Synthesis of some alkoxy based bisthiadiazolines

The bisthiadiazolines 3a–3h built around the alkyl chains of varying lengths have been synthesized in good yields by refluxing bisthiosemicarbazones 2a–2h in acetic anhydride. The reactions of bisaldehydes 1a–1h with thiosemicarbazide in alcoholic medium provided 2a–2h and the former were obtained by using the reported methods. The formation and stereochemical features of the bisthiadiazolines 3a–3h are found to be independent of the internal spacer length. The intermediates 2a–2h and bisheterocyclic compounds 3a–3h have been characterized by means of IR, ¹H NMR, ¹³C NMR, Mass (ESI) and elemental analysis.