Cyclization of N-alkylazinium cations with bifunctional nucleophiles. 25. Oxidation of tetrahydroquinoxalines condensed with six-membered ring heterocycles / V. N. Charushin, L. M. Naumova, M. G. Ponizovskii, V. G. Baklykov, O. N. Chupakhin // Chemistry of Heterocyclic Compounds. - 1987. - Vol. 23, № 9. - P. 1010-1013. - Bibliogr. : p. 1013 (11 ref.).