MN-25 (UR-12) is a drug invented by Bristol-Myers Squibb, that acts as a reasonably selective agonist of peripheral cannabinoid receptors. It has moderate affinity for CB2 receptors with a Ki of 11nM, but 22x lower affinity for the psychoactive CB1 receptors with a Ki of 245nM. The indole 2-methyl derivative has the ratio of affinities reversed however, with a Ki of 8nM at CB1 and 29nM at CB2, which contrasts with the usual trend of 2-methyl derivatives having increased selectivity for CB2 (cf. JWH-018 vs JWH-007, JWH-081 vs JWH-098).
2-methyl derivative; Chemically, it is closely related to another indole-3-carboxamide synthetic cannabinoid, Org 28611, but with a different cycloalkyl substitution on the carboxamide, and the cyclohexylmethyl group replaced by morpholinylethyl, as in JWH-200 or A-796,260. Early compounds such as these have subsequently led to the development of a large number of related indole-3-carboxamide cannabinoid ligands.