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

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