HYDROGEN-SULFIDE SPLITTING OF N,N'-DIMETHYL BIS-SALTS OF THIOQUINANTHRENE AND ISOTHIOQUINANTHRENE

The reactions of bis-salts of N,N'-dimethyl-1,4-dithiino[beta-gamma':beta'-gamma or beta-beta':gamma-gamma']diquinolines 3 or 5 with hydrogen sulfide proceeded with breaking the gamma-quinolinyl-sulfur bond leaving beta-one unaffected and led to aqueous alkali soluble mercapto-thiones 4 or aqueous alkali insoluble dithione 6. It allows for the simple distinction between isomeric dithiinodiquinolines such as 1 and 2. Sulfur assisted thermal isomerization of compound 1 to 2 and vice-versa was also described. H-1 NMR assignment of compounds with 1-methyl-3,4-disubstituted quinoline fragment was presented.