New insight into anionic cyclizations of alkynyl- and ortho-dialkynylarenes: a specific reactivity of 3-alkynyl-2-chloro- and 2,3-dialkynylquinoxalines and related compounds toward CH-acids’ carbanions
作者:Anna V. Gulevskaya、Huong T.L. Nguyen、Alexander S. Tyaglivy、Alexander F. Pozharskii
DOI:10.1016/j.tet.2011.11.018
日期:2012.1
on the nature of the used C-nucleophile, the thus formed anionic adduct underwent further cyclization via (i) intramolecular nucleophilic substitution of the chlorine atom, (ii) intramolecular acylation of the ring nitrogen atom by the ester side chain or (iii) intramolecular nucleophilic attack on the second CC bond. Reactions of 3-alkynyl-2-chloro- and 2,3-dialkynylpyrazines with 1,3-dimethylbarbituric
研究了3-炔基-2-氯喹喔啉,2,3-二炔基喹喔啉和一些相关的吡嗪衍生物对CH-酸(丙二腈,氰基乙酸乙酯,丙二酸二乙酯,1,3-二甲基巴比妥酸)的碳负离子的反应性。观察到的大多数反应以串联或级联环化进行,从而产生多核杂环化合物。该过程开始于将亲核试剂加至炔三键。根据所用的C-亲核试剂的性质,如此形成的阴离子加合物通过(i)氯原子的分子内亲核取代,(ii)环氮原子被酯侧链进行分子内酰化或(iii)进行进一步环化。分子内亲核攻击第二个CC键。在t -BuOK存在下3-炔基-2-氯-和2,3-二炔基吡嗪与1,3-二甲基巴比妥酸的反应伴随有1,3-二甲基巴比妥酸部分的环化。