Alpha-dihydroxyanthraquinones used as intermediates in the synthesis of many dyestuffs, such as the Alizarin Saphirols (e.g. Color Constitution No. 63000, 63005, 63010, 63011, 63315 and 63610) can be replaced on an equimolar basis by alpha-di(lower alkoxy)anthraquinones. The alpha-di(lower alkoxy) anthraquinones can be converted in a single step, by treatment with oleum, to the corresponding alpha-dihydroxyanthraquinone-beta-disulfonic acids in almost quantitative yield. The corresponding diamine is obtained by dinitrating followed by reduction of the nitro groups. The known intermediate, leuco 1,4,5,8-tetrahydroxyanthraquinone (see C.I. No. 62500) can be obtained either by reduction of the diamine or by reduction of the dinitro compound. In one embodiment, the alpha-di(lower alkoxy)anthraquinone is obtained from dinitroanthraquinone by treatment thereof with methanol and KOH.
α-二羟
蒽醌是合成许多
染料的中间体,如
茜素蓝(例如,色素构成物号63000、63005、63010、63011、63315和63610),可以以α-二(低烷氧基)
蒽醌的等摩尔基础进行替代。α-二(低烷氧基)
蒽醌可以通过与
油酸处理的单步转化,以几乎定量的产率得到相应的α-二羟
蒽醌-β-二
磺酸。通过二硝基化后还原硝基团,可以得到相应的二胺。已知的中间体,
亚甲基蓝(见C.I. No. 62500)可以通过还原二胺或还原二
硝基化合物得到。在一种实施例中,α-二(低烷氧基)
蒽醌是通过用
甲醇和KOH处理二硝基
蒽醌得到的。