On the alkylation of multisite aromatic heterocycles. Part 2. Formation and thermal decomposition of 4-alkyl-5-alkylimino-1,2,3,4-thiatriazolines

Abstract

Hitherto unknown 4-alkyl derivatives of 5-alkylimino-1,2,3,4-thiatriazolines have been obtained in good yields by alkylation of 5-alkylaminothiatriazoles with trialkyloxonium tetrafluoroborates. 5-Arylamino- and 5-sulphonylamino-thiatriazoles are similarly alkylated in the 4-position. The dialkyliminothiatriazolines undergo thermal decomposition with loss of nitrogen and sulphur to form carbodi-imides. Decomposition can be induced by adding electron-rich alkenes or heterocumulenes in contrast to the corresponding 4-alkyl-5-arylimino- and 4-alkyl-5-sulphonylimino-thiatriazolines.²