Microwave-assisted synthesis and biological evaluation of carbazole-based chalcones, aurones and flavones

Abstract

A new class of chalcones, aurones and flavones derived from carbazole is designed as potential antimicrobial and antioxidant agents. Synthesis of (Z)-2-((9-ethyl-9H-carbazol-3-yl)methylene)benzofuran-3(2H)-ones and 2-(9-ethyl-9H-carbazol-3-yl)-4H-chromen-4-ones was carried out by the oxidation of (E)-3-(9-ethyl-9H-carbazol-3-yl)-1-(2-hydroxyphenyl)prop-2-en-1-ones under microwave irradiation and conventional heating. All the newly synthesized compounds were characterized on the basis of IR, 1H NMR, 13C NMR, mass and analytical data. All the synthesized compounds were evaluated for their antibacterial, antifungal and antioxidant activities. Synthesized compounds were screened in vitro for antibacterial activity against two gram-positive bacterial strains like Staphylococcus aureus and Bacillus subtilis and two gram-negative bacterial strains like Escherichia coli and Klebsiella pneumonia and antifungal activity by inhibitory action against three fungal strains like Fusarium oxysporum, Aspergillus niger and Aspergillus flavus. The synthesized compounds were also evaluated for their DPPH radical scavenging activity. All the newly synthesized compounds have shown good antibacterial, antifungal and antioxidant activities.