Abstract
2, 5-Dimethoxyaniline and α-acetyl-γ-butyrolactone were reacted to 2-[1-(2, 5-dimethoxyphenylimino) ethyl]-γ-butyrolactone (I), which was later treated with phosphorous oxychloride to give 2-methyl-3-(2-chloroethyl)-4-chloro-5, 8-dimethoxyquinoline (II). Treatment of (II) with either acetic acid or thiourea afforded the corresponding 4-methyl-6, 9-dimethoxy-2, 3-dihydrofuro [3, 2-c]-quinoline (III) and 4-methyl-6, 9-dimethoxy-2, 3-dihydrothieno [3, 2-c] quinoline (VI), respectively. (III) and (VI) were treated with 47% hydrobromic acid to give 4-methyl-2, 3-dihydrofuro [3, 2-c] quinoline-6, 9-diol hydrobromide (IV) and 4-methyl-2, 3-dihydrothieno [3, 2-c] quinoline-6, 9-diol hydrobromide (VI) which were converted to 4-methyl-2, 3-dihydrofuro [3, 2-c] quinoline-6, 9-dione (V) and 4-methyl-2, 3-dihydrothieno [3, 2-c] quinoline-6, 9-dione (VIII) respectively by the oxidation of potassium permanganate in sulfuric acid.
