Reactivity of 3-aryl-4-amino-5-mercapto-4H-1,2,4-triazoles: synthesis and biological evaluation of 3,6-diaryl derivatives of 7H-1,2,4-thiazole[3,4-b][1,3,4]thiadiazines, of 3-aryl-4-amino-5-carboxymethylthio-4H-1,2,4-triazoles

Starting from 3-aryl-4-amino-5-mercapto-4H-1,2,4-triazoles (II), two series of 3,6-disubstituted 7H-1,2,4-triazol [3,4-b] [1,3,4] thiadiazines (III) and their 5-carboxymethylthio derivatives (IV) were prepared. From the mercapto-amino-triazoles (II) because of their reactivity in some oxidising media, were obtained the triazole derivatives (V), (VI) and (VII). The synthesis of the alpha-thioketones (VIII) of 3-aryl-5-mercapto-1,3,4-oxadiazoles (I), used in alternative synthesis of triazole-thiadiazines (III), is also reported. All the substances described were subjected to biological screening. In the tests, the carboxymethylthiotriazole (IV) showed weak antiinflammatory activity (carrageenin edema) and more consistent scavanger activity, in vitro, on superoxide anions. The triazole-thiadiazines (III) and triazoles (II), (V) and (VI) showed moderate antimycotic activity.