Expeditious one-pot synthesis of highly substituted thiazolo[3,2-a]pyridines involving chromones
作者:Michael A. Terzidis、Julia Stephanidou-Stephanatou、Constantinos A. Tsoleridis、Aristides Terzis、Catherine P. Raptopoulou、Vassilis Psycharis
DOI:10.1016/j.tet.2009.11.096
日期:2010.1
resulting, after an unusual rearrangement, in the facile synthesis of thiazolo[3,2-a]pyridine derivatives; in the case of electron-donating substituents in the chromone ring tetracyclic chromenothiazolopyridines are isolated as the main reaction products. However, at higher temperature after an unexpected 1,2-aroyl migration 8-formyl-5H-[1,3]thiazolo[3,2-a]pyridines are formed as a mixture of two rotamers
研究表明,衍生自4,5-二甲基噻唑和乙炔二羧酸盐的1,4-两性离子在低温下容易与3-甲酰基色酮(色酮-3-羧醛)发生反应,经过不寻常的重排后,即可轻松合成噻唑啉[3]。 ,2- a ]吡啶衍生物;在色酮环中供电子性取代基的情况下,以四环铬基非噻唑并吡啶为主要反应产物。然而,在较高的温度下,在意外的1,2-芳酰基迁移之后,形成了作为两个旋转异构体的混合物的8-甲酰基-5 H- [1,3]噻唑并[3,2- a ]吡啶。新化合物的结构分配以及1 H和13的完整分配C NMR信号基于其1 H和13 C NMR(1D和2D),IR,MS和元素分析数据的分析。提出了合理的机制。