Development of Polyfunctionalized Pyridines Directed Toward Functional Materials

多功能化吡啶作为具有多种功能的材料或作为这些材料的合成试剂是非常重要的。从而研究了乙基在吡啶上的直接引入及其化学转化。发现n-氧化物吡啶与苯甲酰氯原位生成Reissert-Henze盐，与乙酰银反应生成2-乙基吡啶。该方法适用于多种取代乙炔和取代吡啶，包括喹啉和异喹啉。特别是当具有反应性取代基的吡啶如MeCO， MeOCO， CN等，从而可以合成许多迄今为止未知的多功能化吡啶时，该方法是有利的。讨论了反应的区域选择性。乙基吡啶的化学转化得到双环吡啶是成功的。例如，由3-取代的2-乙基吡啶合成了喹啉醇、呋喃吡啶和吡咯洛吡啶等杂环化合物。此外，还发现了以乙基吡啶为原料，用二甲基乙炔二羧酸酯处理乙基吡啶合成吲哚嗪衍生物的新途径。因此，以乙基化吡啶为原料，开发了多种多功能化吡啶衍生物的合成路线。

Polyfunctionalized pyridines are very important as materials having various functions or as synthetic reagents for such materials. Thus direct introduction of ethynyl group, which undergoes various types of reactions, to pyridines and their chemical transformations were studied.It was found that a Reissert-Henze salt generated in-situ from pyridine N-oxide and benzoyl chloride reacted with a silver acetylide to afford 2-ethynyl-pyridine. The method is applicable to a variety of substituted acetylenes and substituted pyridines including quinoline and isoquinoline. Especially the method is advantageous when pyridines having a reactive substituent such as MeCO, MeOCO, CN and, hence, many hitherto unknown polyfunctionalized pyridines could be synthesized. Regioselectivity of the reaction was also discussed.Chemical transformations of ethynylpyridines leading to bicyclic pyridines were successful. For example, heterocycles such as quinolinol, furopyridines, and pyrrolopyridine were synthesized from 3-substituted 2-ethynyl pyridines. Furthermore, new synthetic route to indolizine derivatives was found by treating ethynylpyridine with dimethyl acetylenedicarboxylate.As results, various synthetic routes to polyfunctionalized pyiridine derivatives were developed by utilizing ethynylated pyridines.