Fatty acids in heterocyclic synthesis part XI: Facile and convenient routes to synthesize ecofriendly polyfunctionalized thiadiazoles, triazole, thiadiazolo [3,2-a] pyrimidines and imidazo [2,1-b] thiadiazole for pharmaceutical and industrial purposes

IN an one pot procedure 1,3- and 1,2-dicarbonyl compounds (ethyl cyanoacetate, ethyl acetoacetate, diethyl malonate, acetylacetone and oxalyl chloride) were reacted in different solvents with the readily available 2-amino-5-heptadecyl thiadiazole to produce novel polyfunctionalized thiadiazoles, fused thiadiazolo [3,2-a] pyrimidines, and imidazo [2,1-a]thiadiazole. The reaction of 2-amino-5-heptadecyl thiadiazole with triethylorthoformate, 2-naphthaldehyde, succinic anhydride, and hydroxylamine hydrochloride was also carried out. Moreover, the biological activities of the synthesized compounds were screened in vitro against some bacteria and fungi. Tetracycline was taken as a standard antibacterial agent and amphotericin B as a standard antifungal agent. It was reported that 3-amino-5-heptadecyl [1,2,4] triazol-4-ol showed very high activity against G^- bacteria, while thiadiazolo [3,2-a] pyrimidines and imidazo [2,1-a] thiadiazole exhibited high activity against G⁺ bacteria. In addition structure-activity relationship (SAR) study was carried out. For industrial purposes, propylene oxide was added to the synthesized compounds and for the produced compounds. Surface properties such as surface and interfacial tension, cloud point, wetting time, emulsion stability, and foam height which can be used were measured. They indicate a possibility to use these compounds in the manufacture of textiles, dyes, and cosmetics. Their biodegradability has been evaluated to ensure that these compounds are ecofriendly ones.