Abstract：
In this study, a novel preparation method of theaflavin (TF) has been established. Our findings indicated that the formation of TF was significantly enhanced by using an ice bath (2-3°C). Additionally, increasing the ratio of (-)-epigallocatechin (EGC) under the ice bath could further improve its yield. This approach prevented the appearance of a dark solution within 3 h, effectively protecting TF from oxidation. Our study on the generation mechanism of TF suggested that EGC-quinone I (EGC-Q-I) with two carbanions could potentially serve as one of synthons based on the retrosynthetic analysis of the bicyclo[3.2.1]octane-type intermediate. Subsequently, quantum mechanical calculations further supported this hypothesis. Practical Application: In this study, we have developed a novel method for the synthesis of theaflavin (TF), demonstrating that the use of ice bath significantly enhanced its yield. Increasing the ratio of (-)-epigallocatechin (EGC) under the ice bath further improved TF yields and prevented darkening of the solution for at least 3 h, thereby protecting TF from oxidation. Our study suggested that EGC-quinone I is a potential synthon based on the retrosynthetic analysis of the bicyclo[3.2.1]octane-type intermediate (BOI). This hypothesis is supported by QM calculations.
摘要：
在这项研究中,建立了一种新的茶黄素(TF)的制备方法。我们的发现表明，使用冰浴（2-3°C）可显着增强TF的形成。此外,在冰浴条件下增加（-）-表没食子儿茶素（EGC）的比例可以进一步提高其收率。这种方法在3小时内防止了深色溶液的出现，有效保护TF免受氧化。我们对TF生成机理的研究表明，基于双环[3.2.1]辛烷型中间体的逆合成分析，具有两个碳阴离子的EGC-醌I（EGC-Q-I）可能作为合成子之一。随后，量子力学计算进一步支持了这一假设。实际应用：在这项研究中，我们开发了一种合成茶黄素（TF）的新方法，证明使用冰浴显著提高了产量。在冰浴下增加（-）-表没食子儿茶素（EGC）的比例，进一步提高TF产量，并防止溶液变黑至少3小时，从而保护TF免受氧化。我们的研究表明，基于双环[3.2.1]辛烷型中间体（BOI）的反合成分析，EGC-醌I是潜在的合成子。QM计算支持这一假设。
