Reaction of 5-aryl-3-chloro-4-phenyl-1,2,4-triazoles (1 & 2)
with hydrazine hydrate afforded the hydrazino derivatives 3
and 4. Reaction of 3 and 4 with carboxylic acids, CS2 and
phenylisothiocyanate gave the s-triazole-fused ring systems
5–12. On the other hand, reaction of 3 and 4 with nitrous
acid gave tetrazole-fused ring systems 13 and 14, respectively.
Mannich reaction on compounds 9 and 10 afforded Mannich
bases 15 and 16.