Synthesis and microbial activity of novel 3-methyl-2-pyrazolin-5-one derivatives

2-oxo-2h-chromene-3-carbohydrazide derivatives 2a,b react with 2-{[4-(substituted thiazol-2-yl)iminoethyl)-phenyl]hydrazono}-3-oxo-butyric acid ethyl esters 4a-c to give 3-methyl-1-[(2-oxo-2h-chromen-3-yl) carbonyl]-4-{[4-(substituted thiazol-2-yl)iminoethyl)-phenyl]hydrazono}]-2- pyrazolin-5-one derivatives 5a-f. a considerable increase in the reaction rate had been observed with better yield using microwave irradiation for the synthesis of compounds 2a,b,3a-c,and 5a-f. the synthesized products were tested against b. subtilis,s. aureus,and e. coli as well as c. albicans compared with tetracycline and nystatin as reference drugs. © 2013 mohamed s. mostafa et al.