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-二羟基
蒽醌被用作合成许多
染料的中间体,例如Alizarin Saphirols(例如Color Constitution No. 63000、63005、63010、63011、63315和63610),可以以等摩尔比例被α-二(较低烷氧基)
蒽醌所取代。α-二(较低烷氧基)
蒽醌可以通过与
油酸的处理,在几乎定量收率下,一步转化为相应的α-二羟基
蒽醌-β-二
磺酸。通过硝化后还原硝基团,可以得到相应的二胺。已知的中间体,亮1,4,5,8-四羟基
蒽醌(参见C.I. No. 62500),可以通过还原二胺或还原二
硝基化合物来获得。在一种实施方案中,α-二(较低烷氧基)
蒽醌是通过将二硝基
蒽醌与
甲醇和
氢氧化钾处理而获得的。