Synthesis, spectral studies and antimicrobial activities of some 2-naphthyl pyrazoline derivatives

A series of 2-naphthyl pyrazolines were synthesized by the cyclization of 2-naphthyl chalcones and phenylhydrazine hydrochloride in the presence of sodium acetate. The yields of pyrazoline derivatives are more than 80%. The synthesized pyrazolines were characterized by their physical constants, IR, 1H, 13C and MS spectra. From the IR and NMR spectra the CN (cm−1) stretches, the pyrazoline ring proton chemical shifts (ppm) of δHaδHa, Hb and Hc and also the carbon chemical shifts (ppm) of δCN are correlated with Hammett substituent constants, F and R, and Swain–Lupton’s parameters using single and multi-regression analyses. From the results of linear regression analysis, the effect of substituents on the group frequencies has been predicted. The antimicrobial activities of all synthesized pyrazolines have been studied.

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► More than 80% yield of some 2-naphthyl pyrazolines were synthesized.
► The synthesized pyrazolines were characterized by their physical constants, IR, 1H, 13C and MS spectra.
► Antimicrobial activities of these pyrazolines have been studied using Bauer–Kirby method.