REACTIONS OF 3-SUBSTITUTED-4-AMINO-5-MERCAPTO-1,2,4-TRIAZOLES WITH ACETYLENIC KETONES AND ALPHA-BROMOCHALCONES

The acetylenic ketones (3) have been condensed with 3-substituted-4-am ino-5-mercapto-1,2,4-triazoles (5) in ethanol to give the Michael addu cts (6), which on treatment with cone. H2SO4 yield hienyl)-1,2,4-triaz olo[3,4-b]-1,3,4-thiadiazepines (7) whose structures have been establi shed on the basis of analytical and spectral data. Thiadiazepines (7) are also synthesized from the reaction of alpha-bromochalcones (4) wit h triazoles (5) using sodium acetate as catalyst. However, the chalcon e dibromides (2) on treatment with triazoles (5) in the presence of tr iethylamine undergo debromination to give the corresponding chalcones( 1).