Base-promoted cyclization of 3-alkynylquinoxaline-2-carbonitriles with CH-acids: a new method for the phenazine ring synthesis
作者:Huong T.L. Nguyen、Anna V. Gulevskaya、Alexander F. Pozharskii、Julia I. Nelina-Nemtseva
DOI:10.1016/j.tet.2014.05.023
日期:2014.8
THF or DMSO. A new cascade process includes nucleophilic addition of a CH-acid carbanion to the CC bond of 3-alkynylquinoxaline-2-carbonitrile, 6-exo-dig cyclization of the intermediate allyl carbanion with the formation of 2,2-disubstituted 1-imino-1,2-dihydrophenazine and its aromatization via elimination of the C(2)-substituent. Several secondary reactions were also disclosed and discussed.
3- Alkynylquinoxaline -2-腈直接通过用CH-酸(丙二酸二乙酯,氰基乙酸乙酯,丙二腈,2- tosylacetonitrile,2-(1-甲基-1-处理转化为2,3-二取代的吩嗪-1-胺ħ -在THF或DMSO中的苯并[ d ]咪唑-2-基)乙腈,硝基甲烷)和t- BuOK。一种新的级联工艺包括将CH-酸碳负离子亲核加成到3-炔基喹喔啉-2-甲腈的C C键上,中间烯丙基碳负离子的6- exo - dig环化反应,形成2,2-二取代的1-亚氨基-1,2-二氢吩嗪及其通过消除C(2)取代基的芳香化作用。还公开和讨论了一些次级反应。