FORMATION OF 1,4-THIAZINE 1,1-DIOXIDES BY THE CYCLOADDITION–EXTRUSION–RING EXPANSION REACTIONS OF MESOIONIC OXAZOLONES WITH DIPHENYLTHIIRENE DIOXIDE

Abstract

Abstract The reactions of diphenylthiirene dioxide 5 with a mesoionic oxazol-5-one 4a and an oxazolin-5-one 9 gave the corresponding 4H-1,4-thiazine 1,1-dioxides 7.