Reactions in water as a safe and cheap solvent is a major goal of green chemistry. Actual synthesis of pyrido-dipyrimidine scaffold, named DNA-base hybrids, involves catalysis in hazardous solvents. Here we synthesised pyrido-dipyrimidines by one-pot heterocyclization of thiobarbituric acid, vanillic aldehydes and amines in water. Enamine and vanillidene are key intermediates of the Biginelli-like reaction mechanism. Our synthetic method displays several benefits such as the use of a green medium and various substrates, and yields up to 99%.

中文翻译：

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水中吡啶基-双嘧啶DNA基杂种的绿色一锅合成

在水中作为安全廉价的溶剂进行反应是绿色化学的主要目标。吡啶-二嘧啶骨架的实际合成，称为DNA-based杂种，涉及在危险溶剂中的催化作用。在这里，我们通过一锅中硫代巴比妥酸，香草醛和胺在水中的一环杂环化反应合成了吡啶基-二嘧啶。烯胺和香草醛是Biginelli样反应机理的关键中间体。我们的合成方法具有多种优势，例如使用绿色介质和各种底物，收率高达99％。