Synthesis and Antibacterial Evaluation of Benzopyran Derivatives Based on Microwave-Mediated Molecular Cyclization

Almost all of synthetic strategies of benzopyran derivatives suffer from some drawbacks such as multistep sequence, time consuming and expensive purification processes, by-products, low product yields, or longer reaction time. So we recently reported an efficient method that three new benzopyran derivatives were synthesized, 2-amidogen-3-phenylsulfonyl-4-tolyl-4H-benzochroene(4A), 2-amidogen-3-phenylsulfonyl-4-nitrophenyl-4H-benzochroene ( 4B ) and 2-amidogen-3-phenylsulfonyl-4-ethylphenyl)-4H-benzochroene(4C) by the multicomponent reaction （MCR）of 1-naphthol , aromatic aldehydes and benzenesulfonyl acetonitrile s via solvent-free using piperidine as catalyst. This method has many advantages, such as high yield, wide range of substrates, simple experiment, short reaction time, and easy availability of raw materials. The prepared product was characterized and confirmed by 1H NMR, HR-ESI-MS and 13C NMR. At the same time, the antibacterial evaluation of three benzochromene derivatives was further screened for minimum bactericidal concentration.