Utility of 4,5-Diphenylimidazol-2-thione in Synthesis of Fused Heterocyclic Ring Systems with Biological Interest (original) (raw)

The reaction of 4,5-diphenylimidazol-2-thione 1 with chloroacetic acid in presence of acetic acid and sodium acetate afforded 5,6-diphenylimidazo [2,1-b]thiazole-3-one 3. Compound 3, when treated with acetic anhydride in presence of sodium acetate, dimethyl formamide dimethylacetal (DMFDMA), thiophene-2-carbaldehyde and 2-thenylidene activated nitriles gave 5,6-diphenylimidazo[2,1-b] thiazole derivatives 4, 6, 8 and 7,8-diphenyl imidazo[2,1-b] thiazolo [2,3-b] pyran derivatives 9 e,f , 10. Claisen condensation of compound 4 with diethyl oxalate gives 7,8-diphenylimidazo [2,1-b] thiazolo [2,3-b]-4-pyron derivatives 5 a,b thiazolo[2,3-c] oxazole or (N-phenylpyrazole) 7 c,d were obtained directly upon reaction of 6 with hydroxylamine hydrochloride and phenyl hydrazine. Compound 1 reacted with α-chloroacetylacetone and α-chloroethylacetoacetate to give 2-acetyl or (2-ethoxycarbonyl) 3-methyl-5,6-diphenylimidazo[2,1-b] thiazole 12 h,i . Treatment of 12 h with thiophene-2-carbaldehyde led to the formation of 3-methyl-5, 6-diphenyl-2(2-thenylidene-2-propenoyl) imidazo[2,1-b]thiazole 13 h . Compound 13 h react with each of 2-chlorophenyl hydrazine and benzamidine hydrochloride to give 14 h and 15 h . Cyclocondensation of 12 h with hydroxylamine hydrochloride and hydrazine hydrate gave 16 j and 16 k . The newly synthesized compounds were tested for antibacterial and antifungal activity. Most of the tested compounds showed activity toward fungi while many of these did not have activity toward bacteria.