WO2009140210A2

WO2009140210A2 - Radiotracers for imaging cannabinoid sub-type1 (cb1) receptor

Info

Publication number: WO2009140210A2
Application number: PCT/US2009/043491
Authority: WO
Inventors: Victor W. Pike; Sean R. Donohue; Christer Halldin
Original assignee: The Government Of The United States Of America As Represented By The Secretary Of The Department Of Health And Human Services
Priority date: 2008-05-12
Filing date: 2009-05-11
Publication date: 2009-11-19
Also published as: WO2009140210A3; WO2009140210A9

Abstract

Imaging of cannabinoid subtype-1 (CB₁) receptors in vivo is important for understanding their role in neuropsychiatric disorders and for drug development. Radioligands for imaging with PET or SPECT are required for this purpose. The present invention provides new ligands, including (-)-3-(4-chlorophenyl)-N'-[(4-cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro-1H-pyrazole-1-carboxamidine) and 1-(2-iodophenyl)-4-cyano-5-(4-methoxyphenyl)-N-(piperidin-1-yl)-1H-pyrazole-3-carboxylate, which were found to have high affinity and selectivity for binding to CB1 receptors. These compounds were labeled and evaluated as a PET and SPECT radioligands for use in mammals. After injection of [¹¹C] (-)-3-(4-chlorophenyl)-N'-[(4-cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro-1H-pyrazole-1-carboxamidine) into mammals, high uptake and retention of radioactivity across brain according to the rank order of CB₁ receptor densities was observed. Likewise ¹²⁵I-labeled 1-(2-iodophenyl)-4-cyano-5-(4-methoxyphenyl)-N-(piperidin-1-yl)-1H-pyrazole-3-carboxylate showed a distinct regional distribution of radioactivity in brain tissue according to the known CB₁ receptor densities. Ligands of the present invention are useful for in vivo imaging CB₁ receptor function in mammals.

Description

RADIOTRACERS FOR IMAGING CANNABINOID SUB-TYPEl

(CB₁) RECEPTOR

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. provisional application Ser. No. 61/052,581, filed May 12, 2008, the disclosure of which is incorporated herein in its entirety.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[0002] This invention was made with government support by the Intramural Program of the National Institute of Mental Health under projects #Z01-MH-002795-04 and #ZOMH0902793-06. The government has certain rights in this invention.

FIELD OF THE INVENTION

[0003] The present invention relates generally to radiotracers and radiolabeled compounds that are ligands for a cannabinoid subtype-1 (CBi) receptor. Compounds of the present invention are useful for labeling and diagnostic imaging of CBi receptor for clinical research, diagnostics and for drug discovery and development. Radiotracers of the present invention include 3,4 diarylpyrazoline compounds which permit precise accurate quantification of CBi receptor function in vitro and in vivo. Another preferred radiotracer of the present invention is l-(2-iodophenyl)-4-cyano-5-(4-methoxyphenyl)-N-(piperidin-l-yl)-lH-pyrazole-3- carboxylate) having a radioactive iodine. BACKGROUND OF THE INVENTION

[0004] The psychotropic, analgesic and healing properties of Cannabis saliva (marijuana) have been known throughout documented history (Vincent et ai, 1983, Drugs 25:52-62). Marijuana is one of the oldest known plant derived therapeutics, owing mainly to its antinociceptive properties (Lambert, 2001, J Pharm BeIg 56:1 1 1-1 18). Some beneficial effects of cannabis intake may include anti-emesis and appetite stimulation. As for some other plant-derived medications (e.g., opium), there has been significant abuse of marijuana mainly because of an accompanying feeling of relaxation and psychological "high" (Mackie, 2005, Annu Rev Pharmacol Toxicol 46: 101-122; Lambert and Fowler, 2005, J Med Chem 48:5059- 5087). Nevertheless, legitimate medical use of marijuana may extend to the treatment of chemotherapy-induced emesis (Izzo and Courts, 2005, Handb Exp Pharmacol 168:573-598; Darmani and Crim, 2005, Pharmacol Biochem Behav 80:35-44), appetite stimulation in autoimmune deficiency syndrome (Beal et ai, 1995, J Pain Symptom Manage 10:89-97; Beal et al., 1997, J Pain Sympt Manage 14:7-14) and movement disorders caused by multiple sclerosis (Grundy et ai, 2002, Expert Opin Investig Drugs 1 1 : 1365-1374; Pryce et ai, 2003, Brain 126:2191-2202).

[0005] Efforts to elucidate the biological response to marijuana intake have identified (-)- (6a/?₎ 10aΛ)-6₁6_>9-trimethyl-3-pentyl-6a,7,8,10a-tetrahydro-6H-benzo[c]chromen- l-ol (Δ⁹- TΗC) as its most abundant active compound (Gaoni and Mechoulam, 1964, J Am Chem Soc 86: 1646-1647, Mechoulam and Gaoni, 1967, Tetrahedron Lett 12: 1109-11 11). Δ⁹-TΗC has the following structure (Formula (I)):

I

[0006] Δ^y-THC interacts with two main receptor types, namely caπnabinoid subtype- 1 (CBi) and cannabinoid subtype-2 (CB₂) receptors (Devane et ai, 1988, Molecular Pharmacology 34:605-613; Munro et al., 1993, Nature 365:61-65; Howlett et ai, 2002, Pharmacol Rev 54.161-202).

[0007] Two spliced variants of the CB] receptor have also been identified, CB]_A and CBm (Shire et ai, 1995, J Biol Chem 270:3726-3731 ; Ryberg et al., 2005, FEBS Lett 579:259- 264). CBi receptors are located throughout the body and have high densities in regions of the brain, such as the hippocampus, striatum and basal ganglia (Herkenham et ai, 1990, Proc Natl Acad Sci USA 87: 1932-1936; Herkenham el ai, 1991 , Neurosci 1 1 :563-583).

[0008] By contrast, CB₂ receptors are located mainly in peripheral tissues and are associated with the immune system and are of less interest to neuropsychiatry research (Munro et ai, 1993, Nature 365:61-65; Lynn and Herkenham, 1994, J Pharmacol Exp Ther 268: 1612-1623; Griffin et ai , 1997; Eur J Pharmacol 339:53-61; Lynn el ai, 1994 J Pharmacol Exp Ther 268: 1612-1623; Gong et al., 2006, Brain Res 1071 : 10-23).

[0009] In recent years CBi receptors have been found and investigated in animal and human brain. They are among the most abundant G-protein coupled receptors in brain and likely have very important normal physiological functions. Moreover, abnormalities in CBi receptors expression and function have been linked to various neuropsychiatric conditions, including drug addiction and obesity (Van Laere, 2007, Eur J Nucl Med MoI Imaging 34: 1719-1726). As such, CBi receptors are promising targets of therapeutic drug development. An ability to image and measure brain CBi receptors non-invasively with radiation computed tomography would assist neuropsychiatric research and drug development. Using appropriate radiotracers with positron emission tomography (PET) or single-photon emission computed tomography (SPECT), it should be possible to image and quantify CBi receptors in human brain. [0010] In 1994, Sanofi-Syntlilabo introduced N-(piperin-l-yl)- l-(2,4-dichlorophenyl)-5-(4- chlorophenyl)-4-methyl-lH-pyrazole-3-carboxamide (SR141716A, rimonabant) as a high- affinity inverse agonist at CBi receptors (Rinaldi-Carmona et ai, 1994, FEBS Lett 350:240- 244). SR 141716A has the following structure (Formula (II)):

II

[0011] SR141716A gained approval for use in the European Union as a treatment for morbid obesity. The therapeutic use of SR 141716A may extend to addiction and neurodegenerative disorders. Consequently, there has been a considerable effort by pharmaceutical industry to develop novel CBi receptor inverse agonist platforms. Solvay AB succeeded with the development of (4.S)-3-(4-chlorophenyl)-N-methyl-N'-[(4- chlorophenyl)sulfonyl]-4-phenyl-4,5-dihydro-lH-pyrazole-l-carboxaiτύdine (SLV319; Lange et ai, WO2002/076949; Lange et ai , 2004, J Med Chem 47:627-643). SLV319 has the following structure (Formula (111)):

111

[0012] Brain CBi receptors may be involved in several neuropsychiatric disorders. Currently, there is a need for suitable ligands that are amenable to labeling with positron- and/or gamma-emitters for non-invasively imaging CBi receptors in vivo with PET or SPECT under control and diseased states. Previous attempts at radioligand development have focused on the modification of the 1 ,5-diarylpyrazole CBi receptor class of Formula (II) to allow for labeling with carbon- 1 1 (ti/2 = 20.4 min), fluorine- 18 (ti/2 = 109.7 min) or iodine- 124 (ti/₂ = 4.15 d). Some success has been achieved with this approach, namely through the development of [^{1 1}C]OMAR, also referred to as [^MC]JHU75528 (Horti el ai, 2006, JNucl Med 47: 1689- 1696; Fan et ai , 2006, J Label Compd Radiopharm 49: 1021 - 1036) and [' ^lC]JHU75575 (Fan et ai , 2006, J Label Compd Radiopharm 49: 1021 - 1036: Donohue et ai , 2008, Curr Radiopharm 1 :93-102). [^UC]JHU75528 and [¹¹C]OMAR have the following Formula (IV):

IV

[0013] [' 'C]JHU75575 has the following Formula (V):

[0014] Promising PET radioligands from other structural platforms have recently been reported, such as [^πC]PipISB (Donohue et al., 2008, J Label Compd Radiopharm 51 : 146- 152) having Formula (VI):

VI

₁ [-18 F]PipISB (Donohue et al, 200$, J Label Compd RadiopharmS 1 : 146- 152; Finnema et al., 2009, Synapse 63:22-30) having Formula (VII):

VII r [l^l8^βτF]MK-9470 (Burns et a!., 2007, Proc Natl Acad Sci USA 104:9800-9805; Liu et al., 2007, ./ Med Cham 50- 3427-3430) having Formula (VTII)

viπ

[¹¹C]CB-1 19 (Bums el a!., 2009, MoI Imaging Biol DOl: 10.1007/sl 1307-008-0194-8) having Formula (IX):

IX

[^{1 1}C]MePPEP (Yasuno et al, 2008, Neuropsychopharmacology 33:259-269; Donohue et al. 2008, J Med Chem 51 :5833-5842) having Formula (X):

X and

[^πC]SD5014 (Donohue et al., 2008, J Med Chem 51 :5608-5616) having Formula (XI):

XI

[0015] A 3,4-diarylpyrazoline class of CBi receptor ligands presents favorable physiological and pharmacological attributes for PET radioligand development. For example, SLV319 shows high selectivity and potency for CBi receptors with little or no substrate behavior for P-glycoprotein efflux pumps (Lange at ai, 2004, ./ Med Chum 47:627- 643). Nevertheless, this structural class has remained largely unexplored for PET radioligand development.

[0016J An effective PET or SPECT radioligand for brain CBi receptors would assist clinical research in several areas and also enhance drug discovery and development. The present invention provides novel CBi ligands and radiotracers for use in imaging CBi receptors. More specifically, the present invention provides synthesis, receptor screening, radioiodination and in vitro autoradiographic evaluation of novel PET and SPECT radioligands, also referred to herein as radiotracers.

BRIEF SUMMARY OF THE INVENTION

[0017] Imaging of cannabinoid subtype-1 (CBi) receptors in vivo is important for understanding their role in neuropsychiatric disorders and for drug development. Radioligands for imaging with PET or SPECT are required for this purpose.

[0018] The present invention relates to novel CBi ligands and radiotracers for use in imaging CBi receptors. Specifically, in one aspect, the present invention provides 3,4- diarylpyrazoline CBi ligands with high affinity and selectivity for CBi receptors. In one preferred embodiment, the present invention provides a compound according to Formula (XII):

XII wherein A is H, each of R¹, R² and R³ are independently aiyl or a 5-6 membered heteroaryl ring, at least one of which is substituted with 1-3 R⁵ groups, R⁴ is selected from the group consisting of H, Cj-galkyl and Ci.ghaloalkyl; each R⁵ is independently selected from the group consisting of Ci-salkyl, cyano, Ci-salkoxy, CHO, Ci-salkylcarbonyl, aminocarbonyl, halo, haloCi.«alkoxy, nitro, Ci.salkylthio, amino,

and Ci._salkoxycarbonylamino; wherein one atom selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, halogen and sulfur atom comprises or is replaced by a detectable amount of a radioisotope selected from the group consisting Of ²H, ³H, ^{1 1}C, ¹⁴C, ¹³N, ¹⁵O, ¹⁸F, ⁷⁵ Br, ⁷⁶Br, ⁷⁷Br₃ ¹²³I, ¹²⁴I, ¹²⁵I, and ¹³¹I. The invention also provides all stereoisomers or pharmaceutically acceptable salts thereof.

[0019] In one preferred embodiment, at least one of R, R¹ and R² of a compound according to Formula (XII) is heteroaryl, optionally substituted with 1-3 R⁵ groups. Each heteroaryl may be independently selected from the group consisting of pyridinyl, pyrazinyl and pyrimidinyl.

[0020] In another preferred embodiment, at least one of R, R¹ and R² of a compound according to Formula (XTT) is aryl, optionally substituted with 1 -3 R^s groups. Preferably, the aryl is phenyl. [0021] In yet another preferred embodiment. R⁴ of a compound according to Formula (XII) is Ci.8haloalkyl, preferably, C_n(H2n+i or D₂,₁₊i)F.

[0022] In yet another preferred embodiment, R⁴ of a compound according to Formula (XII) is R⁴ is Ci-galkyl, preferably, CH₃.

[0023] In another preferred embodiment, R⁴ of a compound according to Formula (XII) is H. [0024] In yet another preferred embodiment, at least one R⁵ of a compound according to Formula (XII) is selected from the group consisting of ²H, ³H₃ ¹¹CN, ¹¹CH₃, O¹¹CH₃, S¹¹CH₃, ^{1 1}CHO, ¹¹COCH₃, CO¹¹CH₃, ¹¹CONH₂, and ¹⁸F.

[0025] In another preferred embodiment, at least one R⁵ of a compound according to Formula (XII) is OC_n(H_2n+I or D_2n+OF or OC_n(H_2n+I or D_2n+1)¹⁸F and n is the integer 1 , 2 or 3. Preferably, the integer n = 1.

[0026] Also preferred are compounds according to Formula (XII) are wherein A is ²H or ^JH.

[0027] In yet another preferred embodiment a compound according to Formula (XII) is a compound having the Formula (XITT):

XIII wherein each of R^5A, R^5B and R^5C are as defined for R⁵ and the wavy line indicates the presence of either stereoisomer. Preferably, R^5A is cyano or halogen; R^5B is H; and R^5c is halogen. R^5A may be selected from the group consisting of CN, ¹¹CN, I, ¹²³I, ¹²⁴I, ¹²⁵I, and

[0028] In yet another preferred embodiment, the compound according to Formula (XIII) has the Formula (XIV):

xrv wherein R^5a is halo or cyano and the wavy line indicates the presence of either stereoisomer. A more preferred compound having Formula (XIV) is a compound wherein R^5a is ¹¹CN Preferred are the (-)-enantiomer and the (+) enantiomer of that compound.

[0029] One racemic ligand, compound ((±)-l2a; shown herein by the structure having Formula (XV), its eutomer compound ((-)-12a; shown herein by the structure having Formula

(XVI) and its distomer compound ((+)-12a; shown herein by the structure having Formula

(XVII) were successfully labeled with carbon-1 1 in high specific radioactivity. Compound [^πC](-)-12a (shown herein by the structure having Formula (XVlil); also shown as Formula (XIV) and Formula (XI) ((-)-["C]SD5014)) was found to be a suitable PET radioligand for imaging brain CBi receptors in mammals, in particular, in humans.

[0030| Further, the present invention provides new ligands from a 3.4 diarylpyrazoline platform such as (-)-3-(4-chlorophenyl)-N'-[(4-cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro- lH-pyrazole-1-carboxamidine) which has high affinity and selectivity for binding to CBi receptors. (-)-3-(4-chlorophenyl)-N'-[(4-cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro- lH- pyrazole- 1 -carboxamidine) can be labeled with carbon-1 1 (ti/₂ = 20.4 min) using

[' 'C]cyanide ion as labeling agent and be used as a PET radioligand. After injection of [¹¹C](-)-3-(4-chlorophenyl)-N'-[(4-cyanophenyl)sulfonyl]-4-phenyl-4₎5-dihydro-lH- pyrazole-1 -carboxamidine high uptake and retention of radioactivity across brain according to the rank order of CBi receptor densities is achieved demonstrating its usefulness for in vivo imaging CB] receptor function in mammals.

[0031| In another preferred embodiment, a compound binding to a CBj receptor is a 4- cyano-l,5-diphenyl-lH-pyrazole-3-carboxamide having the Formula (XIX):

XIX wherein R¹ is halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci-salkoxy, haloCi. galkoxy, Ci.₈alkylthio, haloC|.₈alkylthio, nitro, CHO, or Ci.₈alkylsulfoxy, amino, C|. 8alkylamino and Ci-salkoxycarbonylamino; wherein R² is halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci-salkoxy, haloCuβalkoxy, Ci-salkylthio, haloCi-salkylthio, CHO, amino, Ci-galkylamino, Ci-salkoxycarbonlamino and Q-galkylsulfoxy substituted at 2 and/or 4 positions; wherein R³ is piperidinyl, morpholinyl, pyrrolidinyl, and azepanyl, d-galkyl and C5-scycloalkyl; and wherein one atom selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, halogen and sulfur atom comprises or is replaced by a detectable amount of a radioisotope selected from the group consisting of ²H, ³H, ¹¹C, ¹⁴C, ¹³N, ¹⁵O, ¹⁸F, ⁷⁵ Br, ⁷⁶Br, ⁷⁷Br, ¹²³I₁ ¹²⁴1, ¹²⁵I, and ¹³¹I.

[0032] In another preferred embodiment, a compound having Formula (XIX) is a compound wherein R¹ is halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci-salkoxy, haloCi-galkoxy, Ci.galkylthio, haloCi-galkylthio, nitro, CHO, or Cj.salkylsulfoxy, amino, Ci- galkylamino and Ci-salkoxycarbonylamino; wherein R² is iodo or fluoro, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci-galkoxy, haloCi-salkoxy,

haloCi-salkylthio, CHO, amino, Ci.galkylamino, Ci.salkoxycarbonlamino and Ci.galkylsulfo\y substituted at 2 and/or 4 positions; wherein R³ is piperidinyl, morpholinyl, pyrrolidinyl, and azepanyl, Ci. galkyl and Cs-gcycloalkyl; and wherein one atom selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, halogen and sulfur atom comprises or is replaced by a detectable amount of a radioisotope selected from the group consisting of ²H, ³H, ¹¹C. ¹⁴C, '-¹N, ¹⁵O, ¹⁸F, ⁷⁵ Br, ⁷⁶Br, ⁷⁷Br, ¹²¹T, ¹²⁴T, ¹²⁵T, and ¹³¹I.

[0033] A preferred compound having Formula (XIX) is a compound wherein either R¹ is halogen or R² is halogen. Preferably, the halogen comprises a label. Preferably, R² is iodo or fluoro and comprises a label. A preferred compound of Formula (XlX) is wherein R¹ is a labeled halogen. Another preferred compound of Formula (XIX) is a compound wherein R² is a labeled halogen. Another preferred compound of Formula (XIX) is a compound wherein R² is a labeled iodo or fluoro.

[0034] Another preferred compound binding to a CBi receptor having Formula (XX) is provided:

XX wherein R² is selected from halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci- βalkoxy, haloCi-βalkoxy, Ci-salkylthio, haloCi-salkylthio, nitro, CHO, amino, Ci-βalkylamino, Ci-galkoxycarbonylamino and Q-salkylsulfoxy substituted at 2 and/or 4 positions. Preferably, R² is a halogen. More preferred is a compound having Formula (XX), wherein the halogen comprises a label. The label may be any label as described herein, preferably, an iodine label, such as ¹²³1, ¹²⁴1, ¹²⁵I, or ¹³¹I.

[0035] Another preferred compound binding to a CBi receptor having Formula (XX) is a compound wherein R² is selected from iodo or fluoro, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci_₈alkoxy, haloCi-galkoxy, C|.galkylthio, haloCi.galkylthio, nitro, CHO, amino, Ci-βalkylamino, Ci-βalkoxycarbonylamino and Ci-salkylsulfoxy substituted at 2 and/or 4 positions. Preferably, R² is a iodo, fluoro. More preferred is a compound having Formula (XX), wherein the iodo or fluoro comprises a label. The label may be any label as described herein, preferably, an iodine label, such as ¹²³1, ¹²⁴I, ¹²⁵I, or ¹³¹I.

[0036] A preferred compound according to Formula (XX) is a compound having Formula (XXI):

XXI

Another preferred compound of Formula (XXI) is a compound wherein the iodine comprises a label. Preferably, the label is ¹²³1, ¹²⁴1, ¹²⁵I, or ¹³¹I.

[0037] In a preferred embodiment, compounds of the present invention are provided in isolated and purified form.

[0038] The present invention also provides pharmaceutical compositions comprising a compound of the present invention and a pharmaceutically acceptable carrier or excipient.

[0039] In another aspect, the present invention provides a kit or system comprising a compound of the present invention and a preparation of a cannabinoid subtype- 1 receptor.

[0040] In yet another aspect, the present invention provides methods of producing a compound of the present invention. A preferred embodiment comprises a method for producing a compound according to Formula (XII). In a preferred embodiment, this method comprises the steps of: (a) reacting a compound having the Formula (XXII):

XXII

with a compound having the Formula (XXIII):

XXIII to form a product and (b) reacting the product from step (a) with a compound having the formula NH² -R⁴ to provide a compound according to Formula (XII), wherein R⁶ is C\- Cgalkyl and one carbon or halogen atom comprises a detectable amount of a radioisotope.

[0041] Another preferred embodiment comprises a method for producing a compound according to Formula (XIII). In a preferred embodiment, this method comprises the steps of: (a) reacting a compound having the Formula (XXIV):

xxrv with a compound having the Formula (XXV):

XXV to form a product; and (b) reacting the product from step (a) with a compound having the formula NH² -R⁴ to provide a compound according to Formula (XIII), wherein R⁶ is C i - Cgalkyl and one carbon or halogen atom comprises a detectable amount of a radioisotope. Preferably, R^5A is cyano or halogen; R⁵ⁿ is H; and R^5c is halogen. More preferably, R^5A is

¹¹CN.

[0042] In another aspect, the present invention provides methods for measuring an interaction of a radiolabeled compound of the present invention with a cannabinoid subtype- 1 (CBi) receptor. In a preferred embodiment, this method comprises the steps of (a) contacting a cannabinoid subtype-1 (CBi) receptor with a radiolabeled compound of the present invention to produce a cannabinoid subtype- 1 (CBi) receptor-radiolabeled compound complex and (b) measuring an interaction of the radiolabeled compound with the cannabinoid subtype- 1 (CB₁) receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the cannabinoid subtype-1 (CBi) receptor. The measurable signal may be recorded, preferably in an electronic or optical database. A preferred radiolabeled compound is a compound selected from the group consisting of a radiolabeled compound of Formula (XII), a radiolabeled having the Formula (XIII), a radiolabeled compound of Formula (XV), a radiolabeled compound of Formula (XVI), a radiolabeled compound of Formula (XVII), a radiolabeled having the Formula (XIII), a radiolabeled compound of Formula (XIX), a radiolabeled compound of Formula (XX), a radiolabeled compound of Formula (XXI), and a radiolabeled compound having the Formula (XXVlIl).

[0043] In yet another aspect, the present invention provides methods for measuring an interaction of a test compound with a cannabinoid subtype-1 (CBi) receptor. In a preferred embodiment, this method comprises the steps of (a) contacting a cannabinoid subtype-1 (CBi) receptor preparation with a radiolabeled compound of the present invention to produce a cannabinoid subtype-1 (CBi) receptor-radiolabeled compound complex, (b) measuring an interaction of the radiolabeled compound with the cannabinoid subtype-1 (CBi) receptor thereby obtaining a first measurable signal, (c) contacting the cannabinoid subtype-1 (CBi) receptor-radiolabeled compound complex with a test compound under conditions whereby the interaction of the radiolabeled compound with the cannabinoid subtype-1 (CBi) receptor is prevented by the test compound, and (d) detecting a second measurable signal. A higher second measurable signal when compared to the first measurable signal is indicative of the test compound interacting with the cannabinoid subtype-1 (CBj) receptor. Preferred cannabinoid subtype-1 (CBi) receptor preparation are a cannabinoid subtype-1 (CBi) receptor membrane preparation or a cannabinoid subtype-1 (CBi) receptor whole cell preparation. In a preferred embodiment of the method, the cannabinoid subtype-1 (CBi) receptor is bound to a solid support. A preferred radiolabeled compound is a compound selected from the group consisting of a radiolabeled compound of Formula (XII), a radiolabeled having the Formula (XIII), a radiolabeled compound of Formula (XV), a radiolabeled compound of Formula (XVI), a radiolabeled compound of Formula (XVII), a radiolabeled having the Formula (XIII), a radiolabeled compound of Formula (XIX), a radiolabeled compound of Formula (XX), a radiolabeled compound of Formula (XXI), and a radiolabeled compound having the Formula (XXVIII). [0044] In another preferred embodiment, the method for measuring an interaction of a test compound with a cannabinoid subtype-1 (CBi) receptor comprises the steps of (a) contacting a cannabinoid subtype-1 (CBi) receptor preparation with a mixture comprising (i) a radiolabeled compound of the present invention and (ii) a test compound to produce a cannabinoid subtype-1 (CBi) receptor-radiolabeled compound complex and a cannabinoid subtype-1 (CB ι) receptor-test compound complex, (b) measuring the interaction of the radiolabeled compound with the cannabinoid subtype-1 (CBO receptor thereby obtaining a first measurable signal, and (c) comparing the first measurable signal to a second measurable signal obtained by contacting the cannabinoid subtype-1 (CBi) receptor with the radiolabeled compound in the absence of the test compound. A lower first measurable signal when compared to the second measurable signal is indicative of the test compound interacting with the cannabinoid subtype-1 (CBi) receptor. Preferred cannabinoid subtype- 1 (CBi) receptor preparation are a cannabinoid subtype-1 (CBi) receptor membrane preparation or a cannabinoid subtype-1 (CBj) receptor whole cell preparation. In a preferred embodiment of the method, the cannabinoid subtype-1 (CBi) receptor is bound to a solid support. A preferred radiolabeled compound is a compound selected from the group consisting of a radiolabeled compound of Formula (XII), a radiolabeled having the Formula (XIII), a radiolabeled compound of Formula (XV), a radiolabeled compound of Formula (XVI), a radiolabeled compound of Formula (XVIl), a radiolabeled having the Formula (XlIl), a radiolabeled compound of Formula (XIX), a radiolabeled compound of Formula (XX), a radiolabeled compound of Formula (XXI), and a radiolabeled compound having the Formula (XXVIII).

[0045) In yet another aspect of the present invention, a method of assessing cannabinoid subtype-1 (CBi) receptor function in a subject having a neurological condition is provided. In a preferred embodiment, this method comprises the steps of (a) administering a radiolabeled compound of the present invention to the subject and (b) measuring transport of the radiolabeled compound across the blood brain barrier. Neurological disorders amenable for assessing cannabinoid subtype-1 (CBi) receptor function include, but are not limited to, obesity, alcohol or tobacco dependency and memory loss. A preferred radiolabeled compound is a compound selected from the group consisting of a radiolabeled compound of Fonnula (XII), a radiolabeled having the Formula (XIII), a radiolabeled compound of Formula (XV), a radiolabeled compound of Formula (XVI), a radiolabeled compound of Formula (XVII), a radiolabeled having the Formula (XIII), a radiolabeled compound of Formula (XIX), a radiolabeled compound of Formula (XX), a radiolabeled compound of Formula (XXI), and a radiolabeled compound having the Formula (XXVIII).

[0046] Further, the present invention provides methods for measuring the density of a CBi receptor in a subject having a disease or being suspected of having a disease. In a preferred embodiment, this method comprises the steps of (a) administering to the subject a radiolabeled compound of the present invention and (b) measuring the density of the CBi receptor. The disease is selected from the group consisting of depression, mood disorder, anxiety, schizophrenia, drug addiction, alcohol disorder, obesity, anorexia, memory dysfunction, Gilles de Ia Tourette Syndrome, Parkinson's disease, Hungtington's disease, Alzheimer's disease, multiple sclerosis, acute pain, chronic pain, neuropathic pain, nausea, and emesis. A preferred radiolabeled compound is a compound selected from the group consisting of a radiolabeled compound of Formula (XII), a radiolabeled having the Formula (XITT), a radiolabeled compound of Formula (XV), a radiolabeled compound of Formula (XVI), a radiolabeled compound of Formula (XVII), a radiolabeled having the Foπnula (XIII), a radiolabeled compound of Formula (XIX), a radiolabeled compound of Formula (XX), a radiolabeled compound of Formula (XXI), and a radiolabeled compound having the Formula (XXVIII).

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 depicts regional time-radioactivity curves after i.v. injection of compound [' 'C](±)-12a (shown herein by the structure having Formula (XXVI)) in cynomolgus monkey under baseline condition (Panel A), with 6 (1 mg/kg, i.v.) administered as a displacing agent at 25 min (Panel B), or pretreatment condition with 6 ( 1 mg/kg, i.v.) (Panel C). Key: *, striatum; Δ, cerebellum; O, frontal cortex; D, lateral temporal cortex; +, thalamus; o, medial temporal cortex; A , pons. Details are described in Example 10. [0048] Figure 2 depicts regional time-radioactivity curves after i.v. injection of compound [^UC](-)-12a (100 MBq; shown herein by the structure having Formula (XVIII)) (Panel A) or compound [^{l !}C](+)-12a (98 MBq; shown herein by the structure having Formula (XXVlI) (Panel B) in cynomolgus monkey. Key: *, striatum; Δ, cerebellum; O, frontal cortex; α, lateral temporal cortex; +, thalamus; o, medial temporal cortex; A , pons. Details are described in Example 1 1. [0049J Figure 3 depicts horizontal PET images, obtained at the level of the striatum from data acquired between 9 and 93 min after injection of compound [^πC](-)-12a (100 MBq; Formula (XVlIl); Panel A) or compound ["C](+)-12a (98 MBq, Formula (XXVIl); Panel B). Details are described in Example 12. [0050] Figure 4 depicts radio-HPLC of plasma at 15 min after injection of compound [^πC](-)-12a (Formula (XVIlI) in cynomolgus monkey (Panel A), and time course of radioactivity in plasma represented by parent radioligand and radiometabolite fractions (Panel B). Key: D, compound [¹¹C] (-)-12a; Δ, metabolite a; V, metabolite b; o, metabolite c. Details are described in Example 13. [005 IJ Figure 5 shows a general synthesis of preferred compounds of the present invention.

[0052] Figure 6 shows a general synthesis of preferred compounds of the present invention having Formula (XIX) and Formula (XX).

[0053] Figure 7 shows whole-hemisphere horizontal cryosections of human-brain post mortem incubated with compound [¹²⁵I]13. Abbreviations: Ca, caudate nucleus, Ce, cerebellum: Th, thalamus; WM, white matter. Details are described in Example 14.

DETAILED DESCRIPTION OF THE INVENTION

I. DEFINITIONS

[0054] Unless defined otherwise, all technical and scientific terms used herein have the meaning commonly understood by a person skilled in the art to which this invention belongs. The following references provide one of skill with a general definition of many of the terms used in this invention- Singleton et al , Dictionary oj Microbiology and Molecular Biology (2nd ed. 1994); The Cambridge Dictionary of Science and Technology (Walker ed., 1988); The Glossary of Genetics, 5th Ed., Rieger el al. (eds.), Springer Verlag (1991); and Hale & Marham, The Harper Collins Dictionary of Biology (1991). As used herein, the following terms have the meanings ascribed to them unless specified otherwise.

[0055] It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a compound" includes mixtures of compounds, reference to "a pharmaceutical carrier" includes mixtures of two or more such carriers, and the like. [0056] The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description or the claims. As used throughout this application, the word "may" is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words "include", "including", and "includes" mean including, but not limited to.

[0057] Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context The use of any and all examples, or exemplary language (e. g. "such as") provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention. [0058] "Alkoxy" refers to -OR^ wherein R^ is alkyl as defined herein. Representative examples of alkoxy groups include methoxy, ethoxy, /-butoxy, trifluoromethoxy, and the like.

[0059] "Alkoxycarbonyl" refers to -C(=O)OR^d wherein R^d is alkyl. Representative alkoxycarbonyl groups include, for example, those shown below. These alkoxycarbonyl groups can be further substituted as will be apparent to those having skill in the organic and medicinal chemistry arts in conjunction with the disclosure herein.

[0060] "Alkoxycarbonylamino " refers to to -NR^aC(O)0R^d wherein R^d is alkyl.

[0061] As used herein, the term "alkyl" refers to a straight or branched chain hydrocarbon radical, and can include di- and multivalent radicals, having the number of carbon atoms designated (i.e. Ci-Cβ means one to six carbons). Examples of saturated hydrocarbon radicals include groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isobutyl, sec-butyl, homologs and isomers of, for example, n-pentyl, n-hexyl, n-heptyl, n-octyl, and the like.

[0062] "Alkylcarbonylaraino" refers to -NR^aC(=O)R^c wherein R^c is alkyl. Representative alkylcarbonylamino groups include, for example, -NHCf=O)CH₃, -NHC(K))CH₂CH₃, -NHC(=O)CH₂NH(CH₃), -NHC(O)CH₂N(CHj)₂, or -NHC(=O)(CH₂)₃OH. [0063] "Alkylsulfanyl", "alkylthio", or "thioalkoxy" refers to the group S-R^d. where R^d is alkyl. [0064] "Alkylcarbonyl" refers to the group -C(=O)R^C where R^c is alkyl.

[0065] "Amino" refers to a monovalent radical -NR^aR^b or divalent radical -NR^a-. The term "alkylamino" refers to the group -NR^aR^b where R^a is alkyl and R^b is H or alkyl. The term "arylamino" refers to the group -NR^aR^b where R^a is aryl and R^b is hydrogen, alkyl, aryl, or heterocyclyl. The term "(alkyl)(aryl)amino" refers to the group -NR^aR^b where R^a is alkyl and R^b is aryl. Additionally, for dialkylamino groups, the alkyl portions can be the same or different and can also be combined to form a 3-7 membered ring with the nitrogen atom to which each is attached. Accordingly, a group represented as -NR"R^b is meant to include piperidinyl, pyrrolidinyl, morpholinyl, azetidinyl, azepane, and the like. [0066] "Aminocarbonyl" or "aminoacyl" refers to the amide -C(=O)-NR^aR^b. The term "alkylaminocarbonyl" refers herein to the group -C(=O)-NR^aR^b where R^a is alkyl and R^b is H or alkyl. The term "arylaminocarbonyl" refers herein to the group -C(=O)-NR^aR^b where R^a or R^b is aryl. Representative aminocarbonyl groups include, for example, those shown below. These aminocarbonyl group can be further substituted as will be apparent to those having skill in the organic and medicinal chemistry arts in conjunction with the disclosure herein.

[0067] As used herein, the term "aryl" refers to an aromatic hydrocarbon having 5-12 carbon ring members, which can be a single ring or multiple rings (up to three rings) which are fused together or linked covalently. Non-limiting examples of aryl groups include phenyl, 1-naphthyl, 2-naphthyl, 4-biphenyl, and benzyl. Other aryl groups are also useful in the present invention, including heteroaryl groups in which the heteroatom may be nitrogen.

[0068] In each of the above embodiments designating a number of atoms e.g. "C i_g" is meant to include all possible embodiments that have one fewer atom. Non-limiting examples include C] .η, C2-8. C2.7, C3.8, C3.7 and the like. [0069] "Cyano" refers to -CN.

[0070] "Hydroxy" or "hydroxyl" refers to the group -OH.

[0071] "Halo" or "halogen" by themselves or as part of another substituent, mean, unless otherwise stated, a fluorine, chlorine, bromine, or iodine atom. Additionally, terms such as "haloalkyl", are meant to include alkyl in which one or more hydrogen is substituted with halogen atoms which can be the same or different, in a number ranging from one up to the maximum number of halogens permitted e.g. for alkyl, (2m'+l), where m' is the total number of carbon atoms in the alkyl group. For example, the term "haloCi.galkyl" is meant to include trifluoromethyl, 2,2,2-trifluoroethyl, 4-chlorobutyl, 3-bromopropyl, and the like. The term "perhaloalkyl" means, unless otherwise stated, alkyl substituted with (2m'+l) halogen atoms, where m' is the total number of carbon atoms in the alkyl group. For example, the term "perhaloCi_8^alkyl'\ is meant to include trifluoromethyl, pentachloroethyl, l,l, l-trifluoro-2-bromo-2-chloroethyl, and the like. Additionally, term "haloalkoxy" refers to an alkoxy radical substituted with one or more halogen atoms.

[0072J "Heteroaryl" refers to a cyclic or polycyclic aromatic radical that contain from one to five heteroatoms selected from N, O, and S, wherein the nitrogen and sulfur atoms are optionally oxidized, and the nitrogen atom(s) are optionally quaternized. A heteroaryl group can be attached to the remainder of the molecule through a heteroatom or through a carbon atom and can contain 5 to 10 carbon atoms. Non-limiting examples of heteroaryl groups include 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 1-pyrazolyl, 3-pyrazolyl, 2-imidazolyl, 4- iinidazolyl, pyrazinyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, 5- isoxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 2- pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrimidyl and 4-pyrimidyl. If not specifically stated, substituents for each of the above noted aryl and heteroaryl ring systems are selected from the group of acceptable substituents described herein. "Substituted heteroaryl" refers to a unsubstituted heteroaryl group as defined above in which one or more of the ring members is bonded to a non-hydrogen atom such as described above with respect to substituted alkyl groups and substituted aryl groups. Representative substituents include straight and branched chain alkyl groups-CH₃, -C2^H5 . -CH2OH, -OH, -OCH3, -OC2H5, -OCF₃, - 0C(=0)CH_3> -OC(=O)NH₂, -OC(=O)N(CH₃)_2; .CN, -NO₂ , -C(=O)CH_3> -CO₂H, - CO₂CH₃, -CONH₂, -NH₂ -N(CH₃)₂, -NHSO₂CH₃, -NHCOCH₃, -NHC(=O)OCH₃, - NHSO-₂CH₃, -SO₂CH₃, -SO₂NH₂ and halo.

[0073] Each of the terms herein (e.g., "alkyl," "heteroalkyl," "aryl" and "heteroaryl") is meant to include both "unsubstituted" and optionally "substituted" forms of the indicated radical, unless otherwise indicated. Typically each radical is substituted with O, 1 , 2 3 4 or 5 substituents, unless otherwise indicated. Examples of substituents for each type of radical are provided below.

[0074] Compounds that have the same molecular formula but differ in the nature or sequence of bonding of their atoms or the arrangement of their atoms in space are termed "isomers". Isomers that differ in the arrangement of their atoms in space are termed "stereoisomers." "Stereoisomer" and "stereoisomers" refer to compounds that exist in different stereoisomeric forms if they possess one or more asymmetric centers or a double bond with asymmetric substitution and, therefore, can be produced as individual stereoisomers or as mixtures. Stereoisomers include enantiomers and diastereomers.

Stereoisomers that are not mirror images of one another are termed "diastereomers" and those that are non-superimposable mirror images of each other are termed "enantiomers". When a compound has an asymmetric center, for example, it is bonded to four different groups, a pair of enantiomers is possible. An enantiomer can be characterized by the absolute configuration of its asymmetric center and is described by the R- and S-sequencing rules of Cahn and Prelog, or by the manner in which the molecule rotates the plane of polarized light and designated as dextrorotatory or levorotatory (i.e., as (+) or (-)-isomers). A chiral compound can exist as either individual enantiomer or as a mixture thereof. A mixture containing equal proportions of the enantiomers is called a "racemic mixture". Unless otherwise indicated, the description is intended to include individual stereoisomers as well as mixtures. The methods for the determination of stereochemistry and the separation of stereoisomers are well-known in the art (see discussion in Chapter 4 of MARCH'S ADVANCED ORGANIC CHEMISTRY, 5th edition M. B. Smith & J. March, John Wiley and Sons, New York, 2001 or STEREOCHEMISTRY OF ORGANIC COMPOUNDS, E.L. Eliel & S.H. Wilen,, J. Wiley & Co, New York, 1994) differ in the chirality of one or more stereocenters.

[0075] "Nitro" refers to -NO₂.

[0076] "Substituted" refers to a group as defined herein in which one or more bonds to a carbon(s) or hydrogen(s) are replaced by a bond to non-hydrogen and non-carbon atom "substituents" such as, but not limited to, a halogen atom such as F, Cl, Br, and I; an oxygen atom in groups such as hydroxyl groups, alkoxy groups, aryloxy, and acyloxy groups; a sulfur atom in groups such as thiol groups, alkyl and aryl sulfide groups, sulfone groups, sulfonyl groups, and sulfoxide groups; a nitrogen atom in groups such as amino, alkylamines, dialkylamines, arylamines, alkylarylamines, diarylamines, alkoxyamino, hydroxyamino, acylamino, sulfonylamino, N-oxides, imides, and enamines; and other heteroatoms in various other groups. "Substituents" also include groups in which one or more bonds to a carbon(s) or hydrogen(s) atom is replaced by a higher-order bond (e.g., a double- or triple- bond) to a heteroatom such as oxygen in oxo, acyl, amido, alkoxycarbonyl, aminocarbonyl, carboxyl, and ester groups; nitrogen in groups such as imines, oximes, hydrazones, and nitriles. "Substitυents" further include groups in which one or more bonds to a carbon(s) or hydrogen(s) atoms is replaced by a bond to a cycloalkyl, heterocyclyl, aryl, and heteroaryl groups. Representative "substituents" include, among others, groups in which one or more bonds to a carbon or hydrogen atom is/are replaced by one or more bonds to fluoro, chloro, or bromo group. Another representative "substituent" is the trifluoromethyl group and other groups that contain the trifluoromethyl group. Other representative "substituents" include those in which one or more bonds to a carbon or hydrogen atom is replaced by a bond to an oxygen atom such that the substituted alkyl group contains a hydroxyl, alkoxy, or aryloxy group. Other representative "substituents" include alkyl groups that have an amine, or a substituted or unsubstituted alkylamine, dialkylamine, arylamine, (alkyl)(aryl)amine, diarylamine, heterocyclylamine, diheterocyclylamine, (alkyl)(heterocyclyl)amine, or (aryl)(heterocyclyl)amine group. Still other representative "substituents" include those in which one or more bonds to a carbon(s) or hydrogen(s) atoms is replaced by a bond to an alkyl, cycloalkyl, aryl, heteroaryl, or heterocyclyl group. [0077] The herein-defined groups may include prefixes and/or suffixes that are commonly used in the art to create additional well-recognized substituent groups. As examples,

"alkylamino" refers to a group of the formula -NR^aR.b. Unless stated otherwise, for the following groups containing R^a, R^, R^c, Rd and R^e: R^a, and R^ are each independently selected from H, alkyl, alkoxy, thioalkoxy, cycloalkyl, aryl, heteroaryl, or heterocyclyl or are optionally joined together with the atom(s) to which they are attached to foπn a cyclic group. When R^a and R^ are attached to the same nitrogen atom, they can be combined with the nitrogen atom to form a 5-, 6- or 7-membered ring. For example, -NR^aRb is meant to include 1 -pyrrolidinyl and 4-morpholinyl.

[0078] R^c, R^, R^ and R^1* are each independently selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl, heterocyclyl or alkylenearyl as defined herein.

[0079] Typically, a particular radical will have 0, 1 , 2 or 3 substituents, with those groups having two or fewer substituents being preferred in the present invention. More preferably, a radical will be unsubstituted or monosubstituted. Most preferably, a radical will be unsubstituted. [0080] "Substituents" for the alkyl and heteroalkyl radicals (as well as those groups referred to as alkylene, alkenyl, heteroalkylene, heteroalkenyl, alkynyl, cycloalkyl, heterocyclyl) can be a variety of groups selected from: -OR^a, =0, =NR^a, =N-OR^a, -NR^aR^b, -SR^a _; halogen, -SiRaRbRC, -OC(O)Ra -C(O)Ra, -CO₂R^a, -CONRaRb, -OC(O)NRaRb, -NR^bC(O)R^a, -NRa-C(O)NRbRC, -NRa-SO₂NRbRC, -NRbCO₂Ra, -NH-C(NH₂)=NH, -NR^aC(NH₂)=NH,

-NH-C(NH₂)=NR^a, -S(O)R^a, -SO₂R^a, -SO₂NR^aRb, -NRbSO₂R, -CN and -NO₂, in a number ranging from zero to three, with those groups having zero, one or two substituents being particularly preferred.

[0081] In some embodiments, "substituents" for the alkyl and heteroalkyl radicals are selected from: -0R^a, =0, - NR^aRb, -SR^a, halogen, -SiR^aRbRC, -OC(O)Ra, -C(O)R^a, -CO 2Ra, -CONR^aRb, -OC(O)NRaRb₅ -NRbc(0)R^a, -NR^bC0₂R^a, -NRa-SO₂NRbRC, -S(O)R^a, -SO₂R^a, -SO₂NR^aRb, -NR^CSO₂R, -CN and -NO₂, where R^a and R^b are as defined above. In some embodiments, substituents are selected from: -0R^a, =0, - NR^aRb, halogen, -OC(O)R^a, -CO₂R^a, -CONRaRb₁ -OC(O)NR^aRb, -NRbC(O)R^a, -NRbCO₂R^a, -NR^a-SO₂NRbRC, -SO₂Ra, -SO₂NR^aRb, -NR¹¹SO₂R, -CN and -NO₂.

[0082] Examples of substituted alkyl are: -(CH₂)3NH₂, -(CH₂)3NH(CH₃), -(CH₂)3NH(CH₃)₂, -CH₂Q=CH₂)CH₂NH₂₅ -CH₂C(=O)CH₂NH_2j -CH₂S(O)₂CH₃ - CH₂ OCH₂NH₂₅ -CO₂H Examples of substituents of substituted alkyl are: CH₂OH, -OH, -OCH3, -OC₂H₅, -OCF3, -OC(O)CH₃ OC(O)NH₂, -OCC=O)N (CH₃ )₂₎ -CN, -NO₂, - C(O)CH₃, -CO₂H, -CO₂CH₃, -CONH₂, -NH₂ ,-N(CH₃)₂, -NHSO₂CH₃, -NHCOCH₃, -NHC(O)OCH₃, -NHSO-₂CH₃, -SO₂CH₃, -SO₂NH₂, and halo. [0083] Similarly, "substituents" for the aryl and heteroaryl groups are varied and are selected from, -halogen, -0R^a, -0C(0)R^a, -NRaRb, __SRa, __Ra_; _CN, __No₂, -CO₂R^a, -CONR^aRb, -C(O)R^a, -OC(O)NR^aRb, -NRbC(O)R^a, -NRbC(O)₂R^a, -NRa-C(O)NRbRC, -NH-C(NH₂)=NH, -NR^aC(NH₂)=NH, -NH-C(NH₂)=NRa , -S(O)R^a, -S(O)₂R^a,

-S(O)₂NR^aRb, -Nj, -CH(Ph)₂, perfJuoroCi.salkoxy, and perfluoroCi-galkyl, in a number ranging from zero to the total number of open valences on the aromatic ring system; and where R^a, Rb and R^c are independently selected from hydrogen,

and heteroalkyl, unsubstituted aryl and heteroaryl, (unsubstituted aryl)-Ci.₈alkyl, and (unsubstituted aryl)oxy-Ci-8alkyl. [0084] Two or three of the "substituents" on adjacent atoms of the aryl or heteroaryl ring may optionally be replaced with a substituent of the formula -T-C(O)-(CH₂)q-U-, wherein T and U are independently -NH-, -O-, -CH2- or a single bond, and q is 0, 1 or 2. Alternatively, two of the substituents on adjacent atoms of the aryl or heteroaryl ring may optionally be replaced with a substituent of the formula -A-(CHj)T-B-, wherein A and B are independently -CH₂-, -O-, -NH-, -S-, -S(O)-, -S(O)₂-, -S(O)₂NRa- _{or a s}i_ngi_e bond, and r is 1, 2 or 3. One of the single bonds of the new ring so formed may optionally be replaced with a double bond. Alternatively, two of the substituents on adjacent atoms of the aryl or heteroaryl ring may optionally be replaced with a substituent of the formula -(CH₂)_S-X-(CH₂)_I- -, where s and t are independently integers of from 0 to 3, and X is -O-, -NR^a", -S- , -S(O)-, -S(O)₂-, or

-S(O)₂NR^a-. The substituent R^a in -NR^a" and -S(O)₂NR^a" is selected from hydrogen or unsubstituted

Otherwise, R' is as defined above.

[0085] Unless indicated otherwise, the nomenclature of substituents that are not explicitly defined herein are arrived at by naming the terminal portion of the functionality followed by the adjacent functionality toward the point of attachment. For example, the substituent "arylalkyloxycarbonyl" refers to the group (aryl)-(alkyl)-O-C(O)-.

[0086] As used herein, the term "agonist" refers to a compound which will elicit a response similar to a natural ligand, especially in terms of cell signaling and responses.

[0087] As used herein, the term "antagonist" refers to a compound which will bind to a receptor, thereby blocking the action of its ligand or other agonist, but will not elicit a response or cause and further changes in a target cell type.

[0088] As used herein, the term "biological sample" refers to a sample of biological tissue or fluid that contains nucleic acids or polypeptides, e.g., of a breast cancer protein, polynucleotide or transcript. Such samples are typically from humans, but include tissues isolated from non-human primates (e.g., monkeys) or rodents (e.g., mice, and rats).

Numerous types of biological samples can be used in the present invention, including, but not limited to, sections of tissues such as biopsy and autopsy samples, frozen sections taken for histologic purposes, blood, plasma, serum, sputum, stool, tears, mucus, hair, skin, etc. Biological samples also include explants and primary and/or transformed cell cultures derived from patient tissues. A "biological sample" also refers to a cell or population of cells or a quantity of tissue or fluid from an animal. Most often, the sample has been removed from an animal, but the term "biological sample" can also refer to cells or tissue analyzed in vivo, i.e., without removal from the animal.

[0089] "Correlating an amount" means comparing an amount of a substance, molecule or marker (such as radiotracer) that has been determined in one sample to an amount of the same substance, molecule or marker determined in another sample. The amount of the same substance, molecule or marker determined in another sample may be specific for a given cancer or disorder.

[0090] As used herein, the phrase "measuring the density of a protein target" refers to estimation of absolute or relative concentrations of target protein (e.g., CBi receptor) in volumes or regions of interest (such as regional brain tissues).

[0091 J Synonyms of the term "determining an amount" are contemplated within the scope of the present invention and include, but are not limited to, detecting, measuring, testing or determining, the presence, absence, amount or concentration of a molecule, such as a radiotracer or a radiometabolite of a radiotracer. [0092J By "determining a functional effect" is meant assaying for a compound that increases or decreases a parameter that is indirectly or directly under the influence of that compound (e.g., a radiotracer), e.g., functional, enzymatic, physical and chemical effects. Such functional effects can be measured by any means known to those skilled in the art, e.g., changes in CBi imaging, PET scanning, SPECT analysis, spectroscopic characteristics (e.g., fluorescence, absorbance, refractive index), hydrodynamic (e.g., shape), chromatographic, or solubility properties for the protein, measuring inducible markers or transcriptional activation of a CBi; measuring binding activity, e.g., binding of a radiotracer to a CBi, measuring cellular proliferation, measuring apoptosis, or the like. The functional effects can be evaluated by many means known to those skilled in the art, e.g., microscopy for quantitative or qualitative measures of alterations in morphological features, measurement of changes in CB) RNA or protein levels. "Functional effects" include in vitro, in vivo, and ex vivo activities.

[0093] As used herein, the term "distomer" refers to the less potent enantiomer of a pair of enantiomers for binding to or acting upon a target protein (e.g., CBi receptor). [0094] As used herein, the terms "effective amount" or "therapeutic amount" refer to the amount of an active compound, e.g., a compound of the present invention, such as a radiotracer, to provide an effect or effectiveness that is desirable and that is an intended effect associated with the administration of the active compound according to the invention.

[0095] As used herein, the term "enantiomer" refers to two stereoisomers that are non- superimposable mirror images of each other. Both are "chiral." [0096] As used herein, the term "eutomer" refers to the more potent enantiomer of a pair of enantiomers for binding to or acting upon a target protein (e.g., CB] receptor).

[0097] The abbreviation "GTP7S" refers to guanosine-5'-(γ-thio)-triphosphate. [0098] The abbreviation "HPLC" refers to high performance liquid chromatography.

[0099] As used herein, the term "inverse agonist" refers to a compound which will bind to a receptor, block agonist binding, and will elicit a response in the opposite direction of that elicited by a natural or endogenous ligand.

[0100] As used herein, a "label" or "radiolabel" is a composition detectable by spectroscopic, photochemical, biochemical, immunochemical, chemical, or other physical means. For example, useful radiolabels include, but are not limited to, ¹¹C, ¹⁸F, ¹⁵0, ¹³N, ⁷⁶Br, ^99mTc, ^94mTc, ¹²³1, ¹²⁴1, ¹²⁵I, or ¹³¹I, or other entities which can be made detectable, e.g., by incorporating a radiolabel into a compound. The terms "labeled compound," "radiolabeled compound," or "radioactive compound" are used interchangeably herein and refer to a compound having a "label" or "radiolabel."

[0101] The abbreviation "MeCN" refers to acetonitrile. [0102] As used herein, the term "modulator" of a receptor, such as CBi receptor, is meant to include all ligands of a particular receptor regardless of the functional consequences of its binding or interaction with the receptor and includes agonists, inverse agonists, and antagonists. It includes activators and/or inhibitors of that receptor and is used to refer to a compound that activates or inhibits an activity of the receptor. A preferred receptor is a CB₁ receptor.

[0103] The abbreviation "MTBE" refers to tert-buty\ methyl ether.

[0104] The terms "optional" or "optionally" as used throughout the specification means that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances in which it does not. For example, "heterocyclo group optionally mono- or di- substituted with an alkyl group means that the alkyl may but need not be present, and the description includes situations where the heterocyclo group is mono- or disubstiruted with an alkyl group and situations where the heterocyclo group is not substituted with the alkyl group.

[0105] The abbreviation "PET" refers to positron emission tomography. [0106] The term "pharmaceutically acceptable" refers to compositions that are physiologically tolerable and do not typically produce an allergic or similar untoward reaction when administered to a subject, preferably a human subject. Preferably, as used herein, the term "pharmaceutically acceptable" means approved by a regulatory agency of a Federal or state government or listed in the U.S. Pharmacopeia or other generally recognized pharmacopeia for use in animals, and more particularly in humans.

[0107] As used herein, the term "prodrug" refers to compounds that readily undergo chemical changes under physiological conditions to provide the compounds of the present invention. Additionally, prodrugs can be converted to the compounds of the present invention by chemical or biochemical methods in an ex vivo environment. For example, prodrugs can be slowly converted to the compounds of the present invention when placed in a transdermal patch reservoir with a suitable enzyme or chemical reagent.

[0108] "Providing a biological sample" means to obtain a biological sample for use in methods described in this invention. Most often, this will be done by removing a sample of cells from a patient, but can also be accomplished by using previously isolated cells (e.g., isolated by another person, at another time, and/or for another purpose), or by performing the methods of the invention in vivo. Archival tissues, having treatment or outcome history, will be particularly useful.

[0109] The terms "purified," "isolated," or "biologically pure" refer to material that is substantially or essentially free from components that normally accompany it as found in its native state. Purity and homogeneity are typically determined using analytical chemistry techniques such as polyacrylamide gel electrophoresis or high performance liquid chromatography or mass spectrometry or elemental analysis. A compound that is the predominant species present in a preparation is substantially purified. The term "purified" or "isolated" in some embodiments denotes that a compound gives rise to essentially one band or peak in an analytical analysis. Preferably, it means that the compound is at least 85% pure, more preferably at least 95% pure, and most preferably at least 99% pure. "Purify," "isolate" or "purification," or "isolation" in other embodiments means removing at least one contaminant from the composition to be purified. In this sense, purification does not require that the purified compound be homogenous, e.g., 100% pure.

[0110] As used herein, the term "racemate" refers to a mixture of equal amounts of two enantiomeric isomers of a chiral molecule. [0111] As used herein, the terms "radiotracer" or "radioligand" refer to a compound into which a radionuclide suitable for PET or SPECT scanning is incorporated. Useful radionuclides are isotopes with short half-lives, such as ¹¹C, ¹³N, ^1SO, ¹⁸F, ⁷⁶Br, ¹²³I, ¹²⁴I, ¹²⁵I, and ¹³¹I. The terms also refer to a compound in which a radionuclide suitable for detection by other means has been incorporated (e.g., ³H or ¹²³I for detection by scintigraphy or autoradiography).

[0112] As used herein, the term "salts" refers to salts of a compound which is prepared with relatively nontoxic acids or bases, depending on the particular substituents found on the compounds described herein. When compounds of the present invention contain relatively acidic functionalities, base addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of the desired base, either neat or in a suitable inert solvent. Examples of pharmaceutically acceptable base addition salts include sodium, potassium, calcium, ammonium, organic amino, or magnesium salt, or a similar salt. When compounds of the present invention contain relatively basic functionalities, acid addition salts can be obtained by contacting the neutral form of such compounds with a sufficient amount of the desired acid, either neat or in a suitable inert solvent. Examples of pharmaceutically acceptable acid addition salts include those derived from inorganic acids like hydrochloric, hydrobromic, nitric, carbonic, monohydrogencarbonic, phosphoric, monohydrogenphosphoric, dihydrogenphosphoric, sulfuric, monohydrogensulfuric, hydriodic, or phosphorous acids and the like, as well as the salts derived from relatively nontoxic organic acids like acetic, propionic, isobutyric, maleic, malonic, benzoic, succinic, suberic, fumaric, mandelic, phthalic, benzenesulfonic, p-tolylsulfonic, citric, tartaric, methanesulfonic, and the like. Also included are salts of amino acids such as arginate and the like, and salts of organic acids like glucuronic or galacrunoric acids and the like (see, for example, Berge e/ α/., 1977, "Pharmaceutical Salts", , lυυrnal υf Pharmaceutical Science, 66: 1-19). Certain specific compounds of the present invention contain both basic and acidic functionalities that allow the compounds to be converted into either base or acid addition salts. [0113] The neutral forms of a compound may be regenerated by contacting the salt with a base or acid and isolating the parent compound in the conventional manner. The parent form of the compound differs from the various salt forms in certain physical properties, such as solubility in polar solvents, but otherwise the salts are equivalent to the parent form of the compound for the purposes of the present invention.

[0114] As used herein, the term "solid support" refers to any insoluble material including particles (e.g., beads), fibers, monoliths, membranes, filters, plastic strips and the like.

[0115] The abbreviation "SPECT" refers to single photon emission computed tomography.

[0116] The terms "subject" or "patient" refer to a mammal, preferably a human, in need of treatment for a condition, such as a disorder, or disease or in need of a diagnostic evaluation.

[0117] The term "substantially free" or similar grammatical equivalents refers to a preparation of a compound of interest which does not include detectable amounts of impurities which would inhibit, block or interfere with a function or activity of the compound of interest. [0118] As used herein, the term "tautomer" refer to a compound that exhibits tautomerism.

[0119] As used herein; the term "tautomerism" refers to the ability of organic compounds to react in isomeric structures that differ from each other in the position of a hydrogen atom and a double bond.

[0120] As used herein, the terms "test compound" or "test agent" refer to any compound which may act as a substrate or inhibitor of a CBi. A 'substrate' interacts with CBi and mediates CBi signaling. An 'inhibitor' is bound to CBi and inhibits binding of a CBi substrate or ligand and/or CBi signaling.

[0121 ] The abbreviation "THC" refers to tetrahydrocannabinol.

[0122] As used herein, a "tissue biopsy" refers to an amount of tissue removed from an animal for diagnostic analysis. In a patient with cancer, tissue may be removed from a tumor, allowing the analysis of cells within the tumor. "Tissue biopsy" can refer to any type of biopsy, such as needle biopsy, fine needle biopsy, surgical biopsy, etc.

[0123] As used herein, the terms "treat", "treating", and "treatment" include: (1 ) preventing a disease, such as cancer, i.e. causing the clinical symptoms of the disease not to develop in a subject that may be predisposed to the disease but does not yet experience any symptoms of the disease; (2) inhibiting the disease, i.e. arresting or reducing the development of the disease or its clinical symptoms; or (3) relieving the disease, i.e. causing regression of the disease or its clinical symptoms. Treatment means any manner in which the symptoms or pathology of a condition, disorder, or disease are ameliorated or otherwise beneficially altered. Preferably, the subject in need of such treatment is a mammal, more preferable a human.

II. COMPOUNDS

[0124J This invention provides novel CBi receptor ligands and radiotracers for imaging CBi receptor in brains of mammals, in particular humans. Compounds of the present invention bind to a CBj receptor.

A. 3,4-Diarylpyrazoline Compounds

[01251 ^{m a} further aspect of the present invention, a compound binding to a CBi receptor is a 3,4-diarylpyrazoline. A preferred 3,4-diarylpyrazoline is 3-(4-chlorophenyl)-N'-[(4- cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro- 1 H-pyrazole- 1 -carboxamidine having Formula (XV):

XV

[0126| The compound having Formula (XV) will also be referred to herein as compound

(±)-12a. 1. Enantiomers of 3,4-Diarylpyrazoline

[0127] Further, the present invention provides eutomers and distomers of the compound according to Formula (XV).

[0128] In a preferred embodiment of the present invention, an eutomer is (-)-3-(4- chlorophenyl)-N'-[(4-cyanophenyl)sυlfonyl]-4-phenyl-4,5-dihydro-l H-pyrazole- 1- carboxamidine having Formula (XVI):

XVI fO129| The compound having Formula (XVI) will also be referred to herein as compound (-)-12a.

[0130] In another preferred embodiment of the present invention, a distomer is (+)-3-(4- chloropheTiyl)-A"-[(4-cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro-1 H-pyrazo]e-l - carboxamidine having Formula (XVII):

XVII [0131] The compound having Formula (XVII) will also be referred to herein as compound

(+)-12a.

[0132] The invention also provides all compounds according to Formula (XV), (XVl) and (XVII) in isolated and purified form.

B. ^Cvano-KS-diphenyl-IH-Dyrazole-S-carboxamide Compounds [0133] In a further aspect of the present invention, a compound binding to a CBi receptor is a 4-cyano-l,5-diphenyl-lH-pyrazole-3-carboxamide compound having Formula (XIX):

XIX wherein R¹ is halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci.galkoxy, haloCi. galkoxy, Ci-salkylthio, haloCi-galkylthio, nitro, CHO, or C i -Ralkylsulfoxy, amino, Ci- galkylamino and Ci-galkoxycarbonylamino; wherein R² is halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci.galkoxy, haloCi-galkoxy, Cusalkylthio, haloCi.galkylthio, CHO, amino, Ci-salkylamino, Ci-salkoxycarbonlamino and

substituted at 2 and/or 4 positions; and wherein R³ is piperidinyl, morpholinyl, pyrrolidinyl, and azepanyl, Ci.galkyl and Cs-scycloalkyl.

[0134| In another preferred embodiment, a compound having Formula (XIX) is a compound wherein R¹ is halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci-galkoxy, haloCi-salkoxy, Ci.Ralkylthio, haloCi-salkylthio, nitro, CHO, or Ci-aalkylsulfoxy, amino, Ci. galkylamino and Ci-salkoxycarbonylamino; wherein R² is iodo or fluoro, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, d.galkoxy, haloCi.salkoxy, d-galkylthio, haloCi.galkylthio, CHO, amino, d-salkylamino, Ci-salkoxycarbonlamino and Q-galkylsulfoxy substituted at 2 and/or 4 positions and wherein R^' is piperidinyl, morpholinyl, pyrrolidinyl, and azepanyl, Cj. salkyl and Cs-scycloalkyl.

[0135] In a preferred embodiment, a compound having Formula (XIX) is a compound wherein either R¹ is halogen or R² is halogen. A preferred compound having Formula (XlX) is a compound wherein R² is halogen. In another preferred embodiment, a compound having Formula (XIX) is a compound wherein either R¹ is halogen or R² is iodo or fluoro. A preferred compound having Formula (XIX) is a compound wherein R² is iodo or fluoro.

[0136] A preferred 4-cyano- 1 ,5-diphenyl- lH-pyrazole-3-carboxamide compound is a compound having Formula (XX):

XX wherein R² is selected from halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci. βalkoxy, haloCi-βalkoxy, Ci-salkylthio, haloCi-salkylthio, nitro, CHO, amino, Ci-salkylamino, Ci-βalkoxycarbonylamino and Ci-salkylsulfoxy substituted at 2 and/or 4 positions. Preferably, R² is a halogen. More preferred is a compound having Formula (XX), wherein the halogen comprises a label. The label may be any label as described herein, preferably, an iodine label, such as ¹²³1, ¹²⁴1, ¹²⁵I, or ¹³¹I.

[0137] Another preferred 4-cyano-l,5-diphenyl-lH-pyrazole-3-carboxamide compound having Formula (XX) is a compound wherein R² is selected from iodo or fluoro, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci_-8alkoxy, haloCi-galkoxy, Ci-salkylthio, haloC]. salkylthio, nitro, CΗO, amino, Ci-βalkylamino, Ci-βalkoxycarbonylamino and Ci. galkylsulfoxy substituted at 2 and/or 4 positions. Preferably, R² is iodo or fluoro. More preferred is a compound having Formula (XX), wherein the iodo or fluoro comprises a label. The label may be any label as described herein, preferably, an iodine label, such as ¹²³1, ¹²⁴I, ¹²⁵I₁ Or ¹³¹I.

[0138] A preferred compound according to Formula (XX) is compound 13, wherein R² is iodine and having Formula (XXI):

XXI

[0139J The invention also provides all compounds according to Formula (XIX), (XX), and (XXI) in isolated and purified form. C. Modulators Qf CB₁ Receptor

[0140J Some compounds of the present invention are modulators of CB i receptors. Modulators of CBi receptors include CBi receptor agonists, CBi receptor antagonists and CBi receptor inverse agonists.

1. CBi Receptor Agonists and CBi Receptor Inverse Agonists [0141] In one aspect of the present invention, a modulator of a CBi receptor is a CBi receptor agonist. CBi receptor agonists or inverse agonist have therapeutic utility, e.g., treating a disorder described herein. Until recently, CBi agonists (including cannabinoids and other compounds) were thought to be competitive ligands at a common or overlapping/interacting binding region on the CBi receptor. It now appears that different CBi ligands may also bind to distinct recognition sites, or in different manners within an overlapping recognition site, and thus may be selectively displaced by a CBi antagonist.

[0142] CBi receptor agonists and CBi receptor inverse agonists are compounds of the present invention that, e.g., bind to, stimulate, increase, open, activate, facilitate, or enhance activation, sensitize or up regulate the activity of a CBi receptor. Assays for agonists are described herein and include, e.g., applying a compound to cells expressing a CBj receptor and then determining the functional effects. Samples or assays comprising a CBi receptor that are treated with a compound of the present invention suspected to function as a CBi receptor agonist are compared to control samples without the compound to examine the extent of effect. Control samples (untreated with the compound) are assigned a relative activity value of 100%. Activation or stimulation of the CBi receptor is achieved when the CB| receptor activity value relative to the control is 1 10%, optionally 130%, 150%. optionally 200%, 300%, 400%, 500%, or 1 ,000-3,000% or more higher.

2. CBi Receptor Antagonists [0143] In another aspect of the present invention, a modulator of a CBi receptor is a CBi receptor antagonist. A CBj receptor antagonist has the potential for treating a disorder as described herein, likely through affecting G-protein uncoupling and specificity of CBi receptors.

[0144J CB, receptor antagonists are compounds of the present invention that, e.g., bind to, decrease, close, inactivate, impede, or reduce activation, desensitize or down regulate the activity of a CBi receptor. Assays for antagonists are described herein and include, e.g., applying a compound to cells expressing a CBi receptor and then determining the functional effects. Samples or assays comprising a CBi receptor that are treated with a compound of the present invention suspected to function as a CBi receptor antagonist are compared to control samples without the antagonist to examine the extent of effect. Control samples (untreated with the compound) are assigned a relative activity value of 100%. Inhibition of the CBi receptor is achieved when the CBi receptor activity value relative to the control is reduced by 10%, optionally 20%, optionally 30%, optionally 40%, optionally 50%, 60%, 70%, 80%, or 90-100%. D. Radiotracers For CB₁ Receptors

[0145] Although racemate PET radiotracers for imaging cannabinoid sub-type- 1 (CBi) receptors are known in the art, homochiral, i.e., single entantiomer, PET radioligands have not been disclosed. Homochiral radioligands have distinct advantages over the racemate, including greater sensitivity. This invention concerns the preparation and use of radiotracers for imaging CBi receptors in vitro and in vivu. Radiotracers of the present invention, also referred to as radioligands and radiolabeled compounds from time to time, are useful for assessing CBi receptors using PET or SPECT, particularly in patient populations, and preferably in subjects having or being diagnosed with having a disorder as described herein. Further, radiotracers of the present invention are useful in drug development and drug discovery, for example, in neuroscience to assess the interaction of drugs with CBi receptors. In addition, radiotracers of the present invention are also useful for clinical investigation of CBi receptors in disorders as described herein. [0146] The present invention provides novel radiotracers for uses described herein. A preferred compound of the present invention is a radioligand/radiotracer. Thus, the present invention also provides isotopically-labeled compounds of the present invention which are identical to those recited herein, but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature. Examples of isotopes, preferably short-lived isotopes, that can be incorporated into compounds of the invention include isotopes of hydrogen, carbon, nitrogen, oxygen, fluorine, bromine, technetium, and iodine, such as ³H, ¹¹C, ¹³N, ¹⁵O, ^1HF, ⁷⁶Br, ⁷⁷Br, ^99mTc, ⁹⁴¹¹¹Tc, ¹²³1, ¹²⁴I, ¹²⁵I, and ¹³¹I, respectively. The choice of radioactive atom to be incorporated into the compound of the present invention will depend on the specific analytical, diagnostic, clinical research, or pharmaceutical application. For example, for /// vitro labeling of CBi receptors and competition assays, compounds of the present invention that incoφorate ³H, ¹²⁵1, ³⁵S or ⁸²Br will typically be most useful. For diagnostic radiotracers, compounds that incorporate ^{1 1}C, ¹³N, ¹⁵O, ¹⁸F, ⁷⁶Br, ⁷⁷Br, ¹²³1, ¹²⁴I, ¹²⁵I and ¹³¹I are preferred. In the present invention, ^{1 1}C is preferred because of its ease for incorporating into compounds. Also particularly preferred is ¹⁸F because of its longer half-life. Using ¹⁸F- labeled compounds, imaging can be carried out long enough to allow more specific signal to develop and thus, improve on CBi receptor quantification. ¹²³1, ¹²⁴I (positron-emitter and used for PET), and ¹²⁵I labeled compounds having even longer half livers are particularly preferred as SPECT radioligands.

[0147] The present invention provides novel radiotracers for uses described herein. In one embodiment, a compound of the present invention is Formula (XII):

XII wherein A is H; each of R¹, R² and R³ are independently aryl or a 5-6 membered heteroaryl ring, at least one of which is substituted with 1-3 R⁵ groups, R⁴ is selected from the group consisting of H, Ci.galkyl and Ci.ghaloalkyl; each R⁵ is independently selected from the group consisting of Ci-salkyl, cyano, Ci-salkoxy, CHO, Ci-aalkylcarbonyl, aminocarbonyl, halo, haloCi-8alkoxy, nitro, Ci.galkylthio, amino, Ci.galkylamino and Cj.galkoxycarbonylainino; wherein one atom selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, halogen and sulfur atom comprises or is replaced by a detectable amount of a radioisotope selected from the group consisting Of²H, ³H, ^{1 1}C, ¹X ¹⁵O, ¹⁸F, ⁷⁵ Br, ⁷⁶Br, ⁷⁷Br, ¹²³I, ¹²⁴I, ¹²⁵I, and ¹³¹I. The invention also provides all stereoisomers or pharmaceutically acceptable salts thereof.

[0148] In one embodiment of the compound according to Formula (XIl), at least one of R, R¹ and R² is heteroaryl, optionally substituted with 1-3 R⁵ gτoups. [0149] In another embodiment of the compound according to Formula (XII), each heteroaryl is independently selected from the group consisting of pyridinyl, pyrazinyl and pyrimidinyl.

[0150] In yet another preferred embodiment of the compound according to Formula (XII), at least one of R, R¹ and R² are aryl, optionally substituted with 1-3 R⁵ groups. [0151] In one embodiment of the compound according to Formula (XII), aryl is phenyl.

[0152J In another preferred embodiment of the compound according to Formula (XII), R⁴ is Ci-ghaloalkyl.

[0153] In yet another embodiment of the compound according to Formula (XII), R⁴ is

[0154J In one embodiment of the compound according to Formula (XII), R⁴ is Ci.galkyl. [0155] In another embodiment of the compound according to Formula (XII), R⁴ is CH₁. [0156] In yet another embodiment of the compound according to Formula (XII), R⁴ is H.

[0157] In one embodiment of the compound according to Formula (XIl), at least one R⁵ is selected from the group consisting of ²H, ³H, ^{1 1}CN, ^{1 1}CH₃, O^{1 1}CH₁, S^{1 1}CH,, ^{1 1}CHO, ^{1 1}COCH₃, CO¹¹CH₃, ¹¹CONH₂ and ¹⁸F.

[0158] In another embodiment of the compound according to Formula (XII), at least one R³ is OC_n(H_2nI i or D_2n, i)F or OC_n(H_2n. i or D_2n, ,)¹⁸F; and n is the integer 1, 2 or 3.

[0159| In yet another embodiment of the compound according to Formula (XIl), n is 1. [0160] In one embodiment of the compound according to Formula (XII), A is ²H. [0161] In another embodiment of the compound according to Formula (XII), A is ³H.

(0162) The invention provides all compounds according to Formula (XII) in isolated and purified form.

1. 3,4-DiarylpyrazoIine Radiotracers [0163) In yet another embodiment the compound has the Formula (XIII):

XIII wherein each of R , 5A , _D R5B and R are as defined for R ; and the wavy line indicates the presence of either stereoisomer. [0164] In one embodiment of the compound according to Formula (XIII), R^5A is cyano or halogen; R^5B is H; and R^5c is halogen.

[0165] In another embodiment of the compound according to Formula (XIII), R^5Λ is selected from the group consisting of CN, ^{1 1}CN, I, ¹²³I, ¹²⁴I, ¹²⁵I, and ¹³¹I.

[0166] In yet another embodiment the compound has the Formula (XlV):

XIV wherein R^5a is halo or cyano; and the wavy line indicates the presence of either stereoisomer. [0167] In one embodiment of the compound according to Formula (XFV), R^5a is ' ¹CN. [0168] In another embodiment of the compound according to Formula (XIV), is the (-)- enantiomer.

[0169] In yet another embodiment of the compound according to Formula (XIV), is the (+)- enantiomer.

[0170) In a further aspect of the present invention, a 3,4 diarylpyrazoline radiotracer is provided. A preferred 3,4 diarylpyrazoline radiotracer is 3-(4-chlorophenyl)-N'-[(4- cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro-lH-pyrazole-l-carboxamidine having Formula (XV):

XV wherein one atom is labeled with a short-lived positron-emitter.

[0171] A preferred radiolabeled 3,4 diarylpyrazoline radiotracer is 3-(4-chlorophenyl)-N'- [(4-cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro- lH-pyrazole- 1 -carboxamidine comprises a ^{1 1}C according to Formula (XXVI):

XXVI

a) Enantiomers of 3,4-DiaryIpyrazoline Radiotracers

[0172] Further, the present invention provides eutomers and distomers of the compound according to Formula (XV). In a preferred embodiment of the present invention, the eutomer is (-)-3-(4-chlorophenyl)-N'-[(4-cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro-lH-pyrazole- 1 -carboxamidine having Formula (XVI):

XVI wherein one atom is labeled with a short-lived positron-emitter.

[0173| A preferred radiolabeled eutomer is (-)-3-(4-chlorophenyl)-N'-[(4- cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro-lH-pyrazole-l-carboxamidine which comprises a ¹¹C and having Formula (XVIII):

XVIII

[0174) The compound having Formula (XVIII) will also be referred to herein as compound [^πC](-)-12a.

[0175] In another preferred embodiment of the present invention, the distomer is (+)-3-(4- chlorophenyl)-N '-[(4-cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro- lH-pyrazole- 1 - carboxamidine having Formula (XVII):

XVII wherein one atom is labeled with a short-lived positron-emitter. [0176] A preferred radiolabeled distomer is (+)-3-(4-chlorophenyl)-N'-[(4- cyanophenyl)sulfonyl]-4-phenyl-4,5-dihydro-lH-pyrazole-l-carboxamidine which comprises a ¹¹C and having Formula (XXVIl):

XXVII

[0177] The compound having Formula (XXVII) will also be referred to herein as compound [^πC](+)-12a.

[0178] The invention also provides all compounds according to Formula (XIII). (XIV), (XV), (XXVI), (XVT), (XVTIT), (XVTT), and (XXVTI) in isolated and purified form

2. 4-Cyano-l,5-diphenyl-lH-pyrazole-3-carboxamide Radiotracers [0179] In a further aspect of the present invention, a labeled compound binding to a CB₁ receptor is a 4-cyano-l,5-diphenyl-lH-pyrazole-3-carboxamide compound having Formula (XIX):

XlX wherein R¹ is halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Q.jjalkoxy, haloCi. galkoxy, Ci.galkylthio, haloQ-galkylthio, nitro, CΗO, or Q^alkylsuifoxy, amino, Q- 8alkylamino and Q-galkoxycarbonylamino; wherein R² is halogen, aryl. heteroaryl, nitrile, alkyl, trifluoromethyl, Q.galkoxy, haloCi-galkoxy, Q-galkylthio, haloCi.galkylthio, CΗO, amino, Ci.galkylamino, Ci.galkoxycarbonlamino and Q-galkylsulfoxy substituted at 2 and/or 4 positions; wherein R³ is piperidinyl, morpholinyl, pyrrolidinyl, and azepanyl, Ci-salkyl and C₅.₈cycloalkyl; and wherein one atom selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, halogen and sulfur atom comprises or is replaced by a detectable amount of a radioisotope selected from the group consisting of ²H, ³H, ^{1 1}C, ¹³N, ¹⁵0, ¹⁸F, ⁷⁵ Br, ⁷⁶Br, ⁷⁷Br, ¹²¹I, ¹²⁴I, ¹²⁵I, and ¹¹¹T. The invention also provides all stereoisomers or pharmaceutically acceptable salts thereof.

[0180] A preferred labeled compound according to Formula (XIX) is a compound wherein either R¹ is a halogen or R² is a halogen, and wherein either halogen comprises a label.

[0181] In a preferred embodiment, a labeled compound binding to a CBi receptor having Formula (XIX) is a compound wherein R¹ is halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci-salkoxy, haloCi-salkoxy, Ci-salkyltliio, haloCi-salkylthio, nitro, CHO, or d-salkylsulfoxy, amino, Ci-salkylamino and

wherein R^" is iodo or tluoro, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci.galkoxy, haloCi_-8alkoxy, Ci- 8alkylthio, haloCi-salkylthio, CHO, amino, Ci.galkylamino, Ci.salkoxycarbonlamino and Ci. galkylsulfoxy substituted at 2 and/or 4 positions; wherein R³ is piperidinyl, morpholinyl, pyrrolidinyl, and azepanyl, Ci-salkyl and Cs-βcycloalkyl; and wherein one atom selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, halogen and sulfur atom comprises or is replaced by a detectable amount of a radioisotope selected from the group consisting of ²H, ³H, ¹¹C, ¹³N, ¹⁵O, ¹⁸F, ⁷⁵ Br, ⁷⁶Br, ⁷⁷Br, ¹²³I, ¹²⁴I, ¹²⁵I, and ¹³¹I. The invention also provides all stereoisomers or pharmaceutically acceptable salts thereof.

[0182] A preferred labeled compound according to Formula (XlX) is a compound wherein either R¹ is a halogen or R² is iodo or fluoro, and wherein either the halogen or the iodo or fluoro comprises a label.

[0183] In one embodiment of the compound according to Formula (XIX), R¹ is heteroaryl, optionally substituted with 1-3 R⁵ groups.

[0184] In another embodiment of the compound according to Formula (XIX), the heteroaryl is selected from the group consisting of pyridinyl, pyrazinyl and pyrimidinyl.

[0185] In yet another preferred embodiment of the compound according to Formula (XIX), R¹ is aryl, optionally substituted with^' 1-3 R⁵ groups. [0186] In one embodiment of the compound according to Formula (XIX), aryl is phenyl. [0187] In one embodiment of the compound according to Formula (XIX), R¹ is Ci-galkyl. [0188] In another embodiment of the compound according to Formula (XII), R¹ is CH₃. [0189] In yet another embodiment of the compound according to Formula (XIX), R¹ is H.

[0190] In one embodiment of the compound according to Formula (XII), at least one R⁵ is selected from the group consisting of ²H, ³H, ^{1 1}CN, ^{1 1}CH₃, O^{1 1}CH₃, S¹¹CH₃, ^{1 1}CHO₁ 1¹COCH₃, CO^{1 1}CH₃, ¹¹CONH₂ and ¹⁸F.

[0191] In another embodiment of the' compound according to Formula (XIX), at least one R⁵ is OC_n(H_2n+I or D_2n+1)F or OC_n(H_2n+I or D_2n+O¹⁸F; and n is the integer 1 , 2 or 3.

[0192] In yet another embodiment of the compound according to Formula (XIX), n is 1. [0193] A preferred 4-cyano-l,5-diphenyl-lH-pyrazole-3-carboxamide radiotracer is a compound having Formula (XX):

XX wherein R² is selected from halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci- ₈alkoxy, haloCi-salkoxy, Ci-salkylthio, haloCi-βalkylthio, nitro, CΗO, amino, Ci-βalkylamino, Ci-βalkoxycarbonylamino and d-galkylsulfoxy substituted at 2 and/or 4 positions and wherein one atom selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, halogen and sulfur atom comprises or is replaced by a detectable amount of a radioisotope selected from the group consisting of ²H, ³H, ^{1 1}C, ¹³N, ¹⁵O, ¹⁸F, ⁷⁵ Br, ⁷⁶Br, ⁷⁷Br, ¹²³I, ¹²⁴I, ¹²⁵I, and ¹³¹I. The invention also provides all stereoisomers or pharmaceutically acceptable salts thereof. [0194] A preferred labeled compound having Formula (XX) is a compound wherein R² is halogen comprising a detectable amount of a radioisotope selected from the group consisting

Of¹⁸F, ° Br, ^/bBr, ''Br₁ ^u% ¹²⁴I, '"1, and ^M11.

[0195J Another preferred 4-cyano-l,5-diphenyl-lH-pyrazole-3-carboxamide radiotracer having Formula (XX) is a compound wherein R² is selected from iodo or fluoro, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci-βalkoxy, haloCi-βalkoxy, Ci-salkylthio, haloCi. salkylthio, nitro, CΗO, amino, Ci-galkylamino, Ci-βalkoxycarbonylamino and Ci. 8alkylsulfoxy substituted at 2 and'or 4 positions and wherein one atom selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, halogen and sulfur atom comprises or is replaced by a detectable amount of a radioisotope selected from the group consisting of ²H, ³H, ^{1 1}C, ¹³N, ¹⁵O, ¹⁸F, " Br, ⁷⁶Br, ⁷⁷Br, ¹²³I, ¹²⁴I, ¹²⁵I₁ and ¹³¹I. The invention also provides all stereoisomers or pharmaceutically acceptable salts thereof.

[0196] More preferred is a labeled compound having Formula (XX) wherein R² is a iodo and the radioisotope is selected from the group consisting of ^l2jI, ¹²⁴1, ¹²⁵I, and ¹³¹I. A preferred radiolabeled compound of Formula (XX) is a radiolabeled compound 13, l-(2- iodophenyl)-4-cyano-5-(4-methoxyphenyl)-N-(piperidin-l-yl)-lH-pyrazole-3-carboxylate), having Formula (XXIX):

XXIX wherein I* indicates a label, e.g., I ¹2²31τ, 1¹2²4⁴,I, 1¹2²J³rI, o __r 1 ^m3 1 ,I.

[0197] In one embodiment of the compound according to Formula (XXIX), the radioisotope is 123 ^* , I.

[0198] In one embodiment of the compound according to Formula (XXIX), the radioisotope is ¹²⁴I. [0199J 1° ^one embodiment of the compound according to Formula (XXIX), the radioisotope is ¹²⁵I.

[0200] In one embodiment of the compound according to Formula (XXIX), the radioisotope is ¹³¹I. [0201 j The invention provides all compounds according to Formula (XIX), (XX), (XXI), and (XXIX) in isolated and purified form.

E. Methods of Producing a Radiotracer

[0202] The present invention provides methods for producing radiolabeled compounds of the present invention. 1. Radiolabeling

[0203] Compounds of the present invention may be prepared by known organic synthesis techniques and the methods described in more detail in the Examples. In general, the compounds of Formula (XII) above may be made by as illustrated in Figure 5, wherein all substituents are as defined above unless indicated otherwise. [0204] Compounds having Formula (XII) may be prepared according to Figure 5. Briefly, in step (a), the appropriate 4-substimted benzenesulfonamide (A) is treated a carbamate forming reagent such as an alkyl haloformate under basic conditions to give the corresponding carbamic acid esters (B). In step (b), compound (B) is then treated with the ^' appropriately substituted 1 H-pyrazole (C) (available commercially or synthesized using methods known to those skilled in the art) to give (D). Treatment of (D) with a dehydrating agent such as PCI5 in steps (c, d) gave the crude activated imino intermediate, which is readily converted with the appropriately substituted amine R⁴-NΗ₂ (available commercially or synthesized using methods known to those skilled in the art) into the target ligands, I. These ligands can be resolved into their enantiomers with chiral HPLC as further described herein.

[0205] Thus, in one embodiment the method of producing a radiotracer comprises the steps of: (a) reacting a compound having the Formula (XXII):

XXII with a compound having the Formula (XXIII):

XXIII to form a product; (b) reacting the product from step (a) with a compound having the formula NH²-R⁴ to provide a compound of claim 1 ; wherein R⁶ is Ci -Cgalkyl; and one carbon or halogen atom comprises a detectable amount of a radioisotope.

2. Methods of Producing a 3,4-DiarylpyrazoIine Radiotracer

[0206] Similarly, compounds having Formula (XII) may be prepared according to Figure 5, wherein R¹, R² and R³ are phenyl. Thus, in another embodiment is provided a method of producing a compound according to Formula (XII). In one embodiment, the method comprises the steps of: (a) reacting (or treating) a compound having the Formula (XXIV):

R5A

XXlV

with a compound having the Formula (XXV):

XXV to form a product; (b) reacting the product from step (a) with a compound having the formula NH²-R⁴ to provide a compound having Formula (XIII):

xm wherein R⁶ is Cj-Cgalkyl; and one carbon or halogen atom comprises a detectable amount of a radioisotope. [0207] A detailed protocol for the synthesis of compounds of the invention is provided in the Examples. One of skill in the art would appreciate that the conditions of the labeling reaction may be varied with respect to amount of precursor amide, solvent, base, temperature and time. For example, the reaction may be promoted thermally or by microwaves. The reaction may be performed in conventional automated radiosynthetic devices or in microfluidic devices.

3. Methods of Producing a 4-Cyano-l,5-diphenyl-l-H-pyrazole-3- carboxamide Radiotracer

[0208] Compounds having Formula (XIX) and Formula XX) may be prepared according to Figure 6. The appropriate substituted chloro[(phenyl)hydrazono]ethyl acetate (B) is synthesized by converting the substituted aniline (A) into a diazonium salt, followed by treatment with ethyl 2-chloro acetoacetate under basic conditions. A mixture of substituted benzoylacetonitrile (C), base and (B) dissolved in appropriate solvent (e.g., ethanol, tert- butanol, isopropanol, acetonitrile) gives (D). Hydrolosis of (D) using appropriate base (e.g. LiOH, NaOH, KOH) gives a carboxylic acid. The carboxylic acid can then be converted to acyl halide and then reacted with amine to give (E).

[0209] Methods of producing a SPECT radioligand (a iodinated derivative of compound 13, 1 -(2-iodophenyl)-4-cyano-5-(4-methoxyphenyl)-N-(piperidin- 1 -yl)- lH-pyrazole-3- carboxylate), having Formula (XXIX) are disclosed herein, e.g., in Example 9. III. METHODS OF USING COMPOUNDS

A. Measuring an Interaction of a Radiotracer with a CB^ Receptor

1. Binding Assays

[0210J Several CBi receptor binding assays are described herein. In addition, CBi receptor binding assays, which also find use in the present invention, are described in WO08/032156. WO07/ 125049, WO07/ 125048, WO06/045799, WO05/009479, WO04/074844, WO03/088968, WO02/076949, WO01/029007, which are hereby incorporated by reference in their entireties.

2. Measuring an Interaction of a Radiotracer with a CBi Receptor [0211] The present invention provides methods for measuring an interaction of a compound of the present invention, in particular, a radiolabeled compound, such as a radiotracer, with a CBi receptor. In one embodiment, the method for measuring an interaction of a radiolabeled compound with a CBi receptor comprises the steps of (a) contacting a CBi receptor with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor.

[0212] The radiolabeled compound may be any radiotracer described herein, preferably a radiotracer selected from the group consisting of a compound having the Formula (XlII), a compound having the Formula (XV), a compound having the Formula (XXVI), a compound having the Formula (XVIII), a compound having the Formula (XXVII), a compound having the Formula (XlX), a compound having the Formula (XX), a compound having the Formula (XXI), and a compound having the Formula (XXVIII).

[0213] The CBi receptor is contacted with a radiolabeled compound using an effective amount of the radiolabeled compound to achieve the desired effect.

[0214] The CBi receptor may be a CBi receptor in a mammal, a CBi receptor in a tissue, preferably a mammalian tissue, a CBj receptor in a cell, preferably a mammalian cell, a CBi receptor in a CBi receptor preparation, or an isolated CBi receptor, preferably a recombinant CBi receptor. [0215] The measurable signal may be recorded in, e.g., an electronic or optical database. B. Imaging CB₁ Receptors

[0216] The present invention provides methods for imaging a CBi receptor. In one embodiment, the method for imaging a CBi receptor comprises the steps of (a) contacting a CBi receptor with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) imaging the radiolabeled compound with the CBi receptor using PET. Preferably, step (a) is performed in vivo. Preferably, the radiolabeled compound is administered to a mammal, more preferably to a human.

[0217] In another embodiment, the method for imaging a CB) receptor comprises the steps of (a) contacting a CBi receptor with a radiolabeled compound to produce a CBj receptor- radiolabeled compound complex; and (b) imaging the radiolabeled compound with the CBi receptor using SPECT. Preferably, step (a) is performed in vivo. Preferably, the radiolabeled compound is administered to a mammal, more preferably to a human.

[0218] The radiolabeled compound may be any radiotracer described herein, preferably a radiotracer selected from the group consisting of a compound having the Formula (XITI), a compound having the Formula (XV), a compound having the Formula (XXVI), a compound having the Formula (XVIII), a compound having the Formula (XXVII). a compound having the Formula (XIX), a compound having the Formula (XX), a compound having the Formula (XXI), and a compound having the Formula (XXVIII).

1. Positron Emission Tomography (PET) [0219] A preferred method for imaging CBi function in vivo and which can be used for methods described herein is Positron Emission Tomography (PET). PET is a nuclear medicine imaging technique which produces sequential three-dimensional image or map of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radioisotope, which is introduced into the body on a biochemical or drug-like molecule. Images of radiotracer distribution in space are then reconstructed by computer analysis, often in modern scanners aided by results from a CT X-ray scan performed on the patient at the same time, in the same machine. The radiotracer, according to its design and distribution reports on some particular aspect of biochemistry or physiology e.g., receptor distribution, transporter distribution, blood flow, protein synthesis, glucose utilization.

[0220] To conduct the scan, typically, a short-lived radioisotope, which decays by emitting a positron, which also has been chemically incorporated into the radiotracer (e.g., as described herein), is injected into the living subject (usually into blood circulation), placed in an imaging scanner. There is a waiting period while the radiotracer becomes concentrated in a tissue of interest.

[0221] As the radioisotope undergoes positron emission decay (also known as positive beta decay), it emits a positron, the antimatter counterpart of an electron. After traveling up to a few millimeters the positron encounters and annihilates with an electron, producing a pair of annihilation (gamma) photons moving in opposite directions. These are each detected when they reach a scintillator material in the scanning device, creating a burst of light which is detected by photomultiplier tubes or silicon avalanche photodiodes (Si APD). The technique depends on simultaneous or coincident detection of the pair of photons; photons which do not arrive in pairs (i.e., within a few nanoseconds) are ignored.

[0222] The most significant fraction of electron-positron decays result in two 51 1 keV gamma photons being emitted at almost 180 degrees to each other; hence it is possible to localize their source along a straight line of coincidence (also called formally the line of response or LOR). In practice the LOR has a finite width as the emitted photons are not exactly 180 degrees apart. If the recovery time of detectors is in the picosecond range rather than the lO's of nanosecond range, it is possible to calculate the single point on the LOR at which an annihilation event originated, by measuring the "time of flight" of the two photons. This technology is not yet common, but it is available on some new systems. [0223] Radionuclides used in PET scanning are typically isotopes with short half-lives such as ¹¹C (-20 min), ¹³N (-10 min), ¹⁵O (-2 min), and ¹⁸F (-110 min). These radionuclides are incorporated either into compounds or analogs of compounds normally used by the body such as glucose (or glucose analogues), water or ammonia, or into molecules that bind to receptors or other sites of drug action. Such labeled compounds are known as radiotracers, also referred to as radioligands. Some radiotracers distribute in tissues by partially following the metabolic pathways of their natural analogues; others interact with or bind with specificity in the tissues containing the particular receptor proteins for which they have affinity. It is important to recognize that PET technology can be used to trace the biodistribution of any compound (plus its radiometabolites) in living humans (and many other species as well), provided it can be radiolabeled with a PET isotope. The PET scanners can measure the distribution of radioactivity, but they cannot inform on the chemical species containing the radioactivity i.e., they cannot distinguish parent radiotracer from its radiometabolites in any field of view. Due to the short half-lives of most radioisotopes, the radiotracers must be produced using a cyclotron and radiochemistry laboratory that are in close proximity to the PET imaging facility. The half-life of ¹⁸F is long enough such that ^lsF-labeled radiotracers can be manufactured commercially at an offsite location. As such, ¹⁸F is widely used because it decays largely (97%) by positron emission, can be incorporated into drug-like organic molecules, can be used for dynamic imaging is scan sessions longer than 250 minutes, and is readily produced from both particle accelerators and nuclear reactors, using a wide variety of nuclear reactions.

[0224] In comparison, although the radiochemistry of ¹¹C is also well developed for synthesizing ' 'C-labeled PET ligands, its short half-life (Ti₇₂ = 20.4 min) limits its utility to sites at or very near to its production. Ultimately, the decision on which radionuclide is preferred depends on many factors on a case-by-case basis (e.g. slow or long kinetics of radiotracer, mode of metabolism, presence of F in tracer molecule or not, availability of ^{1 1}C etc). [0225) PET or SPECT scanning can involve whole body scanning or scanning of a tissue of interest, such as brain. Examples for each are presented herein.

2. Single Photon Emission Computed Tomography (SPECT)

[0226] Radiotracers of the present invention can be used both for PET imaging and for CBi receptor imaging using single photon emission computed tomography (SPECT). PET imaging provides better sensitivity (a more precise quantification of the regional distribution of the tracer), and in general sharper images than those derived from SPECT. However, worldwide, there are ~ 50,000 SPECT scanners and only ~ 2,500 PET scanners. Therefore, the choice of PET vs. SPECT may not only be dictated as much by the preference/desire for a better quality image as the availability of the imaging instrumentation, but also by the availability of a SPECT or PET scanner.

[0227] A SPECT image reflects distribution of the radiotracer captured through detection of the photons (γ-rays) emitted by the radionuclide. ¹²³I (tiα = 13.1 h) is commercially available and commonly used. However, many promising tracer molecules do not contain an iodine atom in their structure, and the introduction of an iodine atom into analogs frequently annuls favorable properties (for example, by increasing lipophilicity, altering pharmacology etc). Successful SPECT radiotracers labeled with ¹²³1, ¹²⁴I, ¹²⁵I, or ¹³¹I are of commercial interest because their relatively long-life allows marketability to diagnostic or clinical research scanning facilities.

[0228] Currently, an exploitable SPECT radioligand for CBi receptors does not exist. Due to the quite long half-life of the radioiodine used in SPECT radioligands (¹²³I, tj/₂ ⁼ 13.2 h), such SPECT radioligands are of great interest. Compound 13, as described herein as a radioligand is particularly suitable for SPECT when labeled with iodine- 123. Labeling conditions for iodine-123 are identical to ¹²⁵I and are shown in scheme 9. However, its structure is also amenable to labeling with the positron-emitter carbon-1 1 in one of several positions, a preferred position is a methoxy position. Such labeling of compound 13 provides a radioligand for imaging with PET, which in certain circumstances may be preferred because of the greater anatomical resolution of PET compared to SPECT.

C. Quantifying CB₁ Density

1. Diagnostic Imaging of a CB, Receptor in a Subject

[0229J Radioligands have been used to measure the density of CBj receptors, i.e., to quantify CBi receptor density, in subjects. For example, to determine whether changes in the cannabinoid system were present in the brains of subjects with schizophrenia, Dean et al. (2001 , Neiirυscience 103:9-15) used in situ radioligand binding and autoradiography to measure the binding of [³H]CP-55940 to the CBi receptor in schizophrenic and control subjects. An increase in the density of [³H]CP-55940 binding to the CBj receptor in schizophrenic subjects was found, indicating an increase in the density of the CBi receptor and that changes in CBi receptors may be associated with the pathology of schizophrenia {Oean et al. 2001 , Neurosciencc 103:9-15; Newell et al., 2006, Exp Brain Res 172:556-560). Similarly, a significant increase in [³H]SR141716A specific binding to CBi receptors was found in a schizophrenic group as compared to a control group (Zavitsanou et al., 2004, Prog Neuropsychυpharmacol Biol Psychiatry 28:355-60)

[0230] Compounds of the present invention can be used to measure and quantify CBi receptor density in vitro and in vivo.

[0231] Thus, in a further aspect of the present invention, methods for measuring the density of a protein target, preferably, a CBi receptor, across brain regions are provided. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring the density of the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CB] receptor, i.e., the density of the CB₁ receptor. The density of a protein target, such as a CB₁ receptor, is the number of measurable protein targets in a given volume, and often expressed as fmol/mg protein, fmol/mL or some other unit (e.g., nM). Sometimes, and most often, only relative and not absolute measures are obtained, called binding potentials (BP) or specific volumes of distribution (e.g., See, Innis et al, 2007, J Cereb Blood Flow Metab 27(9): 1533-1539; incorporated hereby by reference in its entirety).

[0232] The radiolabeled compound may be any radiotracer described herein, preferably a radiotracer selected from the group consisting of a compound having the Formula (XIII), a compound having the Formula (XV), a compound having the Formula (XXVI), a compound having the Formula (XVIII), a compound having the Formula (XXVII), a compound having the Formula (XIX), a compound having the Formula (XX), a compound having the Formula (XXI), and a compound having the Formula (XXVITI).

[0233] In a preferred embodiment of the present invention, step (a) is perfoπned by administering the radiolabeled compound to a mammal, more preferably to a human, in need of diagnostic imaging. The human may be a human having a condition, disorder or disease as described herein. Compounds of the present invention radiolabeled with a short-lived positron-emitting radionuclide are almost always administered via intravenous injection within less than one hour of their synthesis. [0234] Optionally, the method for measuring the density of the CB₁ receptor comprises the step of administering the radiolabeled compound to a diseased subject, preferably a diseased human, and obtaining a first measurable signal. The radiolabeled compound may also be administered to a healthy, normal or control subject, whereby, after measuring the CBj receptor density in the healthy, normal, or control subject, a second measurable signal is obtained. Further, optionally, the first measurable signal is compared to the second measurable signal. Depending on the condition, disorder, or disease of the subject, a higher or lower first measurable signal when compared to the second measurable signal is indicative of the condition, disorder, or disease.

[0235] Performing the above method sheds light on the involvement of the CBi receptor in disease progression. The above method may also be used to monitor the effect of established or experimental therapies on protein target density, preferably, a CB, receptor. 2. Diagnostic Imaging of CBi Receptors in Subjects Having a

Neurological, Neuropsychiatric, Neurodegenerative or Other Condition and Treatment

[0236] Several recent studies have indicated that impairment of the CBi receptor mediated signaling may play a critical role in the pathophysiology of various neurological, neuropsychiatric and other disorders (e.g., Vinod and Hungund, 2006, Expert Opin I her Targets 10:203-210). An effective PET or SPECT radioligand for CBi receptors would have utility for clinical studies aimed at elucidating their role in various disorders. The noninvasive nature of PET or SPECT would allow information to be gained longitudinally from living individuals on disease progression and on experimental treatments. A radioligand coupled with SPECT rather than with PET would have the attraction of much wider applicability (it is estimated that there are about 50,000 SPET cameras worldwide compared with only about 2,500 PET cameras).

[0237] Conditions which can be diagnosed and/or treated using the compounds of the present invention include, but are not limited to, e.g., psychiatric disorders (e.g., depression, mood disorders, anxiety, schizophrenia, dug addiction, alcoholism), metabolic disorders (e.g., obesity, anorexia, conditions involving cardiometabolic risk factors), neurodegenerative disorders (e.g., Gilles de Ia Tourette Syndrome, Parkinson's disease, Huntington's disease, and Alzheimer's disease), pain and inflammation disorders (e.g., acute pain, chronic pain, naturopathic pain), memory dysfunction, multiple sclerosis, nausea and emesis.

[0238] The radiolabeled compound for use in diagnostic imaging of CBi receptors in subjects having a neurological, neuropsychiatric, neurodegenerative or other condition may be any radiotracer described herein, preferably a radiotracer selected from the group consisting of a compound having the Formula (XIII), a compound having the Formula (XV), a compound having the Formula (XXVl), a compound having the Formula (XVlIl), a compound having the Formula (XXVII), a compound having the Formula (XIX), a compound having the Formula (XX), a compound having the Formula (XXl), and a compound having the Formula (XXVIII). a) Depression, and Mood Disorder [0239J Mood disorders such as generalized anxiety or panic disorder, major depressive disorder and bipolar disorder (manic depressive illness) are very common, often serious, and potentially life-threatening conditions. More than 20% of the adult population experiences a mood disorder at some point during their life. In up to 15% of individuals with major depressive disorder the cause of death is suicide. According to a World Health Organization forecast, by the year 2020 depression will become the second leading cause of premature death and disability worldwide (Pacher and Kecskemeti, 2004, Curr Med Chem 1 1 :925-943). Although significant advances have been made in the treatment of mood disorders during the past decades, 30% of the population do not respond to current therapies, and the search for novel pharmacological approaches continues (reviewed in Pacher and Kecskemeti, 2004, Curr Med Chem 1 1 :925-943).

[0240] Cannabinoids are well known modulators of mood and emotional behavior (Pacher et al., 2006, Pharmacol Rev 58:389-462). Current research supports a role for endocannabinoid signaling in the treatment of depression. Changes in levels of CB i receptor or the endogenous CBi receptor ligands, anandamide and 2- AG, are observed both in humans suffering from depression and in animal models of depression. (Mangieri and Piomelli, 2007, Pharmacol Rex 56:360-366). Importantly, inhibitors of anandamide inactivation have demonstrated efficacy in enhancing stress-coping and mood-related behavior. (Mangieri and Piomelli, 2007, Pharmacol Res 56:360-366). Moreover, a few studies have reported an interaction of antidepressants with the endocannabinoid system. With regard to clinical studies, several authors have reported an alteration of endocannabinoid serum levels in depression, while post mortem studies have demonstrated increased levels of endocannabinoids associated to a concomitant hyperactivity of CBi receptor in the prefrontal cortex of suicide victims (Serra and Fratta, 2007, Clin Pract Epidemol MeM Health 3 :25).

[0241] Compounds of the present invention may be used for the management of depression, and, in particular, as therapeutics for the treatment of depression.

[0242] Thus, the present invention provides methods for diagnosing depression or a mood disorder in a subject. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having depression or a mood disorder with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor. The measurable signal obtained from the subject suspected of having depression or a mood disorder may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having depression or mood disorder, is indicative that the subject has depression or a mood disorder. A significantly lower or higher measurable signal from the subject suspected of having depression or a mood disorder differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%. [0243] The present invention also provides methods for treating a subject having depression or a mood disorder. In a preferred embodiment, this method comprises the step of administering to a subject having depression or a mood disorder a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient. b) Anxiety

[0244] Studies have shown that the cannabinoidergic system is involved in anxiety (Pacher et al., 2006, Pharmacol Rev 58:389-462). There is general consensus that the effects of cannabinoid agonists on anxiety seem to be biphasic, with low doses being anxiolytic (anxiety relieving) and high doses ineffective or possibly anxiogenic (causing anxiety) (Rubino e/ tf/., 2008, Neuropharmacology 54: 151-160). For example, it has been shown that administration of the CBi receptor agonist W1N55212-2 dose dependently exhibited an anxiolytic effect (Naderi et al, 2008, Pharmacol Biochem Behav 89:64-75).

[0245] Similarly, as WIN55212-2 or cannabinoid, compounds of the present invention may be used for the management of anxiety, and, in particular, as therapeutics for the treatment of anxiety.

[0246] Thus, the present invention provides methods for diagnosing anxiety in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having anxiety with a radiolabeled compound to produce a CBi receptor- radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor. The measurable signal obtained from the subject suspected of having anxiety may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having d anxiety, is indicative that the subject has anxiety. A significantly lower or higher measurable signal from the subject suspected of having anxiety differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%.

[0247] The present invention also provides methods for treating a subject having anxiety. In a preferred embodiment, this method comprises the step of administering to a subject having anxiety a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient. c) Schizophrenia

[0248] Schizophrenia is the second most common mental disorder with a lifetime prevalence of approximately 0.2 to 2% worldwide (Ban, 2004, Prog Neuropsychopharmacol Biol Psychiatry 28:753-762). Evidence suggests that cannabinoid receptors, the pharmacological target of cannabis-derived drugs, and their accompanying system of endogenous activators may be dysfunctional in schizophrenia. Recently, it was demonstrated that cerebrospinal concentrations of two endogenous cannabinoids, anandamide and palmitylethanolamide were significantly higher in schizophrenic patients than non- schizophrenic controls which may contribute to the pathogenesis of schizophrenia (Leweke et al, 1999m Neuroreport 10: 1655-1659).

[0249J Compounds of the present invention, preferably a CB i receptor antagonist, are useful for the management of schizophrenia, and, in particular, as therapeutics for the treatment of schizophrenia. [0250] Thus, the present invention provides methods for diagnosing schizophrenia in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having schizophrenia with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor. The measurable signal obtained from the subject suspected of having schizophrenia may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having d schizophrenia, is indicative that the subject has schizophrenia. A significantly lower or higher measurable signal from the subject suspected of having schizophrenia differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60% at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%. [0251] The present invention also provides methods for treating a subject having schizophrenia. In a preferred embodiment, this method comprises the step of administering to a subject having schizophrenia a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient. d) Drug Addiction and Alcohol Disorder

[0252] Compounds of the present invention are useful for the treatment of drug addition, smoking addiction and alcoholism. For example, rimonabant was shown to significantly increase the cigarette smoking quit rates compared with placebo (Gelfand and Cannon, 2006, Expert Opin Investig Drugs 15:307-315). Specifically, compounds of the present invention may be used as a selective blocker of the CBi receptor for the management of smoking cessation and, in particular, as therapeutics for the treatment of smoking addiction.

[0253] Research into the endocannabinoid signaling system has grown exponentially in recent years following the discovery of cannabinoid receptors (CB) and their endogenous ligands, such as anandamide (AEA) and 2-arachidonoylglycerol (2-AG). The endocannabinoid signaling system has been implied in various aspects of alcoholism, including alcohol-seeking behavior (Basavarajappa, 2007, Mini Rev Med Chem 7:769-779). Alcohol increases the synthesis or impairs the degradation of endocannabinoids, leading to a locally elevated endocannabinoid tone within the brain resulting in compensatory down- regulation Of CB₁ receptors or dampened signal transduction. Mice treated with the CBi receptor antagonist SR141716A (rimonabant) or homozygous for a deletion of the CBi receptor gene exhibit reduced voluntary alcohol intake (Basavarajappa, 2007, Mini Rev Med Chem 7:769-779). Conversely, activation of CBi receptor promotes alcohol intake (Basavarajappa, 2007, Mini Rev Med Chem 7:769-779). [0254] Similar to rimonabant, compounds of the present invention may be used as a selective blocker of the CBi receptor for the management of alcoholism, and, in particular, as therapeutics for the treatment of alcoholism.

[0255] Thus, the present invention provides methods for diagnosing a drug addiction or an alcoholic disorder in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having a drug addiction or an alcoholic disorder with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBt receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CB, receptor. The measurable signal obtained from the subject suspected of having the drug addiction or alcoholic disorder may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having a drug addiction or an alcoholic disorder, is indicative that the subject has a drug addiction or an alcoholic disorder. A significantly lower or higher measurable signal from the subject suspected of having a drug addiction or an alcoholic disorder differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%.

[0256J The present invention also provides methods for treating a subject having a drug addiction or an alcoholic disorder. In a preferred embodiment, this method comprises the step of administering to a subject having a drug addiction or an alcoholic disorder a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient.

10257] Further, a compound of the present invention may be a useful adjunct to lifestyle and behavior modification in the treatment of drug addiction, cigarette smoking, and alcoholism. e) Obesity, Anorexia, Appetite Control, and Cardiometabolic Risk Factors

[0258] Roughly two thirds of US adults meet the criteria for overweight or obesity (Hedley et ai, 2004, JAMA 291 :2847-2850), which greatly increases the risk of developing diabetes mellitus and cardiovascular disease (Klein el a/., 2004, Circulation 1 10:2952-2967) and related mortality (Solomon and Manson, 1997, Am J Clin Nutr 66: 10445- 10505). In addition to weight loss, obesity management should target reduction in the cardiometabolic risk factors of atherogenic dyslipidemia, excess abdominal obesity, and elevated glucose.

[0259] Compounds of the present invention are useful for the treatment of obesity and appetite control (Gelfand and Cannon, 2006, Expert Opin Inves/ig Drugs 15:307-315). Rimonabant was shown to reduce weight and waist circumference, improve cardiovascular disease risk factors in obese patients with metabolic syndrome or multiple cardiovascular disease risk factors and to improve glycemic control and lipids in patients with type 2 diabetes mellitus (Kakafika et at., 2007, J Clin Pharmacol 47:642-652; Hollander, 2007, Am J Med 120(2 Suppl l):S18-32; Gelfand and Cannon, 2006, Expert Opin Inves tig Drugs 15:307-315; Van Gaal e/ al., 2005, Lancet 365: 1389-1397).

[0260] Similarly, as rimonabant, compounds of the present invention may be used as a selective blocker of the CBi receptor for the management of obesity, appetite control and cardiometabolic risk factors and, in particular, as therapeutics for the treatment of obesity, anorexia, appetite control, and cardiometabolic risk factors.

[02611 Thus, the present invention provides methods for diagnosing obesity, anorexia or cardiometabolic risk factors in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having obesity, anorexia or cardiometabolic risk factors with a radiolabeled compound to produce a CBi receptor- radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor. The measurable signal obtained from the subject suspected of having obesity, anorexia or cardiometabolic risk factors may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having obesity, anorexia or cardiometabolic risk factors, is indicative that the subject has obesity, anorexia or cardiovascular risk factors. A significantly lower or higher measurable signal from the subject suspected of having obesity, anorexia or cardiometabolic risk factors differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%.

[0262] The present invention also provides methods for treating a subject having obesity, anorexia or cardiometabolic risk factors. In a preferred embodiment, this method comprises the step of administering to a subject having obesity, anorexia or cardiometabolic risk factors a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient.

[0263] Treatment of a subject having cardiometabolic risk factors with a compound of the present invention may lead to favorable changes, such as better glycemic control in type 2 diabetes mellitus, improved lipid profile, reduced blood pressure, increased adiponectin levels, fall in high-sensitivity C-reactive protein concentration, and an overall decrease in-the prevalence of the metabolic syndrome. [0264] Further, a compound of the present invention may be a useful adjunct to lifestyle and behavior modification in the treatment of obese subjects with metabolic syndrome or multiple cardiometabolic risk factors. f) Memory Dysfunction [0265] The administration of Δ^y-THC, the principle psychoactive ingredient in marijuana, or the endogenous cannabinoid anandamide, has been shown to impair recent memory (Sullivan 2000, Learn Mem 7: 132-139). Recently, it was shown that the cannabinoid CBi receptor antagonist SR141716A could attenuate the memory impairment and learning deficit produced by Δ⁹-THC or anandamide (Mallet and Beninger, 1998, Psychopharmacology 140: 11-19; Braida and SaIa, 2000, Neuroreporl 11 :2025-2029; Da and Takahashi, 2002, Prog Neuropsychopharmacol Biol Psychiatry 26:321-325)

[0266] Similarly, as SR141716A, compounds of the present invention, preferably a CBi receptor antagonist, may be used for the management of memory dysfunction and, in particular, as therapeutics for the treatment of memory dysfunction. [0267] Thus, the present invention provides methods for diagnosing memory dysfunction in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having a memory dysfunction with a radiolabeled compound to produce a CB₁ receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBj receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor. The measurable signal obtained from the subject suspected of having the memory dysfunction may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having the memory dysfunction, is indicative that the subject has memory dysfunction. A significantly lower or higher measurable signal from the subject suspected of having memory dysfunction differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%.

[0268] The present invention also provides methods for treating a subject having memory dysfunction. In a preferred embodiment, this method comprises the step of administering to a subject having memory dysfunction a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient. g) Gilles de Ia Tourette Syndrome

[0269] In 1992, endogenous ligands of the cannabinoid system were discovered for the first time {e.g. anandamide and 2-arachidonylglycerol). The physiological role of these arachidonic acid derivates is still unclear. A dysregulation in the endogenous cannabinoid/anandamide system could possibly play an import role in the etiology of Gilles de Ia Tourette syndrome (TS; Schneider el al, 2000, Fortschr Neurol Psychialr 68:433-438; Pacher et al, 2006, Pharmacol Rev 58:389-462). TS is a neurological syndrome that becomes evident in early childhood and is characterized by multiple motor and vocal tics lasting for more than 1 year. Administration of cannabinoids affects the symptoms of the Gilles de Ia Tourette syndrome positively (Schneider el al., 2000, Fortschr Neurol Psychiatr 68:433-438).

[0270) Compounds of the present invention, preferably a CBi receptor agonist, are useful for the management of Gilles de Ia Tourette syndrome, and, in particular, as therapeutics for the treatment of Gilles de Ia Tourette Syndrome.

[027 IJ Thus, the present invention provides methods for diagnosing Gilles de Ia Tourette Syndrome in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having Gilles de Ia Tourette Syndrome with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor. The measurable signal obtained from the subject suspected of having Gilles de Ia Tourette Syndrome may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having Gilles de Ia Tourette Syndrome, is indicative that the subject has Gilles de Ia Tourette Syndrome. A significantly lower or higher measurable signal from the subject suspected of having Gilles de Ia Tourette Syndrome differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%.

[0272[ The present invention also provides methods for treating a subject having Gilles de Ia Tourette Syndrome. In a preferred embodiment, this method comprises the step of administering to a subject having Gilles de Ia Tourette Syndrome a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient. h) Parkinson's Disease [0273] Parkinson's disease is the second most common neurodegerative disease of adult onset, with incidence of 16- 19/100,000 people worldwide (Pacher et al., 2006, Pharmacol Rev 58:389-462). Enhanced endocannabinoid signaling may be involved in the pathophysiology of Parkinson's Disease (van der Stelt, 2005, FASEB J 19: 1 140-1 142; (Pacher et a/., 2006, Pharmacol Rev 58:389-462). Further, recent studies in animal models and in the clinic suggest that CB i receptor antagonists could prove useful in the treatment of Parkinsonian symptoms (Brotchie, 2003, Curr Opin Pharmacol 3:54-61).

[0274] Thus, the present invention provides methods for diagnosing Parkinson's disease in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having Parkinson's disease with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CB _t receptor. The measurable signal obtained from the subject suspected of having Parkinson's disease may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having Parkinson's disease, is indicative that the subject has Parkinson's disease. A significantly lower or higher measurable signal from the subject suspected of having Parkinson's disease differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%.

[0275] The present invention also provides methods for treating a subject having Parkinson's disease. In a preferred embodiment, this method comprises the step of administering to a subject having Parkinson's disease a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient. i) Hungtington's Disease

[0276] Huntington's disease (HD) an inherited, autosomal dominant, progressive neuropsychiatric disorder of midlife and is characterized by the degeration of neurons in the basal ganglia and cortical regions (Pacher et al., 2006, Pharmacol Rev 58:389-462). It has been clearly demonstrated, both in postmortem human tissue and in chemically induced and transgenic animal models that a decrease in CB₁ receptor level and signaling activity in the basal ganglia is one of the earliest changes in HD, preceding nerve loss and clinical symptoms. Furthermore, decreased levels of anandamide and 2-AG in the striatum and an increase of anandamide in the ventral mesencephalon, where the substantia nigra is located, have been documented in a rat model of HD (see, Pacher et a/., 2006, Pharmacol Rev 58:389- 462). Thus, it appears that endocannabinoid signaling in the basal ganglia is hypofunctional in HD, which probably contributes to the hyperkinesia associated with the disease. These studies also suggest that the endocannabinoid system is involved in the pathogenesis and/or progression of HD, and cannabinoid agonists could be of significant therapeutic benefit in HD because of their anthyperkinetic and neuroprotective effects.

[0277] Compounds of the present invention are useful for the treatment of Huntington's disease. Specifically, compounds of the present invention , in particular agonists for the CBi receptor are useful for the management of Huntington's disease, and, in particular, as therapeutics for the treatment of Huntington's disease. [0278] Thus, the present invention provides methods for diagnosing Huntington's disease in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having Huntington's disease with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor. The measurable signal obtained from the subject suspected of having Huntington's disease may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having Huntington's disease, is indicative that the subject has Huntington's disease. A significantly lower or higher measurable signal from the subject suspected of having Huntington's disease differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%. [0279] The present invention also provides methods for treating a subject having Huntington's disease. In a preferred embodiment, this method comprises the step of administering to a subject having Huntington's disease a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient. j) Alzheimer's Disease

[0280] Alzheimer's disease (AD) is a progressive neurodegenerative disorder that accounts for the vast majority of age-related dementia and is one of the most serious health problems in the industrialized world. The disease is characterized by the formation of neuritic plaques rich in -amyloid (A/?) peptide, neurofibrillary tangles rich in hyperphosphorylated protein, gliosis, and a neuroinflammatory response involving astrocytes and microglia, inevitably leading to progressive global cognitive decline (Weksler et ai, 2005, Immunol Rev 205:244- 256). In an in vitro cell culture model of AD, the CBi receptor agonist anandamide prevented Aβ- induced neurotoxicity (Milton, 2002, Neurosci Lett 332: 127-130). [0281 J Thus, the present invention provides methods for diagnosing Alzheimer's disease in a subject., in a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having Alzheimer's disease with a radiolabeled compound to produce a CB₁ receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor. The measurable signal obtained from the subject suspected of having Alzheimer's disease may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having Alzheimer's disease, is indicative that the subject has Alzheimer's disease. A significantly lower or higher measurable signal from the subject suspected of having Alzheimer's disease differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%.

[0282] The present invention also provides methods for treating a subject having Alzheimer's disease. In a preferred embodiment, this method comprises the step of administering to a subject having Alzheimer's disease a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient. k) Multiple Sclerosis

[0283] Multiple sclerosis (MS) is a complex, immune-mediated, inflammatory disease of the white matter of the brain, which compromises impulse conduction due to the loss of the myelin sheath of neurons and the secondary axonal loss. MS affects 2 to 5 million people worldwide and commonly presents with an unpredictable, relapsing-remitting course and a range of clinical symptoms depending on where the demyelination and axonal loss have occurred. Although there are numerous drugs available that target the immune system to slow down the progression of the disease, they are only moderately effective, and the treatment of MS remains mostly symptomatic and far from satisfactory (Pacher et ai, 2006, Pharmacol Rev 58:389-462). Cannabis had been used in ancient Greece, Rome, China, and India for relieving muscle cramps, spasm, and pain and cannabinoid-based compounds may be useful for relieving MS symptoms (Pacher et ai, 2006, Pharmacol Rev 58:389-462). [0284] Thus, the present invention provides methods for diagnosing multiple sclerosis in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having multiple sclerosis with a radiolabeled compound to produce a CB₁ receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBj receptor. The measurable signal obtained from the subject suspected of having multiple sclerosis may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having multiple sclerosis, is indicative that the subject has multiple sclerosis. A significantly lower or higher measurable signal from the subject suspected of having multiple sclerosis differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%.

[0285] The present invention also provides methods for treating a subject having multiple sclerosis. In a preferred embodiment, this method comprises the step of administering to a subject having multiple sclerosis a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient. 1) Acute, Chronic, and Neuropathic Pain

[0286] One of the earliest uses of cannabis was to neat pain. Historical documents reveal the use of cannabis for surgical anesthesia in ancient China and to relieve pain of diverse origin in ancient Israel, Greece, Rome, and India. In acute pain, anandamide, THC, cannabidiol, and synthetic cannabinoids such as CP55,940 and WTN 55,212-2 are effective against chemical, mechanical, and thermal pain stimuli {see, Pacher et al., 2006, Pharmacol Rev 58:389-462). Recent animal studies indicate that anandamide and cannabinoid ligands are also very effective against chronic pain of both neuropathic and inflammatory origin (see, Pacher et al, 2006, Pharmacol Rev 58:389-462). [0287] Compounds of the present invention are useful for the treatment of pain (Walker et al., 1999, Life Sci 65:665-673; Pacher et al., 2006, Pharmacol Rev 58:389-462). Specifically, compounds of the present invention may be used as a selective blocker of the CBi receptor for the management of acute, chronic and neuropathic pain, and, in particular, as therapeutics for the treatment of acute, chronic and neuropathic pain. [0288] Thus, the present invention provides methods for diagnosing acute, chronic or neuropathic pain in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a subject suspected of having acute, chronic or neuropathic pain with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor. The measurable signal obtained from the subject suspected of having acute, chronic or neuropathic pain may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having acute, chronic or neuropathic pain, is indicative that the subject has acute, chronic or neuropathic pain. A significantly lower or higher measurable signal from the subject suspected of having acute, chronic or neuropathic pain differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%. [0289] The present invention also provides methods for treating a subject having acute, chronic or neuropathic pain. In a preferred embodiment, this method comprises the step of administering to a subject having acute, chronic or neuropathic pain a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient. in) Nausea and Emesis

[0290] Nausea and vomiting (emesis) can present as symptoms of a variety of diseases or as secondary consequences of chemotherapy or radiotherapy of cancer. It is for this latter indication that THC has gained acceptance as a highly efficacious therapeutic agent, often effective in cases resistant to other, more conventional, medications (Pacher et al, 2006, Pharmacol Rev 58:389-462). Emesis is thought to involve activation of specific receptors on sensory nerve endings in the gut and also in brainstem regions including the medullary chemoreceptor trigger zone and the lateral reticular formation. The involvement Of CB₁ receptors is clearly indicated by the ability of SR141716 to reverse the effects of THC and synthetic agonists in suppressing vomiting caused by cisplatin or lithium chloride, or by the ability of these agonist to reverse the emesis elicited by SR141716 in the least shrew (Pacher et al, 2006, Pharmacol Rev 58:389-462). [0291] Compounds of the present invention are useful for the treatment of nausea and emesis (Simoneau el al., 2001 , Anesthesiology 94.882-887, Pacher el al, 2006, Pharmacol Rev 58:389-462). Specifically, compounds of the present invention may be used as a selective blocker of the CB₁ receptor for the management of nausea and emesis, and, in particular, as therapeutics for the treatment of nausea and emesis. [0292] Thus, the present invention provides methods for diagnosing nausea or emesis in a subject.. In a preferred embodiment, this method comprises the steps of (a) contacting a CB₁ receptor in a subject suspected of having nausea or emesis with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor. The measurable signal obtained from the subject suspected of having nausea or emesis may optionally be compared to a measurable signal obtained in a healthy, normal, or control subject. A significantly lower or higher measurable signal in the subject suspected of having nausea or emesis, is indicative that the subject has nausea or emesis. A significantly lower or higher measurable signal from the subject suspected of having nausea or emesis differs from the control measurable signal by at least 20%, at least 30%, at least 40%, at least 50%, at least 60% at least 70%, at least 80%, at least 90%, at least 100%, at least 150%, or at least 200%. [0293] The present invention also provides methods for treating a subject having nausea or emesis. In a preferred embodiment, this method comprises the step of administering to a subject having nausea or emesis a therapeutically effective amount of a composition comprising (i) a compound of the present invention and (ii) a pharmaceutically acceptable carrier or excipient.

3. Diagnostic Imaging of a Tissue Having a CBi Receptor

[0294] In another aspect of the present invention, methods for measuring the density of a protein target, preferably a CBi receptor, in a tissue are provided. In a preferred embodiment, this method comprises the steps of (a) contacting a CBi receptor in a tissue with a radiolabeled compound to produce a CBi receptor-radiolabeled compound complex; and (b) measuring the density of the CBi receptor. A measurable signal is indicative of the amount of the radiolabeled compound interacting with the CBi receptor, i.e., the density of the CBi receptor in the tissue.

[0295] A preferred tissue is brain. Methods for brain tissue and brain membrane preparations and CBj binding assays are known in the art (Devane et al., 1988, Science

258: 1946-1949; Compton el al, 1993, J Pharmacol Exp Ther 265:218-226; Thomas el al, 1998, JPharm Exp Ther 285:285-292). Further, whole rat brains may be obtained from Charles River or Pel-Freez Biologicals. Human brain sections may be obtained from the National Disease Research Institute. Other tissues of interest are peripheral tissues also expressing CBi receptors, including liver, pancreas, skeletal muscle and fat (Mackie, 2008, NϋuroEntlocrinology 20:10-14).

D. Measuring an Interaction of a Test Compound with CBi Receptors In Vitro and In Vivo

1. Measuring Binding of a Test Compound to a CBi Receptors [0296] CBi receptors are important targets for the development of drugs to counter pain, obesity, neuropsychiatry and neurodegenerative disorders, smoking addiction, and the like. For the purpose of clinical trials, it is important to know the range of drug dose to be tested. Too low a range may compromise observation of drug efficacy of the drug, while choice of too high a dose range would expose otherwise avoidable toxicological effects, and terminate drug development. PET or SPECT can be a uniquely useful tool for assessing the optimal range of drug dose to be used in clinical trials, provided a suitable radioligand, such as those provided by the present invention, is available to image and quantify the available drug target. The radioligand binds to a small representative proportion of the available drug target, i.e. the CB₁ receptor. The degree to which the CB₁ receptor is occupied by the developmental drug (or test compound) can be detected and measured as reduced binding of the radioligand to the CBj receptor. In this way the dose response of target receptor occupancy can be determined and the range of dose to be used in clinical trials can be set to achieve desirable receptor occupancy. Properly titrated occupancy curves enable determination of the range of doses required for achieving desirable CB i receptor occupancy of the drug, and result in fewer subjects needed for the clinical trial than would be needed without this important guiding information. This provides a more sound scientific basis for the trial and saves enormous expenses on unnecessarily broad trials in large numbers of human subjects. This phase of drug development can cost an appreciable fraction of the typical cost of drug development (~ $ 1 billion). A typical RO study may require 10 to 20 PET scans at a commercial rate of perhaps up to $40,000 per scan.

[0297] The CBi receptor mediates several pharmacological effects and is an active target for therapeutic drug development (Howlett et al., 2002, Pharmacol Rev 54: 161-202; Le Foil and Goldberg, 2005, ./ Pharmacol Exp 7/?<?Λ 312:875-883). Success of drug development for neuropsychiatry and other indications is significantly enhanced with the ability to directly measure spatial and temporal binding of compounds to receptors on central compartment.

[0298] Radiotracers of the present invention compete with unlabeled CBi receptor antagonists, inverse agonists, agonists, and test compounds.

[0299J Thus, in another aspect of the present invention, methods are provided to assess the amount of developmental drug (or test compound) required to achieve a necessary level of protein target (preferably a CBi receptor) occupancy by the drug. Such a study, known as a Receptor Occupancy (RO) study is generally performed preceding clinical trails of the developmental drug. The RO study data, obtained through PET imaging, are extremely useful preceding clinical trials of developmental drugs. They may determine the best dose range to be used in the clinical trial.

[0300] The present invention provides methods for measuring an interaction of a test compound with a CBi receptor. In a preferred embodiment of the present invention, this method comprises the steps of (a) contacting a CBi receptor preparation with a radiolabeled compound, e.g. a radiotracer as described herein, to produce a CBi receptor-radiolabeled compound complex, (b) measuring an interaction of the radiolabeled compound with the CBi receptor; wherein a first measurable signal is obtained, (c) contacting the CBi receptor- radiolabeled compound complex with a test compound under conditions whereby the interaction of the radiolabeled compound with the CBi receptor is prevented by the test compound, and (d) detecting a second measurable signal. A higher second measurable signal when compared to the first measurable signal is indicative of the test compound interacting with the CBi receptor. A second measurable signal which is substantially the same as the first measurable signal is indicative that the test compound does not interact with the CBi receptor. The radiolabeled compound for measuring an interaction of a test compound with CBi receptors in vitro and in vivo may be any radiotracer described herein, preferably a radiotracer selected from the group consisting of a compound having the Formula (XIII), a compound having the Formula (XV), a compound having the Formula (XXVI), a compound having the Formula (XVIII), a compound having the Formula (XXVII)₅ a compound having the Formula (XIX)₇ a compound having the Formula (XX), a compound having the Formula (XXI), and a compound having the Formula (XXVIII). [03011 The CB] receptor preparation is contacted with a radiolabeled compound using an effective amount of the radiolabeled compound to achieve the desired effect.

[0302] In another preferred embodiment of the present invention, the method for measuring an interaction of a test compound with a CB i receptor comprises the steps of (a) contacting a CBi receptor preparation with a mixture comprising (i) a radiolabeled compound, such as a radiotracer, and (ii) a test compound to produce a CBi receptor-radiolabeled compound complex and a CBi receptor-test compound complex, (b) measuring the interaction of the radiolabeled compound with the CBi receptor; wherein a first measurable signal is obtained, and (c) comparing the first measurable signal to a second measurable signal obtained by contacting the CBi receptor with the radiolabeled compound in the absence of the test compound. A lower first measurable signal when compared to the second measurable signal is indicative of the test compound interacting with the CB] receptor.

[0303] The first and second measurable signals may be recorded, e.g., in an electronic or optical database.

2. CBi Receptor Preparation [0304] λ'arious CBi receptor preparations are useful in the above methods. In some embodiments, the CB) receptor preparation is a membrane preparation. Alternatively, the CBi receptor preparation is a whole cell preparation. [0305] The CBi receptor preparation may be a mammalian cell expressing CBi receptor. Mammalian cells, in particular human cell lines, may be used in the methods of the present invention. Expression of CBi receptor can be confirmed by detecting the CBi receptor polypeptide and/or detecting CBi receptor mRNA using methods known in the art (e.g., Western blotting, immunoassays, Northern blotting and PCR; e.g., see Sambrook, Fritsch, and Maniatis, "Molecular Cloning A Laboratory Manual " published by Cold Spring Harbor Laboratory Press, 2nd edition, 1989; Inis e/ al. (1990) PCR Protocols, A Guide to Methods and Applications, Academic Press, Inc. N. Y)).

[0306] In another embodiment, the CBi receptor preparation comprises an isolated CBi receptor, preferably a recombinantly produced CBi receptor. Nucleotide sequences and protein sequences for making recombinant CBi receptor are known in the art and are available, e.g., from GenBank. Further, methods for making and purifying recombinant proteins are known in the art.

[0307] In some embodiments the CBj receptor preparation is immobilized to a solid support or supports. A preferred support or supports is a collection of beads or particles. The solid support or supports can be selected from the group consisting of discrete particles (spherical or irregular), beads, fibers, filters, membranes, nanoparticles, and monoliths.

3. Test Compounds

[0308] Suitably, the test compound is a chemical compound. For-example, the test compound may be a naturally occurring compound, such as a peptide or a nucleic acid. Typically, the test compound will be a drug or drug candidate. In general, drugs or drug candidates are low molecular weight organic compounds which have been specifically synthesized or optimized to evaluate their biological efficacy in a drug discovery/evaluation program. The test compound may also be an organic toxin, or a candidate for radiolabeling and development as an imaging agent.

[0309] A preferred test compound is a compound which is a suspected inhibitor of a CBj receptor function, such as a CBj receptor antagonist.

[0310] Another preferred test compound is a compound which is a suspected substrate of a CBi receptor. [0311] In a preferred embodiment, a test compound is a radiotracer other than a radiolabeled compound of Formula (XHI), a compound having the Formula (XV), a compound having the Formula (XXVI), a compound having the Formula (XVIII), a compound having the Formula (XXVII), a compound having the Formula (XIX), a compound having the Formula (XX), a compound having the Formula (XXl), and a compound having the Formula (XXVIII), which may be evaluated for use as a radiotracer. In a preferred embodiment, CBi receptor functionality is determined in the presence of this radiotracer and a CBi receptor inhibitor.

IV. PHARMACEUTICAL COMPOSITIONS

[0312] In one aspect the present invention provides a pharmaceutical composition or a medicament comprising at least one compound of the present invention and optionally a pharmaceutically acceptable carrier. A pharmaceutical composition or medicament can be administered to a patient for the diagnosis or treatment of a condition, such as diarrhea, gastroenteritis, irritable bowel syndrome, cancer or a neuropsychiatric condition.

A. Formulations and Administrations

[0313] The compounds of the present invention are useful in the manufacture of a pharmaceutical composition or a medicament comprising an effective amount thereof in conjunction or mixture with excipients or carriers suitable for either enteral or parenteral application.

[0314] Pharmaceutical compositions or medicaments for use in the present invention can be formulated by standard techniques using one or more physiologically acceptable carriers or excipients. Suitable pharmaceutical carriers are described herein and in "Remington's

Pharmaceutical Sciences" by E. W. Martin. The compounds of the present invention and their physiologically acceptable salts and solvates can be formulated for administration by any suitable route, including via inhalation, topically, nasally, orally, parenterally, or rectally. Thus, the administration of the pharmaceutical composition may be made by intradermal, subdermal, intravenous, intramuscular, intranasal, intracerebral, intratracheal, intraarterial, intraperitoneal, intravesical, intrapleural, intracoronary or intratumoral injection, with a syringe or other devices. Transdermal administration is also contemplated, as are inhalation or aerosol administration. Tablets and capsules can be administered orally, rectally or vaginally. [0315] For oral administration, a pharmaceutical composition or a medicament can take the form of, for example, a tablet or a capsule prepared by conventional means with a pharmaceutically acceptable excipient. Preferred are tablets and gelatin capsules comprising the active ingredient, i.e., a composition of the present invention, together with (a) diluents or fillers, e.g., lactose, dextrose, sucrose, mannitol, sorbitol, cellulose (e.g., ethyl cellulose, microcrystalline cellulose), glycine, pectin, polyacrylates and/or calcium hydrogen phosphate, calcium sulfate, (b) lubricants, e.g., silica, talcum, stearic acid, its magnesium or calcium salt, metallic stearates, colloidal silicon dioxide, hydrogenated vegetable oil, com starch, sodium benzoate, sodium acetate and/or polyethyleneglycol: for tablets also (c) binders, e.g., magnesium aluminum silicate, starch paste, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, polyvinylpyrrolidone and/or hydroxypropyl methylcellulose; if desired (d) disintegrants, e.g., starches (e.g., potato starch or sodium starch), glycolate, agar, alginic acid or its sodium salt, or effervescent mixtures; (e) wetting agents, e.g., sodium lauryl sulphate, and/or (f) absorbents, colorants, flavors and sweeteners.

[0316] For oral administration, a pharmaceutical composition or a medicament can take the form of, for example, a tablet or a capsule prepared by conventional means with a pharmaceutically acceptable excipient. Preferred are tablets and gelatin capsules comprising the active ingredient, i.e., a composition of the present invention, together with (a) diluents or fillers, e.g., lactose, dextrose, sucrose, mannitol, sorbitol, cellulose (e.g., ethyl cellulose, microcrystalline cellulose), glycine, pectin, polyacrylates and/or calcium hydrogen phosphate, calcium sulfate, (b) lubricants, e.g., silica, talcum, stearic acid, its magnesium or calcium salt, metallic stearates, colloidal silicon dioxide, hydrogenated vegetable oil, corn starch, sodium benzoate, sodium acetate and/or polyethyleneglycol; for tablets also (c) binders, e.g., magnesium aluminum silicate, starch paste, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose, polyvinylpyrrolidone and/or hydroxypropyl methylcellulose; if desired (d) disintegrants, e.g., starches (e.g., potato starch or sodium starch), glycolate, agar, alginic acid or its sodium salt, or effervescent mixtures; (e) wetting agents, e.g., sodium lauryl sulphate, and/or (f) absorbents, colorants, flavors and sweeteners.

[0317] Tablets may be either film coated or enteric coated according to methods known in the art. Liquid preparations for oral administration can take the form of, for example, solutions, syrups, or suspensions, or they can be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations can be prepared by conventional means with pharmaceutically acceptable additives, for example, suspending agents, for example, sorbitol syrup, cellulose derivatives, or hydrogenated edible fats; emulsifying agents, for example, lecithin or acacia; non-aqueous vehicles, for example, almond oil, oily esters, ethyl alcohol, or fractionated vegetable oils; and preservatives, for example, methyl or propyl-p-hydroxybenzoates or sorbic acid. The preparations can also contain buffer salts, flavoring, coloring, and/or sweetening agents as appropriate. If desired, preparations for oral administration can be suitably formulated to give controlled release of the active composition.

[0318] For administration by inhalation the compounds may be conveniently delivered in the form of an aerosol spray presentation from pressurized packs or a nebulizer, with the use of a suitable propellant, for example, dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, 1, 1,1,2-tetrafluorethane, carbon dioxide, or other suitable gas. In the case of a pressurized aerosol, the dosage unit can be determined by providing a valve to deliver a metered amount. Capsules and cartridges of, for example, gelatin for use in an inhaler or insufflator can be formulated containing a powder mix of the compound and a suitable powder base, for example, lactose or starch.

[0319] The compounds of the present invention can be formulated for parenteral administration by injection, for example by bolus injection or continuous infusion.

Formulations for injection can be presented in unit dosage form, for example, in ampoules or in multi-dose containers, with an added preservative. Injectable compositions are preferably aqueous isotonic solutions or suspensions, and suppositories are preferably prepared from fatty emulsions or suspensions. The compositions may be sterilized and/or contain adjuvants, such as preserving, stabilizing, wetting or emulsifying agents, solution promoters, salts for regulating the osmotic pressure and/or buffers. Alternatively, the active ingredient can be in powder form for constitution with a suitable vehicle, for example, sterile pyrogen-free water, before use. In addition, they may also contain other therapeutically valuable substances. The compositions are prepared according to conventional mixing, granulating or coating methods, respectively, and contain about 0.1 to 75%, preferably about 1 to 50%, of the active ingredient

[0320] Suitable formulations for transdermal application include an effective amount of a composition of the present invention with carrier. Preferred carriers include absorbable pharmacologically acceptable solvents to assist passage through the skin of the host. For example, transdermal devices are in the form of a bandage comprising a backing member, a reservoir containing the composition optionally with carriers, optionally a rate controlling barrier to deliver the composition to the skin of the host at a controlled and predetermined rate over a prolonged period of time, and means to secure the device to the skin. Matrix transdermal formulations may also be used.

[0321] Suitable formulations for topical application, e.g., to the skin and eyes, are preferably aqueous solutions, ointments, creams or gels well-known in the art. Such may contain solubilizers, stabilizers, tonicity enhancing agents, buffers and preservatives.

[0322] Suitable formulations for topical application, e.g., to the skin and eyes, are preferably aqueous solutions, ointments, creams or gels well-known in the art. Such may contain solubilizers, stabilizers, tonicity enhancing agents, buffers and preservatives.

[0323] Furthermore, the compositions can be formulated as a depot preparation. Such long-acting formulations can be administered by implantation (for example, subcutaneously or intramuscularly) or by intramuscular injection. Thus, for example, the composition can be formulated with suitable polymeric or hydrophobic materials (for example as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, for example, as a sparingly soluble salt. [0324] The compositions can, if desired, be presented in a pack or dispenser device that can contain one or more unit dosage forms containing the active ingredient. The pack can, for example, comprise metal or plastic foil, for example, a blister pack. The pack or dispenser device can be accompanied by instructions for administration.

[0325] In one embodiment of the present invention, a pharmaceutical composition or medicament comprises an effective amount of a compound of the present invention and another therapeutic agent.

[0326] In one aspect of the present invention, a therapeutically effective amount of a compound of the present invention is administered in combination with surgery, and optionally administration of another chemotherapeutic agent. B. Dosing

[0327] In one embodiment of the present invention, a pharmaceutical composition or medicament is administered to a patient at a therapeutically effective dose to diagnose, prevent, treat, or control a neuropsychciatric condition, a neurological condition, or multidrug resistance. The pharmaceutical composition or medicament is administered to a patient in an amount sufficient to elicit an effective therapeutic or diagnostic response in the patient. An effective therapeutic or diagnostic response is a response that at least partially arrests or slows the symptoms or complications of the disease or permits diagnosis of the disease. An amount adequate to accomplish this is defined as "therapeutically effective dose."

[0328] The dosage of active compounds or compositions administered is dependent on the species of warm-blooded animal (mammal), the body weight, age, individual condition, surface area of the area to be treated and on the form of administration. The size of the dose also will be determined by the existence, nature, and extent of any adverse effects that accompany the administration of a particular compound in a particular subject. A unit dosage for administration to a mammal of about 50 to 70 kg may contain between about 5 and 500 mg of the active ingredient. Typically, a dosage of the compound of the present invention, is a dosage that is sufficient to achieve the desired effect.

[0329] Optimal dosing schedules can be calculated from measurements of compound accumulation in the body of a subject. In general, dosage is from 1 ng to 1 ,000 mg per kg of body weight and may be given once or more daily, weekly, monthly, or yearly. Persons of ordinary skill in the art can easily determine optimum dosages, dosing methodologies and repetition rates. One of skill in the art will be able to determine optimal dosing for administration of a radiotracer to a human being following established protocols known in the art, the disclosure herein, in particular, the experimental details where radiotracers were administered to monkeys.

[0330] Optimum dosages, toxicity, and therapeutic efficacy of some compounds may vary depending on the relative potency of individual compounds and can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, for example, by determining the LD^ (the dose lethal to 50% of the population) and the ED.™ (the dose therapeutically effective in 50% of the population). The dose ratio between toxic and therapeutic effects is the therapeutic index and can be expressed as the ratio, LD50/ED50. Compounds that exhibit large therapeutic indices are preferred. While compounds that exhibit toxic side effects can be used, care should be taken to design a delivery system that targets such compounds to the site of affected tissue to minimize potential damage to normal cells and, thereby, reduce side effects.

[0331] The data obtained from, for example, animal studies (e.g. rodents and monkeys herein) can be used to formulate a dosage range for use in humans. The dosage of compounds of the present invention lies preferably within a range of circulating concentrations that include the ED50 with little or no toxicity. The dosage can vary within this range depending upon the dosage form employed and the route of administration. For any small molecule compound used in the methods of the invention, the therapeutically effective dose can be estimated initially from cell culture assays. A dose can be formulated in animal models to achieve a circulating plasma concentration range that includes the IC50 (the concentration of the test compound that achieves a half-maximal inhibition of symptoms) as determined in cell culture. Such information can be used to more accurately determine useful doses in humans. Levels in plasma can be measured, for example, by high performance liquid chromatography (HPLC). In general, the dose equivalent of a small molecule compound is from about 1 ng/kg to 100 mg/kg for a typical subject. [0332] The dosage of active compositions administered is also dependent on the nature of the agent. For example, a therapeutically effective amount of a compound of the present invention (i.e., an effective dosage) for, e.g., treatment of diarrhea, ranges from about 0.001 to 30 mg/kg body weight, preferably about 0.01 to 25 mg/kg body weight, more preferably about 0.1 to 20 mg/kg body weight, and even more preferably about 1 to 10 mg/kg, 2 to 9 mg/kg, 3 to 8 mg/kg, 4 to 7 mg/kg, or 5 to 6 mg/kg body weight. The compound can be administered one time per week for between about 1 to 10 weeks, preferably between 2 to 8 weeks, more preferably between about 3 to 7 weeks, and even more preferably for about 4, 5, or 6 weeks.

[0333] Exemplary doses of the compositions described herein, include milligram or microgram amounts of the composition per kilogram of subject or sample weight (e.g., about 1 microgram per-kilogram to about 500 milligrams per kilogram, about 100 micrograms per kilogram to about 5 milligrams per kilogram, or about 1 microgram per kilogram to about 50 micrograms per kilogram. It is furthermore understood that appropriate doses of a composition depend upon the potency of the composition with respect to the desired effect to be achieved. When one or more of these compositions is to be administered to an animal, a physician, veterinarian, or researcher may, for example, prescribe a relatively low dose at first, subsequently increasing the dose until an appropriate response is obtained. In addition, it is understood that the specific dose level for any particular animal subject will depend upon a variety of factors including the activity of the specific composition employed, the age, body weight, general health, gender, and diet of the subject, the time of administration, the route of administration, the rate of excretion, any drug combination, and the degree of expression or activity to be modulated. [0334] In one embodiment of the present invention, a pharmaceutical composition or medicament comprising a compound of the present invention is administered, e.g., in a daily ■ dose in the range from about 1 mg of compound per kg of subject weight (1 mg/kg) to about lg/kg. In another embodiment, the dose is a dose in the range of about 5 mg/kg to about 500 mg/kg. In yet another embodiment, the dose is about 10 mg/kg to about 250 mg/kg. In another embodiment, the dose is about 25 mg/kg to about 150 mg/kg. A preferred dose is about 10 mg/kg. The daily dose can be administered once per day or divided into subdoses and administered in multiple doses, e.g., twice, three times, or four times per day. However, as will be appreciated by a skilled artisan, compositions identified by methods of the present invention may be administered in different amounts and at different times. The skilled artisan will also appreciate that certain factors may influence the dosage and timing required to effectively treat a subject, including but not limited to the severity of the disease or disorder, previous treatments, the general health and/or age of the subject, and other diseases present. Moreover, treatment of a subject with a therapeutically effective amount of a composition can include a single treatment or, preferably, can include a series of treatments.

[0335J To achieve the desired therapeutic effect, compositions may be administered for multiple days at the therapeutically effective daily dose. Thus, therapeutically effective administration of compositions to treat a pathological condition or disease described herein in a subject requires periodic (e.g., daily) administration that continues for a period ranging from three days to two weeks or longer. Typically, compounds or compositions will be administered for at least three consecutive days, often for at least five consecutive days, more often for at least ten, and sometimes for 20, 30, 40 or more consecutive days. While consecutive daily doses are a preferred route to achieve a therapeutically effective dose, a therapeutically beneficial effect can be achieved even if the compounds or compositions are not administered daily, so long as the administration is repeated frequently enough to maintain a therapeutically effective concentration of the compound in the subject. For, example, one can administer a compound or composition every other day, every third day, or, if higher dose ranges are employed and tolerated by the subject, once a week

[0336] Following successful treatment, it may be desirable to have the subject undergo maintenance therapy to prevent the recurrence of the condition or disease treated. V. KITS AND SYSTEMS

[0337] For use in diagnostic, research, and therapeutic applications suggested above, kits and systems are also provided by the invention. In the diagnostic and research applications such kits and systems may include any or all of the following: assay reagents, buffers, a compound of the present invention, a CBi receptor preparation, a CBi receptor polypeptide, etc. A therapeutic product may include sterile saline or another pharmaceutically acceptable emulsion and suspension base.

[0338] n addition, the kits and systems may include instructional materials containing directions (i.e., protocols) for the practice of the methods of this invention. The instructions may be present in the subject kits in a variety of forms, one or more of which may be present in the kit. While the instructional materials typically comprise written or printed materials they are not limited to such. Any medium capable of storing such instructions and communicating them to an end user is contemplated by this invention. Such media include, but are not limited to electronic storage media (e.g., magnetic discs, tapes, cartridges, chips). optical media (e.g., CD ROM), and the like. Such media may include addresses to internet sites that provide such instructional materials.

[0339] A wide variety of kits, systems, and components can be prepared according to the present invention, depending upon the intended user of the kit and system and the particular needs of the user. [0340] In a preferred embodiment of the present invention, the kit or system comprises a compound of the present invention, preferably an isolated radiolabeled compound selected from the group consisting of a compound having the Formula (XIII), a compound having the Formula (XV), a compound having the Formula (XXVI), a compound having the Formula (XVlIl), a compound having the Formula (XXVIl), a compound having the Formula (XlX), a compound having the Formula (XX), a compound having the Formula (XXI), and a compound having the Formula (XXVIII); and (ii) a preparation of a CBi receptor.

[0341] The kits or systems according to the present invention may further comprise a reagent for assessing CB₁ receptor function. Such reagents are described herein or are well known to those skilled in the art. [0342] Additional kit embodiments of the present invention include optional functional components that would allow one of ordinary skill in the art to perform any of the method variations described herein. [0343) Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Although the forgoing invention has been described in some detail by way of illustration and example for clarity and understanding, it will be readily apparent to one of ordinary skill in the art in light of the teachings of this invention that certain variations, changes, modifications and substitutions of equivalents may be made thereto without necessarily departing from the spirit and scope of this invention. As a result, the embodiments described herein are subject to various modifications, changes and the like, with the scope of this invention being determined solely by reference to the claims appended hereto. Those of skill in the art will readily recognize a variety of non-critical parameters that could be changed, altered or modified to yield essentially similar results.

[0344] While each of the elements of the present invention is described herein as containing multiple embodiments, it should be understood that, unless indicated otherwise, each of the embodiments of a given element of the present invention is capable of being used with each of the embodiments of the other elements of the present invention and each such use is intended to form a distinct embodiment of the present invention.

[0345] The referenced patents, patent applications, and scientific literature, including accession numbers to GenBank database sequences, referred to herein are hereby incorporated by reference in their entirety as if each individual publication, patent or patent application were specifically and individually indicated to be incorporated by reference. Any conflict between any reference cited herein and the specific teachings of this specification shall be resolved in favor of the latter. Likewise, any conflict between an art-understood definition of a word or phrase and a definition of the word or phrase as specifically taught in this specification shall be resolved in favor of the latter. [0346] As can be appreciated from the disclosure above, the present invention has a wide variety of applications. The invention is further illustrated by the following examples, which are only illustrative and are not intended to limit the definition and scope of the invention in any way.

VI. EXAMPLES Example 1: General Methods

(a) Reagents and Reactions [0347] All reagents were of ACS or HPLC quality and purchased from commercial sources, and were used as received unless otherwise stated. 4-Cyanophenylsulfonamide, 4 bromophenylsulfonamide and 4-iodophenylsulfonamide were synthesized by known procedures (Jaffe and Leffler, 1975, J Org Chem 40:797-799). 3-(4-Chloroρhenyl)-4,5- dihydro-4-phenyl-1 H-pyrazole was also synthesized as reported (Grosscurtt et al., 1979, J Agric Food Chem 27:406-409). Compounds 16 and rimonabant were synthesized as previously described (Fan et al., 2006, J Label Compd Radiopharm 49: 1021-1036; Donohue at al., 2008, Tetrahedron Lett 49:2789-2791 ). Unlabeled N-(4 fluorobenzyl)-4-(3-(piperidin- l-yl)-indole- l-sulfonyl)benzamide (PipISB, Formula (XXIX)):

XXIX was provided by Eli Lilly and Co.

(b) ΝMR Spectra and High-Resolution Mass Spectra

[0348) ¹H (400 MHz) and ¹³C ( 100 MHz) ΝMR spectra were recorded at room temperature on an Avance-400 spectrometer (Brucker; Billerica, MA). Chemical shifts are reported in e> units (ppm) downfield relative to the chemical shift for tetramethylsilane (TMS). Signals are quoted as s (singlet), d (doublet), dd (double doublet), dt (double triplet), t (triplet), q (quartet) or m (multiplet). High-resolution mass spectra were determined using a time-of- flight electrospray instrument (University of Illinois at Urbana, Champaign, IL, USA). (c) Melting Points, Elemental Analysis and Lipophiliciries

[0349] Melting points were determined using a Mel-temp melting point apparatus (Electrothermal, Fisher Scientific, USA) and were uncorrected. Elemental analysis was acquired from Midwest Microlab, LLC (Indianapolis, IN, USA). Lipophilicities were computed with Advanced Chemistry Development (ACD) 9.2.

(d) Chiral HPLC

[0350] Chiral HPLC, for the preparative resolution of racemates to enantiomers, was performed on a chiral column (ChiralPak AD, 20 ^x 250 mm) eluted with acetonitrile at 6 or 8 mL/min, as later specified. The enantiomeric excess (ee) of each resolved compound was measured by HPLC with the same method as used for resolution.

(e) Measurements of Optical and Specific Rotations

[0351] Optical rotations ( [a]^ ) were measured with a P- 1010 polarimeter (JASCO; Easton, MD). Specific rotations were obtained at room temperature.

(f) Mass Spectra

[0352] Mass spectra were acquired using a LCQ^DECA (Thermo Fisher Scientific; Waltham, MA, USA) or a LCQ^DECA LC-MS instrument (Thermo Finnigan; San Jose, CA, USA) fitted with a reverse phase LC column (Luna, C 18; 5 μm, 2 x 150 mm; Phenomenex; Torrance, CA, USA) and eluted at 150 uL/min with MeOH-H₂O mixture. High-resolution mass spectra (HRMS) were determined with time-of-flight electrospray instrumentation (University of Illinois at Urbana, Champaign, IL, USA).

(g) Radiosyntheses

[0353] Radiosyntheses were performed in a custom-made remotely-controlled apparatus (Cheng et a!., 1973, Biochem Pharmacol 22:3099-3108).

(h) Separation of Radioligands and Determination of Purity and Radioactivity

[0354] Radioligand separations were performed with HPLC on a reverse phase column (μ-Bondapak C-18; 7.8 x 300 mm, 10 μm; Waters). The column outlet was connected to an absorbance detector (λ = 254 nm) in series with a GM-tube for radiation detection.

Compounds ["C](±)-12a, [^πC](-)-12a and [^πC](+)-12a were purified in this system using MeCN-0.01 M H3PO₄ (55: 45, v/v) as mobile phase at 6 mL/min. The radiochemical purities and specific radioactivities of each product were determined with reverse phase HPLC on a μ-Bondapak C-18 column (3.9 x 300 mm, 10 μm; Waters) eluted at 3 mL/min with MeCN- H3PO₄ (0.01 M; 55: 45 v/v) as mobile phase. Eluate was monitored with an absorbance detector (λ = 254 nm) in series with a β-flow detector (Beckman) for radiation detection. The enantiomeric excess of each labelled product was measured by chiral HPLC, as described above; eluate was monitored for absorbance and radioactivity. Specific radioactivities (GBq/μmol) were determined with analytical HPLC calibrated for absorbance (λ = 254 nm) response per mass of ligand. The specific radioactivity was calculated as the radioactivity of the radioligand peak (decay-corrected) (GBq) divided by the mass of the associated carrier peak (μmol). The metabolism of compound [^uC](-)-12a was assessed with HPLC on a reverse phase (μ-Bondapak C- 18 column; 7.8 * 300 mm, 10 μm; Waters) eluted at 6 mL/min with a gradient of MeCN (A) and Uq-H₃PO₄ (0.01 M) (B), with A increased linearly to 65% v/v for 6 min and then to 35% v/v over the next 2 min and then held for 4 min. The column outlet was connected to an absorbance detector (λ = 270 nm) in series with a GM-tube for radiation detection.

(i) CBi and CB₂ Receptor Binding Assays

[0355J Frozen cell membranes (recombinant hCBlr or hCB2r; Perkin Elmer) were thawed and diluted (7 μg/well) in membrane buffer (final concentrations: 100 mM NaCl, 5 mM MgCl₂, 1 mM EDTA₁ 50 mM HEPES, 10 μM GDP, 100 μM DTT, 0 01% fatty acid free BSA).

[0356) [³⁵S]GTPyS was diluted with distilled water to a final concentration of 0.5 nM. The inhibitory effect of test ligands was measured against a concentration (ECgo) of the CB,r/CB₂r agonist CP-55,940 (Tocris) added to the solution. [0357] Membrane solution (100 μL) and radioligand solution (100 μL) were added to an assay plate together with 2 μL compound (concentration-response in DMSO) and incubated for 45 min at 3O⁰C. Bound [³⁵S]GTPyS was separated from free [³⁵S]GTPyS by rapid filtration under vacuum through Whatman GF/B glass fiber filters, followed by washes with cold wash solution (final concentration: 50 mM Tris, 5 mM MgCl₂, 50 mM NaCl). The filters were dried for 60 min at 5O⁰C. Scintillation film was melted onto the filters, which were then counted in a Microbeta scintillation counter. Non-specific binding was determined in the presence of a saturating concentration of GTPyS (final concentration 20 μM). ICso values were converted to K_x values according to the Cheng and Prusoff equation (Cheng et al., 1973, Biochem Pharmacol 22:3099-3108). The data represent K₁ ± SD (nM) from triplicate determinations vs. CBir or CB₂r. y — -^ SO

Q) Brain Tissue

[0358| Human brains were obtained post mortem by clinical autopsy at the National Institute of Forensic Medicine, Karolinska Institutet, Stockholm, Sweden. The studies were approved by the Ethics Committee at Karolinska Institutet and the Swedish Board of Social Welfare. Whole-hemispheres were removed, frozen and cryosectioned as described earlier using a cryomicrotome (Leica Cryomacrocut, CM3600, Leica, Nussloch, Germany). The tissue cryosections were transferred to gelatinized or poly-L-lysine-treated glass plates (10 x 22 cm), dried at room temperature and then stored with dehydrating agents (- 25°C) until use.

Example 2: Synthesis of CB₁ Receptor Ligands (12a-c)

[0359] 3,4-diarylpyrazoline derivatives, CBi ligands (12a-c) of the present invention, were synthesized by modifications of known general procedures (Scheme 1; e.g., see Lange at al., 2004 J Med Chem 47:627-643):

[0360] Scheme 1. Synthesis of 3,4-diarylpyrazoline derivatives.

9a, R¹ = CN 10a. R' = CN, 52% yield 11a, R¹ = CN, 78% yield b. R¹ = Br b, R¹ = Br.48% yield b, R' = Br, Θ2% yield c, R¹ = I C R¹ = I, 56% yield C, R¹ = I, 74% yield

c, d

(+)-12a. R¹ = CN (•)-12a, R¹ = CN (+/-)12a, R¹ = CN, 37% yield b. R¹ = Br b. R¹ = Br b. R¹ = Br, 43% yield c, R¹ = l C R¹ = l C R¹ = I, 64% yield Conditions: a) methyl chloroformate, TEA, MeCN; b) 3-(4-chlorophenyl)-4,5-dihydro-4- phenyl-lH-pyrazole, toluene, reflux; c) chlorobenzene, PCI₅; d) methanolic NH₃; e) ChiralPak AD, MeCN, 8 mL/min for compounds 12a and 12b and 6 mL/min for compound 12c. [0361] Briefly, in step (a), the appropriate 4-substituted benzenesulfonamides (9a-c) were treated with methyl chloroformate plus triethylamine in acetonitrile to give the corresponding carbamic acid methyl esters (lOa-c). In step (b), compounds lOa-c were then treated with 3 (4-chlorophenyl)-4,5-dihydro-4-phenyl-lH-pyrazole in toluene to give lla-c in good yields. Treatment of lla-c with PC15 in chlorobenzene in steps (c, d) gave the crude imino chlorides, which were readily converted with methanolic NH₃ into the target ligands, 12a-c. In step (e), these ligands were then resolved into their enantiomers (-)-12a-c and (+)-12a-c, respectively, with chiral HPLC as further described herein. The conditions were as follows: step (a), methyl chloroformate, TEA, MeCN; step (b), 3-(4-chlorophenyl)-4,5-dihydro-4- phenyl-lH-pyrazole, toluene, reflux; step (c), chlorobenzene, PC15; step (d) methanolic NH₃; step (e) ChiralPak AD, MeCN, 8 mL/min for 12a and 12b and 6 mL/min for 12c.

[0362| The following provides details of steps (a) through (e).

(i) W-[(4-Cyanophenyl)sulfonyl] carbamic acid methyl ester (Compound 10a)

[0363] Methyl chloroformate (6.34 mL, 82.4 mmol) was slowly added to a stirred solution of 4 cyanobenzenesulfonamide (10 g, 54.9 mmol) and triethylamine (23 mL, 165 mmol) in acetonitrile (75 mL). The reaction was stirred at room temperature for 16 h and then evaporated to dryness in vacuo. After addition of ethyl acetate and aq. NaHCO₃ to the crude residue, the aqueous layer was separated and acidified. The oily precipitate crystallized on standing and was filtered off, washed with water and dried to give compound 10a (6.9 g, 52% yield); mp 130-132^ϋC; ¹H NMR (400 MHz, CDCl₃) δ 3.72 (s, 3H), 7.87 (2H, dt, J = 8.76 and 1.96 Hz), 8.19 (2H, dt, J = 8.76 and 1 .96 Hz), NH proton invisible.

(ii) Λ'-[(4-Bromophenyl)sulfonyl]carbamic acid methyl ester (Compound 10b)

[0364] Compound 10b was prepared from 4 bromobenzenesulfonamide in 48% yield by the method described for compound 10a; mp 120-122⁰C; IH NMR (400 MHz, CDCl₃) δ ^• 3.72 (s, 3H), 7.71 (2H, dt, ./ = 8.76 and 1.96 Hz), 7.93 (2H, dt, ./ = 8.76 and 1.96 Hz), NH proton invisible. (iii) N-[(4-Iodophenyl)sulfonyl]carbamic acid methyl ester (Compound 10c)

[0365) Compound 10c was prepared from 4 iodoobenzenesulfonamide in 56% yield by the method described for compound 10a; mp 1 16-1 18°C; IH NMR (400.13 MHz, CDCl₃) δ 3.72 (s, 3H), 7.77 (2H, dt, ./ = 8.76 and 1.96 Hz), 7.93 (2H, dt, ./ = 8.76 and 1.96 Hz), NH proton invisible.

(iv) 3-(4-Chlorophenyl)-./V-[(4-cyanophenyl)sulfonyll-4-phenyl-4,5- dihydro-lH-pyrazole-l-carboxamide (Compound Ha)

[0366| To a solution of 3-(4-chlorophenyl)-4,5-dihydro-4-phenyl- lH-pyrazole (6.4 g, 25.4 mmol) in toluene (100 mL) was added compound 10a (6.1 g, 25.4 mmol) and the resulting solution was heated to reflux for 2 h. After cooling to room temperature, compound 1 Ia began to crystallize slowly from solution. The crystals were filtered off and washed twice with MTBE to give pure compound 11a (9.2 g, 78% yield); mp 208-210⁰C; ¹H NMR (400 MHz, CDCb) δ 3.92 (IH, dd, J = 6.16 and 5.18 Hz)₁ 4.34 (IH, t, J = 4.34.Hz), 4.75 (I H, dd, J = 6.16 and 5.18 Hz), 7.12 (2H, dt, ./ = 6.60 and 1.60 Hz), 7.33-7.24 (5H, m), 7.55 (2H, dt, ./ = 8.60 and 1.76 Hz), 7.86 (2H, dt, J= 8.6 and 1.76 Hz), 8.30 (2H, dt, J= 8.60 and 1.76 Hz), 8.8 (IH, bs); ¹³C NMR (100 MHz, CDCl₃) δ 51.54, 54.02, 1 17.39, 127.21, 127.92, 128.25, 128.74, 129.08, 129.23, 129.61, 132.72, 136.85, 138.93, 143.06, 147.55, 156.82; LC-MS m/z (M⁺ + H) = 464.9; HRMS calcd for C₂₃H_{) fi}N₄O₃SCl (M⁺ + H), 465.0788, found: 465.0774, error (ppm): - 3.0.

(v) 3-(4-Chlorophenyl)-Λ^r-[(4-bromophenyl)sulfonyI]-4-phenyl-4,5- dihydro-lH-pyrazole-1-carboxamide (Compound lib)

[0367) Compound lib was prepared from 3-(4-chlorophenyl)-4,5-dihydro-4-phenyl-lH- pyrazole and compound 10b in 82% yield by the method described for compound 11a; mp 214-216°C; ¹H NMR (400 MHz, CDCl₃) r>^"; 3.92 (IH, dd, J = 6.16 and 5.18 Hz)₃ 4.34 (I H, t, J= 4.34 Hz), 4.75 (IH, dd, J= 6.16 and 5.18 Hz), 7.12 (2H, dt, J = 6.6 and 1.6 Hz), 7.33-7.24 (5H, m), 7.55 (2H, dt, J= 8.6 and 1.76 Hz), 7.71 (2H, dt. J= 8.6 and 1.76 Hz), 8.04 (2H, dt, ./ = 8.6 and 1.76 Hz), 8.76 (IH, s); ¹³C NMR (100.62 MHz, OUSO-(J₆) ό » 21.02, 49.43, 54.53, 101.86, 125.28, 127.25, 127.48, 128.17, 128.56, 128.87, 129.06, 129.17, 129.26, 134.69; 137.31 , 137.92, 138.16, 139.59, 140.15, 148.52, 155.89; LC-MS nVz (M⁺ + H) = 519.9; HRMS calcd for C₂₂Hi₈N₃O₃SClBr (M⁺ + H), 517.9941, found 517.9929, error (ppm) - 2.3. (vi) 3-(4-Chlorophenyl)-./V-[(4-iodophenyl)sulfonyl]-4-phenyl-4,5- dihydro-lH-pyrazole-1-carboxamide (Compound lie)

[0368] Compound lie was prepared from 3-(4-hlorophenyl)-4,5-dihydro-4-phenyl- IH- pyrazole and compound 10c in 74.5% yield by the method described for compound 11a; mp 212-214⁰C; ¹H NMR (400 MHz, CDCl₃) δ, 3.92 (IH, dd, ./ = 6.16 and 5.18 Hz), 4.34 (IH, t, J= 4.34 Hz), 4.73 (IH, dd, J= 6.16 and 5.18 Hz), 7.16 (2H, dt, J = 6.6 and 1.6 Hz), 7.33- 7.24 (5H, m), 7.55 (2H, dt, J= 8.7 and 1.96 Hz), 7.71 (4H, qt, J = 9.82, 8.8 and 1.76 Hz), 8.8 (IH, s); ¹³C NMR (100.62 MHz, CDCl₃) ^ 51.5, 54.0,127.2, 128.1, 128.2, 128.3, 128.7, 129.1, 129.6, 129.9, 132.3, 136.7, 138.1, 139.1, 147.8, 156.4; LC-MS m/z (M⁺ + H) = 565.8; HRMS calcd for C₂₂H₁₈N₃O₃SClI (M⁺ + H), 565.9802, found: 565.9801 , error (ppm) - 0.2.

(vϋ) 3-(4-Chlorophenyl)-Λ^r>-[(4-cyanophenyl)sulfonyl]-4-phenyI-4,5- dihydro-lH-pyrazole-1-carboxamidine (Compound 12a)

[0369] A mixture of compound 11a (6 g, 12.9 mmol) and PCIs (2.8 g, 13.5 mmol) was dissolved in chlorobenzene (80 mL), refluxed for 1 h and then concentrated in vacuo. The residue was treated with methanolic NH₃ (IM, 5 mL). The mixture was stirred at room temperature for 1 h and then concentrated in vacuo. The product was recrystallized from MeOH to give compound 12a (2.2 g, 37%); mp 208-210^ϋC; ¹H NMR (400.13 MHz, CDCl₃) δ 4.02 (dd, J = 12 and 4 Hz, 1 H), 4.42 (t, J = 12 Hz, 1 H), 4.76 (dd, J = 12 and 4 Hz, 1 H), 7.10 (dt, J= 6.4 and 2.0 Hz, 2H), 7.34-2.25 (m, 3H), 7.55 (dt, J= 8.7 and 1.96 Hz, 2H), 7.6 (d, J= 8 Hz, 2H), 7.75 (dt, J= 8.6 and 1.44 Hz, 2H), 8.05 (dt, J= 8.6 and 1.44 Hz, 2H); ¹³C NMR (100.62 MHz, CDCl₃) <5 51.42, 55.34, 1 15.29, 1 17.77, 126.87, 127.18, 128.04, 128.22, 128.69, 129.09, 129.61, 132.58, 136.89, 138.93, 147.60, 152.72, 158.05; LC-MS m/z (M⁺ + H), 464.0; HRMS calcd for C₂₃H₁₉N₅O₂SCl (M⁺ + H) 464.0948, found 464.0957, error (ppm) 1.9. (vϋi) (-)-3-(4-Chlorophenyl)-Λ"-[(4-cyanophenyl)sulfonyl]-4-phenyl-4,5- dihydro-lH-pyrazole-1-carboxamidine (Compound (-)-12a)

[037Oj Resolution of compound 12a by chiral HPLC (see General Methods) gave compound (~)-12a (l_R = 9.8 min at 8 mL/min, > 98% ee); [«β² = - 69.3", c = 0.010, CH₂Cl₂; mp 208-210⁰C; ¹H-NMR: as found for 12a; MS m/z (M⁺ + H), 464.1 ; HRMS calcd for C₂₃H₁₉N₅O₂SCl (M⁺ + H) 464.0948, found 464.0962, error (ppm) 3.0; calcd for C₂₃H₁₈ClN₅O₂S: C, 59.54; H, 3.91; N, 15.10, found: C, 59.38; H 4.09; N, 14.86. (ix) (+)-3-(4-Chlorophenyl)-γV-[(4-cyanophenyl)sulfonyI]-4-phenyl-4,5- dihydro-lH-pyrazole-1-carboxamidine (Compound (+)-12a)

[03711 Resolution of compound 12a by chiral ΗPLC (see General Methods) gave compound (+)-12a (t_R = 12.27 min at 8 mL/min, > 98% ee); [a^ = + 66.3°, c = 0.01 1 , CH₂Cl₂; mp 208-210⁰C; ¹H-NMR: as found for compound 12a; MS m/z (M⁺ + H) 464.1; HRMS calcd for C₂₁H₁₉N₅O₂SCl (M⁺ + H) 464.0948, found: 464.0961 , error (ppm) 2.8; calcd for C₂₃H₁₈ClN₅O₂S: C, 59.54; H, 3.91; N, 15.10, found: C, 59.72; H 3.95; N, 14.89.

(x) 3-(4-ChIorophenyl)-7V-[(4-broraophenyl)sulfonylJ-4-phenyl-4,5- dihydro-lH-pyrazoIe-1-carboxaraidine (Compound 12b) [0372] Compound 12b was prepared from compound lib in 43% yield by the method described for compound 12a; mp 214-216⁰C; ¹H NMR (400.13 MHz, DMSO-J₆) δ 3.80 (IH. dd, J = 6.6 and 4.7 Hz)₅ 4.37( 1 H, t, J= 1 1.5 Hz), 5.04 ( I H, dd, J= 6.6 and 4.7 Hz), 7.16 (2H, d, J= 7.1 Hz), 7.25 (IH t, J= 7.2 Hz), 7.35 (2H, t, J= 7.6 Hz), 7.44 (2H, d, J= 8.6 Hz), 7.76 (2H, d, J= 8.4 Hz), 7.79-7.71 (2H, m); ¹³C NMR (100.62 MHz, DMSO-J₆) δ 49.62, 55.60, 125.22, 127.20, 127.52, 127.85, 128.60, 128.83, 129.12, 129.21, 131.83, 134.92, 140.05, 142^{^}96, 152.76, 157.60; LC-MS m/z [M + H]⁺ 517.0; HRMS calcd for C₂₂H₁₉N₄O₂SClBr (M⁺ + H) 517.0101 , found: 517.01 17, error (ppm): 3.1.

(xi) (-)-3-(4-Chlorophenyl)-Λ^r>-[(4-bromophenyl)sulfonyl|-4-phenyl- 4,5-dihydro-lH-pyrazole-l-carboxamidine (Compound (-)-12b) [0373| Resolution of compound 12b by chiral ΗPLC (see General Methods) gave compound (-)-12b (f_R = 13.78 min at 8 mL/min, > 98% ee); [a]£ = - 65.7°, c = 0.010, CH₂Cl₂; mp 214-216°C; ' H NMR: as found for compound 12b; MS m/z (M⁺ + H) 517.0. HRMS calcd for C₂₂Hi₉N₄O₂SClBr (M⁺ + H) 517.0101, found: 517.0126, error (ppm) 4.8.

(xii) (+)-3-(4-ChlorophenyI)-7V-[(4-bromophenyl)sulfonyll-4-phenyl- 4,5-dihydro-lH-pyrazole-l-carboxamidine (Compound (+)-12b)

[0374] Resolution of compound 12b by chiral HPLC (see General Methods) gave compound (+)-12b (f_R = 18.14 min at 8 mL/min, > 98% ee); [«]" = 65.2°, c = 0.010, CH₂Cl₂; mp 214-216⁰C; ¹H NMR: as found for compound 12b; MS m/z (M⁺ + H) 517.0; HRMS calcd for C₂₂H₁₉N₄O₂SClBr (M⁺ + H) 517.0101 , found: 517.01 10, error (ppm) 1.7. (xiii) 3-(4-Chlorophenyl)-Λ^-[(4-iodophenyl)sulfoiiyl]-4-phenyl-4,5- dihydro-lH-pyrazole-1-carboxamidine (Compound 12c)

[0375| Compound 12c was prepared from compound lie in 64% yield by the method described for compound 12a; mp 222-224°C; ¹H NMR (400 MHz, DMSO-αV,) δ 3.80 (I H, dd, J= 6.6 and 4.7 Hz), 4.37(1H, t, J= 11.5 Hz), 5.04 (IH, dd, J= 6.6 and 4.7 Hz), 7.18 (2H, d, J= 7.1 Hz), 7.26 (IH t, J= 7.2 Hz), 7.35 (2H, t, J= 7.6 Hz), 7.44 (2H, d, J= 8.6 Hz), 7.62 (2H, d, J= 8.4 Hz), 7.77 (2H, d, J= 8.6 Hz), 7.90 (2H, d, J= 8.4 Hz); ¹³C NMR ( 100.62 MHz, DMSO-Cy₆) δ 49.60, 55.59, 99.28, 127.19, 127.52, 127.59, 128.69, 128.83, 129.1 1 , 129.21 , 134.92, 137.65, 140.05, 143.30, 152.74, 157.57; LC-MS m/z (M⁺ + H) 565.1 ; HRMS calcd for C₂₂Hi₉N₄O₂SClI (M⁺ + H) 564.9962, found: 564.9974, error (ppm) 2.1.

(xiv) 3-(4-ChlorophenyI)-JV-[(4-iodophenyl)sulfonyl]-4-phenyl-4,5- dihydro-lH-pyrazole-1-carboxamidine (Compound (-)-12c)

[0376] Resolution of compound 12c by chiral ΗPLC (see General Methods) gave compound (-)-i 2c (/_R = 18.18 min at 6 mL/min, > 98% ee); [«]" = - 160°, C = O OI l , CHCl₃; mp 222-224⁰C; ¹H NMR: as found for compound 12c; LC-MS m/z (M⁺ + H) 565.1 ; HRMS calcd for C₂₂H₁₉N₄O₂SClI (M⁺+ H):564.9962, found: 564.9960, error (ppm) - O.4.; calcd. for C₂₂Hi₈CUN₄O₂S: C, 46.78; H, 3.21 ; N, 9.92, found: C, 46.82; H 3.33; N, 9.67.

(xv) (+)-3-(4-ChlorophenyI)-;V-[(4-iodophenyl)sulfonyl]-4-phenyl-4,5- dihydro-lH-pyrazole-1-carboxamidine (Compound (+)-12c)

[0377] Resolution of compound 12c by chiral ΗPLC (see General Methods) gave compound (+)-12c (/_R = 24.38 min at 6 mL/min, > 98% ee); [a]* = + 151°, c = 0.010, CHCl₃; mp 222-224⁰C; ¹H NMR: as found for compound 12c; LC-MS m/z (M⁺ + H) 565.0; HRMS calcd for C₂₂Hi₉N₄O₂SClI (M ⁺+ H) 564.9962, found: 564.9960, error (ppm) - 0.4; calcd for C₂₂H₁₈ClIN₄O₂S: C, 46.78; H, 3.21 ; N, 9.92, found: C, 46.88; H 3.24; N, 9.71.

Example 3: Synthesis of CBi Receptor Ligand Compound 13

[0378| Ligand compound 13 was prepared in four steps starting from commercially available 2-iodoaniline (see Scheme 2, below). More specifically, compound 13 was synthesized according to a previously established procedure but with some modifications (Scheme 2 below; Fan et al. , 2006, J Label Compel Radiυpharm 49: 1021 - 1036). Chloro[(2- iodophenyl)hydrazono]ethyl acetate (14) was synthesized by converting 2-iodoaniline into a diazonium salt, followed by treatment with ethyl 2-chloroacetoacetate in ethanol-water solution under basic conditions. A mixture of 4-methoxybenzoylacetonitrile, N₃N- diisopropylethylamine and 14 dissolved in tøV-butanol heated to reflux gave 15 in low but adequate yield. Hydrolysis of 15 was achieved with <7^-LiOH dissolved in tetrahydrofuran. The corresponding carboxylic acid was converted into an acyl chloride with oxalyl chloride and a catalytic amount of N,N-dimethylformamide. The synthesis of 13 was completed by coupling the acyl chloride with 1-aminopiperidine under basic conditions. The precursor for radiolabeling, 17, was synthesized by reflυxing a solution of 16 and hexamethylditin in the presence of palladium catalyst.

[0379] Scheme 2. Synthesis of SPECT radioligand (13, l-(2-iodophenyl)-4-cyano-5-(4- methoxyphenyl)-N-(piperidin-1 -yl)-l H-pyrazole-3-carboxy1ate).

14 15

13

16 17 Reagents and conditions: (a) concentrated HCl, NaNC>₂, ethyl 2-chloroacetoacetate, NaOAc, EtOH-H₂O; (b) 4-methoxybenzoylacetonitrile, DIPEA, /erΛ-BuOH, reflux, 6%; (c) σ^-LiOH, THF, 65⁰C; (d) DMF_(cat), (COCl)₂, DCM; (e) 1-aminopiperidine, DlPEA, DCM, 73%; (f) hexamethylditin, Pd(PPh₃)₄, toluene, 32%. (i) Chloro[(2-iodophenyl)hydrazono]ethyl acetate (Compound 14)

[0380| A solution of 2-iodoaniiine (9.9 g, 45 mmol) in concentrated HCl (12 M, 5.4 mL) plus H₂O (200 mL) was stirred in a 1 L round bottomed flask for 30 min. The reaction mixture was cooled to about 5⁰C in an ice-water bath. A solution of sodium nitrite (3.2 g, 46 mmol) in H₂O ( 10 mL) was slowly added to the reaction mixture so that the reaction temperature remained below 15⁰C. The reaction mixture was then stirred for an additional 30 min. A separate solution of sodium acetate (3.5 g, 43 mmol) and ethyl 2-chloroacetoacetate (6.2 mL, 45 mmol) dissolved in EtOH-H₂O (400 mL, 4: 1 v/v) was added drop-wise. The reaction mixture was allowed to warm to room temperature and stirred overnight (16 h). The precipitate was filtered off. washed with water and dried to give compound 14 ( 1 1 .5 g, 72%) as a light maroon solid. Mp 1 12-1 14⁰C; ¹H NMR (400 MHz, CDCl₃) δ 8.76 ( IH, s), 7.73 (IH, dd, J= 8.0 and 1.8 Hz), 7.56 (IH, dd, J = 8.0 and 1.8 Hz), 7.36 (IH, t, J = 8.0 Hz), 6.8 (IH, t, J= 8.0 Hz), 4.43 (2H, q, J = 7.1 Hz), 1.43 (3H, X, J= 7.1); ¹³C NMR ( 100 Hz) δ 159.46, 140.89, 138.92, 129.69, 124.42, 1 18.22, 1 15.83, 83.03, 62.97, 14.26; HRMS (m/z) [M + Hf calcd for Ci₀Hi ₁N₂O₂ClI 352.9544, found 352.9553 error (ppm) -3.1. (ii) Ethyl l-(2-iodophenyl)-4-cyaiio-5-(4-methoxypheiiyl)-lH-pyrazole-

3-carboxylate (Compound 15)

[0381] A solution of compound 14 (8.2 g, 22.8 mmol) and 4-methoxybenzoylacetonitile (4.0 g, 22.8 mmol) in N,N-diisopropylethylamine (11.9 mL, 68.4 mmol) was refluxed in tert- butanol ( 100 mL) for 16 h. This reaction mixture was concentrated in vacuo and the crude product extracted with ether (3 x 100 mL). The ether extracts were combined and concentrated in vacuo. The crude product was purified with flash chromatography (hexanes- EtOAc, 7:3 v/v) to give compound 15 (726 mg, 6%) as a pale white solid, mp 164-166⁰C; ¹H ΝMR (400 MHz, CDCl₃) δ 7.88 ( IH, dd, J= 8.0, 1.8 Hz), 7.47 (2H, m), 7.31 (2H, dt, J = 8.6, 2.0), 7.21 ( IH, t, 8.0 Hz), 6.88 (2H, dt, J= 8.6, 1.8 Hz), 4.55 (2H, q, J= 7.1 Hz), 3.80 (3H, s), 1.49 (3H, t, J = 7.1 Hz); ¹³C ΝMR ( 100 MHz, CDCl₃) δ 161.18, 159.90, 151.10, 145.23, 141.16, 140.07, 131.73, 130.72, 129.48, 129.24, 1 17.65, 1 14.47, 1 13.08, 96.83, 62.24, 55.36, 14.25. MS {m/z) [M+ H]⁺ 474.1, HRMS (m/z) [M+ H]+ ]⁺ calcd for C₂₀H_nN₃O₃I 474.0315, found 474.0309 error (ppm) -1.3. (iϋ) l-(2-Iodophenyl)-4-cyano-5-(4-methoxyphenyl)-./V-(piperidin-l-yI)- lH-pyrazole-3-carboxylate (Compound 13)

[0382] A solution of compound 15 (400 mg, 0.8 mmol) in aq. LiOH (3 niL, IM) was heated to 65°C for 4 h and then concentrated in vacuo. The residue was dissolved in Η₂O (10 mL) and neutralized with 10% aq-HCl. A portion of the crude acid (200 mg, 450 μmol) was dissolved in dichloromethane ( 15 mL). To the stirred solution were added NJV- dimethylformamide (1 drop) and oxalyl chloride (57 μL, 674 μmol). After bubbling had ceased, the reaction was concentrated in vacuo. A solution of 1-aminopiperidine (58 μL, 540 μmol) and N,N-diisopropylethylamine (235 μL, 1.3 mmol) dissolved in dichloromethane ( 10 mL) was added to the acid chloride, stirred at room temperature for 2 h and then concentrated in vacuo. The residue was purified with silica flash chromatography (hexanes-EtOAc, 1 : 1 v/v) to give compound 13 (172 mg, 73%) as a white solid, mp 226-228T; ¹H ΝMR (400 MHz, CDCl₃) δ 7.93 (IH, dd, ./ = 8.0, 1.8 Hz), 7.59 (IH, s), 7.49 (IH, t, 8.0 Hz), 7.37 (IH, dd, J= 8.0, 18 Hz), 7.27 (2H, dt, J= 8.6, 1.8 Hz)₅ 7.24 (IH, t, J = 8.0 Hz), 6.85 (2H, dt, J = 8.6, 1.8 Hz), 3.79 (3H, s), 2.91-2.89 (4H, m), 1.78-1.72 (4H, m), 1.45-1.43 (2H, m). ¹³C NMR (IOO Mz, CDCl₃) O^' 161.1 1, 156.72, 151.15, 147.48, 141.13, 140.29, 131.71, 130.68, 129.37, 1 17.73, 1 14.45, 1 12.90, 96.76, 93.39, 56.89, 55.36, 25.39, 23.27; MS (m/z) [M+ H]⁺ 528.1, HRMS (m/z) [M+ H]^" calcd for C₂₃H₂₃N₃O₂I 528.0897, found 528.0897 error (ppm) 0. Anal, calcd for C₂₃H₂₂N₅O₂I: C (52.38), H (4.20), N (13.28), found C (52.26), H (4.21), N (13.17).

(iv) 4-Cyano-5-(methoxyphenyl)-l-(2-(trimethyIstannyl)phenyl)-N- (piperidin-1-yl)-1H-pyrazole-3-carboxamide (Compound 17)

[0383J A solution of compound 16 ( 150 mg, 313 μmol), Pd(PPh₃)₄ (18 mg 15.6 μmol) and hexamethylditin (130 μL, 626 μmol) in toluene (3 mL) was heated to reflux for 20 h. The reaction mixture was concentrated in vacuo. The residue was purified with silica flash chromatography (hexanes-EtOAc, 1 : 1 v/v) to give compound 17 (56 mg, 32%) as a tan solid, mp 216-218⁰C; ¹H NMR (400 MHz, CDCl₃) <5 7.68 (IH, dd, J = 8.0, 1.8 Hz), 7.51 (3H, s), 7.41 (IH, t, J= 8.0 Hz), 7.24-7.19 (4H, m), 6.87 (2H, dt, J= 8.6, 1.8), 3.79 (3H, s), 2.87- 2.85 (4H, m), 1.78-1.72 (4H, m), 1.26-1.24 (2H,m); ¹³C NMR ( 100 Mz, CDCl₃) δ 161.01, 156.48, 150.05, 147.00, 144.19, 140.47, 137.74, 130.69, 129.25, 128.94, 126.46, 117.98, 114.52, 1 12.93, 93.59, 57.16, 55.39, 25.34, 23.22; LC-MS (m/z) [M + H]⁺ = 566.0. Example 4: CBi and CB? Receptor Binding Assays Using Compounds of the Present Invention

(i) Compound 12

[0384] High affinity is a prerequisite in candidate radioligands for PET imaging of neuroreceptors (Laruelle et ai, 2003, MoI Imaging Biol 5:363-375). Generally, the more sparse the receptor the higher the affinity must be to permit successful imaging. As a guide, binding potentials represented by

should well exceed unity, when B_mm and Kd (or as surrogate, K₁ or IC₅0) are expressed in nM (Laruelle et al, 2003, MoI Imaging Biol 5:363- 375). CBi receptors are amongst the most abundant receptors in brain (Herkenham et ai, 1990, Proc Natl Acad Sci USA 87: 1932-1936; Herkenman et a!. , \99 \ , J Neurosci 1 1 :563- 583), and hence moderately high affinity (K_\ < 10 nM) may be acceptable. The IC50 and K values of rimonabant, and compounds (-)-12a, (+)-12a, (-)-12c and (+)-12c were determined and are shown in Table 1.

[0385] Table 1. IC50 and Ki values for the CBi and CB₂ receptors and cLogf data for compounds 2, m(rimonabant), (-)-12a, (+)-12a, (-)-12c, and (+)-12c.

Ligand R¹ CBi IC₅₀ CB₂ IC₅₀ CB, A:, CB₂ AT, (nM)^a (nM)' (nM)^a (nM)^a

2 (rimonabant) 2.2 ± 0.5 4,570 ± 410 0.4 ± 0. 1 697 ± 63 6.95

H-12a CN 2.8 ± 0.3 > 33,000 0.5 ± 0.1 > 5,000 3.85

(+)-12a CN 100 ± 10.0 > 33,000 16.9 ± 2.0 > 5,000 3.85

H-12c 1 1 .9 ± 0.7 > 33,000 0.3 ± 0. 1 > 5,000 5.07

(+)-12c 1 103.5 ± 9.0 > 33,000 17.4 ± 2.0 > 5000 5.07 ^a Values are represent the mean ± SD of three determinations. ^b cLogP values were calculated by using the Pallas 3.0 software (Compudrug, USA).

[0386] The (-)-enantiomers exhibited high affinities for CB₁ receptors with ΪC₅₀ values and KiS in low or sub nM range, respectively. These values compare well with other successful radioligands targeting CB] receptors, which generally have potencies or affinities in the nM range {e.g., [^1KF]MK-9760 ([¹⁸F]-labeled compound of Formula (VIII) (Burns et al., 2007, Proc Natl Acad Sci USA 104:9800-9805; Liu et ai, 2007 , J Med Chem 50:3427-3430) and [¹¹C]MePPEP ([^πC]-labeled compound of Formula (X) (Yasuno et al, 2008, Neuropsychopharmacology 33:259-269). The (+)-enantioraers of compounds 12a and 12c exhibited lower CB] receptor affinities than their (-)-enantiomers; eudismic ratios were found to be about 35 for compound 12a and 56 for compound 12c. These ratios are similar to those of similar CBi receptor ligands from the 3,4-diarylpyrazoline class (Lange et al. ,2004, J Med Chem 47:627-643). The eutomer of one such ligand has been shown to have the S configuration by X-ray crystallography (Lange et o/.,2004, ./ Med Chem 47:627-643). Hence, the eutomers of compounds 12a and 12c are also predicted to have 5 configuration. (ii) Compound 13

[03871 A suitable radioligand for imaging brain CB _\ receptors should possess high affinity and low lipophilicity to facilitate biomathematical modeling and accurate computation of output measures, such as binding potential (Laruelle et al., 2003, MoI Imaging Biol 5:363- 375; Waterhouse, 2003, MoI Imaging Biol 5:376-389). CB, receptors are one of the most abundant G protein-coupled brain receptors, reaching a concentration (B_n]ax) of 1752 mg/g protein (175 nM) in rat cerebellum (Hirst et αl., 1996, Neurosci Lett 220: 101-104). Generally, a successful PET or SPECT radioligand should show a B_max/Kά value of 5. Hence, a suitable CBi receptor radioligand should have an affinity (K\ or Kd value) of < 35 nM. Calculated molecular lipophilicity can be an important predictor of blood-brain barrier (BBB) penetration and brain non-specific binding. Moderate lipophilicity is usually preferred for adequate brain entry without excessive non-specific binding. The data in Table 4 show that compound 13 has acceptable CBi receptor affinity and lipophilicity. Compound 13 showed computed lipophilicity (cLogD = 4.14 at pH 7.4) and selective, high CBi receptor affinity (K₁ = 3.40 ± 0.43 nM. n = 3). 10388] Table 4. K, values for CBi and CB₂ receptors, selectivities for CBi versus CB₂ receptors and calculated lipophilicities.

Ligand CBi ATi (nM)^a CB₂ K (nM)^a CBi versus CB₂ cLogD? 4^b selectivity (nM)^a rimonabant 1 .38 ± 0.17 927 ± 66 672 ± 94 6.01 Compound 13 3.40 ± 0.43 548 ± 23 161 ± 47 4.14

\ Values represent mean ± SD of three determinations. ^b, cLogP values were calculated using Advanced Chemistry Development (ACD) 9.2.

Example 5: Receptor Screening Using Compounds M-12a And 13

[0389] In addition to acceptable binding affinity and lipophilicity suitable PET and SPECT radioligands should be selective for binding to their target protein. Compounds (-)-12a and 13 were screened for binding to a wide range of receptors and transporters by the National Institute of Mental Health Psychoactive Drug Screening Program. Detailed protocols are available on-line for all binding assays at the NIMH-PDSP web site.

[0390] Compound (-)-12a showed < 50% inhibition (/; = 4) for the following receptors and binding sites: 5-HT,_A-E, 5-HT_2B-C, 5-HT₃, 5-HT_JA, 5-HT₆, 5-HT₇, α,_A.B, α_2A-c, βι-₃, D,-₅, DAT, DOR, Hi.4, KOR, M,-₅, MOR, NET, SERT, σ,,₂. K₁ values (n = 3) of > 7,710 ± 1 ,1 10 nM for the 5-HT_2A and > 10,000 nM for H_{2 3} receptors were found. Hence, compound (-)- 12a was found to have excellent CBj receptor selectivity for development as a PET radioligand. [0391] Ligand compound 13 at 10 μM concentration showed < 50% inhibition (n = 4) for radioligand binding to the following receptors and binding sites: 5-HTi_{B E}, 5-HT_{2Λ C}, 5-HT₃, 5-HTJΛ, 5-HT₆, 5-HT₇, αi_Λ,_B, α_2Λ.B, βi 3, Di ₄, DAT, DOR, H_{1 4}, M₁ ,, NET, SERT, σ,,₂₎ VIA.IB.2. Ki values (n = 3) of 93.5 ± 20.4 nM (5-HT_1A), > 10,000 nM (α_2C), 1,477 ± 148 nM (KOR), 1,496 ± 216 nM (MOR) and 3,166 ± 586 nM (PBR) were found. Hence, compound 13 has excellent CBi receptor selectivity for use as a SPECT or PET radioligand.

Example 6: Compounds 12(a) Enter the Brain Readily

[0392] The lipophilicity of a radioligand may critically influence its ability to penetrate the blood-brain barrier. Generally, a Logf value in the range 2.0 to 3.5 is considered desirable for adequate brain entry without excessive non-specific binding to brain tissue (i.e., fats, proteins; see, e.g., Waterhouse, 2003, Mo/ Imaging Biol 5:376-389). cLogP is a useful tool for predicting lipophilicity trends among compounds of the same structural class (Laruelle el al, 2003, MoI Imaging Biol 5:363-375; . Waterhouse, 2003, MoI Imaging Biol 5:376-389). cLogP was computed for compounds (-)-12a, (+)-12a, (-)-12c and (+)-12c (Table 1 ). The compound of Formula (III) has previously been shown to penetrate the blood-brain barrier, despite its very high cLogP value (5.01) (Lange et al. ,2004, J Med Chem 47 627-643). The cLogP values of compound 12a and its enantiomers are substantially lower (3.85) than that of compound 3 (Table 1), and hence they may be expected to enter brain readily. The values for compound 12c and its enantiomers are similar to compound 3 and hence they may also be expected to enter brain adequately.

Example 7: Production of [¹¹ClHCN

[0393| [^{1 1}C]HCN, was prepared from cyclotron produced ["C]methane, was trapped in a DMSO solution of KOH, and Kryptofix^® 2.2.2 yielding a [¹¹C]CN-K⁺- Kryptofϊx^® 2.2.2. complex.

[0394] Specifically, [' 'C]Methane was produced at the Karolinska Hospital with a GEMS PETtrace cyclotron using 16.4 MeV protons in the ¹⁴N(p,α)^πC reaction on N₂(g) containing 10% H₂(g) (Christman et al. , 1975, lntl J Appl Radial Jsυt 26:435-442). The target gas was irradiated for 5 min with a beam intensity of 35μA. The [' 'C]methane was isolated from the target gas in a Porapak Q trap, which was cooled with N₂(I). The Porapak Q trap was warmed and the [^πC]methane passed in nitrogen (200 mL/min) with NH.i(g) (20-30 mL/min) over heated (990⁰C) Pt wire (1.3 g, 0.127 mm, 99%; Sigma Aldrich) in a quartz tube within a carbolite furnace (MTF 10/15). The resulting [' ¹C]NH₄CN was bubbled through aq. 50% H₂SO₄ (2 mL) at 56⁰C to generate [^{1 1}C]HCN. Example 8: Radiosvntheses of Compounds [ⁿClf±)-12a, lⁿClM-12a and lⁿCI(+M2a

[0395] An effective and rapid method for labeling compound according to Formula (XXI) as its racemate is provided herein. [ⁿC]Cyanide ion is a useful precursor for labeling molecules with an aryl nitrile group (Andersson et al., 1994, J Chem Soc Perkin Trans 1 1 : 1395-1400). The incorporation of [^uC]cyanide ion into an aryl ring is best achieved with copper (Ponchant el al., 1997, Appl Radial hot 48.755-762, Mathews et al., 2006, ./ Label Compd Radiopharm 49:829-834) or palladium (Andersson et al., 1994, J Chem Soc Perkin Trans 1 1.1395-1400) catalyzed reactions. Each method was considered for labeling compound (±)-12a. At first glance, [^{1 1}C]Cu(I)CN appeared attractive for labeling PET radiopharmaceuticals. In general, use of this labeling agent requires one-pot and is insensitive to H₂O or NH₃ accompanying the production Of [¹¹C]HCN. However, the overall radiochemical yields can be very low (e.g., 2.5%), and inferior to those from the palladium- catalyzed method (Carson, 2000, Nucl Med Biol 27:657-660). Hence, the latter method was selected for labeling compound (±)-12a.

[0396] The generated [' ¹C]HCN (~ 12.4 GBq) was trapped in a V-vial (5-mL) containing DMSO (400 μL) base (KOH, 1 mg, 17.8 μmol; K 2.2.2., 5 mg, 13.3 μmol) for compound [^πC](±)-12a or KH₂PO₄ ( 1 mg, 7.34 μmol) for compound [^πC](-)-12a or compound [' 'C](+)-12a. After trapping of [¹¹C]HCN was complete, the solution was transferred into another V-vial (10-mL) which contained DMSO (400 μL), Pd(PPh₃)₄ (5.5 mg, 4.8 μmol) and the requisite precursor compounds ((±)-12b, (-)-12 b, (~)-12c or (+)-12c; 1 mg). The reaction was heated 135°C for 4 min and then cooled to room temperature. HPLC mobile phase (800 μL) was added to the V-vial and the radioactive product separated with HPLC (see General Methods). The radioactive fraction (/_R = 12.3 min) was collected, evaporated to dryness, and taken up in ethanol-propylene glycol (30: 70 v/v, 3 mL) with sterile phosphate buffer (0.2 M, pH = 7.4, 5 mL) and filtered through a sterile filter (MiIIeX³⁰GV, 0.22 μm pore size; Millipore Corp., Corrigtwohill, Co. Cork, Ireland).⁴⁰ A sample (100 ~ μL) was analyzed by HPLC for radiochemical purity and measurement of specific radioactivity (see General methods).

[0397] The [^{1 1}C] CN-K¹- Kryptofix^® 2.2.2. complex was added to the bromo precursor ((±)-12b) and Pd(PPh₃)₄ in DMSO and heated a shown in Scheme 6 below.

[0398] Scheme 6: Radiosynthesis of compound [^πC]12a.

Conditions, reagents and yield: a) [¹¹C]KCN, Pd(PPh₁),,, KOH, K2.2.2, DMSO, 1 10 ⁰C, 36%

(/? = 2).

[0399] Compound [ⁿC](±)-12a was separated from the crude product with reverse phase HPLC. The fraction containing compound [^uC](±)-12a was evaporated to dryness and formulated for safe intravenous injection. The overall radiosynthesis time was about 30 min. The non-optimized decay-corrected yield was 36% (n = 2). There was no great improvement in yield when using the iodo compound (-)-12c as precursor. Compound [^πC](±)-12a was obtained in high radiochemical purity (> 98%) and was free of labeling precursors. Specific radioactivities were > 56 GBq/μmol at time of injection. Product identity was confirmed by LC-MS of associated carrier and by co-injection with compound 12 in HPLC analysis and observation of co-elution.

[0400] Preparation of compound [^πC](-)-12a was attempted from precursor compounds (-)-12b or (-)-12c under the reaction conditions used to prepare compound [^πC](±)-12a. However, chiral HPLC analyses of the collected radioactive products revealed that complete racemization had occurred during the reactions (Table 5).

[0401] Table 5. Enantiomer composition (%) of compound [^πC]12a after treating compounds (-)-12b, (-)-12c or (+)-12c with [^πC]cyanide ion in DMSO the presence of various bases.

Precursor Base (a) ["C](-)-12a ["C](+)-12a

(%) (%)

(-)-12b KOH, 1^2.2.2 50 50

NaHCO., 90 10

(-)-12c NaOAc 50 50

NaHCO₃ 90 10

KH₂PO₄ > 97 (n = 4) < 3 (« = 4)

(+)-12c KH₂PO₄ < 3 (n = 1) > 97 (n = 1)

[0402] Without being bound by theory, racemization was likely promoted by the strong base (KOH plus Kryptofix^® 2.2.2) according to Scheme 7 of below.

[0403] Scheme 7: Proposed mechanism for the epimerization of [' 'C](-)-12a under labeling conditions.

[0404] To try to avoid racemization, several weaker bases were used in place of the KOH plus Kryptofix^® 2.2.2. Surprisingly, the use of NaHCO., as base gave compounds [' 'C](-)- 12a to [^πC](+)-12a in a 9: 1 ratio. Serendipitously, it was found that the use Of KH₂PO₄ (see, Table 2) gave compound [^πC](-)-12a in > 95% ee (« = 4). These conditions were also used with (+)-12c as precursor and the resulting product, compound [ⁿC](+)-12a, was also obtained in > 95% ee. The chemical identities of compounds [ⁿC](-)-12a and [ⁿC](+)-12a were confirmed with LC-MS of associated carrier. Thus, compounds [ⁿC](-)-12a and [^πC](+)-12a were obtained in high chiral purity for evaluation as radioligands in mammals with PET.

[0405J An alternative scheme for preparing [ⁿC](±)12a is shown below in Scheme 8:

^1<!N(p.α:) ^{l 1}C on N₂-O₂

[^{1 t}C](+/-}-12

[0406] Radiosynthesis of [^uC](±)-12. Conditions and reagents: a) Pt, NH₃ (20-30 mL/min), 990⁰C; b) 50% H₂SO₄, 90⁰C; and c) precursor compound according to Formula (XlV), wherein R^5A = Br, Pd(PPh₃J₄, KOH, K2.2.2, DMSO, 1 10⁰C.

Example 9: Radioiodination of Compound 13 And Autoradiography

[0407] [^l25!]iodostannylation of a trimethylstannyl precursor (compound 16) gave [^I25Ϊ]13 in adequate yield, specific radioactivity and purity for further evaluation with sensitive autoradiographic evaluation on horizontal whole-hemisphere human brain slices.

Compound 13, where I* indicates label, e.g., ¹²³1, ¹²⁴I, ¹²⁵I, or ¹³¹I.

[04081 More specifically, [¹²⁵I]13 was prepared by [¹²⁵I]iodostannylation of a trimethylstannyl precursor (compound 17), which was itself prepared by palladium-catalyzed coupling using hexamethylditin, with [¹²⁵I]NaI, α^-HCl and chloramine-T (oxidizer) in MeOH (Scheme 9). The crude product was purified with high-performance liquid chromatography (HPLC) as described herein. The decay-corrected radiochemical yields of [¹²⁵I]13 ranged from 48 to 59%. The specific radioactivity of the product was 81.4 GBq/μmol and the radiochemical purity > 98%. [¹²⁵I]13 was thus obtained in adequate yields and purity for further evaluation with sensitive post mortem autoradiography in vitro. Furthermore, these conditions would be applicable to the ^mI-labeling of compound 13 for SPECT imaging.

¹²«Xe(π,y)^12£Xe -»- «»1

17 ['^I]13, R^z = '"I

Scheme 9: Radiosynthesis of [ ^* 1]13. Reagent, conditions and yields: [ I]NaI, chloramine- T, aq-HC\, MeOH. ['"I] 13 was prepared in 48-59% (decay-corrected).

[0409] Compound 17 (0.3-0.5 mg, 0.5-0.9 μmol in MeOH (80 μL) was treated with r [l25I]NaI (10 μL), chloramine-T (40 μL) and aq-BC\ (40 μL, 0.2 M) at room temperature for 5 min. The crude [¹²⁵I]13 (/_R = 9.8 min) was purified on a revered-phase HPLC column (Merk Hitachi) using a Waters column (μ-Bondapak C-18; 7.8 x 300 mm, 10 μm) eluted with MeCN-^-H₃PO₄ (0.01M) (1 : 1 v/v) at 5 mL/min. Solvents collected in [^l25I]13 fraction was evaporated under vacuum. [¹²⁵I]13 was dissolved in 70% ethanol in water, analyzed by HPLC under same conditions and identified by co-injection with reference [¹³¹I]13.

[0410] Autoradiography was carried out as described previously (Hall et ai, 1998, Niicl Med Biυl 25:715-719). Brain sections were incubated for 60 min at room temperature with [¹²⁵I]U (ca. 17 pM) in Tris-HCl buffer (pH 7.4, 50 mM) containing MgCl₂ (5 mM), EGTA (1 mM) and pargyline (10 μM). After incubation, the brain sections were washed with cold Tris buffer (pH 7.4, 50 mM) containing MgCl₂ (5 mM) and EGTA ( 1 mM) for 3 x 10 rain, briefly dipped into distilled water and dried on a warm-plate. Hyperfilm βmax or Kodak BioMax MR films (Amersham Pharmacia Biotech, Uppsala, Sweden) were applied to the sections for 4 days before development (developer: Kodak D 19; fixation; Kodak Fixer 3000).

[0411 J Autoradiograms were digitized using a Scan Maker E6 high resolution scanner (Kicrotek) and Adobe Photoshop 5.0. Microsoft PowerPoint was use for processing of images. Measurements were carried-out using Adobe Photoshop 6.0. Example 10: PET Measurements in Monkey Using Compounds [ⁿCU±)-

12a

[0412] Cynomolgus monkey (Macaca fascicularis) experiments were performed at the Karolinska Institutet (KI) according to "Guidelines for planning, conducting and documenting experimental research" (Dnr 4820/06-600) of the KI as well as the "Guide for the Care and Use of Laboratory Animals" (Clark et a I., 1996, Guide for Care and Use of Laboratory Animals; National academic Press; Washington, DC). The study was approved by the Animal Ethics Committee of the Swedish Animal Welfare Agency.

[0413] Two cynomolgus monkeys (3.4 and 4.8 kg) were used in the PET experiments. Anesthesia was induced and maintained with repeated i.m. injections of a mixture of ketamine hydrochloride (3.75 mg/kg^'1 h^'1 Ketalar^®, Pfizer) and xylazine hydrochloride ( 1.5 mg/kg^'1 h^'1 Rompun^® Vet., Bayer). The head for each monkey was immobilized in a stereotactic frame for the duration of scans (Karlsson el al., 1993, Psychopharmacology 113: 149- 156). The body temperature was maintained by a Bair Hugger Model 505 (Arizant Healthcare, MN, USA) and monitored by rectal thermometer (Precision Thermometer, Harvard Apparatus, MA, USA).

(a) Baseline Experiments

[0414] In baseline experiments, each radioligand was administered by bolus injection over about 5 s, with injected activities of 56, 100, and 98 MBq and specific radioactivities of 78, 65, and 56 GBq/μmol for compound ["C](±)-12a, compound [^πC](-)-12a and compound [^πC](+)-12a, respectively. The masses of injected carrier ligand were 0.33 μg (0.72 nmol), 0.71 μg (1.53 nmol), and 0.81 1 μg (1 .75 nmol) for compound [^MC](±)-12a, compound [^πC](-)-12a and compound [^πC](+)-12a. [0415] After intravenous injection of compound [ⁿC](±)-12a into cynomolgus monkey, the brain radioactivity distributed according to the rank order of regional CBi receptor densities (Panel A, Figure 1). The highest radioactivity uptake was in CB i receptor-rich striatum, reaching 220% SUV at 30 min after injection. This slowly diminished to 180% SUV at 90 min after injection. The lowest maximal brain uptake was in pons reaching 150% SUV at 24 min after injection. The concentration of radioactivity in this region diminished to 124% SUV at 90 min after injection.

(b) Displacement Experiments [0416] In a displacement experiment, a compound 6 (according to Formula (Vl); 1 mg/kg, i.v.) was infused at 25 min after injection of compound [^{l l}C](±)-12a For this purpose, compound 6 was formulated in vehicle solution (8 mL) (saline/alcohol/cremophore EL, 9: 1 : 0.1 by vol.). The solution was homogenized by vortexing and then passed through a sterile filter (0.2 μm pore size, Millex-GV, Millipore) The injected activity was 56 MBq with a specific radioactivity of 80.3 GBq/μmol. The mass of carrier associated with the injected radioactivity was 0.32 μg (0.70 nmol).

[0417J In an experiment in which the CBi receptor-selective ligand 6 was given in high dose ( 1 mg/kg, i.v.) at 25 min after injection of [^πC](±)-12a, the regional brain radioactivity became homogeneous and diminished to about 95% SUV at 90 min after injection (Panel B, Figure 1). (c) Pre-Block Experiments

[0418] A pre-block experiment was performed at 5 h after the baseline experiment. Compound 6 was infused at 20 min before injection of radioligand. The injected activity was 57 MBq with specific radioactivities of 75.4 GBq/μmol. The mass of carrier associated with the injected radioactivity was 0.35 μg (0.76 nmol). In each PET experiment, scans were acquired in 3 frames over 93 min.

[0419] When compound 6 ( 1 mg/kg, i v.) was given at 20 min before injection of compound [' 'C](±)-12a, brain radioactivity became homogenous and was characterized by a lower maximal uptake and fast washout, reaching 175% SUV at 15 min after injection and declining to 185% SUV at 90 min after injection (Panel C, Figure. 1 ). Example 11: PET Measurements in Monkey Using Homochiral

Compounds [ⁿCl(-)-12a and F"CK+M2a

[0420] Taken together, the results shown in Figure 1 demonstrated that a high proportion of brain radioactivity in the baseline experiment was reversibly bound to CBi receptors. The higher affinity enantiomer in this racemic radioligand was expected to be responsible for the majority of receptor-specific binding, while the lower affinity enantiomer was expected to bind mostly non-specifically. Therefore, in a subsequent experiment, the homochiral radioligands, [^πC](-)-12a and [^πC](+)-12a, were injected to test these expectations. [0421] After intravenous injection of the higher affinity enantiomer, compound [^πC](-)- 12a, into monkey, the brain radioactivity again distributed according to the regional rank order of CBi receptor densities. The highest uptake of radioactivity was in striatum, reaching 200% SUV at 48 min after injection. The lowest maximal brain uptake was in pons reaching and maintaining - 125% SUV from 24 min after injection (Panel A, Figure 2). These time- activity curves are consistent with a high proportion of receptor- specific binding in all examined brain regions, as also seen in the experiment with racemic radioligand (Panel A, Figure 1).

[0422] In these experiments, as in PET imaging studies of other CBi receptor radioligands (Burns et al., 2007, Proc Natl Acad Sci USA 104:9800-9805; Yasuno et a/., 2008, Neuropsychopharmacology 33:259-269), no region could be identified to represent nonspecific binding only. Pons does not serve this purpose, since it contains some CBi receptors (Herkenman et al, 1990, Proc Natl Acad Sci USA 87: 1932- 1936; Herkenham et al., 1994, J Pharmacol Exp Ther 268: 1612-1623; Burns et al. , Proc Natl Acad Sci USA 104:9800-9805) and measurements of its radioactivity concentration are contaminated from other nearby regions (e.g., CBi receptor-rich cerebellum) through the partial volume effect. In the absence of a reference region, ratios of specific to non-specific binding cannot be estimated at all accurately by visual inspection of time-activity curves. Bolus plus constant infusion (Carson et al., 2000, Nucl Med Biol 27:657-660) or full kinetic compartmental modeling (Yasuno et al., 2008, Neuropsychopharmacology 33:259-269) utilizing an arterial input function would be required to extract this information.

[0423] By contrast with results from compound [ⁿC](-)-12a, after intravenous injection of the lower affinity enantiomer, compound [^uC](+)-12a, into monkey, maximal brain radioactivity concentration reached 280% SUV at 1.5 min, but then rapidly declined in all regions to about 95% SUV at 90 min (Panel B, Figure 2). These features of the time-activity curves are consistent with a high proportion of non-specific binding in all examined regions, and are consistent with the lower affinity of the radioligand. Example 12: PET Imaging

[0424] Radioactivity in brain was measured with the Siemens ECAT EXACT HR system. The three ring detector block architecture gives a 15-cm wide field of view. All acquisitions were acquired in 3D-mode (Wienhard e/ o/., 1994, J Comp Assist Tomogr 18: 1 10-118). The transversal resolution in the reconstructed image is about 3.8 mm full width half maximum (FWHM) and the axial resolution, 3.125 mm. The data were corrected for attenuation with three rotating ⁶⁸Ge rod sources. Raw PET data were then reconstructed using standard filtered back projection consisting of the following reconstruction parameters: 2-mm Hanning filter, scatter correction, a zoom factor of 2.17, and a 128 x 128 matrix size (Wienhard et al., 1994, J Comp Assist Tomogr 18: 1 10-1 18). Emission data were collected continuously for 93 min, according to a preprogrammed series of 20 frames starting immediately after i.v. injection of radioligand. The 3 initial frames were 1 min each, followed by 4 frames of 3 min each and 13 frames of 6 min each.

[0425] The mean image of the PET measurements (9-93 min) was transformed into a standard anatomical space using the monkey version of the Human Brain Atlas developed at the Karolinska Institutet (Roland et al., 1994, Human Brain Mapping 1 : 173-184). The transformation matrix generated on this image was applied to all frames of the corresponding baseline, displacement and pretreatment experiments. PET data were subsequently re-sliced to a resolution of 1.00, 1.00, 1.00 mm. VOIs were manually defined on the coronal planes of an average monkey MRI. Similar VOIs were applied, as reported by Yasuno et al. (2008, Neuropsychopharmacology 33:259-269) including cerebellum (1.9 cm¹), frontal cortex (7.4 cm³), lateral temporal cortex (5.0 cm³), medial temporal cortex (2.9 cm³), striatum (2.1 cm³), thalamus (0.9 cm³) and pons (0.7 cm³). Tissue radioactivity concentrations were expressed as % standardized uptake values (%SUV). Tissue radioactivity concentrations were decay- corrected and, in order to normalize for injected dose and body weight, expressed as % standardized uptake values (%SUV), where:

% injected activity

%SUV = xbody weight (g) brain tissue (g)

[0426] Horizontal PET images, shown in Figure 3, obtained at the level of the striatum from data acquired between 9 and 93 min after injection of compound [^uC](-)-12a showed a distribution of radioactivity consistent with a large proportion of specific binding to CBi receptors, whereas corresponding images obtained with compound [^πC](+)-12a were strikingly homogeneous indicating little receptor-specific binding.

Example 13: Emergence of Radiometabolites of l"Cl(-)-12a in Plasma [0427] The metabolism of a suitable PET radioligand should be such that no or only small amounts of blood-brain-barrier (BBB)-permeable radiometabolites are formed that may contribute to brain radioactivity, since the PET camera merely measures radioactivity and does not distinguish between radiochemical entities. An estimate of the relative lipophilicity of a formed radiometabolite, and thus, its BBB permeability, as well as quantitative data on the rate of metabolism of a radioligand, can be obtained by, e.g., radiochromatography techniques, such as thin layer chromatography (TLC), and/or high performance liquid chromatography (HPLC). The latter coupled with mass spectrometry may be especially useful in the identification of radiometabolites.

[0428] For radiometabolite measurements, venous blood (1 mL) was sampled from monkey at 5, 15, 30 and 45 min after injection of each radioligand. Plasma samples were measured as described previously (Halldin et ah, 1995, Radioligand disposition and metabolism in PET or Drug Development and Evaluation; Kluver Academic Publishers; Dordrecht. Netherlands; pp. 55-65). Briefly, the supernatant liquid (0.5 mL) obtained after centrifugation at 2000 ^χ g for 1 min was mixed with MeCN (0.7 mL) containing standard compound 12a. The supernatant liquid (1 mL) after another centrifugation at 2000 ^x g for 1 min was counted in a well counter and subsequently injected onto HPLC.

[0429] Analysis of venous samples showed that after injection of compound [ⁿC](-)-12a into cynomolgus monkey, three less lipophilic radiometabolite fractions (/_RS = 2.3, 5.8 and 8 min, cf. /_R = 8.5 min for compound [^uC](-)-12a) emerged in plasma (Panel A, Figure 4). Unchanged radioligand had declined to 50% of radioactivity in plasma at 45 min after injection (Panel B, Figure 4). The presence of the three radiometabolite fractions slowly increased as a percentage of total radioactivity in plasma throughout the scan. In this study, the identities of any of these radiometabolite fractions were not determined nor whether they crossed the blood-brain barrier.

[0430] Finally, compound (-)-12c was not labeled with radioiodine in this study, but its properties (high affinity, high selectivity and lipophilicity) also suggest it has potential for use as a radioligand for imaging brain CBi receptors, either for PET or SPECT. Example 14: Post Mortem Autoradiography Using [¹²⁵Il 13 And SPECT [04311 CBi receptors are spread heterogeneously in brain, with high densities appearing in striatum, globus pallidus and cerebellum (Herkenham et ai, 1991 , J Neurosci 1 1 :563-583; Glass et ai, 1997, Neuroscience 77:299-318). Brain regions with low CBi receptor densities are thalamus and white matter. In post mortem autoradiography in vitro, [¹²⁵T]13 bound substantially to brain regions with high receptor density. Additionally [¹²⁵I] 13 showed lower binding in brain regions with low CBi receptor density. Therefore, the regional selectivity and low non-specific binding of [^I25I]13 indicate that ¹²⁵I-labeled 13 is a suitable radioligand for imaging brain CBi receptors with SPECT or PET. [0432] Compound 13 demonstrated high affinity and selectivity to CB| receptors. [^{I 25}I]13 was labeled in acceptable radiochemical yield, specific radioactivity and purity for evaluation in vitro. Autoradiographic brain images of [¹²⁵I] 13 showed a distinct regional distribution of radioactivity according to the known brain CBj receptor densities (Figure 7). [¹²³I]O is expected to show similar distinct regional distribution of radioactivity in human brain.

Claims

WHAT IS CLAIMED IS:

1. A compound of Formula (XII):

_P4 _n O I S-R¹

wherein: A is H; each of R¹, R² and R³ are independently aryl or a 5-6 membered heteroaryl ring, at least one of which is substituted with 1-3 R⁵ groups, R⁴ is selected from the group consisting of H, Q.galkyl and Ci.ghaloalkyl; each R⁵ is independently selected from the group

cyano, Ci-salkoxy, CHO, Ci.salkylcarbonyl, aminocarbonyl, halo, haloCi.galkoxy, nitro, Ci- galkylthio, amino, Ci-salkylamino and Ci-salkoxycarbonylamino; and all stereoisomers or pharmaceutically acceptable salts thereof; wherein one atom selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, halogen and sulfur atom comprises or is replaced by a detectable amount of a radioisotope selected from the group consisting of ²H, ³H, ¹¹C, ¹³N, ¹⁵O, ¹⁸F, ⁷⁵ Br, ⁷⁶Br, ⁷⁷Br₅ ¹²³I, ¹²⁴I, ¹²⁵I, and ¹³¹I.

2. The compound according to claim 1, wherein at least one of R, R¹ and R² is heteroaryl, optionally substituted with 1-3 R³ groups.

3. The compound according to claim 2, wherein each heteroaryl is independently selected from the group consisting of pyridinyl, pyrazinyl and pyrimidinyl.

4. The compound according to claim 1 , wherein at least one of R, R¹ and R² are aryl, optionally substituted with 1-3 R⁵ groups.

5. The compound according to claim 4, wherein aryl is phenyl.

6. The compound according to claim 1, wherein R⁴ is Ci.ghaloalkyl.

7. The compound according to claim 6, wherein R⁴ is C_n(H_2n-_I or D_2n+i)F.

8. The compound according to claim 1, wherein R⁴ is Ci-salkyl.

9. The compound according to claim 8, wherein R⁴ is CH₃.

10. The compound according to claim 1, wherein R⁴ is H.

11. The compound according to claim 1, wherein at least one R⁵ is selected from the group consisting of ²H, ³H, ¹¹CN, ¹¹CH₃, O¹¹CH₃, S¹¹CH₃, ¹¹CHO, ¹¹COCH₃, CO¹¹CH₃, ¹¹CONH₂ and ¹⁸F.

12. The compound according to claim 1, wherein at least one R⁵ is

_\18_T

F; and n is the integer 1, 2 or 3.

13. The compound according to claim 13, wherein n is 1.

14. The compound according to claim 1, wherein A is ²H.

15. The compound according to claim 1, wherein A is ^"H.

16. The compound according to claim 1, having the Formula (XIII):

wherein each of R^3A, R^5B and R^5C are as defined for R⁵; and the wavy line indicates the presence of either stereoisomer.

17. The compound according to claim 16, wherein R^5A is cyano or halogen; R^3B is H; and R^5c is halogen.

18. The compound according to claim 17, wherein R^5A is selected from the group consisting of CN, ¹¹CN, I, ¹²³I, ¹²⁴I, ¹²⁵I, and ¹³¹I.

19. The compound according to claim 18 having the Formula (XIV):

wherein R , 5a^a i •s halo or cyano; and the wavy line indicates the presence of either stereoisomer.

20. The compound according to claim 19, wherein R ^a is CN.

21. The compound according to claim 19, which is the (-)-enantiomer.

22. The compound according to claim 19, which is the (+)-enantiomer

23. A compound of Formula (XIX):

wherein R¹ is halogen, aryl, heteroaryl, nitrile, alkyl, trifiuoromethyl,

Ci-salkoxy, haloCi-salkoxy, Ci.galkylthio, haloCi.galkylthio, nitro, CHO, or Ci.galkylsulfoxy, amino, Ci-salkylamino and Ci-salkoxycarbonylamino; wherein R² is halogen, aryl, heteroaryl, nitrile, alkyl, trifiuoromethyl,

Ci_8alkoxy, haloCi-galkoxy, Ci-salkylthio, haloCi-salkylthio, CHO, amino, Ci-salkylamino, Ci- galkoxycarbonlamino and Ci.galkylsulfoxy substituted at 2 and/or 4 positions; wherein R^' is piperidinyl, morpholinyl, pyrrolidinyl, and azepanyl, Ci- ₈alkyl and Cs.scycloalkyl. and wherein one atom selected from the group consisting of carbon, hydrogen, nitrogen, oxygen, halogen and sulfur atom comprises or is replaced by a detectable amount of a radioisotope selected from the group consisting of ²H, ³H, ¹¹C, ¹⁴C, ¹³N, ¹³O, ¹⁸F, ⁷⁵ Br, ⁷⁶Br, ⁷⁷Br, ¹²³I, ¹²⁴1, ¹²⁵I, and ¹³¹I.

24. The compound according to claim 23, wherein either R¹ is halogen or R' is a halogen and either halogen comprises a label.

25. The compound according to claim 23, having the Formula (XIX):

wherein R² is selected from halogen, aryl, heteroaryl, nitrile, alkyl, trifluoromethyl, Ci_salkoxy, haloCi-salkoxy, Ci.galkylthio, haloQ-salkylthio, nitro, CHO, amino, Ci_₈alkylamino, Ci_₈alkoxycarbonylamino and Ci_-8alkylsulfoxy substituted at 2 and/or 4 positions.

26. The compound according to claim 25, wherein R »2 i ^■s a halogen.

27. The compound according to claim 26, having the Formula (XXI):

28. The compound according to claim 27, wherein the iodine comprises a label selected from the group consisting of ¹²³1, ¹²⁴1, ¹²³I, and ¹³¹I.

29. The compound according to any of the preceding claims in isolated and purified form.

30. A pharmaceutical composition comprising." (i) a compound according to any of the preceding claims; and (ii) a pharmaceutically acceptable carrier or excipient.

31. A kit or system comprising." (i) a compound according to any of the preceding claims; and (ii) a preparation of a cannabinoid subtype-1 (CBi) receptor.

32. A method of producing a compound according to claim 1 comprising the steps of: (a) reacting a compound having the Formula (XXII)

with a compound having the Formula (XXIII):

to form a product; and (b) reacting the product from step (a) with a compound having the formula NH²-R⁴ to provide a compound of claim 1 ; wherein R⁶ is C j-Cgalkyl; and one carbon or halogen atom comprises a detectable amount of a radioisotope.

33. A method of producing a compound according to claim 16 comprising the steps of: (a) reacting a compound having the Formula (XXIV) R

with a compound having the Formula (XXV):

to form a product; and (b) reacting the product from step (a) with a compound having the formula NH²-R⁴ to provide a compound of claim 16; wherein R⁶ is Cj-Cgalkyl; and one carbon or halogen atom comprises a detectable amount of a radioisotope.

34. The method according to claim 32, wherein R^3A is cyano or halogen; R^5B is H; and R^5c is halogen.

35. The method according to claim 32, wherein R^5a is ¹¹CN.

36. A method for measuring an interaction of a radiolabeled compound with a cannabinoid subtype- 1 (CB₁) receptor comprising the steps of: (a) contacting a cannabinoid subtype- 1 (CBi) receptor with a radiolabeled compound selected from the group consisting of a compound according to any of the preceding claims to produce a cannabinoid subtype-1 (CBi) receptor-radiolabeled compound complex; and (b) measuring an interaction of the radiolabeled compound with the cannabinoid subtype- 1 (CBi) receptor; wherein a measurable signal is indicative of the amount of the radiolabeled compound interacting with the cannabinoid subtype-1 (CBi) receptor.

37. The method according to claim 36, wherein the measurable signal is recorded.

38. The method according to claim 37, wherein the measurable signal is recorded in an electronic or optical database.

39. A method for measuring an interaction of a test compound with a cannabinoid subtype- 1 (CBi) receptor comprising the steps of: (a) contacting a cannabinoid subtype- 1 (CBi) receptor preparation with a radiolabeled selected from the group consisting of a compound according to any of the preceding claims to produce a cannabinoid subtype- 1 (CBi) receptor -radiolabeled compound complex; (b) measuring an interaction of the radiolabeled compound with the cannabinoid subtype- 1 (CBi) receptor; wherein a first measurable signal is obtained; (c) contacting the cannabinoid subtype- 1 (CBi) receptor - radiolabeled compound complex with a test compound under conditions whereby the interaction of the radiolabeled compound with the cannabinoid subtype- 1 (CBi) receptor is prevented by the test compound; and (d) detecting a second measurable signal; wherein a higher second measurable signal when compared to the first measurable signal is indicative of the test compound interacting with the cannabinoid subtype- 1 (CBi) receptor.

40. The method according to claim 39, wherein the cannabinoid subtype- 1 (CBi) receptor preparation is a cannabinoid subtype- 1 (CBi) receptor membrane preparation.

41. The method according to claim 39, wherein the cannabinoid subtype- 1 (CBi) receptor preparation is a cannabinoid subtype- 1 (CBi) receptor whole cell preparation.

42. The method according to claim 39, wherein the cannabinoid subtype-1 (CBi) receptor is bound to a solid support.

43. A method for measuring an interaction of a test compound with a cannabinoid subtype-1 (CBi) receptor comprising the steps of: (a) contacting a cannabinoid subtype-1 (CBi) receptor preparation with a mixture comprising: (i) a radiolabeled compound selected from the group consisting of a compound according to any of the preceding claims; and (ii) a test compound; to produce a cannabinoid subtype- 1 (CBi) receptor -radiolabeled compound complex and a cannabinoid subtype- 1 (CB₁) receptor -test compound complex; (b) measuring the interaction of the radiolabeled compound with the cannabinoid subtype-1 (CBi) receptor; wherein a first measurable signal is obtained; and (c) comparing the first measurable signal to a second measurable signal obtained by contacting the cannabinoid subtype-1 (CB]) receptor with the radiolabeled compound in the absence of the test compound; wherein a lower first measurable signal when compared to the second measurable signal is indicative of the test compound interacting with the cannabinoid subtype- 1 (CB i ) receptor.

44. The method according to claim 43, wherein the cannabinoid subtype-1 (CBi) receptor preparation is a cannabinoid subtype-1 (CBi) receptor membrane preparation.

45. The method according to claim 43, wherein the cannabinoid subtype-1 (CBi) receptor preparation is a cannabinoid subtype-1 (CBi) receptor whole cell preparation.

46. The method according to claim 42, wherein the cannabinoid subtype-1 (CBi) receptor is bound to a solid support

47. A method of assessing cannabinoid subtype- 1 (CBi) receptor function in a subject having a neurological condition comprising the steps of: (a) administering a radiolabeled compound selected from the group consisting of a compound according to any of the preceding claims to the subject; and (b) measuring transport of the radiolabeled compound across the blood brain barrier.

48. The method according to claim 47, wherein the neurological condition is selected from the group consisting of obesity, alcohol or tobacco dependency and memory loss.

49. A method for measuring the density of a cannabinoid subtype- 1 (CBi) receptor in a subject having a disease or being suspected of having a disease, comprising the steps of: (a) administering to the subject a radiolabeled compound selected from the group consisting of a radiolabeled having the Formula (XIII), a radiolabeled compound having the Formula (XV), a radiolabeled compound having the Formula (XXVI), a radiolabeled compound having the Formula (XVIII), a radiolabeled compound having the Formula (XXVII), a radiolabeled compound having the Formula (XIX), a radiolabeled compound having the Formula (XX), a radiolabeled compound having the Formula (XXI), and a radiolabeled compound having the Formula (XXVIII).; and (b) measuring the density of the CBi receptor.

50. The method according to claim 49, wherein the disease is selected from the group consisting of depression, mood disorder, anxiety, schizophrenia, drug addiction, alcohol disorder, obesity, anorexia, memory dysfunction, Gilles de Ia Tourette Syndrome, Parkinson's disease, Hungtington's disease, Alzheimer's disease, multiple sclerosis, acute pain, chronic pain, neuropathic pain, nausea, and emesis.