Reactions of ketene dithioacetal for a new versatile synthesis of 4,5-substituted 3-aminothiophene-2-carboxylate derivatives

Abstract

Poly substituted 3-aminothiophenes were successfully synthesized in good yields by using a one-pot protocol via ketene S,S-acetal as an intermediate in basic medium (K2CO3/N,N-dimethylformamide) followed by Dieckmann condensation with ethyl bromoacetate. Further, chemistry of thiophenes was explored using active functional groups such as C3–NH2, C4–CN and C5–SCH3 on the thiophene nucleus. Synthesis of ethyl 3-acetamido-4-cyano-5-(methylthio)thiophene-2-carboxylate derivatives and ethyl 3-amino-4-carbamoyl-5-(methylthio)thiophene-2-carboxylate derivatives.</p