SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF SOME NEW N1-SUBSTITUTED- PYRAZOL-4-CARBALDEHYDE BEARING 2, 4-DICHLORO PHENYL MOIETY

Abstract

A series of new 3-(2,4-dichlorophenyl)-1-(2-(substituted phenoxy) acetyl)-1H-pyrazole-4-carbaldehyde were synthesized from substituted simple phenols. Substituted simple phenols were refluxed with ethylchloroacetate in presence of anhydrous potassium carbonate to yield substituted ethyl phenoxy acetate . Further substituted ethyl phenoxy acetate on treatment with hydrazine hydrate in ethanol yielded substituted 2-phenoxyacetohydrazide inturn on refluxing with 2,4-dichloro acetophenones yielded N'-(1-(2,4-dichlorophenyl)ethylidene)-2-(substituted phenoxy) acetohydrazides which on further treatment with DMF and POCl3 undergo Vilsmer-Haack reaction to yield the title compounds i.e. 3-(2,4-dichlorophenyl)-1-(2 (substituted phenoxy)acetyl)-1H-pyrazole-4-carbaldehyde (4a-j). The chemical structures of these compounds were confirmed by various physic-chemical methods viz, IR, 1H NMR, mass spectral data and elemental analysis. Newly synthesized compounds were screened in vitro for their antimicrobial activity against varieties of gram +ve and gram -ve bacterial strains such as Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and fungi strains Candida albicans & Aspergillus niger. Antimicrobial activity was carried out by cup-plate method; zone of inhibition shown by the compounds against selected microorganisms was measured by using antibiotic zone reader. The minimum inhibitory concentration was carried out for the promising compounds were determined by serial dilution method. The chloro & bromo possessing moiety have shown enhanced biological activity stimulated to synthesise more efficient drug containing more electronegative moiety against pathogenic microorganisms