抄録
p-Dithiino [2, 3-b] quinoxaline-2, 3-dinitrile was synthesized by the reaction of 2, 3-dichloroquinoxaline and sodium salt of cis-1, 2-dimercapto-1, 2-dicyanoethane in a mixture of acetone and water. 1) Heating p-dithiino [2, 3-b] quinoxaline-2, 3-dinitrile in conc. H2SO4 at 50-80° for a short period of time gave 1, 3-dihydro-2H-pyrrolo-[3′, 4′:5, 6]-dithiino [2, 3-b] quinoxaline-1, 3-dione. 2) Reacting p-dithiino [2, 3-b] quinoxaline-2, 3-dinitrile in either conc. H2SO4 or 10% NaOH at 100° for a long period of time afforded the compound which was supposed to be p-dithiino [2, 3-b] quinoxaline-2, 3-dicarboxylic acid, though its structure has not been determined, because of the difficulty to obtain in a purified state.
