Quinoxalines and related compounds. Part IX. Preparation of 2-aryloxyquinoxalines and their cyclisation to benzofuro[2,3-b]quinoxalines

Abstract

When 2-chloroquinoxaline is treated with a sodium aryloxide in an excess of the corresponding phenol, a mixture of the expected quinoxalinyl ether and the corresponding benzofuro[2,3-b]quinoxaline is obtained. Polyphosphoric acid has been found to be the best reagent for the cyclisation of the isolated quinoxalinyl ethers to the benzofuroquinoxalines.