Synthesis of some new fused and polyfused quinoxalines

2,3-Dimercaptoquinoxaline I 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)thi- azino-, and pyrroloquinoxalines 3a-5b. The addition of compound 1 to a,P-unsaturated nitriles was investigated to give the corresponding (1,5)dithiapinoquinoxalines 6a-7b and thiapinaquinoxalines 8a,b. The treatment of compound 1 with active nitriles furnished the corresponding thienoquinoxalines 9a-c and pyridazinoquinoxaline 10.