6-(2-Chloroacetyl)-aminocoumarins 2a-c were prepared by reacting the 6-aminocoumarins 1a-c and chloroacetylchloride in dry benzene. Compound 2a-c on treatment with thiourea yields 6-(2′-amino-1′,3′-thiazol-4′-yl)aminocoumarins 3a-c. Compounds 3a-c were treated with aromatic aldehydes, resulted in the formation of 6-(arylidenimino-1′-3′-thiazole-4′-yl)aminocoumarin 4a-f. The arylidenoiminos 4a-f on cyclisation with chloroacetylchloride/triethylamine and thioglycollic acid gave 6-[2′-(3”-chloro-2”-oxo-4”-phenyl-1”-azetidinyl)-1′,3′-thiazole-4′-yl]aminocoumarins 5a-f and 6-[2′-(2”-phenyl-4”-thiazolidinone-3”-yl)-1′, 3”-thiazole-4′-yl]aminocoumarin 6a-f respectively. Compounds 4a-f were also treated with aniline and sodium nitrite in the presence of conc. HCl to yield 6-[2′-(1”-phenyl-3”-phenylformazane-4”-yl)-1′,3′-thiazole-4′-yl]aminocoumarins 7a-f. The structure of these compounds have been established on the basis of their analytical and spectroscopic data. All the above compounds were screened for their antimicrobial activity. Some were found to show significant antimicrobial activity.
