Synthesis, Characterization and Antifungal Study of Five New Derivatives of E-1-(2-Hydroxyphenyl)chalcone

In an attempt to search for new and efficient antifungal agents, five chalcones namely (E)-3-(4′-diethylaminophenyl), (E)-3-(2′-ethoxyphenyl), (E)-3-(3′,4′-diethoxyphenyl), (E)-3-(2′,3′-dihydrobenzofuran-5-yl) and (E)-3-(3′,5′-bis[trifluoromethyl]phenyl)-1-(2-hydroxyphenyl) prop-2-en-1-one were synthesized from 2-hydroxyacetophenone with the corresponding substituted benzaldehydes. The synthesized chalcones were characterized by GC–MS, FTIR, 1H NMR and 13C NMR spectra analysis. The antifungal activities of these chalcone derivatives were evaluated against five candida species using the agar diffusion method. All the compounds showed varying degrees of activity against the fungi with the compounds containing the 4′-(diethylamino)phenyl and 2′-ethoxyphenyl moieties being the most potent in the series against the pathogens with MIC between 25 and 50 µg mL−1. Results clearly revealed the electronic effect of substituents on the B-ring of the chalcone on its antimicrobial activity with the compound containing the 4′-(diethylamino) substituent which is a strong electron releasing substituent, showing the highest activity while the compound containing the 3′,5′-bis[trifluoromethyl] substituent, which is a strong electron withdrawing substituent, showing a lower potency against the tested candida species.