水辅助的氢转移对一种特殊的亚胺加成物生成过程的重要影响

The Important Effect of Water Mediated Hydrogen Transfers on the Formation of an Unusual Imine Adduct

在笔者实验室发表于J.Org.Chem.的论文(本文参考文献[12])中提出的芳香胺离子与腺苷反应所得到非常特殊的亚胺加成物的生成机理指出,腺嘌呤对4-联苯胺离子中对位碳原子初始进攻是得到非常特殊的亚胺加成物的最可行生成路径,而腺嘌呤对4-联苯胺离子中邻位碳原子初始进攻的其它3个反应路径,由于涉及几个氢转移过程的反应的能垒较高,所以,理论上讲,它们是不能发生的。但是,研究发现,如果在这些氢转移过程中有水作为媒介,它们的能垒会大大的降低,从而可能使腺嘌呤对4-联苯胺离子中邻位碳原子初始进攻的3个反应路径成为对对位碳原子初始进攻路径的竞争性反应路径。

The mechanism of unusual benzene imine N6 adduct formation in carcinogenic reactions of arylnitrenium ions with adenosine had been explored in paper published at J. Org. Chem., 2007, 72：10058 - 10064. It was predicted that the reaction pathway initiated by attack of adenine at ortho site of arylnitrenium ion is favored than those initiated by attack of adenine at para site of arylnitrenium ion. However, it is found that the para attack can be dramatically accelerated through introducing water as medium to several H-transfer steps. It means that the reaction pathways initiated by attack of adenine at para site or ortho site of arylnitrenium ion can be competitive pathways.