Biarylcarbamoylindolines Are Novel and Selective 5-HT2C Receptor Inverse Agonists:  Identification of 5-Methyl-1-[[2-[(2-methyl-3-pyridyl)oxy]- 5-pyridyl]carbamoyl]-6-trifluoromethylindoline (SB-243213) as a Potential Antidepressant/Anxiolytic Agent

The evolution, synthesis, and biological activity of a novel series of 5-HT2C receptor inverse agonists are reported. Biarylcarbamoylindolines have been identified with excellent 5-HT2C affinity and selectivity over 5-HT2A receptors. In addition, (pyridyloxypyridyl)carbamoylindolines have been discovered with additional selectivity over the closely related 5-HT2B receptor. Compounds from this series are inverse agonists at the human cloned 5-HT2C receptor, completely abolishing basal activity in a functional assay. The new series have reduced P450 inhibitory liability compared to a previously described series of 1-(3-pyridylcarbamoyl)indolines (Bromidge et al. J. Med. Chem. 1998, 41, 1598) from which they evolved. Compounds from this series showed excellent oral activity in a rat mCPP hypolocomotion model and in animal models of anxiety. On the basis of their favorable biological profile, 32 (SB-228357) and 40 (SB-243213) have been selected for further evaluation to determine their therapeutic potential for the treatment of CNS disorders such as depression and anxiety.