A Convenient Synthesis of 2-Substituted 3-Hydroxy- and 3-Amino-Thiophens from Derivatives of 2-Chloroacrylic Acid

Abstract

A valuable synthesis of methyl 3-amino-¹ and 3-hydroxy-² 2-thiophen carboxylates, due to Fiesselmann, involves the base-induced condensation of methyl thioglycollate with 2,3-dihalogeno-propionitrile and 2,3-dihalogenopropionate esters, respectively. It seemed to us that readily accessible 2-halogenoacrylic acid derivatives might be useful substitutes for the halogenated compounds previously employed in these reactions. Accordingly we have used compounds (1a) and (1b) in a modification of the Fiesselmann process, and have obtained good yields of the thiophen derivatives (2a) and (2b):-