Part -IV: Utilities of active methylene compounds and heterocycles bearing active methyl or having an active methine in the synthesis of triazoles, pyridazines, triazines and diazepines

Common and novel synthesized active methylene compounds as well as heterocycles bearing active methyl or having an active methine were used in the syntheses of a wide variety of substituted and fused five-, six- and seven-membered nitrogenous heterocyclic systems of interesting medical and pharmaceutical importance such as triazoles, pyridazines, triazines, and diazepines. Carbothiosemicarbazides, carbothiohydrazones and 2-hydrazinoazaherterocycles were used as suitable starting materials for triazole formation. The preparation of tetrazoles showed a valence ring-chain tautomerism. The key starting materials for the synthesis of pyridazines were acetohydrazide derivative, activated enones, enaminones, and aryl hydrazones. The reaction of 2-chloro or 2-hydrazinoazaheterocycles and thiocarbohydrazones with different reagents under suitable reaction conditions led to the formation of triazines. Diazepines were obtained via treatment of enones with 1,2-diamino derivatives. Also, the antimicrobial activities of some selected synthesized heterocyclic compounds were reported.