Synthesis of biologically active 5-benzopyranylpyridines and triazolopyridines

Abstract

The chalcones of 4-hydroxycoumarins <b>1a-h</b> on treatment with malononitrile in the presence of ammonium acetate in alcohol give 2-amino-4-aryl-3-cyano-6-[2<i>H</i>-4-hydroxy-2-oxo-[1] benzopyran-3-yl]pyridines <b>2a-h</b> which on treatment with acetonitrile in the presence of AlCl₃ yield 2-acetamidino-4-aryl-3-cyano-6-[2<i>H</i>-4-hydroxy-2-oxo-[1] benzopyran-3-yl pyridines <b>3a-h</b>. Compounds <b>3a-h</b> on oxidation in the presence of MnO₂ afford 7-aryl-8-cyano-2-methy l-5-[2<i>H</i>-4-hydroxy-2-oxo-[1] benzopyran-3-yl][1,2,4] triazolo[1,5-<i>a</i>]pyridines <b>4a-h</b>. The above compounds are screened for their antimicrobial activities and some of the compounds have shown significant antibacterial and antifungal activities.