Synthesis, characterization and biological screening of different carbamates derived from 7-hydroxy-4-methyl-2H-1-benzopyran-2-one

A facile and environmentally benign series of carbamates derived from coumarin were synthesized. the synthesis of 7-hydroxy-4-methyl-2h-1-benzopyran-2-one (3) was carried out by gearing up resorcinol (1) and ethyl acetoacetate (2) in a strong acidic media. carbamates 7 and 8 were synthesized by reacting phenylchloroformate (4) with substituted aliphatic amines 5 and 6 under dynamic ph control in aqueous media in the presence of na2co3 solution. the molecules 3, 7, and 8 were brominated to 3a, 7a and 8a. the molecules 9, 9a, 10, and 11 were synthesized by further reaction of 3 and 3a with the electrophilic carbamates 7, 7a, and 8 in a polar aprotic solvent using lih as an activator. finally, the compound 12 was synthesized by the nitration of 10. structures of all the compounds were determined by ir, 1h-nmr, 13c-nmr and ei-ms spectroscopic techniques. the bioactivity results of all the synthesized compounds against four gramnegative and two gram-positive bacteria showed that the synthesized coumarin derivatives exhibited moderate to good %age inhibition activity.