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, (1)H, (13)C and MS spectra. From the IR and NMR spectra the C=N (cm(-1)) stretches, the pyrazoline ring proton chemical shifts (ppm) of δ(Ha), H(b) and H(c) and also the carbon chemical shifts (ppm) of δC=N 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.