Alkylation of 4-anilino-5-phenyl-4H-1,2,4-triazole-3-thiol (1) with some halo compounds
yielded the corresponding sulfides 2a–f. Some sulfides 2e,f were cyclized to give triazolothiadiazines
3 and 4. Triazolothiadiazoles 5 and 6 were prepared through the reaction of
compound 1 with carbon disulfide or ethyl orthoformate, respectively. Treatment of compound
1 with ethyl chloroformate or phenyl isothiocyanate yielded triazolo-thiadiazole and triazole 9
and 10, respectively. Reaction of compound 1 with Lawesson’s reagent gave triazolothiadiazaphosphole
derivative 11. Also, compound 1 underwent cyclocondensation reactions with some
bidentate reagents to give triazolothiazines 4, 12, and 13. Triazolo-thiazepines and triaziepine
14–16 were synthesized via the reaction of compound 1 with β-ketoesters or ethyl cyanoacetate.
Tricyclic systems 19 and 20 were prepared through the reaction of compound 4 with the
appropriate reagent. Some synthesized compounds were tested for antibacterial activity.