A new, one-pot, three-component synthesis of 4H-pyrido[1,2-a]pyrimidines, 4H-pyrimido[1,2-a]pyrimidines, and 4H-pyrazino[1,2-a]pyrimidines
作者:Mehdi Adib、Mohammad Hosein Sayahi、Hakimeh Ziyadi、Hamid Reza Bijanzadeh、Long-Guan Zhu
DOI:10.1016/j.tet.2007.08.024
日期:2007.11
A new, one-pot and three-component synthesis of 4H-pyrido[1,2-a]pyrimidines, 4H-pyrimido[1,2-a]pyrimidines, and 4H-pyrazino[1,2-a]pyrimidines is described. The reactive 1:1 zwitterionic intermediate, formed by the addition of isocyanides to dialkyl acetylenedicarboxylates, was trapped by N-(2-heteroaryl)amides to yield a ketenimine intermediate, which was cyclized and then rearranged under the reaction
一种新的,单釜和4的三组分合成ħ -吡啶并[1,2-一个]嘧啶,4 ħ嘧啶并[1,2一]嘧啶,和4- ħ -吡嗪并[1,2一]描述了嘧啶。通过将异氰酸酯加到乙炔二羧酸二烷基酯上而形成的反应性1:1两性离子中间体被N-(2-杂芳基)酰胺捕获,制得烯酮胺中间体,将其环化,然后在反应条件下重排,得到标题化合物在温和的反应条件下,收率很高。X射线单晶分析最终证实了所获得的桥头双环6-6杂环化合物的结构。