SYNTHESIS OF SOME NEW FUSED AND POLYFUSED QUINOXALINES

Abstract

2,3-Dimercaptoquinoxaline 1 was allowed to react with some dihalo compounds and chloroanil using PTC technique to afford the corresponding polyfused quinoxalines 2a-d. The reaction of compound 1 with different monohalo compounds under the same PTC conditions or in refluxing ethanol in presence of piperidine catalyst gave (1,4)dithiino-, thieno-, (1,4)thiazino-, and pyrroloquinoxalines 3a-5b. The addition of compound 1 to α,β-unsaturated nitriles was investigated to give the corresponding (1,5)dithiapinoquinoxalines 6a-7b and thiapinoquinoxalines 8a,b. The treatment of compound 1 with active nitriles furnished the corresponding thienoquinoxalines 9a-c and pyridazinoquinoxaline 10.

Key Words:

• quinoxalines
• Phase-Transfer Catalysis
• (1,4)dithiinoquinoxaline
• thienoquinoxaline
• (1,4)thiazinoquinoxaline
• pyrroloquinoxaline
• (1,5)dithiapinoquinoxaline