Hydroxymethylation of 6,8-O-dimethyl emodin was easily achieved in good yields by the modified Marschalk reaction. The influence of the amount of solvent, base and formaldehyde toward the hydroxymethylation was discussed. The results showed that a relatively dilute reaction solution facilitated the generation of the desired 2-hydromethyl product, while the thick reaction solution benefited the generation of the methylated quinizarins.

中文翻译：

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对改进的Marschalk反应的研究的贡献：6,8- O-二甲基大黄素的羟甲基化

通过修饰的Marschalk反应容易地以良好的产率实现6，8- O-二甲基大黄素的羟甲基化。讨论了溶剂，碱和甲醛的量对羟甲基化的影响。结果表明，相对稀的反应溶液促进了所需的2-氢甲基产物的产生，而浓的反应溶液则促进了甲基化的奎尼萨林的产生。