Metal free [4+1] and [5+1] annulation reactions to prepare heterocycles using DMF and its derivatives as one-carbon source
作者:Yiwen Xu、Bei Shen、Lingfeng Liu、Chunhua Qiao
DOI:10.1016/j.tetlet.2020.151844
日期:2020.5
in a variety of pharmaceutical and agrochemical agents. Herein, we report a highly efficient and practical method using DMF and its derivative for the [4+1] and [5+1] annulation reactions to prepare these heterocycles. This metal free reaction takes advantages of shelf stable DMF as solvent and carbon donor, imidazole chloride as catalyst, the mild reaction condition tolerates a broad substrate range
1,2,4-三唑并[3,4- a ]吡啶和相关的杂环以及取代的三嗪是在各种药物和农用化学试剂中普遍发现的支架。在这里,我们报告了一种高效且实用的方法,该方法使用DMF及其衍生物进行[4 + 1]和[5 + 1]环化反应,以制备这些杂环。这种无金属的反应利用了贮存稳定的DMF作为溶剂和碳供体,使用咪唑氯化物作为催化剂的优势,温和的反应条件可耐受广泛的底物范围并替代。制备的3-未取代的1,2,4-三唑并[3,4- a ]吡啶和衍生物允许在3-位进一步引入各种官能团。