SYNTHESIS AND ACTIVITY OF 2-METHYL-3-AMINOPROPIOPHENONES AS CENTRALLYACTING MUSCLE-RELAXANTS

Some novel 2-methyl-3-aminopropiophenones were synthesized and their c entrally acting muscle relaxant activities were evaluated for an inhib itory effect on the flexor reflex in rats. The structure-activity rela tionships are discussed. In this series, rrolidino-1-(4-trifluoromethy lphenyl)-propan-1-one (28) showed significant centrally acting muscle relaxant activity. In addition, the activities of each enantiomer (28- (S) and (R)) were studied along with their acute toxicities. Compound 28-(R) was found to exhibit more potent activity and weaker acute toxi city than 28-(S). Accordingly, compound 28-(R) (NK433) is under develo pment as a novel centrally acting muscle relaxant.