SYNTHESIS AND ANTIBACTERIAL SCREENING OF NOVEL (E)-3-(3-(2-(4-FLUOROPHENYL)-4- METHYLTHIAZOL-5-YL)-1-PHENYL-1H-PYRAZOL-4-YL)-1-(2-HYDROXYPHENYL)PROP-2-EN-1- ONES

Abstract

A novel series of chalcone 3a-e was prepared by conventional Claisen–Schmidt condensation of 3-(2-(4-fluorophenyl)-4-methylthiazol-5-yl)-1-phenyl- 1H-pyrazole-4-carbaldehyde 1 with substituted 2-hydroxyacetophenones using 40 % aq. KOH in ethanol. The starting material 3-(2-(4-fluorophenyl)- 4-methylthiazol-5-yl)-1-phenyl-1H-pyrazole-4-carbaldehyde 1 was synthesized by reacting 1-[2-(4-fluorophenyl)-4-methyl-1,3-thiazol-5-yl]ethan-1- one with phenyl hydrazine followed by reaction with DMF/ POCl3. The structures of all newly synthesized compounds were assigned on the basis of spectral data such as IR, H-NMR and mass. These compounds3a-e were evaluated for their antibacterial activity against gram-negative Pseudomonas fluorescens and Escherichia coli and gram positive bacteria, Bacillus subtilis and Staphylococcus aureus. Compounds 3a e showed good activity against gram positive bacterial strain of Bacillus subtilis compared to the standard drug Ampicillin at a concentration of 100 $\mu$ g/mL also compounds 3a, 3c, 3d and 3e showed good activity at a concentration of 30 $\mu$ g/mL but none of them was as active as standard Ampicillin.