Two reaction modes of 1-sulfonyl-1,2,3-triazoles and pyridinium 1,4-zwitterionic thiolates: catalyst-free synthesis of pyrido[1,2-a]pyrazine derivatives and 1,4-thiazine derivatives

Abstract

Two reaction modes of 1-sulfonyl-1,2,3-triazoles and pyridinium 1,4-zwitterionic thiolates were described. Pyrido[1,2-a]pyrazine derivatives were obtained in moderate yields when 4-OEt substituted triazoles were employed in reactions, and 1,4-thiazine derivatives were synthesized when 4-NPhth substituted triazoles were employed. The mechanism may involve a sulfur migration via an addition/elimination process which has never been reported in the previous pyridinium 1,4-zwitterionic thiolate related works.