Tiaprofenic Acid의 합성

Synthesis of Tiaprofenic Acid

A new synthetic method for tiaprofenic acid, which is a potent anti-inflammatory agent, was described. Friedel-Crafts reaction of thiophene with ethyl alpha-chloro-alpha-(methylthio)acetate (1) gave ethyl alpha-methylthio-2-thiopheneacetate (3). Ethyl alpha-methyl-2-thiopheneacetate (5) was prepared by treatment of (3) with NaH and MeI, followed by desulfurization with zinc dust-acetic acid of the resultant ethyl alpha-methyl-alpha-methylthio-2-thiopheneacetate (4). Tiaprofenic acid (7) could be easily synthesized by benzoylation of (5) and hydrolysis of the resultant ethyl 5-benzoyl-alpha-methyl-2-thiopheneacetate (6).