1,3‐cycloaddition reactions of 2‐oxo‐2<i>H</i>‐[1]benzopyran‐4‐carbonitrile <i>N</i>‐oxide. Synthesis of several new 4‐substituted coumarins

Abstract

Abstract 1,3‐Cycloaddition reactions of new 2‐oxo‐2 H ‐[1]benzopyran‐4‐carbonitrile N ‐oxide 2 with dipolarophiles, o ‐aminophenols and o ‐phenylenediamine resulted in 4‐heterocyclic substituted coumarin derivatives. These derivatives are screened for antiinflammatory activity in vitro through their antiproteolytic activity, the interaction with 1,1‐diphenyl‐2‐picrylhydrazyl and the ability to affect superoxide anion and to inhibit β‐glucuronidase and soybean lipoxygenase.