通过甲脒化学法简便合成3-取代咪唑并[1,2 - ]吡啶

Facile synthesis of 3-substituted imidazo[1,2-]pyridines through formimidamide chemistry.

作者信息

Sivappa Rasapalli, Sammeta Vamshikrishna Reddy, Huang Yanchang, Golen James A, Savinov Sergey N

机构信息

Department of Chemistry and Biochemistry, University of Massachusetts 287 Old Westport Rd, North Dartmouth MA-02747 USA

Department of Biochemistry and Molecular Biology, UMass Amherst Amherst MA-01003 USA.

出版信息

RSC Adv. 2019 Sep 19;9(51):29659-29664. doi: 10.1039/c9ra05841a. eCollection 2019 Sep 18.

DOI:10.1039/c9ra05841a

PMID:35531553

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9073381/

Abstract

A facile entry to 3-aryl/alkenyl/alkynyl substituted imidazo[1,2-]pyridines (3a-p, 6a-d & 9a-9e) has been developed from readily available benzyl/allyl/propargyl halides and 2-amino pyridines as substrates formimidamide chemistry that is devoid of caustic or expensive reagents, such as transition metal complexes. Quantum chemical calculations performed to understand the underlying mechanism of the transformation revealed a preference for intramolecular Mannich-type addition over pericyclic 1,5-electrocyclization for the systems reported herein that enable a Baldwin allowed 5--trig cyclization instead of a formally anti-Baldwin 5--trig process.

摘要

已开发出一种简便的方法，以易于获得的苄基/烯丙基/炔丙基卤化物和2-氨基吡啶为底物，通过亚胺酰胺化学合成3-芳基/烯基/炔基取代的咪唑并[1,2 -]吡啶（3a - p、6a - d和9a - 9e），该方法无需使用腐蚀性或昂贵的试剂，如过渡金属配合物。为了解该转化的潜在机制而进行的量子化学计算表明，对于本文报道的体系，分子内曼尼希型加成比周环1,5 - 电环化更受青睐，这使得能够进行鲍德温允许的5 - trig环化，而不是形式上反鲍德温的5 - trig过程。