Synthesis and Biological Evaluation of Novel Chalcone and Pyrazoline Derivatives Bearing Substituted Vanillin Nucleus

A series of novel chalcone 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l and pyrazoline 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l derivatives have been synthesized as potential antibacterial agents. The pyrazoline derivatives 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j , 5k , 5l have been synthesized by reaction of various chalcones 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l with hydrazine hydrate in the presence of acetic acid. The chalcones 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j , 4k , 4l were prepared by the condensation of key aldehyde 3 with appropriate acetophenone using basic condition and ethanol as a solvent. The key aldehyde 3 has been synthesized by reacting 2‐(chloromethyl)‐3‐methyl‐4‐(2,2,2‐trifluoroethoxy)pyridine hydrochloride and vanillin. The structures of the new compounds were established on the basis of ¹H‐NMR, mass, IR, and elemental analysis data. All the newly synthesized compounds were screened for their antibacterial activity against Escherichia coli, Salmonella typhi (Gram‐negative bacteria), Staphylococcus aureus, Micrococcus luteus (Gram‐positive bacteria) and antifungal activity against Candida albicans (fungi).