A practical procedure for the synthesis of esonarimod, (R,S)-2-acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid, an antirheumatic agent. II

摘要

An efficient large-scale synthesis of Esonarimod, (R,S)-2-acetylthiomethyl-4-(4-methylphenyl)-4-oxobutanoic acid (1), a new antirheumatic drug,was established. A small amount of water increased the yield of the Michael addition of thioacetic acid (4) to 2-methylene-4-(4-methylphenyl)-4-oxobutanoic acid (2) to give 1. Multikilogram amounts of 1 (over 25 kg) were successfully obtained using this procedure. In addition,this procedure was repeated nine times, and reproducible results were obtained.