Synthesis, Characterization of Some New 1,3,5-Trisubstituted Pyrazole Derivatives for Their Antifungal Potential

Abstract

The aim of the study was to develop, synthesis, and characterise a novel 1,3,5-trisubstituted-2-pyrazolines derivative, as well as to evaluate its antifungal activity. The reaction of chalcone derivatives with succinic hydrazide in the presence of pyridine yielded the 1,3,5-tri-substituted-2-pyrazolines derivatives. Total 20 compounds has been synthesized and characterized by the IR, 1HNMR and mass spectral analysis. Antifungal activity of the compounds carried out onfour fungal strains i.e. Saccharomyces cerevisiae, A. Niger, C. Albicans and R. Oryzae in two different concentration i.e. 50 and 100 µg/ml by Agar-diffusion method using Cup-plate method. The usual antifungal medicine was ketoconazole. All of the synthesized 1,3,5-trisubstituted pyrazole compounds (ME1-ME8, CL1-CL8, BR1-BR4) showed medium to best action against examined organisms, according to antifungal activity data. The antifungal activity of compounds against fungal strains (Saccharomyces cerevisiae, A. Niger, Candida albicans, and R. Oryzae) revealed the following order of action: CL-4 > BR-4 > CL-3 > CL-2 > ME-3> ME-2> CL-5 > CL-6 > ME-4 > ME-5 > ME-6 > ME-7 > CL-7 > CL-8>ME-8 >CL-1 >ME-1 > CL-5 > CL-6 > ME-4 > ME-5 > ME-6 > ME-7 > CL-7 > CL-8>ME-8 >CL-1 >ME-1. Electronegative groups (Br, Cl, F, and NO2) must be present at the third and fifth positions of the 1,3,5-pyrazoline ring for significant antifungal action. The presence of an electronegative group at the third and fifth positions may be required for the best action against bacterial and fungal strains, however the addition of F, NO2 has demonstrated moderate activity, while the substitution of methyl and methoxy  groups may reduce the activity. The synthesized compounds in the BR-1 through BR-4 class are the most active.