A procedure for the preparation of N,N′-dicyclohexylbarbituric acid from DCC and malonic acid is described. Addition of phosphorus oxychloride to the reaction mixture facilitates dehydration of the insoluble byproduct N,N′-dicyclohexyl urea, enabling operation in continuous flow. A development approach based on in situ monitoring of batch reactions was used, which supported screening and determination of reaction conditions at small scale prior to scaleup in flow. Additional mechanistic understanding and control of impurity formation are presented.

中文翻译：

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不溶性尿素副产物的脱水使DCC和丙二酸在流动中冷凝

描述了由DCC和丙二酸制备N，N′-二环己基巴比妥酸的方法。向反应混合物中加入三氯氧化磷有助于不溶性副产物N，N′-二环己基脲的脱水，使其能够连续流动。使用了基于分批反应的原位监测的开发方法，该方法支持在扩大流量之前以小规模筛选和确定反应条件。介绍了对杂质形成的其他机械理解和控制。