Synthesis, characterization and biological evaluation of three derivatives of 2-hydroxychalcones

Abstract

In an attempt to compare the efficiency of classical method of synthesizing 2-hydroxychalcones with mechanical and microwave-assisted methods, three derivatives of 2-hydroxychalcone, (E)-3-(4’-methyphenyl)-1-(2- hydroxyphenyl)prop-2-en-1-one, (E)-3-(4’-methoxyphenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one and (E)-3-(2’- chlorophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one; were synthesized by a modified Claisen-Schmidt condensation of appropriate acetophenones with various substituted aromatic aldehydes and successfully characterized using spectroscopic analysis. Microwave-assisted and mechanical methods were found to be more efficient in terms of eco-friendly reaction conditions, simple reaction procedure, short reaction time and excellent yields of the product where the reactions took not more than 3 mins to complete under microwave irradiation and not more than 30 mins to complete using mechanical grinding, while it took up to 6 hrs for some reactions to complete under classical method (heating). The synthesized compounds were evaluated for their antimicrobial activity against S. aureus, S. pyogenes, S. feacalis, C. albicans and C. krusei by the agar diffusion method. The compounds exhibited varying degrees of inhibition against the tested pathogens with (E)-3-(2’-chlorophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one, that has the 2’-chlorophenyl moiety as the B-ring displaying moderate inhibition against the tested pathogens [MIC = 50 μg/ml] with the exception of S. feacalis.

Keywords: Chalcones, microwave-assisted, grinding and pathogen