Discovery and stereoselective synthesis of the novel isochroman neurokinin-1 receptor antagonist 'CJ-17,493'

A novel central nervous system (CNS) selective neurokinin-1 (NK1) receptor antagonist, (2S, 3S)-3-[(1R)-6-methoxy- 1-methyl-1-trifluoromethylisochroman-7-yl]-methylamino-2-phenylpiperidine 'CJ-17,493'( compound (+)-1), was synthesized stereoselectively using a kinetic resolution by lipase-PS as a key step. Compound (+)-1 displayed high and selective affinity (K-i = 0.2 nM) for the human NK1 receptor in IM-9 cells, potent activity in the [Sar(9), Met(O-2)(11)] SP-induced gerbil tapping model (ED50 = 0.04 mg/kg, sc) and in the ferret cisplatin (10 mg/kg, ip)-induced anti-emetic activity model (vomiting: ED90 = 0.07 mg/kg, sc), all levels of activity comparable with those of CP-122,721. In addition, compound (+)-1 exhibited linear pharmacokinetics rather than the super dose-proportionality of CP-122,721 and this result provides a potential solution for the clinical issue observed with CP-122,721. (C) 2008 Elsevier Ltd. All rights reserved.