10.22376/ijpbs.2019.10.1.p1-12 Volume 7 Issue 4 2016 (October - December) A series of isoxazolyl schiff's bases (3a-h) were synthesized from lessThan i greaterThan N lessThan /i greaterThan -(5-methyl-3-isoxazolyl)-3-oxobutanamide (1) .The compound (1) upon heating with different primary amines in methanol furnished (E)-3-(methylimino)- lessThan i greaterThan N lessThan /i greaterThan -(5-methylisoxazol-3-yl)butanamides (3a-h) in excellent yield. The structure of all the synthesized compounds has been established by IR, lessThan sup greaterThan 1 lessThan /sup greaterThan H NMR, lessThan sup greaterThan 13 lessThan /sup greaterThan C NMR and mass spectral data. All the synthesized compounds (3a-h) were screened for antibacterial activity against two Gram-positive ( lessThan i greaterThan Bacillus subtilis lessThan /i greaterThan MTCC 121 and lessThan i greaterThan Staphylococcus aureus lessThan /i greaterThan MTCC 96) and two Gram-negative ( lessThan i greaterThan Escherichia coli lessThan /i greaterThan MTCC 43 and lessThan i greaterThan Klebsiella pneumoniae lessThan /i greaterThan MTCC 530) bacterial strains. The Schiff's bases ( lessThan i greaterThan E lessThan /i greaterThan )- lessThan i greaterThan N lessThan /i greaterThan -(5-methylisoxazol-3-yl)-3-(phenylimino)butanamide 3c ( MIC values 11±0.28, 14±0.10, 12±0.31,14±0.31, at 40µg/µL,) and ( lessThan i greaterThan E lessThan /i greaterThan )-3-(benzylimino)- lessThan i greaterThan N lessThan /i greaterThan -(5-methylisoxazol-3-yl)butanamide 3f ( MIC values 12±0.38, 14±0.10, 13±0.21,14±0.32, at 40µg/µL,) showed significant activity against all the bacteria tested compared to other compounds in this series. All other compounds except compounds 3a and 3b have shown considerable antibacterial activity against different bacterial stains. Compound 3a and 3b could show activity only at the high concentration. Furthermore, substitutions at phenyl nucleus have not much affected the antibacterial activity. RAMU KAKKERLA , NAMRATHA VADDIRAJU, AND RAMCHANDER MERUGU Amino isoxazole, primary amines, Schiff's base, antibacterial activity. 192-196