AM-251 (drug)

AM-251 is an inverse agonist at the CB₁ cannabinoid receptor. AM-251 is structurally very close to rimonabant; both are biarylpyrazole cannabinoid receptor antagonists. In AM-251, the p-chloro group attached to the phenyl substituent at C-5 of the pyrazole ring is replaced with a p-iodo group. The resulting compound exhibits slightly better binding affinity for the CB₁ receptor (with a K_i value of 7.5 nM) than rimonabant, which has a K_i value of 11.5 nM, AM-251 is, however, about two-fold more selective for the CB₁ receptor when compared to rimonabant.[1] Like rimonabant, it is additionally a μ-opioid receptor antagonist[2] that attenuates analgesic effects.[3]

AM-251

Identifiers
IUPAC name 1-(2,4-Dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-(1-piperidyl)pyrazole-3-carboxamide
CAS Number	183232-66-8^Y
PubChem CID	2125
IUPHAR/BPS	3317
ChemSpider	2040^Y
UNII	3I4FA44MAI
ChEBI	CHEBI:90724^Y
ChEMBL	ChEMBL285932^Y
CompTox Dashboard (EPA)	DTXSID7042695
ECHA InfoCard	100.162.062
Chemical and physical data
Formula	C22H21Cl2IN4O
Molar mass	555.24 g·mol^−1
3D model (JSmol)	Interactive image
SMILES O=C(NN1CCCCC1)c4nn(c2ccc(Cl)cc2Cl)c(c3ccc(I)cc3)c4C
InChI InChI=1S/C22H21Cl2IN4O/c1-14-20(22(30)27-28-11-3-2-4-12-28)26-29(19-10-7-16(23)13-18(19)24)21(14)15-5-8-17(25)9-6-15/h5-10,13H,2-4,11-12H2,1H3,(H,27,30)^Y Key:BUZAJRPLUGXRAB-UHFFFAOYSA-N^Y
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See also

• Discovery and development of Cannabinoid Receptor 1 Antagonists

References

1. Lan R, Liu Q, Fan P, Lin S, Fernando SR, McCallion D, et al. (February 1999). "Structure-activity relationships of pyrazole derivatives as cannabinoid receptor antagonists". Journal of Medicinal Chemistry. 42 (4): 769–76. doi:10.1021/jm980363y. PMID 10052983.
2. Seely KA, Brents LK, Franks LN, Rajasekaran M, Zimmerman SM, Fantegrossi WE, Prather PL (October 2012). "AM-251 and rimonabant act as direct antagonists at mu-opioid receptors: implications for opioid/cannabinoid interaction studies". Neuropharmacology. 63 (5): 905–15. doi:10.1016/j.neuropharm.2012.06.046. PMC 3408547. PMID 22771770.
3. Seely, Kathryn A.; Brents, Lisa K.; Franks, Lirit N.; Rajasekaran, Maheswari; Zimmerman, Sarah M.; Fantegrossi, William E.; Prather, Paul L. (October 2012). "AM-251 and rimonabant act as direct antagonists at mu-opioid receptors: Implications for opioid/cannabinoid interaction studies". Neuropharmacology. 63 (5): 905–915. doi:10.1016/j.neuropharm.2012.06.046. PMC 3408547. PMID 22771770.