Synthesis, spectroscopic characterization and antimicrobial activities of benzoxazolone derivatives

: Background: Pathogenic microbial diseases are now the key virulence in our daily life. Significant research has been carried out in order to trigger the bacterial infections. Amongst the organic molecules, oxazolone and derivatives were found to have excellent bioactivities including antimicrobial activities.

By keeping in mind the considerable antimicrobial activities of class benzoxazolones, a series of benzoxazolone derivatives 3-16 have been synthesized. Out of which five compounds 10, 11, 14, 15, and 16 were new synthetic derivatives whereas compounds 9, 12, and 13 were already known compounds. These compounds have been synthesized by refluxing of amino phenol and 1,1-carbonyldiimidazole1 (C3H3N2)2CO) (CDI) in a dry THF and then treated with commercially available acid chloride. The structures of the compounds were elucidated on the basis of 1H-NMR, EIMS and elemental analysis. All the compounds were screened for their antibacterial activities and tested by agar well diffusion method.

Compounds 14 and 16 showed good activity against S. aureus. Compound 5 showed good while 14 and 16 were found to be most active against E. coli using cefuroxime as a standard. Antifungal activities were carried out by using standard drug nystatin and compounds 4, 5, 9, 11 and compound 12 were found to be active against C. albicans. Compounds 4, 5, 9 and compound 10 showed good while 7, 11, and compound 13 showed excellent activities against Chrysosporium sp. Compounds 6, 7 and compound 12 were found to be most active against A niger and A. flavus, respectively.

A number of derivatives were identified to have potent antimicrobial activities and may serve as lead compounds for future research.