Synthesis and analgesic activity of novel N-acylarylhydrazones and isosters, derived from natural safrole.

Anew series of antinociceptive compounds belonging to the N-acylarylhydrazone (NAH) class were synthesized from natural safrole (7). The most analgesic derivative represented by 10f, [(4'-N,N-dimethylaminobenzylidene-3-(3', 4'-methylenedioxyphenyl)propionylhydrazine], was more potent than dipyrone and indomethacin, used as standards. The NAH compounds described herein were structurally planned by molecular hybridization and classical bioisosterism strategies on previously reported analgesic NAH in order to identify the pharmacophoric contribution of the N-acylarylhydrazone moiety and investigate the structure-activity relationship (SAR) in these series.