Design, synthesis, and in vitro hMAO-B inhibitory evaluation of some 1-methyl-3,5-diphenyl-4,5-dihydro-1H-pyrazoles

Abstract A series of 1-methyl-3,5-diphenyl-4,5-dihydro-1 H -pyrazoles ( 3a – k and 4a – u ) were designed, synthesized, and evaluated for their inhibitory efficacy towards the two hMAO isoforms. Most of the derivatives were found to be potent and selective hMAO-B inhibitors. In particular, derivative 3g showed greater hMAO-B affinity than selective inhibitor selegiline coupled with high selectivity index (SI = 145). The most selective hMAO-B inhibitor was the 3-methyl analogue 3f with an SI higher than 909.