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 synthesizedThe 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, 7and8,were synthesized by reacting phenylchloroformate (4) with substituted aliphatic amines, 5 and6, under dynamic pH control in aqueous media in the presence of Na2CO3 solution. The molecules 37 and 8 werebrominated to 3a7a and8a. The molecules 99a10 and 11 were synthesized by further reaction of 3 and3a with the electrophilic carbamates, 77a 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, 1HNMR, 13C-NMR and EI-MS spectroscopic techniques. The bioactivity results of all the synthesized compounds against four gram-negative and two gram-positive bacteria showed that the synthesized coumarin derivatives exhibited moderate to good %age inhibition activity.