Abstract

SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF 3,4-DIHYDRO-3- (3,5-DIMETHYL-4-ISOXAZOLYL)-2H-BENZO[e][1,3]-OXAZINES

R. Sanjeev, K. Thirupathaiah and E. Rajanarendar*

ABSTRACT

A new series of 3,4-dihydro-3-(3,5-dimethyl-4-isoxazolyl)-2Hbenzo[ e][1,3]-oxazines (5) have been synthesized from 4-amino-3,5- dimethylisoxazole (1). Compound (1) on condensation with substituted salicylaldehydes (2), followed by reduction with NaBH4, and subsequent ring closure in presence of formaldehyde afforded the title compounds by internal Mannich reaction. All the newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and mass spectral data. Compounds (5a-f) have been screened for antimicrobial activity. Compounds 5a, 5b, and 5c exhibited significant antimicrobial activity when compared to the standard drugs.

Keywords: Isozaxolyl-1,3-benzoxazines, Condensation, Reduction, Ring closure, Internal Mannich reaction, Antimicrobial activity.