Anthraquinone (AQ) derivatives play a prominent role in medicine and also in textile industry. Bromaminic acid (1-amino-4-bromoanthraquinone-2-sulfonic acid) is an important precursor for obtaining dyes as well as biologically active compounds through the replacement of the C4-bromo substituent with different (ar)alkylamino residues. Here we report methods for the synthesis of bromaminic acid analogues bearing different substituents at the 2-position of the anthraquinone core. 1-Aminoanthraquinone was converted to its 2-hydroxymethyl-substituted derivative which, under different reaction conditions, yielded the corresponding carbaldehyde, carboxylic acid, and nitrile derivatives. The latter was further reacted to obtain 1-amino-2-tetrazolylanthraquinone. Subsequent bromination using bromine in DMF led to the corresponding bromaminic acid derivatives in excellent isolated yields (>90%) and high purities. Alternatively, 1-amino-4-bromo-2-hydroxymethylanthraquinone could be directly converted to the desired 2-substituted bromaminic acid analogues in high yields (85–100%). We additionally report the preparation of bromaminic acid sodium salt and 1-amino-2,4-dibromoanthraquinone directly from 1-aminoanthraquinone in excellent yields (94–100%) and high purities. The synthesized brominated AQs are valuable precursors for the preparation of AQ drugs and dyes.
蒽醌(AQ)衍生物在药物和纺织工业中起着重要作用。溴氨基酸(1-氨基-4-溴蒽醌-2-磺酸)是获得染料和生物活性化合物的重要前体,通过用不同的(芳)烷基氨基残基替换C4-溴取代基来实现。在这里,我们报告了合成具有蒽醌核心2位不同取代基的溴氨基酸类似物的方法。1-氨基蒽醌被转化为其2-羟甲基取代衍生物,根据不同的反应条件,得到相应的羰基,羧酸和腈衍生物。后者进一步反应得到1-氨基-2-四唑基蒽醌。在DMF中使用溴素进行溴化反应,得到相应的溴氨基酸衍生物,收率高(>90%)且纯度高。另外,1-氨基-4-溴-2-羟甲基蒽醌可以直接转化为所需的2-取代溴氨基酸类似物,收率高(85-100%)。我们还报告了从1-氨基蒽醌中直接制备溴氨基酸钠盐和1-氨基-2,4-二溴蒽醌,收率高(94-100%)且纯度高。合成的溴化蒽醌是制备蒽醌药物和染料的有价值前体。