Development of Polyfunctionalized Pyridines Directed Toward Functional Materials

多官能化吡啶作为具有各种功能的材料或作为用于这些材料的合成试剂是非常重要的。研究了乙炔基直接引入吡啶及其化学转化，发现吡啶氧化物与苯甲酰氯原位生成的Reissert-Henze盐与乙炔化银反应生成2-乙炔基吡啶。该方法适用于各种取代的乙炔和取代的吡啶，包括喹啉和异喹啉。特别是当可以合成具有反应性取代基如MeCO、MeOCO、CN的吡啶时，该方法是有利的，因此可以合成许多迄今未知的多官能化吡啶。乙炔基吡啶成功地转化为双环吡啶。例如，从3-取代的2-乙炔基吡啶合成杂环如喹啉醇、呋喃并吡啶和吡咯并吡啶。此外，还通过乙炔基吡啶与乙炔二甲酸二甲酯反应，找到了中氮茚衍生物的新合成路线，从而发展了利用乙炔基吡啶合成多功能化吡啶衍生物的多种合成路线。

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.