Reaction of benzofurazan oxides with benzofuran-3(2H)-ones, and a new synthesis of benzofuro[2,3-b]quinoxalines

Abstract

Reaction of benzofurazan oxides (1) with benzofuran-3(2H)-ones (2) provides a general, one-step synthesis of 3-(o-hydroxyaryl)quinoxaline 1-oxides (3). Cyclization of the products in refluxing acetic anhydride to give benzofuro[2,3-b]quinoxalines (4) constitutes a practicable route to a heterocyclic system for which no convenient synthetic methods are available.