SYNTHESIS OF PYRAZOLINE DERIVATIVES AND EVALUATION OF ITS ANTIMICROBIAL ACTIVITY

The present paper represents the synthesis of pyrazoline compounds. Compounds are synthesized from substituted aniline. Substituted
aniline on diazotization gives Ethyl-2-( substituted phenyl hydrazono)-3-oxobutyrates (1a-j). Ethyl-2-(substituted phenyl hydrazono)-
3-oxobutyrates (1a-j) reacts with 8-Quinolinoxyacetic acid hydrazide (3) and gives compounds 1-(8′-Quinolinoxyacetyl)-3-methyl-4-
substituted phenyl hyazdrzono-2-pyrazolin-5-one (4a-j). Further all derivatives are evaluated for their vitro antimicrobial activity. The
antimicrobial activity based on MIC (minimum inhibitory concentration) of tested compounds. The results revealed that most of the
newly synthesized pyrazoline derivatives bearing quinoline moiety (4a-j) exhibited promising anti-bacterial activity. Out of the
compound tested, compound 4i and 4j having 2 & 4 methyl groups in the phenyl ring exhibited remarkable antibacterial activity (MIC
25 µgmL-1) against E. coli (gram negative bacteria) whereas compound 4a having COOH group at 4th position of the phenyl ring
showed similar antibacterial potency (MIC 25 µgmL-1) against S. aureus (gram positive bacteria) as compared with the broad
spectrum antibiotics ofloxacin (MIC 10.0 µgmL-1 against S. aureus and 12.5 µgmL-1 against E. coli). The antifungal screening results
have shown that the compound 4d and 4g having 4-methoxy and 4-chloro respectively groups in the phenyl ring exhibited good
activity (MIC 50 µgmL-1) against A. niger, as compared with standard drug ketoconazole (MIC 12.5 µgmL-1).