Synthesis of Some New Chalcone and 4,5-Dihydro-1H-Pyrazole Derivatives as Potential Antimicrobial Agents

Condensation of 3-acetyl-2,5-dichlorothiophene with 1- or 2-naphthaldehyde led to the formation of the new chalcones (3a,b) in high yields. The latter chalcones were used as a back bone for the synthesis of substituted 3-(2,5-dichlorothiophen-3-yl)-4,5-dihydro-5-(naphthalen-1 or 2-yl)-1H-pyrazole (4a-h) in good yields. All newly synthesized compounds were characterized by standard spectroscopic techniques. The microbiological activity of these new compounds was investigated against bacteria and fungi. The new compounds showed good to excellent activity against all microbial species used for screening.