Synthesis of thiazolo[3,2-a]pyridines from enaminoesters by tandem conjugate addition-cyclization

Abstract Several representative compounds with the new heterocyclic system thiazolo[3,2- a ]pyridine have been obtained by condensation between α,β-unsaturated ketoesters and the N-mercaptoethylenamines of β-ketoesters in a tandem conjugate addition-cyclization process. The stereochemistry of these products is different from that observed for the products obtained from related N-hydroxyethylenamines.