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首页> 外文期刊>Russian Chemical Bulletin >Alternative mechanisms of electrophilic substitution in azole series
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Alternative mechanisms of electrophilic substitution in azole series

机译：吡咯系列亲电取代的替代机理

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摘要

Data on three mechanisms of aromatic electrophilic substitution in azole series have been presented. First of them is similar to an ordinary addition-elimination mechanism including the formation of a cationic sigma-complex (Wheland intermediate). The second mechanism is realized according to the elimination-addition scheme and includes a protonation or a formation of a complex on the "pyridine" N atom, proton abstraction from the C atom adjacent to the above N atom, and addition of a cationoid reagent to the ylide (carbene) formed. The third mechanism proposed by the present authors can be realized for azoles having three and two N atoms of the pyridine type. It does not require the preliminary N-protonation or complex formation and occurs due to a strong electron withdrawing effect of several "pyridine" atoms, resulting in the CH-deprotonation followed by the interaction of the carbanion formed with a cation under mild conditions.
机译：已经提出了关于唑系列芳族亲电子取代的三种机理的数据。首先，它们类似于包括形成阳离子sigma-complex（Wheland中间体）的普通加成消除机理。第二种机制是根据消除加成方案实现的，包括在“吡啶” N原子上质子化或形成络合物，从与上述N原子相邻的C原子中提取质子，并向其中添加阳离子型试剂。形成的叶立德（卡宾）。对于具有三个和两个N个吡啶型原子的唑，可以实现本发明人提出的第三种机理。它不需要初步的N质子化或络合物的形成，并且由于几个“吡啶”原子的强电子吸收作用而发生，导致CH去质子化，随后在温和条件下形成的碳负离子与阳离子相互作用。

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