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.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► 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.