Reactivity of malononitrile towards sulphamide and N-substituted sulphamides: synthesis and hydrolysis reactions of 3,5-diamino-1,2,6-thiadiazine 1,1-dioxides

Abstract

The reaction of sulphamide and N-substituted sulphamides with malononitrile under acid catalysis gave respectively 3,5-diamino- 4H- or 2H-1,2,6-thiadiazine 1,1-dioxides (1) and (3a–d). Mild acid hydrolysis of the latter afforded 5-amino-2H-1,2,6-thiadiazin-3(4H)-one 1,1-dioxides (5a–d) in excellent yield. No convenient methods for the preparation of all these compounds had previously been reported.