A One-Pot Synthesis of 2,3-Dihydro-2-Thioxothieno[2,3-d]Thiazoles

Abstract

A variety of 3,5-disubstituted-2,3-dihydro-2-thioxothieno[2,3-d]thiazoles 3 a - h including alkyl-, aryl- and heteryl-substituents were synthesized in excellent yields in a one pot reaction between 3-substituted-5-(2-aryl (or heteryl)-2-oxoethyl)-4-oxo-2-thioxo-1,3-thiazolidines 1 a - h and either tetraphosphorous decasulfide (Method A) or Lawesson's reagent (Method B). However, fair yields of 3 were also obtained along with unknown oily products when the (E,Z)-5-(2-aryl-2-oxoethylidene) derivatives 2 f,g were similarly treated with the same reagents. Structures of products were supported by microanalytical and spectral evidence. A rationalization for the route of conversion is given.