Green synthesis, antibacterial activity and computational study of pyrazoline and pyrimidine derivatives from 3-(3,4-dimethoxy-phenyl-1-(2,5-dimethyl-thiophen-3-yl)-propenone

Abstract

Various pyrazoline and pyrimidine derivatives were synthesized by the reaction of thiosemicarbazide / phenyl hydrazine / hydrazine hydtate / thiourea / urea with 3-(3,4-dimethoxy-phenyl-1-(2,5-dimethyl-thiophen-3-yl)-propenone under microwave irradiation, which itself was derived from the reaction of 3-acetyl-2,5-dimethylthiophene with 3,4-dimethoxy benzaldehyde. The corresponding pyrazoline and pyrimidine derivatives were obtained in good to excellent yields. All of the new compounds obtained were characterized by IR, ¹H NMR, ¹³C NMR, MS and elemental analyses. The anti-bacterial activity of these compounds were tested in-vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria. The results showed that one of the pyrazoline derivatives is better at inhibiting the growth as compared to chloramphenicol against both types of the bacteria (Gram-positive and Gram-negative). Furthermore, all the molecules were subjected to computational calculation using the density functional theory with B3LYP method to corroborate their antibacterial activities.