Some reactions of ethyl 2-anilino-4-oxo-4,5-dihydrothiophen-3-carboxylate

Abstract

Phenyl isothiocyanate reacts with ethyl γ-chloroacetoacetate in the presence of sodium hydride to give ethyl 2-anilino-4-oxo-4,5-dihydrothiophen-3-carboxylate (1b). The compound (1b) shows typical reactions of a keto methylene compound; the Vilsmeier reagent and phosphorus oxychloride give the chloroformylthiophen (10). A possible sulphine derivative (11) is obtained from (1b) with thionyl chloride. Further exploitation of the chloroformylthiophen (10) yields normal aromatic aldehyde condensation products and with thioglycolic ester the thieno[3,2-b]thiophen (25).