Regioselective Synthesis of Pyrazolo[1,5-<i>a</i>]pyridine via TEMPO-Mediated [3 + 2] Annulation–Aromatization of <i>N</i>-Aminopyridines and α,β-Unsaturated Compounds
作者:Amu Wang、Ya-Zhou Liu、Zhongke Shen、Zeen Qiao、Xiaofeng Ma
DOI:10.1021/acs.orglett.2c00035
日期:2022.2.25
A TEMPO-mediated [3 + 2] annulation–aromatization protocol for the preparation of pyrazolo[1,5-a]pyridines from N-aminopyridines and α,β-unsaturated compounds was developed. The procedure offered multisubstituted pyrazolo[1,5-a]pyridines in good to excellent yield with high and predictable regioselectivity. The modification of marketed drugs including Loratadine, Abiraterone, and Metochalcone, and
开发了一种 TEMPO 介导的 [3 + 2] 环化-芳构化方案,用于从N-氨基吡啶和 α,β-不饱和化合物制备吡唑并[1,5- a ]吡啶。该方法提供了多取代的吡唑并[1,5- a ]吡啶,产率从良好到优异,具有高和可预测的区域选择性。展示了氯雷他定、阿比特龙和甲查耳酮等上市药物的改性,以及用于制备 Selpercatinib 的关键中间体的一锅三步克级规模合成。机理研究表明,TEMPO 既可用作路易斯酸,又可用作氧化剂。