Scientific Overview of Synthesis and Antimicrobial Evaluation of Novel 3-(thiophen-2-yl) -Pyrazoline-5-yl Derivatives

Ten derivatives of N1 substituted/unsubstituted 5-(4-chlorophenyl)-3-(2-thienyl) pyrazoline were synthesised from chalcone-like intermediate and substituted phenyl hydrazines, hydrazine hydrate, and semi/thiosemicarbazide. The chemical structure of compounds was confirmed by means of IR, 1HNMR, mass spectroscopy, and elemental analysis. The antimicrobial activities (antibacterial and antifungal activities) of the synthesized compounds were evaluated against Staphylococcus aureus, Staphylococcus faecalis, Escherichia coli, Salmonella typhi, and Candida albicans by agar diffusion cup plate method. Compound IId (5-[(4-chlorophenyl)-1-(4-methoxyphenyl)]-3-thiophen-2-yl)-4,5- dihydro-2-pyrazoline), IIg (5-(4-chlorophenyl)-1-(2-methylphenyl)-3-(thiophen-2-yl)-4,5-dihydro-2- pyrazoline) showed very good activity. IIi (5-(4-chlorophenyl)-1-thiocarbamoyl-3-(thiophen-2-yl))-2- pyrazoline), IIj (5-(4-chlorophenyl)-1-carbamoyl-3-(thiophen-2-yl))-2-pyrazoline) exhibit mild to moderate inhibitory response against all the tested microbial strains. Compound IId shows excellent significant zone of inhibition (mm) against all the species of microbes, thereby producing promising antimicrobial respectively.