Microwave-assisted synthesis of 2,8-di(alkyl/aryl)-4,6-dichloro-2H,8H-pyrano[3,2-g] chromene-3,7-dicarbaldehydes and their antimicrobial activity

Abstract

A series of 2,8-di(alkyl/aryl)-substituted bischromanone derivatives were synthesized in one pot from 4,6-diacetylresorcinol and aliphatic/aromatic aldehydes in the presence of pyrrolidine/piperidine under conventional heating and microwave irradiation. The 2,8-di(alkyl/aryl)-substituted bischromanones were converted into a new series of 4,6-dichloro-3,7-diformyl-2,8-di(alkyl/aryl)-substituted bischromenes using the Vilsmeier?Haack reagent. The structures of the compounds were established based on elemental analysis, IR, 1H-NMR, 13C- -NMR and LC?MS spectral data. All the synthesized compounds were evaluated for their antimicrobial activity. Some of the compounds showed very good activity compared to standard drugs against all the tested pathogenic bacteria and fungi.