct 19, 2007 |
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60619172 |
Oct 15, 2004 |
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Current U.S.
Class: |
514/340 ;
514/364 |
Current CPC
Class: |
A61P 25/22 20180101;
C07D 271/10 20130101; C07D 413/04 20130101; A61P 29/00 20180101;
A61P 25/14 20180101 |
Class at
Publication: |
514/340 ;
514/364 |
International
Class: |
A61K 31/4439 20060101
A61K031/4439; A61K 31/4245 20060101 A61K031/4245; A61P 25/14
20060101 A61P025/14; A61P 25/22 20060101 A61P025/22; A61P 29/00
20060101 A61P029/00 |
Claims
1. A compound of Formula (I): ##STR24## wherein: Ar is a 5- or
6-membered aryl or heteroaryl ring having a carbon as its point of
attachment; A is a straight-chain C.sub.1-7alkylene having a carbon
as its point of attachment to the carbon in the beta position,
optionally having 1 or 2 carbon atoms each replaced with a sulfur,
oxygen, or nitrogen atom; B is a straight-chain, branched, or
cyclic C.sub.2-10alkylene, or, is an aryl, C.sub.2-10alkenyl, or
C.sub.2-10alkynyl, where an sp.sup.2 hybridized carbon atom in said
aryl, alkenyl, or alkynyl is covalently attached to A; or a
pharmaceutically acceptable salt, pharmaceutically acceptable
prodrug, or pharmaceutically active metabolite of said
compound.
2. A compound as defined in claim 1, wherein Ar is selected from
the group consisting of furanyl, pyridinyl, phenyl, pyridazinyl,
pyrimidinyl, pyrazinyl, thiophenyl, oxazolyl, thiazolyl,
oxadiazolyl, and isoxazolyl.
3. A compound as defined in claim 2, wherein A is a straight-chain
C.sub.1-7alkylene, having no carbon atoms optionally replaced.
4. A compound as defined in claim 3, wherein B is selected from the
group consisting of ethyl, propyl, isopropyl, butyl, sec-butyl,
tert-butyl, phenyl, ethenyl, cis-1-decenyl, trans-1-decenyl,
ethynyl, and 1-decynyl.
5. A compound as defined in claim 1, wherein A is a straight-chain
C.sub.1-7alkylene, optionally having 1 or 2 carbon atoms each
replaced with an oxygen atom.
6. A compound as defined in claim 5, wherein B is selected from the
group consisting of ethyl, propyl, isopropyl, butyl, sec-butyl,
tert-butyl, phenyl, ethenyl, cis-1-decenyl, trans-1-decenyl,
ethynyl, and 1-decynyl.
7. A compound as defined in claim 1, wherein B is selected from the
group consisting of ethyl, propyl, isopropyl, butyl, sec-butyl,
tert-butyl, phenyl, ethenyl, cis-1-decenyl, trans-1-decenyl,
ethynyl, and 1-decynyl.
8. A compound as defined in claim 7, wherein Ar is selected from
the group consisting of furanyl, pyridinyl, phenyl, pyridazinyl,
pyrimidinyl, pyrazinyl, thiophenyl, oxazolyl, thiazolyl,
oxadiazolyl, and isoxazolyl.
9. A compound as defined in claim 1 wherein Ar is selected from the
group consisting of phenyl, 2-pyridinyl, 3-pyridinyl, 4-pyridinyl,
and furanyl.
10. A compound as defined in claim 1, wherein A is a straight-chain
C.sub.1-7alkylene having no carbon atoms optionally replaced.
11. A compound as defined in claim 1, wherein A is selected from
the group consisting of propylene, butylene, pentylene, hexylene,
propoxylene, butoxylene, and pentoxylene.
12. A compound as defined in claim 1, wherein B is phenyl or
cis-1-decenyl.
13. A compound selected from the group consisting of:
7-phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one;
6-phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-hexan-1-one;
8-phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-octan-1-one;
9-phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-nonan-1-one;
1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-octadec-9-en-1-one;
7-phenyl-1-(5-phenyl-1,3,4-oxadiazol-2-yl)-heptan-1-one;
1-(5-phenyl-1,3,4-oxadiazol-2-yl)-octadec-9-en-1-one;
6-phenyl-1-[5-(pyridin-3-yl)-1,3,4-oxadiazol-2-yl]-hexan-1-one;
7-phenyl-1-[5-(pyridin-3-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one;
7-phenyl-1-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one;
1-[5-(furan-2-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one; and
6-phenoxy-1-(5-pyridin-2-yl-[1,3,4]oxadiazol-2-yl)-hexan-1-one.
14. A method of treating a subject suffering from or diagnosed with
a disease, disorder, or medical condition mediated by FAAH
activity, comprising administering to the subject an effective
amount of a compound of Formula (I): ##STR25## wherein: Ar is a 5-
or 6-membered aryl or heteroaryl ring having a carbon as its point
of attachment; A is a straight-chain C.sub.1-7alkylene having a
carbon as its point of attachment to the carbon in the beta
position, optionally having 1 or 2 carbon atoms each replaced with
a sulfur, oxygen, or nitrogen atom; B is a straight-chain,
branched, or cyclic C.sub.2-10alkylene, or, is an aryl,
C.sub.2-10alkenyl, or C.sub.2-10alkynyl, where an sp.sup.2
hybridized carbon atom in said aryl, alkenyl, or alkynyl is
covalently attached to A; or a pharmaceutically acceptable salt,
pharmaceutically acceptable prodrug, or pharmaceutically active
metabolite of said compound.
15. A method according to claim 14, wherein the disease, disorder,
or medical condition is selected from the group consisting of:
anxiety, pain, sleep disorders, eating disorders, inflammation,
movement disorders, HIV wasting syndrome, closed head injury,
stroke, Alzheimer's disease, epilepsy, Tourette's syndrome,
Niemann-Pick disease, Parkinson's disease, Huntington's chorea,
optic neuritis, autoimmune uveitis, drug withdrawal, nausea,
emesis, sexual dysfunction, post-traumatic stress disorder,
cerebral vasospasm, glaucoma, irritable bowel syndrome,
inflammatory bowel disease, immunosuppression, gastroesophageal
reflux disease, paralytic ileus, secretory diarrhea, gastric ulcer,
rheumatoid arthritis, unwanted pregnancy, hypertension, cancer,
hepatitis, allergic airway disease, autoimmune diabetes,
intractable pruritis, and neuroinflammation.
16. A method according to claim 14, wherein the disease, disorder,
or medical condition is selected from the group consisting of:
anxiety, pain, inflammation, sleep disorders, eating disorders, and
movement disorders.
17. A pharmaceutical composition for treating a disease, disorder,
or medical condition mediated by FAAH activity, comprising: (a) an
effective amount of an agent selected from compounds of Formula
(I): ##STR26## wherein: Ar is a 5- or 6-membered aryl or heteroaryl
ring having a carbon as its point of attachment; A is a
straight-chain C.sub.1-7alkylene having a carbon as its point of
attachment to the carbon in the beta position, optionally having 1
or 2 carbon atoms each replaced with a sulfur, oxygen, or nitrogen
atom; B is a straight-chain, branched, or cyclic
C.sub.2-10alkylene, or, is an aryl, C.sub.2-10alkenyl, or
C.sub.2-10alkynyl, where an sp.sup.2 hybridized carbon atom in said
aryl, alkenyl, or alkynyl is covalently attached to A; and
pharmaceutically acceptable salts, pharmaceutically acceptable
prodrugs, and pharmaceutically active metabolites thereof; and (b)
a pharmaceutically acceptable excipient.
18. A pharmaceutical composition according to claim 17, further
comprising: an analgesic selected from the group consisting of
opioids and non-steroidal anti-inflammatory drugs.
19. A pharmaceutical composition according to claim 17, further
comprising: an analgesic selected from the group consisting of
aspirin, acetaminophen, ibuprofen, naproxen, COX-2 inhibitors,
gabapentin, pregabalin, and tramadol.
20. A method according to claim 14, wherein the compound is
selected from the group consisting of:
7-phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one;
6-phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-hexan-1-one;
8-phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-octan-1-one;
9-phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-nonan-1-one;
1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-octadec-9-en-1-one;
7-phenyl-1-(5-phenyl-1,3,4-oxadiazol-2-yl)-heptan-1-one;
1-(5-phenyl-1,3,4-oxadiazol-2-yl)-octadec-9-en-1-one;
6-phenyl-1-[5-(pyridin-3-yl)-1,3,4-oxadiazol-2-yl]-hexan-1-one;
7-phenyl-1-[5-(pyridin-3-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one;
7-phenyl-1-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one;
1-[5-(furan-2-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one; and
6-phenoxy-1-(5-pyridin-2-yl-[1,3,4]oxadiazol-2-yl)-hexan-1-one.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to certain oxadiazole ketone
compounds, pharmaceutical compositions containing them, and methods
of using them for the treatment of disease states, disorders, and
conditions mediated by fatty acid amide hydrolase (FAAH)
activity.
BACKGROUND OF THE INVENTION
[0002] Medicinal benefits have been attributed to the cannabis
plant for centuries. The primary bioactive constituent of cannabis
is A.sup.9-tetrahydrocannabinol (THC). The discovery of THC
eventually led to the identification of two endogenous cannabinoid
receptors responsible for its pharmacological actions, namely
CB.sub.1, and CB.sub.2 (Goya, Exp. Opin. Ther. Patents 2000, 10,
1529). These discoveries not only established the site of action of
THC, but also inspired inquiries into the endogenous agonists of
these receptors, or "endocannabinoids". The first endocannabinoid
identified was the fatty acid amide anandamide (AEA). AEA itself
elicits many of the pharmacological effects of exogenous
cannabinoids (Piomelli, Nat. Rev. Neurosci. 2003, 4, 873).
[0003] The catabolism of AEA is primarily attributable to the
integral membrane bound protein fatty acid amide hydrolase (FAAH),
which hydrolyzes AEA to arachidonic acid. FAAH was characterized in
1996 by Cravatt and co-workers (Cravatt, Nature 1996, 384, 83). It
was subsequently determined that FMH is additionally responsible
for the catabolism of a large number of important lipid signaling
fatty acid amides including: another major endocannabinoid,
2-arachidonoylglycerol (2-AG) (Science 1992, 258, 1946-1949); the
sleep-inducing substance, oleamide (OEA) (Science 1995, 268, 1506);
the appetite-suppressing agent, N-oleoylethanolamine (Rodriguez de
Fonesca, Nature 2001, 414, 209); and the anti-inflammatory agent,
palmitoylethanolamide (PEA) (Lambert, Curr. Med. Chem. 2002, 9,
663).
[0004] Small molecule inhibitors of FAAH should elevate the
concentrations of these endogenous signaling lipids and thereby
produce their associated beneficial pharmacological effects. There
have been some reports of the effects of various FAAH inhibitors in
pre-clinical models.
[0005] Two carbamate-based inhibitors of FAAH were reported to have
analgesic properties in animal models. In rats, BMS-1 (WO
02/087569) was reported to have an analgesic effect in the Chung
spinal nerve ligation model of neuropathic pain, and the Hargraves
test of acute thermal nociception. URB-597 was reported to have
efficacy in the zero plus maze model of anxiety in rats, as well as
analgesic efficacy in the rat hot plate and formalin tests
(Kathuria, Nat. Med. 2003, 9, 76). The sulfonylfluoride AM374 was
also shown to significantly reduce spasticity in chronic relapsing
experimental autoimmune encephalomyelitis (CREAE) mice, an animal
model of multiple sclerosis (Baker, FASEB J. 2001, 15, 300).
##STR1##
[0006] In addition, the oxazolopyridine ketone OL-135 is a potent
inhibitor of FMH, and has been reported to have analgesic activity
in both the hot plate and tail emersion tests of thermal
nociception in rats (WO 04/033652). ##STR2##
[0007] Results of research on the effects of certain exogenous
cannabinoids has elucidated that an FAAH inhibitor may be useful
for treating various conditions, diseases, disorders, or symptoms.
These include pain, nausea/emesis, anorexia, spasticity, movement
disorders, epilepsy and glaucoma. To date, approved therapeutic
uses for cannabinoids include the relief of chemotherapy-induced
nausea and emesis among patients with cancer and appetite
enhancement in patients with HIV/AIDS who experience anorexia as a
result of wasting syndrome. Two products are commercially available
in some countries for these indications, namely, dronabinol
(Marinol.RTM.) and nabilone.
[0008] Apart from the approved indications, the therapeutic field
that has received the most attention for cannabinoid use is
analgesia, i.e., the treatment of pain. Five small randomized
controlled trials showed that THC is superior to placebo, producing
dose-related analgesia (Robson, Br. J. Psychiatry 2001, 178;
107-115). Atlantic Pharmaceuticals is developing a synthetic
cannabinoid, CT-3, a 1,1-dimethyl heptyl derivative of the
carboxylic metabolite of tetrahydrocannabinol, as an orally active
analgesic and anti-inflammatory agent. A pilot phase II trial in
chronic neuropathic pain was initiated with CT-3 in Germany in May
2002.
[0009] Many individuals with multiple sclerosis have claimed a
benefit from cannabis for both disease-related pain and spasticity,
with support from small controlled trials (Svendsen, Br. Med. J.
2004, 329, 253). Likewise, victims of spinal cord injuries, such as
paraplegia, have reported for years that their painful spasms are
alleviated after smoking marijuana. Recently, a report showing that
cannabinoids appear to control spasticity and tremor in the CREAE
model of multiple sclerosis demonstrated that these effects are
mediated by CB.sub.1 and CB.sub.2 receptors (Baker, Nature 2000,
404, 84-87). Phase 3 clinical trials are currently underway in
multiple sclerosis and spinal cord injury patients with a narrow
ratio mixture of tetrahydrocannabinol/cannabidiol (THC/CBD).
[0010] Small-scale controlled trials have been conducted to
investigate other potential uses of cannabinoids. Trials in
volunteers confirmed that oral, injected and smoked cannabinoids
produced dose-related reductions in intraocular pressure (IOP) and
therefore may relieve glaucoma symptoms. Ophthalmologists have
prescribed cannabis for patients with glaucoma in whom other drugs
have failed to adequately control intraocular pressure (Robson,
2001).
[0011] Inhibition of FAAH using a small molecule inhibitor may be
advantageous compared to treatment with a direct-acting CB.sub.1
agonist. Administration of exogenous CB.sub.1 agonists may produce
a range of responses, including reduced nociception, catalepsy,
hypothermia, and increased feeding behavior. These four in
particular are termed the "cannabinoid tetrad." Experiments with
FAAH -/- mice showed reduced responses in tests of nociception, but
did not show catalepsy, hypothermia, or increased feeding behavior
(Cravatt, Proc. Natl. Acad. Sci. USA 2001, 98, 9371). Fasting
caused levels of AEA to increase in rat limbic forebrain, but not
in other brain areas, providing evidence that stimulation of AEA
biosynthesis may be anatomically regionalized to targeted CNS
pathways (Kirkham, Br. J. Pharmacol. 2002, 136, 550). The finding
that AEA increases are localized within the brain, rather than
systemic, suggests that FAAH inhibition with a small molecule could
enhance the actions of AEA and other fatty acid amides in tissue
regions where synthesis and release of these signaling molecules is
occurring in a given pathophysiological condition (Piomelli,
2003).
[0012] In addition to the effects of an FAAH inhibitor on AEA and
other endocannabinoids, inhibitors of FAAH's catabolism of other
lipid mediators may be used in treating other therapeutic
indications. For example, PEA has demonstrated biological effects
in animal models of inflammation, immunosuppression, analgesia, and
neuroprotection (Ueda, J. Biol. Chem. 2001, 276, 3552). Oleamide,
another substrate of FAAH, induces sleep (Boger, Proc. Natl. Acad.
Sci. USA 2000, 97, 5044; Mendelson, Neuropsychopharmacology 2001,
25, S36).
[0013] Thus, there is evidence that small-molecule FAAH inhibitors
may be used in treating pain of various etiologies, anxiety,
multiple sclerosis and other movement disorders, nausea/emesis,
eating disorders, epilepsy, glaucoma, inflammation,
immunosuppression, neuroprotection, and sleep disorders, and
potentially with fewer side effects than treatment with an
exogenous cannabinoid. There remains a need for potent FAAH
modulators with desirable pharmaceutical properties.
SUMMARY OF THE INVENTION
[0014] Certain 2-keto-oxadiazole derivatives have now been found to
have FAAH-modulating activity.
[0015] In one general aspect, the invention relates to compounds of
the following Formula (I) ##STR3## wherein: [0016] Ar is a 5- or
6-membered aryl or heteroaryl ring having a carbon as its point of
attachment; [0017] A is a straight-chain C.sub.1-7alkylene having a
carbon as its point of attachment to the carbon in the beta
position shown above, which optionally has 1 or 2 carbon atoms
replaced with an atom selected from sulfur, oxygen, and nitrogen;
[0018] B is a straight-chain, branched, or cyclic C.sub.2-10alkyl,
or is a moiety selected from the group consisting of aryl,
C.sub.2-10alkenyl, and C.sub.2-10alkynyl, where an sp.sup.2 or sp
hybridized carbon atom in the aryl, alkenyl, or alkynyl is
covalently attached to A; or a pharmaceutically acceptable salt,
pharmaceutically acceptable prodrug, or pharmaceutically active
metabolite of such compound.
[0019] In a further general aspect, the invention relates to
pharmaceutical compositions each comprising: (a) an effective
amount of an agent selected from compounds of Formula (I) and
pharmaceutically acceptable salts, pharmaceutically acceptable
prodrugs, and pharmaceutically active metabolites thereof; and (b)
a pharmaceutically acceptable excipient.
[0020] In another general aspect, the invention is directed to a
method of treating a subject suffering from or diagnosed with a
disease, disorder, or medical condition mediated by FAAH activity,
comprising administering to the subject an effective amount of a
compound of Formula (I) or a pharmaceutically acceptable salt,
pharmaceutically acceptable prodrug, or pharmaceutically active
metabolite of such compound.
[0021] In certain preferred embodiments of the method, the disease,
disorder, or medical condition is selected from: anxiety, pain,
sleep disorders, eating disorders, inflammation, multiple sclerosis
and other movement disorders, HIV wasting syndrome, closed head
injury, stroke, Alzheimer's disease, epilepsy, Tourette's syndrome,
Niemann-Pick disease, Parkinson's disease, Huntington's chorea,
optic neuritis, autoimmune uveitis, symptoms of drug withdrawal,
nausea, emesis, sexual dysfunction, post-traumatic stress disorder,
cerebral vasospasm, glaucoma, irritable bowel syndrome,
inflammatory bowel disease, immunosuppression, gastroesophageal
reflux disease, paralytic ileus, secretory diarrhea, gastric ulcer,
rheumatoid arthritis, unwanted pregnancy, hypertension, cancer,
hepatitis, allergic airway disease, auto-immune diabetes,
intractable pruritis, and neuroinflammation.
[0022] Additional embodiments, features, and advantages of the
invention will be apparent from the appended claims, which are
incorporated into this summary by reference, as well as from the
following detailed description.
DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS
[0023] The invention may be more fully appreciated by reference to
the following description, including the following glossary of
terms and the concluding examples. For the sake of brevity, the
disclosures of the publications cited in this specification are
herein incorporated by reference.
[0024] As used herein, the terms "including", "containing" and
"comprising" are used herein in their open, non-limiting sense.
[0025] The term "alkyl" refers to a straight- or branched-chain
alkyl group having from 1 to 12 carbon atoms in the chain.
Exemplary alkyl groups include methyl (Me, which also may be
structurally depicted by /), ethyl (Et), n-propyl, isopropyl,
butyl, isobutyl, sec-butyl, tert-butyl (tBu), pentyl, isopentyl,
tert-pentyl, hexyl, isohexyl, and the like.
[0026] The term "alkylene" refers to a divalent straight- or
branched-chain alkyl group having from 1 to 12 carbon atoms in the
chain. Exemplary alkylene groups include methylene, ethylene,
propylene, and the like.
[0027] The term "alkenyl" refers to a straight- or branched-chain
alkenyl group having from 2 to 12 carbon atoms in the chain. The
double bond of the alkenyl group consists of two sp.sup.2
hybridized carbon atoms. Illustrative alkenyl groups include
prop-2-enyl, but-2-enyl, but-3-enyl, 2-methylprop-2-enyl,
hex-2-enyl, and the like.
[0028] The term "alkynyl" refers to a straight- or branched-chain
alkynyl group having from 2 to 12 carbon atoms in the chain. The
triple bond of the alkynyl group consists of two sp hybridized
carbon atoms. Illustrative alkynyl groups include prop-2-ynyl,
but-2-ynyl, but-3-ynyl, 2-methylbut-2-ynyl, hex-2-ynyl, and the
like.
[0029] The term "aryl" refers to a monocyclic, fused bicyclic, or
fused polycyclic, aromatic carbocycle (ring structure having ring
atoms that are all carbon) having from 3 to 12 ring atoms per
carbocycle. Carbon atoms in aryl groups are sp.sup.2 hybridized.
Illustrative examples of aryl groups include phenyl, naphthyl,
anthracenyl, phenanthrenyl, and the like.
[0030] The term "heteroaryl" refers to a monocyclic, fused
bicyclic, or fused polycyclic, aromatic heterocycle (ring structure
having ring atoms selected from carbon atoms as well as nitrogen,
oxygen, and sulfur heteroatoms) having from 3 to 12 ring atoms per
heterocycle. Illustrative examples of heteroaryl groups include the
following moieties: ##STR4## and the like.
[0031] The term "cycloalkyl" refers to a saturated or partially
saturated, monocyclic, fused polycylic, or spiro polycyclic,
carbocycle having from 3 to 12 ring atoms per carbocycle.
Illustrative examples of cycloalkyl groups include the following
moieties: ##STR5## and the like.
[0032] A "heterocycloalkyl" refers to a monocyclic, fused
polycyclic, or spiro polycyclic, ring structure that is saturated
or partially saturated and has from 3 to 12 ring atoms per ring
structure selected from C atoms and N, O, and S heteroatoms.
Illustrative examples of heterocycloalkyl groups include:
##STR6##
[0033] The term "halogen" represents chlorine, fluorine, bromine or
iodine. The term "halo" represents chloro, fluoro, bromo or
iodo.
[0034] The term "substituted" means that the specified group or
moiety bears one or more substituents. The term "unsubstituted"
means that the specified group bears no substituents. The term
"optionally substituted" means that the specified group is
unsubstituted or substituted by one or more substituents. Where the
term "substituted" is used to describe a structural system, the
substitution is meant to occur at any valency-allowed position on
the system.
[0035] When referring to any formula given herein, the selection of
a particular moiety from a list of possible species for a specified
variable is not intended to define the moiety for the variable
appearing elsewhere. In other words, where a variable appears more
than once, the choice of the species from a specified list is
independent of the choice of the species for the same variable
elsewhere in the formula.
[0036] In reference to Formula (I), the variable Ar represents a 5-
or 6-membered aryl or heteroaryl ring, with the ring having a
carbon atom as its point of attachment to the oxadiazole moiety
shown in the formula. Preferably, Ar is selected from the group
consisting of furanyl, pyridinyl, phenyl, pyridazinyl, pyrimidinyl,
pyrazinyl, thiophenyl, oxazolyl, thiazolyl, oxadiazolyl, and
isoxazolyl. More preferably, Ar is selected from the group
consisting of phenyl, 2-pyridinyl, 3-pyridinyl, 4-pyridinyl, and
furanyl.
[0037] The variable A in Formula (I) represents a straight-chain
C.sub.1-7alkylene. This alkylene moiety has a carbon as its point
of attachment to the carbon in the beta position shown in the
formula. Optionally, 1 or 2 carbon atoms of the alkylene may be
replaced with a sulfur, oxygen, or nitrogen atom. Preferably, A is
a straight-chain C.sub.1-7alkylene, optionally having 1 or 2 carbon
atoms replaced with oxygen. More preferably, A is a straight-chain
C.sub.1-7alkylene, without the optional replacement of any carbon
atoms. Even more preferably, A is selected from the group
consisting of propylene, butylene, pentylene, hexylene,
propoxylene, butoxylene, and pentoxylene.
[0038] In general embodiments, the variable B in Formula (I)
represents a straight-chain, branched, or cyclic
C.sub.2-10alkylene, or an aryl, C.sub.2-10alkenyl, or
C.sub.2-10alkynyl group with an sp.sup.2 or sp hybridized carbon
atom in the aryl, alkenyl, or alkynyl group covalently attached to
variable A. In preferred embodiments, B is ethyl, propyl,
isopropyl, butyl, sec-butyl, tert-butyl, phenyl, ethenyl,
cis-1-decenyl, trans-1-decenyl, ethynyl, or 1-decynyl. More
preferably, B is phenyl or cis-1-decenyl.
[0039] Preferred examples of compounds of the present invention are
selected from the group consisting of: TABLE-US-00001 Example
Compound 1
7-Phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one; 2
6-Phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-hexan-1-one; 3
8-Phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-octan-1-one; 4
9-Phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-nonan-1-one; 5
1-[5-(Pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-octadec-9-en-1-one; 6
7-Phenyl-1-(5-phenyl-1,3,4-oxadiazol-2-yl)-heptan-1-one; 7
1-(5-Phenyl-1,3,4-oxadiazol-2-yl)-octadec-9-en-1-one; 8
6-Phenyl-1-[5-(pyridin-3-yl)-1,3,4-oxadiazol-2-yl]-hexan-1-one; 9
7-Phenyl-1-[5-(pyridin-3-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one; 10
7-Phenyl-1-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one; 11
1-[5-(Furan-2-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one; and 12
6-Phenoxy-1-[5-(pyridin-2-yl)-[1,3,4]oxadiazol-2-yl]-hexan-1-one.
[0040] Any formula given herein is intended to represent compounds
having structures depicted by the structural formula as well as
certain variations or forms. In particular, compounds of any given
formula given herein may have asymmetric centers and therefore
exist in different enantiomeric forms. All optical isomers and
stereoisomers of the compounds of the formula, and mixtures
thereof, are considered within the scope of the formula. Thus, any
given formula given herein is intended to represent a racemate, one
or more enantiomeric forms, one or more diastereomeric forms, one
or more atropisomeric forms, and mixtures thereof.
[0041] Furthermore, certain structures may exist as geometric
isomers (i.e., cis and trans isomers), as tautomers, or as
atropisomers. Additionally, any formula given herein is intended to
represent hydrates, solvates, and polymorphs of such compounds, and
mixtures thereof.
[0042] Any formula given herein is also intended to represent
unlabeled forms as well as isotopically labeled forms of the
compounds. Isotopically labeled compounds have structures depicted
by the formulas given herein except that one or more atoms are
replaced by an atom having a selected atomic mass or mass number.
Examples of isotopes that can be incorporated into compounds of the
invention include isotopes of hydrogen, carbon, nitrogen, oxygen,
phosphorous, fluorine, and chlorine, such as .sup.2H, .sup.3H,
.sup.11C, .sup.13C, .sup.14C, .sup.15N, .sup.18O, .sup.17O,
.sup.31P, .sup.32P, .sup.35S, .sup.18F, and .sup.36Cl,
respectively. Various isotopically-labeled compounds of the present
invention, for example those into which radioactive isotopes such
as .sup.3H, .sup.11C, and .sup.14C are incorporated, are useful in
drug or substrate tissue distribution assays. Tritiated (i.e.,
.sup.3H) and carbon-14 (i.e., .sup.14C) isotopes are particularly
preferred for their ease of preparation and detectability. Further,
substitution with heavier isotopes such as deuterium (i.e.,
.sup.2H) may afford certain therapeutic advantages resulting from
greater metabolic stability, for example increased in vivo
half-life or reduced dosage requirements. Isotopically labeled
compounds of this invention and prodrugs thereof can generally be
prepared by carrying out the procedures disclosed in the schemes or
in the examples and preparations described below by substituting a
readily available isotopically labeled reagent for a
non-isotopically labeled reagent.
[0043] The invention includes also pharmaceutically acceptable
salts of the compounds represented by Formula (I). Pharmaceutically
acceptable salts of the above-described specific compounds are
especially preferred.
[0044] A "pharmaceutically acceptable salt" is intended to mean a
salt of a free acid or base of a compound represented by Formula
(I) that is not toxic, biologically intolerable, or otherwise
biologically undesirable. Preferred pharmaceutically acceptable
salts are those that are pharmacologically effective and suitable
for contact with the tissues of patients without undue toxicity,
irritation, or allergic response. A compound of Formula (I) may
possess a sufficiently acidic group, a sufficiently basic group, or
both types of functional groups, and accordingly react with a
number of inorganic or organic bases, and inorganic and organic
acids, to form a pharmaceutically acceptable salt. Exemplary
pharmaceutically acceptable salts include sulfates, pyrosulfates,
bisulfates, sulfites, bisulfites, phosphates,
monohydrogenphosphates, dihydrogenphosphates, metaphosphates,
pyrophosphates, chlorides, bromides, iodides, acetates,
propionates, decanoates, caprylates, acrylates, formates,
isobutyrates, caproates, heptanoates, propiolates, oxalates,
malonates, succinates, suberates, sebacates, fumarates, maleates,
butyne-1,4-dioates, hexyne-1,6-dioates, benzoates, chlorobenzoates,
methylbenzoates, dinitrobenzoates, hydroxybenzoates,
methoxybenzoates, phthalates, sulfonates, xylenesulfonates,
phenylacetates, phenylpropionates, phenylbutyrates, citrates,
lactates, .gamma.-hydroxybutyrates, glycolates, tartrates,
methanesulfonates, propanesulfonates, naphthalene-1-sulfonates,
naphthalene-2-sulfonates, and mandelates.
[0045] If the compound of Formula (I) is a base, the desired
pharmaceutically acceptable salt may be prepared by any suitable
method available in the art, for example, treatment of the free
base with an inorganic acid, such as hydrochloric acid, hydrobromic
acid, sulfuric acid, sulfamic acid, nitric acid, boric acid,
phosphoric acid and the like, or with an organic acid, such as
acetic acid, phenylacetic acid, propionic acid, stearic acid,
lactic acid, ascorbic acid, maleic acid, hydroxymaleic acid,
isethionic acid, succinic acid, valeric acid, fumaric acid, malonic
acid, pyruvic acid, oxalic acid, glycolic acid, salicylic acid,
oleic acid, palmitic acid, lauric acid, a pyranosidyl acid, such as
glucuronic acid or galacturonic acid, an alpha-hydroxy acid, such
as mandelic acid, citric acid or tartaric acid, an amino acid, such
as aspartic acid or glutamic acid, an aromatic acid, such as
benzoic acid, 2-acetoxybenzoic acid, naphthoic acid, or cinnamic
acid, a sulfonic acid, such as laurylsulfonic acid,
p-toluenesulfonic acid, methanesulfonic acid or ethanesulfonic
acid, or the like.
[0046] If the compound of Formula (I) is an acid, the desired
pharmaceutically acceptable salt may be prepared by any suitable
method, for example, treatment of the free acid with an inorganic
or organic base, such as an amine (primary, secondary or tertiary),
an alkali metal hydroxide or alkaline earth metal hydroxide, or the
like. Illustrative examples of suitable salts include organic salts
derived from amino acids, such as glycine and arginine, ammonia,
carbonates, bicarbonates, primary, secondary, and tertiary amines,
and cyclic amines, such as benzylamines, pyrrolidines, piperidine,
morpholine and piperazine, and inorganic salts derived from sodium,
calcium, potassium, magnesium, manganese, iron, copper, zinc,
aluminum and lithium.
[0047] The invention also relates to treatment methods employing
pharmaceutically acceptable prodrugs of the compounds represented
by Formula (I). The term "prodrug" means a precursor of a compound
of the specified formula that, following administration to a
subject, yields the compound in vivo via a chemical or
physiological process such as solvolysis or physiological
conditions (e.g., a prodrug on being brought to physiological pH is
converted to the compound of Formula (I)). A "pharmaceutically
acceptable prodrug" is a prodrug that is not toxic, biologically
intolerable, or otherwise biologically unsuitable for
administration to the subject.
[0048] Exemplary prodrugs include compounds having an amino acid
residue, or a polypeptide chain of two or more (e.g., two, three or
four) amino acid residues, covalently joined through an amide or
ester bond to a free amino, hydroxy or carboxylic acid group of a
compound of Formula (I). Examples of amino acid residues include
the twenty naturally occurring amino acids commonly designated by
three letter symbols as well as 4-hydroxyproline, hydroxylysine,
demosine, isodemosine, 3-methylhistidine, norvaline, beta-alanine,
gamma-aminobutyric acid, citrulline homocysteine, homoserine,
ornithine and methionine sulfone.
[0049] Additional types of prodrugs may be produced, for instance,
by derivatizing free carboxyl groups of structures of Formula (I)
as amides or alkyl esters. Exemplary amides include those derived
from ammonia, primary C.sub.1-6alkyl amines and secondary
di(C.sub.1-6alkyl) amines. Secondary amines include 5- or
6-membered heterocycloalkyl or heteroaryl ring moieties having from
1 to 3 heteroatoms where at least one is a nitrogen atom. Preferred
amides are derived from ammonia, C.sub.1-3alkyl primary amines, and
di(C.sub.1-2alkyl)amines. Exemplary esters of the invention include
C.sub.1-7alkyl, C.sub.5-7-carbocyclyl, phenyl, and
phenyl(C.sub.1-6alkyl) esters. Preferred esters include methyl
esters. Prodrugs may also be prepared by derivatizing free hydroxy
groups using groups including hemisuccinates, phosphate esters,
dimethylaminoacetates, and phosphoryloxymethyloxycarbonyls,
following procedures such as those outlined in Advanced Drug
Delivery Reviews, 1996, 19, 115. Carbamate derivatives of hydroxy
and amino groups also yield prodrugs. Carbonate derivatives,
sulfonate esters and sulfate esters of hydroxy groups also provide
prodrugs. Derivatization of hydroxy groups as (acyloxy)methyl and
(acyloxy)ethyl ethers, wherein the acyl group may be an alkyl
ester, optionally substituted with one or more ether, amine or
carboxylic acid functionalities, or where the acyl group is an
amino acid ester as described above, are also encompassed. Prodrugs
of this type may be prepared as described in J. Med. Chem. 1996,
39, 10. Free amines can also be derivatized as amides, sulfonamides
or phosphonamides. All of these prodrug moieties may incorporate
groups including ether, amine and carboxylic acid
functionalities.
[0050] Pharmaceutically active metabolites may also be used in the
methods of the invention. A "pharmaceutically active metabolite"
means a pharmacologically active product of metabolism in the body
of a compound of Formula (I) or salt thereof. Prodrugs and active
metabolites of a compound may be determined using routine
techniques known in the art. See, e.g., Bertolini et al., J. Med.
Chem. 1997, 40, 2011-2016; Shan et al., J. Pharm. Sci. 86 (7),
765-767; Bagshawe, Drug Dev. Res. 1995, 34, 220-230; Bodor,
Advances in Drug Res. 1984, 13, 224-331; Bundgaard, Design of
Prodrugs (Elsevier Press 1985); and Larsen, Design and Application
of Prodrugs, Drug Design and Development (Krogsgaard-Larsen et al.,
eds., Harwood Academic Publishers, 1991).
[0051] The compounds represented by Formula (I) and their
pharmaceutically acceptable salts, pharmaceutically acceptable
prodrugs, and pharmaceutically active metabolites (collectively,
"agents") of the present invention are useful as FAAH inhibitors in
the methods of the invention. The agents may be used in the
inventive methods for the treatment or prevention of medical
conditions, diseases, or disorders mediated through inhibition or
modulation of FAAH, such as those described herein. Agents
according to the invention may therefore be used as an analgesic,
neuroprotectant, sedative, appetite stimulant, or
contraceptive.
[0052] Exemplary medical conditions, diseases, and disorders
include anxiety, pain, sleep disorders, eating disorders,
inflammation, multiple sclerosis and other movement disorders, HIV
wasting syndrome, closed head injury, stroke, Alzheimer's disease,
epilepsy, Tourette's syndrome, epilepsy, Niemann-Pick disease,
Parkinson's disease, Huntington's chorea, optic neuritis,
autoimmune uveitis, symptoms of drug withdrawal, nausea, emesis,
sexual dysfunction, post-traumatic stress disorder, or cerebral
vasospasm.
[0053] Thus, the pharmaceutical agents may be used to treat
subjects diagnosed with or suffering from a disorder or condition
mediated through FMH activity. The term "treat" or "treating" as
used herein is intended to refer to administration of an agent or
composition of the invention to a subject for the purpose of
effecting a therapeutic or prophylactic benefit through modulation
of FAAH activity. Treating includes reversing, ameliorating,
alleviating, inhibiting the progress of, lessening the severity of,
or preventing a disease, disorder or condition, or one or more
symptoms of such disease, disorder or condition. The term "subject"
refers to a mammalian patient, such as a human. "Modulators"
include both inhibitors and activators, where "inhibitors" refer to
compounds that decrease, prevent, inactivate, desensitize or
down-regulate FMH expression or activity, and "activators" are
compounds that increase, activate, facilitate, sensitize or
up-regulate FAAH expression or activity.
[0054] Accordingly, the invention relates to methods of using the
pharmaceutical agents described herein, including those of the
various preferred embodiments as well as those of the general
embodiments, to treat subjects diagnosed with or suffering from a
disorder or condition mediated through FAAH activity, such as:
anxiety, pain, sleep disorders, eating disorders, inflammation, or
movement disorders (e.g., multiple sclerosis).
[0055] Symptoms or disease states are intended to be included
within the scope of "medical conditions, disorders, or diseases."
For example, pain may be associated with various diseases and
disorders, and may include various etiologies. Illustrative types
of pain treatable with an FAAH-modulating agent according to the
invention include cancer pain, postoperative pain, GI tract pain,
spinal cord injury pain, visceral hyperalgesia, thalamic pain,
headache (including stress headache and migraine), low back pain,
neck pain, musculoskeletal pain, peripheral neuropathic pain,
central neuropathic pain, neurogenerative disorder related pain,
and menstrual pain. HIV wasting syndrome includes associated
symptoms such as appetite loss and nausea. Parkinson's disease
includes, for example, levodopa-induced dyskinesia. Treatment of
multiple sclerosis may include treatment of symptoms such as
spasticity, neurogenic pain, central pain, or bladder dysfunction.
Symptoms of drug withdrawal may be caused by, for example,
addiction to opiates or nicotine. Nausea or emesis may be due to
chemotherapy, postoperative, or opioid related causes. Treatment of
sexual dysfunction may include improving libido or delaying
ejaculation. Treatment of cancer may include treatment of glioma.
Sleep disorders include, for example, sleep apnea, insomnia, and
disorders calling for treatment with an agent having a sedative or
narcotic-type effect. Eating disorders include, for example,
anorexia or appetite loss associated with a disease such as cancer
or HIV infection/AI DS.
[0056] In a treatment method according to the invention, an
effective amount of a pharmaceutical agent according to the
invention is administered to a patient suffering from or diagnosed
as having such a disorder or condition. An "effective amount" means
an amount or dose sufficient to generally bring about the desired
therapeutic or prophylactic benefit in subjects in need of
treatment.
[0057] Effective amounts or doses of the agents of the present
invention may be ascertained by routine methods such as modeling,
dose escalation studies or clinical trials, and by taking into
consideration routine factors, e.g., the mode or route of
administration or drug delivery, the pharmacokinetics of the agent,
the severity and course of the disorder or condition, the subject's
previous or ongoing therapy, the subject's health status and
response to drugs, and the judgment of the treating physician. An
exemplary dose is in the range of from about 0.001 to about 200 mg
of agent per kg of subject's body weight per day, preferably about
0.05 to 100 mg/kg/day, or about 1 to 35 mg/kg/day, in single or
divided dosage units (e.g., BID, TID, QID). For a 70-kg human, an
illustrative range for a suitable dosage amount is from about 0.05
to about 7 g/day, or about 0.2 to about 2.5 g/day.
[0058] Once improvement of the patient's conditions has occurred,
the dose may be adjusted for preventative or maintenance treatment.
For example, the dosage or the frequency of administration, or
both, may be reduced as a function of the symptoms, to a level at
which the desired therapeutic or prophylactic effect is maintained.
Of course, if symptoms have been alleviated to an appropriate
level, treatment may cease. Patients may, however, require
intermittent treatment on a long-term basis upon any recurrence of
symptoms.
[0059] In addition, the agents of the invention may be used in
combination with additional active compounds in the treatment of
the above conditions. The additional compounds may be
coadministered separately with an agent of Formula (I) or included
with such an agent as an additional active ingredient in a
pharmaceutical composition according to the invention. In an
exemplary embodiment, additional active compounds are those that
are known or discovered to be effective in the treatment of
conditions, disorders, or diseases mediated by FAAH activity, such
as another FAAH modulator or a compound active against another
target associated with the particular condition, disorder, or
disease. The combination may serve to increase efficacy (e.g., by
including in the combination a compound potentiating the potency or
effectiveness of an agent according to the invention), decrease one
or more side effects, or decrease the required dose of the agent
according to the invention. In one illustrative embodiment, a
composition according to the invention may contain one or more
additional active ingredients selected from opioids, NSAIDs (e.g.,
ibuprofen, cyclooxygenase-2 (COX-2) inhibitors, and naproxen),
gabapentin, pregabalin, tramadol, acetaminophen, and aspirin.
[0060] The agents of the invention are used, alone or in
combination with one or more other active ingredients, to formulate
pharmaceutical compositions of the invention. A pharmaceutical
composition of the invention comprises: (a) an effective amount of
a pharmaceutical agent in accordance with the invention; and (b) a
pharmaceutically acceptable excipient.
[0061] A "pharmaceutically acceptable excipient" refers to a
substance that is not toxic, biologically intolerable, or otherwise
biologically unsuitable for administration to a subject, such as an
inert substance, added to a pharmacological composition or
otherwise used as a vehicle, carrier, or diluent to facilitate
administration of a pharmaceutical agent and that is compatible
therewith. Examples of excipients include calcium carbonate,
calcium phosphate, various sugars and types of starch, cellulose
derivatives, gelatin, vegetable oils and polyethylene glycols.
[0062] Delivery forms of the pharmaceutical compositions containing
one or more dosage units of the pharmaceutical agents may be
prepared using suitable pharmaceutical excipients and compounding
techniques known to those skilled in the art. The compositions may
be administered in the inventive methods by oral, parenteral,
rectal, topical, or ocular routes or by inhalation.
[0063] The preparation may be in the form of tablets, capsules,
sachets, dragees, powders, granules, lozenges, powders for
reconstitution, liquid preparations, or suppositories. Preferably,
the compositions are formulated for intravenous infusion, topical
administration, or oral administration.
[0064] For oral administration, the compounds of the invention can
be provided in the form of tablets or capsules, or as a solution,
emulsion, or suspension. To prepare the oral compositions, the
agents may be formulated to yield a dosage of, e.g., from about
0.05 to about 50 mg/kg daily, or from about 0.05 to about 20 mg/kg
daily, or from about 0.1 to about 10 mg/kg daily.
[0065] Oral tablets may include the active ingredient mixed with
pharmaceutically acceptable excipients such as inert diluents,
disintegrating agents, binding agents, lubricating agents,
sweetening agents, flavoring agents, coloring agents and
preservative agents. Suitable inert fillers include sodium and
calcium carbonate, sodium and calcium phosphate, lactose, starch,
sugar, glucose, methyl cellulose, magnesium stearate, mannitol,
sorbitol, and the like. Exemplary liquid oral excipients include
ethanol, glycerol, water and the like. Starch,
polyvinyl-pyrrolidone (PVP), sodium starch glycolate,
microcrystalline cellulose, and alginic acid are suitable
disintegrating agents. Binding agents may include starch and
gelatin. The lubricating agent, if present, may be magnesium
stearate, stearic acid or talc. If desired, the tablets may be
coated with a material such as glyceryl monostearate or glyceryl
distearate to delay absorption in the gastrointestinal tract, or
may be coated with an enteric coating.
[0066] Capsules for oral administration include hard and soft
gelatin capsules. To prepare hard gelatin capsules, active
ingredient may be mixed with a solid, semi-solid, or liquid
diluent. Soft gelatin capsules may be prepared by mixing the active
ingredient with water, an oil such as peanut oil or olive oil,
liquid paraffin, a mixture of mono and di-glycerides of short chain
fatty acids, polyethylene glycol 400, or propylene glycol.
[0067] Liquids for oral administration may be in the form of
suspensions, solutions, emulsions or syrups or may be presented as
a dry product for reconstitution with water or other suitable
vehicle before use. Such liquid compositions may optionally
contain: pharmaceutically-acceptable excipients such as suspending
agents (for example, sorbitol, methyl cellulose, sodium alginate,
gelatin, hydroxyethylcellulose, carboxymethylcellulose, aluminum
stearate gel and the like); non-aqueous vehicles, e.g., oil (for
example, almond oil or fractionated coconut oil), propylene glycol,
ethyl alcohol or water; preservatives (for example, methyl or
propyl p-hydroxybenzoate or sorbic acid); wetting agents such as
lecithin; and, if desired, flavoring or coloring agents.
[0068] The agents of this invention may also be administered by
non-oral routes. For example, the compositions may be formulated
for rectal administration as a suppository. For parenteral use,
including intravenous, intramuscular, intraperitoneal, or
subcutaneous routes, the agents of the invention may be provided in
sterile aqueous solutions or suspensions, buffered to an
appropriate pH and isotonicity or in parenterally acceptable oil.
Suitable aqueous vehicles include Ringer's solution and isotonic
sodium chloride. Such forms will be presented in unit-dose form
such as ampules or disposable injection devices, in multi-dose
forms such as vials from which the appropriate dose may be
withdrawn, or in a solid form or pre-concentrate that can be used
to prepare an injectable formulation. Illustrative infusion doses
may range from about 1 to 1000 .mu.g/kg/minute of agent, admixed
with a pharmaceutical carrier over a period ranging from several
minutes to several days.
[0069] For topical administration, the agents may be mixed with a
pharmaceutical carrier at a concentration of about 0.1% to about
10% of drug to vehicle. Another mode of administering the agents of
the invention may utilize a patch formulation to affect transdermal
delivery.
[0070] Agents may alternatively be administered in methods of this
invention by inhalation, via the nasal or oral routes, e.g., in a
spray formulation also containing a suitable carrier.
[0071] Exemplary agents useful in methods of the invention will now
be described by reference to the illustrative synthetic schemes for
their general preparation below and the specific examples that
follow. Artisans will recognize that, to obtain the various
compounds herein, starting materials may be employed that carry the
ultimately desired substituents though the reaction scheme with or
without protection as appropriate to yield the desired product.
Alternatively, it may be necessary to employ, in the place of the
ultimately desired substituent, a suitable group that may be
carried through the reaction scheme and replaced as appropriate
with the desired substituent. Unless otherwise specified, the
variables are as defined above in reference to Formula (I).
##STR7##
[0072] Referring to Scheme A, aryl hydrazides of formula (II) may
be commercially available, or may be prepared by addition of
hydrazine to an aryl acid chloride. Aryl hydrazides may then be
treated with methyl oxalyl chloride to form acylhydrazides of
formula (III). Treatment of compounds of formula (III) with a
dehydrating agent such as p-toluenesulfonyl chloride results in
cyclization to the oxadiazole esters of formula (IV). These esters
may be treated with a nucleophile such as an alkyl Grignard or
alkyllithium reagent to form the FAAH inhibitors of Formula (I).
Generally, the nucleophiles can be obtained from the corresponding
halide by treatment with Mg metal or an alkyl lithium reagent.
##STR8##
[0073] Referring to alternative Scheme B, compounds of Formula (I)
can be obtained by treatment of an appropriate aryloxadiazole of
formula (V) with an alkyllithium reagent, followed by
transmetalation with zinc and copper using the method of Anderson
(Tetrahedron Lett. 1995, 36, 9453-9456), to form the corresponding
cuprate. The cuprate prepared from (V) may be coupled with an
appropriate acid chloride of formula (VI) to provide FAAH
inhibitors of Formula (I).
[0074] The following specific examples are provided to further
illustrate the invention.
EXAMPLES
Experimental
[0075] NMR spectra were obtained on either a Bruker model AMX400
(400 MHz) or DRX500 (500 MHz) spectrometer. The format of the
.sup.1H NMR data below is: chemical shift in ppm down field of the
tetramethylsilane reference (multiplicity, coupling constant J in
Hz, integration).
[0076] Mass spectra were obtained on an Agilent series 1100 MSD
using electrospray ionization (ESI) or Varian VGZAB-VSE or VG
70-VSE MS using FAB or MALDI ionization in either positive or
negative mode as indicated. The "mass calculated" for a molecular
formula is the monoisotopic mass of the compound.
Example 1
[0077] ##STR9##
7-Phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one
[0078] Step A: Methyl
5-(Pyridin-2-yl)-[1,3,4]-oxadiazole-2-carboxylate ##STR10##
2-Picolinyl hydrazide (1.37 g, 10 mmol) and Et.sub.3N (4.15 mL, 30
mmol) were dissolved in CH.sub.2Cl.sub.2 (50 mL) and treated with
methyl oxalyl chloride (0.95 mL, 10 mmol) dropwise at 0.degree. C.
The reaction mixture was slowly warmed to room temperature and
stirred for 6 h before it was treated with p-toluenesulfonyl
chloride (TsCl; 1.91 g, 10 mmol) and stirred overnight. The
reaction mixture was diluted with EtOAc and washed with water,
satd. aq. NaHCO.sub.3 and brine. The organic layer was collected
and concentrated. Flash chromatography (SiO.sub.2, 3.times.15 cm,
70% EtOAc-hexanes) afforded the title compound (1.87 g, 91%) as
white solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 4.07 (s, 3H), 7.52
(ddd, J=7.8, 4.9, 1.2 Hz, 1H), 7.92 (td, J=7.8, 1.8 Hz, 1H), 8.29
(d, J=7.9 Hz, 1H), 8.80 (dd, J=4.2, 1.2 Hz, 1H); .sup.13C NMR
(CDCl.sub.3, 100 MHz) 53.8, 123.8, 126.7, 137.3, 142.3, 150.6,
154.4, 156.8, 165.2.
[0079] Step B:
7-Phenyl-1-[5-(Pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one. A
dry flask was charged with freshly activated Mg turnings (115 mg, 5
mmol), 100 .mu.L of anhydrous THF and a crystal of 12 under Ar.
This mixture was treated dropwise with a solution of
6-bromohexylbenzene (240 mg, 1 mmol) in THF (1 mL) at 60.degree. C.
After the addition was complete, the mixture was stirred for 2 h at
60.degree. C. The resulting gray solution of the Grignard reagent
was added to a solution of the oxadiazole methyl ester from Step A
(40 mg, 0.17 mmol) in THF (2 mL) at -40.degree. C. Stirring was
continued for 4 h before the reaction was quenched with the
addition of brine. The mixture was extracted with EtOAc followed by
separation and concentration. Flash chromatography (SiO.sub.2,
1.times.4 cm, 40% EtOAc-hexanes) afforded the title compound (30
mg, 51%) as white solid. .sup.1H NMR (400 MHz, CDCl.sub.3) 1.43 (m,
4H), 1.66 (quintet, J=7.5 Hz, 2H), 1.82 (quintet, J=7.3 Hz, 2H),
2.62 (dd, J=7.9, 7.6 Hz, 2H), 3.31 (t, J=7.3 Hz, 2H), 7.16-7.19 (m,
3H), 7.26-7.30 (m, 2H), 7.54 (ddd, J=7.6, 4.7, 0.9 Hz, 1H), 7.93
(td, J=7.8, 1.5 Hz, 1H), 8.30 (d, J=7.9 Hz, 0.1H), 8.85 (d, J=4.7
Hz, 1H); .sup.13C NMR (CDCl.sub.3, 100 MHz) 23.5, 28.8, 28.9, 31.2,
35.8, 40.0, 124.0, 125.6, 126.7, 128.2, 128.3, 137.3, 142.6, 150.8,
161.2, 165.0, 187.1; MALDI-FTMS m/z 336.1717
(C.sub.20H.sub.21N.sub.3O.sub.2+H.sup.+ requires 336.1706).
Example 2
[0080] ##STR11##
6-Phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-hexan-1-one
[0081] Starting with methyl
5-(pyridin-2-yl)-[1,3,4]-oxadiazole-2-carboxylate and
5-bromopentylbenzene, the title compound (21 mg, 49%) was obtained
as a white solid, using a procedure similar to Example 1. .sup.1H
NMR (400 MHz, CDCl.sub.3) 1.45 (m, 2H), 1.68 (quintet, J=7.8 Hz,
2H), 1.86 (quintet, J=7.6 Hz, 2H), 2.62 (t, J=7.6 Hz, 2H), 3.31 (t,
J=7.5 Hz, 2H), 7.18-7.20 (m, 3H), 7.27-7.29 (m, 2H), 7.54 (ddd,
J=7.9, 5.0, 1.2 Hz, 1H), 7.94 (td, J=7.6, 1.8 Hz, 1H), 8.30 (d,
J=7.9 Hz, 1H), 8.85 (d, J=5.0 Hz, 1H); C NMR (CDCl.sub.3, 100 MHz)
23.4, 28.6, 31.1, 35.7, 40.0, 124.0, 125.7, 126.7, 128.3, 128.4,
137.3, 142.3, 142.6, 150.8, 161.2, 165.1, 187.0; MALDI-FTMS m/z
322.1557 (C.sub.19H.sub.19N.sub.3O.sub.2+H.sup.+ requires
322.1556).
Example 3
[0082] ##STR12##
8-Phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-octan-1-one
[0083] Starting with methyl
5-(pyridin-2-yl)-[1,3,4]-oxadiazole-2-carboxylate and
7-bromoheptylbenzene, the title compound (25 mg, 41%) was obtained
as a white solid, using a procedure similar to Example 1. .sup.1H
NMR (400 MHz, CDCl.sub.3) 1.38 (m, 6H), 1.63 (quintet, J=7.3 Hz,
2H), 1.80 (quintet, J=7.0 Hz, 2H), 2.61 (dd, J=7.9, 7.6 Hz, 2H),
3.21 (t, J=7.5 Hz, 2H), 7.16-7.19 (m, 3H), 7.26-7.30 (m, 2H), 7.54
(ddd, J=7.6, 4.7, 0.9 Hz, 1H), 7.94 (td, J=7.8, 1.8 Hz, 1H), 8.30
(d, J=7.9 Hz, 1H), 8.85 (d, J=4.7 Hz, 1H); .sup.13C NMR
(CDCl.sub.3, 100 MHz) 23.6, 28.9, 29.0, 29.1, 31.4, 35.7, 35.9,
40.1, 124.0, 125.6, 126.7, 128.2, 128.4, 137.3, 142.6, 142.7,
150.8, 161.2, 165.1, 187.2; MALDI-FTMS m/z 350.1859
(C.sub.21H.sub.23N.sub.3O.sub.2+H.sup.+ requires 350.1863).
Example 4
[0084] ##STR13##
9-Phenyl-1-[5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-nonan-1-one
[0085] Starting with methyl
5-(pyridin-2-yl)-[1,3,4]-oxadiazole-2-carboxylate and
8-bromooctylbenzene, the title compound (28 mg, 43%) was obtained
as a white solid using a procedure similar to Example 1. .sup.1H
NMR (400 MHz, CDCl.sub.3) 1.34 (m, 8H), 1.62 (quintet, J=7.3 Hz,
2H), 1.81 (quintet, J=7.3 Hz, 2H), 2.61 (dd, J=7.9, 7.6 Hz, 2H),
3.21 (t, J=7.5 Hz, 2H), 7.16-7.19 (m, 3H), 7.26-7.30 (m, 2H), 7.54
(dd, J=7.6, 4.7, Hz, 1H), 7.93 (td, J=7.6, 1.5 Hz, 1H), 8.30 (d,
J=7.9 Hz, 1H), 8.85 (d, J=4.7 Hz, 1H); .sup.13C NMR (CDCl.sub.3,
100 MHz) 23.6, 28.9, 29.00, 29.02, 29.2, 31.4, 35.90, 35.92, 40.1,
124.0, 125.5, 126.7, 128.2, 128.4, 137.3, 142.6, 142.8, 150.8,
161.2, 165.0, 187.2; MALDI-FTMS m/z 364.2024
(C.sub.22H.sub.25N.sub.3O.sub.2+H.sup.+ requires 364.2019).
Example 5
[0086] ##STR14##
1-[5-(Pyridin-2-yl)-1,3,4-oxadiazol-2-yl]-octadec-9-en-1-one
[0087] A solution of cis-1-bromo-heptadec-8-ene (60 mg, 0.2 mmol)
in THF (1 mL) was treated with t-BuLi (1.5 M in pentane, 270 .mu.L,
0.4 mmol) at 40.degree. C. After stirring for 30 min, the resulting
alkyl lithium reagent was added to a solution of methyl
5-(pyridin-2-yl)-[1,3,4]-oxadiazole-2-carboxylate (20 mg, 0.1 mmol)
in THF (2 mL) at -40.degree. C. The reaction mixture was stirred
for 4 h before it was quenched with the addition of brine. The
mixture was extracted with EtOAc, concentrated, and purified by
flash chromatography (SiO.sub.2, 1.times.3 cm, 30% EtOAc-hexanes)
to provide the title compound (8.5 mg, 23%) as white solid. .sup.1H
NMR (400 MHz, CDCl.sub.3) 8.85 (dd, J=5, 1.2 Hz, 1H), 8.30 (dd,
J=7.9, 1.2 Hz, 1H), 7.94 (td, J=7.6, 1.5 Hz, 1H), 7.54 (ddd, J=7.6,
4.7, 1.2 Hz, 1H), 5.34-5.37 (m, 2H), 3.22 (t, J=7.3 Hz, 2H), 2.02
(m, 4H), 1.82 (m, 2H), 1.27-1.41 (m, 20H), 0.88 (t, J=6.4 Hz, 3H);
.sup.13C NMR (CDCl.sub.3, 100 MHz) 187.2, 165.1, 161.2, 150.8,
142.6, 150.8, 142.6, 137.3, 130.0, 129.7, 126.7, 124.0, 40.1, 31.9,
29.8, 29.7, 29.5, 29.3, 29.2, 29.1, 29.0, 27.2, 27.1, 23.6, 22.7,
14.1; MALDI-FTMS m/z 412.2955
(C.sub.25H.sub.37N.sub.3O.sub.2+H.sup.+ requires 412.2958).
Example 6
[0088] ##STR15##
7-Phenyl-1-(5-phenyl-1,3,4-oxadiazol-2-yl)-heptan-1-one
[0089] Step A: Methyl 5-Phenyl-1,3,4-oxadiazole-2-carboxylate
##STR16## Starting with benzoyl hydrazide, the title compound (1.93
g, 94%) was obtained as a white solid, using a method analogous to
that described in Example 1, Step A. .sup.1H NMR (400 MHz,
CDCl.sub.3) 4.05 (s, 3H), 7.48-7.59 (m, 3H), 8.11 (m, 2H); .sup.13C
NMR (CDCl.sub.3, 100 MHz) 53.7, 122.5, 127.4, 129.1, 132.7, 154.6,
156.1, 166.3; MALDI-FTMS m/z 205.0602
(C.sub.9H.sub.8N.sub.2O.sub.3+H.sup.+ requires 205.0608).
[0090] Step B:
7-Phenyl-1-(5-phenyl-1,3,4-oxadiazol-2-yl)-heptan-1-one. Starting
with methyl 5-phenyl-1,3,4-oxadiazole-2-carboxylate, the title
compound (32 mg, 49%) was obtained as white solid, using a method
analogous to that described in Example 1, Step B. .sup.1H NMR (400
MHz, CDCl.sub.3) 1.44 (m, 4H), 1.66 (quintet, J=7.4 Hz, 2H), 1.82
(quintet, J=7.3 Hz, 2H), 2.63 (dd, J=7.9, 7.4 Hz, 2H), 3.20 (t,
J=7.3 Hz, 2H), 7.16-7.20 (m, 3H), 7.26-7.30 (m, 2H), 7.54-7.62 (m,
3H), 8.17-8.20 (m, 2H); .sup.13C NMR (CDCl.sub.3, 100 MHz) 23.6,
28.8, 28.9, 31.2, 35.8, 35.9, 39.8, 122.8, 125.6, 127.7, 128.2,
128.4, 129.2, 132.9, 142.6, 160.8, 166.3, 187.5; MALDI-FTMS m/z
335.1758 (C.sub.21H.sub.22N.sub.2O.sub.2+H.sup.+ requires
335.1754).
Example 7
[0091] ##STR17##
1-(5-Phenyl-1,3,4-oxadiazol-2-yl)-octadec-9-en-1-one
[0092] A solution of 2-phenyl-[1,3,4]-oxadiazole (73 mg, 0.5 mmol)
in THF (5 mL) was treated with 2.5 M BuLi (240 .mu.L, 0.6 mmol) at
-78.degree. C. After stirring for 30 min, ZnCl.sub.2 (1 M in
diethyl ether, 1 mL, 1 mmol) was added. The reaction mixture was
warmed to 0.degree. C. and stirred for 45 min before CuI (100 mg,
0.5 mmol) was added. After stirring for 15 min, the reaction
mixture was treated with a solution of oleoyl chloride (400 .mu.L,
1 mmol) in THF (2 mL) and reaction mixture was stirred for 5 h
before it was quenched with the addition of brine. The mixture was
extracted with EtOAc, concentrated, and purified by flash
chromatography (SiO.sub.2, 1.times.3 cm, 20% EtOAc-hexanes) to
provide the title compound (40 mg, 20%) as thick oil. .sup.1H NMR
(400 MHz, CDCl.sub.3) 8.18 (dd, J=7, 1.5 Hz, 2H), 7.61 (m, 1H),
7.55 (m, 2H), 5.34-5.39 (m, 2H), 3.20 (t, J=7.4 Hz, 2H), 2.01 (m,
4H), 1.81 (quintet, J=7.4 Hz, 2H), 1.27-1.42 (m, 20H), 0.88 (t,
J=7.0 Hz, 3H); .sup.13C NMR (CDCl.sub.3, 100 MHz) 187.6, 160.9,
132.8, 130.0, 129.7, 129.2, 127.8, 122.8, 39.9, 31.9, 29.8, 29.7,
29.5, 29.3, 29.2, 29.1, 27.2, 27.1, 23.7, 22.7, 14.1; MALDI-FTMS
m/z 411.3010 (C.sub.26H.sub.38N.sub.2O.sub.2+H.sup.+ requires
411.3006).
Example 8
[0093] ##STR18##
6-Phenyl-1-[5-(pyridin-3-yl)-1,3,4-oxadiazol-2-yl]-hexan-1-one
[0094] Step A: Methyl
5-(pyridin-3-yl)-1,3,4-oxadiazole-2-carboxylate ##STR19## Starting
with 3-picolinyl hydrazide, the title compound (1.53 g, 75%) was
obtained as a white solid, using a method analogous to that
described in Example 1, Step A. .sup.1H NMR (500 MHz, CDCl.sub.3)
4.11 (s, 3H), 7.52 (ddd, J=8.1, 4.8, 1.1 Hz, 1H), 8.46 (dt, J=8.1,
2.0 Hz, 1H), 8.85 (dd, J=5.2, 1.6 Hz, 1H), 9.39 (d, J=2.2 Hz, 1H);
.sup.13C NMR (CDCl.sub.3, 100 MHz) 53.9, 119.3, 123.9, 134.7,
148.4, 153.4, 154.5, 156.6, 164.4; MALDI-FTMS m/z 206.0560
(C.sub.9H.sub.7N.sub.3O.sub.3+H.sup.+ requires 206.056).
[0095] Step B:
6-Phenyl-1-[5-(pyridin-3-yl)-1,3,4-oxadiazol-2-yl]-hexan-1-one. By
using procedure analogous to that described in Example 1, Step B,
the title compound was prepared (42 mg, 73%) as white solid.
.sup.1H NMR (400 MHz, CDCl.sub.3) 1.48 (m, 2H), 1.70 (quintet,
J=7.6 Hz, 2H), 1.85 (quintet, J=7.6 Hz, 2H), 2.64 (t, J=7.8 Hz,
2H), 3.21 (t, J=7.5 Hz, 2H), 7.16-7.19 (m, 3H), 7.26-7.30 (m, 2H),
7.52 (ddd, J=8.2, 5.0, 0.9 Hz, 1H), 8.45 (dt, J=7.9, 2.0 Hz, 1H),
8.85 (dd, J=4.7, 1.8 Hz, 1H), 9.41 (d, J=2 Hz, 1H); .sup.13C NMR
(CDCl.sub.3, 100 MHz) 23.5, 28.5, 31.0, 35.6, 39.9, 119.4, 123.9,
125.7, 128.2, 128.3, 134.8, 142.3, 148.6, 153.4, 161.0, 164.2,
187.2; MALDI-FTMS m/z 322.1540
(C.sub.19H.sub.19N.sub.3O.sub.2+H.sup.+ requires 322.155).
Example 9
[0096] ##STR20##
7-Phenyl-1-[5-(pyridin-3-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one
[0097] Starting with methyl
5-(pyridin-3-yl)-[1,3,4]-oxadiazole-2-carboxylate and
6-bromohexylbenzene, the title compound (20 mg, 34%) was obtained
as a white solid, using a procedure analogous to that described in
Example 1. .sup.1H NMR (400 MHz, CDCl.sub.3) 1.44 (m, 4H), 1.66
(quintet, J=7.5 Hz, 2H), 1.82 (quintet, J=7.3 Hz, 2H), 2.63 (dd,
J=7.9, 7.3 Hz, 2H), 3.21 (t, J=7.4 Hz, 2H), 7.17-7.19 (m, 3H),
7.26-7.30 (m, 2H), 7.52 (ddd, J=7.9, 4.7, 0.6 Hz, 1H), 7.94 (dt,
J=7.9, 1.9 Hz, 1H), 8.85 (dd, J=5.0, 1.8 Hz, 1H), 9.41 (d, J=1.8
Hz, 1H); .sup.13C NMR (CDCl.sub.3, 100 MHz) 23.6, 28.8, 28.9, 31.2,
35.8, 35.9, 40.0, 119.4, 123.9, 125.6, 128.2, 128.4, 134.9, 142.6,
148.7, 153.4, 161.0, 164.3, 187.3; MALDI-FTMS m/z 336.1716
(C.sub.20H.sub.21N.sub.3O.sub.2+H.sup.+ requires 336.1706).
Example 10
[0098] ##STR21##
7-Phenyl-1-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one
[0099] Starting with 4-picolinyl hydrazide and 6-bromohexylbenzene,
the title compound (25 mg, 42%) was obtained as a white solid,
using a procedure analogous to that described in Example 1. .sup.1H
NMR (500 MHz, CDCl.sub.3) 1.44 (m, 4H), 1.66 (quintet, J=7.6 Hz,
2H), 1.82 (quintet, J=7.4 Hz, 2H), 2.63 (t, J=7.7 Hz, 2H), 3.21 (t,
J=7.5 Hz, 2H), 7.17-7.19 (m, 3H), 7.26-7.30 (m, 2H), 8.03 (dd,
J=4.4, 1.5 Hz, 2H), 8.88 (dd, J=4.4, 1.5 Hz, 2H); .sup.13C NMR
(CDCl.sub.3, 100 MHz) 23.5, 28.8, 28.9, 31.2, 35.8, 40.0, 120.8,
125.6, 128.3, 128.4, 129.9, 142.5, 151.1, 161.1, 164.4, 187.2;
MALDI-FTMS m/z 336.1715 (C.sub.20H.sub.21N.sub.3O.sub.2+H.sup.+
requires 336.1706).
Example 11
[0100] ##STR22##
1-[5-(Furan-2-yl)-1,3,4-oxadiazol-2-yl]-heptan-1-one
[0101] Starting with 2-furanyl hydrazide and 6-bromohexylbenzene,
the title compound (47 mg, 57%) was obtained as a white solid,
using a procedure analogous to that described in Example 1. .sup.1H
NMR (400 MHz, CDCl.sub.3) 1.43 (m, 4H), 1.65 (quintet, J=7.3 Hz,
2H), 1.81 (quintet, J=7.3 Hz, 2H), 2.62 (dd, J=7.9, 7.5 Hz, 2H),
3.18 (t, J=7.3 Hz, 2H), 6.66 (ddd, J=3.5, 1.8, 0.9 Hz, 1H),
7.18-7.19 (m, 3H), 7.26-7.30 (m, 2H), 7.36 (dd, J=3.8, 0.9 Hz, 1H),
7.72 (dd, J=1.8, 0.9 Hz, 1H); .sup.13C NMR (CDCl.sub.3, 100 MHz)
23.6, 28.8, 28.9, 31.2, 35.6, 39.9, 112.6, 116.6, 125.6, 128.2,
128.3, 138.5, 142.5, 147.0, 158.7, 159.9, 187.1.
Example 12
[0102] ##STR23##
6-Phenoxy-1-(5-pyridin-2-yl-[1,3,4]oxadiazol-2-yl)-hexan-1-one
[0103] The title compound is prepared using a method analogous to
those described above in Examples 1-11.
Assay Method
[0104] All enzyme assays were performed at 20-23.degree. C. using a
solubilized liver plasma membrane extract containing FAAH in a
reaction buffer of 125 mM Tris, 1 mM EDTA, 0.2% glycerol, 0.02%
Triton X-100, 0.4 mM HEPES, pH 9.0 buffer (Patricelli, M. P. et al.
Bioorg. Med. Chem. Lett. 1998, 8, 613-618; Patterson, J. E., et al.
J. Am. Chem. Soc. 1996, 118, 5938-5945). The initial rates of
hydrolysis were monitored by following the breakdown of
.sup.14C-oleamide to oleic acid as described previously (Cravatt,
B. F. et al. Science 1995, 268, 1506-1509; Patricelli, M. P. et
al., 1998). The inhibition was reversible, non time-dependent.
Linear least squares fits were used for all reaction progress
curves and R.sup.2 values were consistently >0.97. IC.sub.50
values were determined from the inhibition observed at 3-5
different test compound concentrations (from three or more trials
at each concentration) using the formula
IC.sub.50=[I]/[(K.sub.0/K.sub.i)-1], where K.sub.0 is the control
reaction rate without inhibitor and K.sub.i is the rate with test
compound at concentration [I] (Conde-Frieboes, K., et al. J. Am.
Chem. Soc. 1996, 118, 5519-5525). K.sub.i values were determined by
the Dixon Method (x-intercepts of weighted linear fits of [I]
versus 1/rate plots at constant substrate concentration, which were
converted to K.sub.i values using the formula
K.sub.i=-x.sub.int/[1+[S]/K.sub.m]). Data for the identified
examples are presented in Table 1. TABLE-US-00002 TABLE 1 Ex.
K.sub.i (nM) 1 0.29 2 0.85 3 0.77 4 0.83 5 3.0 6 2.0 7 16 8 ND 9
1.0 10 1.0 11 0.56 ND = not determined
Selectivity Assay
[0105] Serine hydrolases represent one of the largest classes of
enzymes collectively comprising approximately 3% of the predicted
Drosophila proteome. Subclasses include serine proteases, lipases,
esterases, amidases, and transacetylases. To date, designed FAAH
inhibitors have not demonstrated competitive inhibition with
respect to other serine hydrolases. Disclosed herein is the use of
a proteome-wide serine hydrolase screen (Kidd, D., et al.,
Biochemistry 2001, 40, 4005-4015; Liu, Y., et al., Proc. Natl.
Acad. Sci. USA 1999, 96, 14694-14699) adapted to assay the
selectivity of FAAH inhibitors (Leung, D., et al., Nature Biotech.
2003, 21, 687-691).
[0106] Biotinylated (B) or fluorescently-tagged (rhodamine, R)
PEG-fluorophosphonate (BPFP or RPFP, respectively) have been used
to isolate and identify (BPFP) or quantitate (RPFP) proteome serine
hydrolases through selective, irreversible active site labeling
(Kidd, D., et al., 2001; Liu, Y., et al., 1999). Extending this to
the assessment of inhibitor selectivity required incubation of the
proteome with RPFP in the presence of systematically varied
concentrations of inhibitor followed by SDS-PAGE to detect serine
hydrolases sensitive to the inhibitor (Leung, D., et al., 2003). A
resulting inhibition of RPFP active site labeling correlated with
inhibitor affinity for the target and permitted the simultaneous
assessment of competitive enzymes. Significantly, the selectivity
screening did not require the use of a competitive substrate, no
modification of the inhibitor was required, and the results were
rapidly quantitated (IC.sub.50's).
[0107] Two enzymes emerged from the screen as competitive targets
for the oxadiazole ketone compounds detailed herein:
triacylglycerol hydrolase (TGH) and an uncharacterized
membrane-bound hydrolase that lacks known substrates and function
(KIAA1363) (Kidd, D., et al., 2001; Liu, Y., et al., 1999; Leung,
D., et al., 2003). The results of the selectivity screen are shown
in Table 2. TABLE-US-00003 TABLE 2 FAAH Ex. K.sub.i (nM) FAAH
IC.sub.50 (nM) KIAA IC.sub.50 (nM) TGH IC.sub.50 (nM) 1 0.29 1 5
.times. 10.sup.4 140 2 0.85 4 9 .times. 10.sup.4 30 3 0.77 0.6 6
.times. 10.sup.4 200 4 0.83 0.8 3 .times. 10.sup.3 500 6 2.0 25
>1 .times. 10.sup.5 250 9 1.0 20 >1 .times. 10.sup.5 100 10
1.0 20 >1 .times. 10.sup.5 30 11 0.56 1 >1 .times. 10.sup.5
80
[0108] While the invention has been illustrated by reference to
exemplary and preferred embodiments, it will be understood that the
invention is intended not to be limited to the foregoing detailed
description, but to be defined by the appended claims as properly
construed under principles of patent law.
* * * * *