Novel bisbenzopyronopyran derivatives: photochemical synthesis and their in‐vitro antimicrobial studies

Abstract

AbstractThe present research work describes the productive synthesis of novel bisbenzopyronopyran derivatives 4(a‐h) and 5(a‐h) via the photocyclization reactions of bischromones 3(a‐h) under the inert conditions. The latter compounds have been realized efficiently through the O‐alkylation reactions of the 3‐hydroxychromone 2 with suitable dihalogenated aliphatic/aromatic/heteroaromatic reagents in the presence of dry acetone/anhydrous K2CO3/Bu4N+I− (PTC). The cyclization reaction of chalcone 1 under the Algar‐Flynn‐Oyamada reaction conditions (KOH/H2O2) could results in the formation of compound 2 in the good yield. The structural scaffolds of the newly prepared bischromones and resultant bisbenzopyronopyrans have been certified from the meticulous analysis of their various spectroscopic parameters such as UV‐Vis, IR, 1H/13C‐NMR, and ESI‐MS. It was found that o/m/p‐xylene and pyridine‐linked final symmetrical bistetracycles exhibited higher antimicrobial potencies as compared to alkyl chain‐linked cyclized products. The bischromones 3(a‐h) could be able to endow modest level of antimicrobial behavior.