A versatile new synthesis of quinolines and related fused pyridines. Part 8. Conversion of anilides into 3-substituted quinolines and into quinoxalines
作者:Otto Meth-Cohn、Salah Rhouati、Brian Tarnowski、Andrew Robinson
DOI:10.1039/p19810001537
日期:——
3-substituted quinolines (7). When N-nitrosodialkylamines are used in place of dimethylformamide as the Vilsmeier agent, the anilides are converted into 2-chloroquinoxalines in low yields. Several by-products are formed and the mechanisms have been explored. Thus, the formation of ethyl N-arylcabamate from the corresponding propionanilide is shown to involve an C→O alkyl migration related to a Wolff rearrangement
苯胺(4)(ArNHCOCH 2 R)在Vilsmeier条件下很容易转化为2-氯-3-R-喹啉(5),可以用锌和乙酸除去2-氯基团,生成3-取代的喹啉(7 )。当使用N-亚硝基二烷基胺代替二甲基甲酰胺作为Vilsmeier剂时,该苯胺化物以低收率转化成2-氯喹喔啉。形成了几种副产物,并研究了其机理。因此,由相应的丙酰苯胺形成的N-芳基氨基甲酸乙酯乙酯显示出与沃尔夫夫重排有关的C→O烷基迁移,而N-芳基甲酰亚胺基二氯化物(18),腈和异氰化物是从被取代的侧链的C-C裂解中衍生而来的。尽管使用磷酰溴而不是氯化物导致苯胺以低收率转化为氯,但Vilsmeier试剂或溶剂的酰氯组分的变化通常是无用的。