Titanium(IV) Chloride Promoted Syntheses of New Imidazo[1,2-<i>a</i>]pyridine Derivatives under Microwave Conditions
作者:Lisheng Cai、Chad Brouwer、Kathryn Sinclair、Jessica Cuevas、Victor W. Pike
DOI:10.1055/s-2005-918490
日期:——
imidazo[1,2-a]pyridine derivatives from the reaction of 2-aminopyridines with α-haloketones. The critical reagent is titanium(IV) chloride, which appears to serve as a strongdehydrating agent to promote formation of putative Schiff base intermediates, which cyclize subsequently to form the products. The reactions were performed rapidly under microwave conditions. Multiple reaction conditions were evaluated
描述了一种由 2-氨基吡啶与 α-卤代酮反应合成咪唑并[1,2-a]吡啶衍生物的新方法。关键试剂是氯化钛 (IV),它似乎是一种强脱水剂,可促进推定的席夫碱中间体的形成,后者随后环化形成产物。反应在微波条件下快速进行。评估了多种反应条件,包括反应温度、溶剂和其他路易斯酸。检查了 α-卤代酮和 2-氨基吡啶底物中取代模式的各种组合,以评估反应的范围。该反应对两种底物中的取代基都非常敏感,尤其是那些具有碱性或配位能力的底物。