作者:Ashabha I. Lansakara、Daniel P. Farrell、F. Christopher Pigge
DOI:10.1039/c3ob42039f
日期:——
incorporated into the side chains of 2- and 4-alkylpyridines participate in intramolecular aldol-like condensations with pyridine benzylic carbons in the presence of Brønsted acid catalysts. Pyridines featuring β-ketoamide side chains undergo cyclization in the presence of 10 mol% TfOH to afford pyridyl-substituted hydroxy lactams in good yield. These products were found to be resistant to further dehydration
在布朗斯台德酸催化剂的存在下,结合到2-和4-烷基吡啶的侧链中的醛和酮亲电子试剂与吡啶苄基碳一起参与分子内的醛醇状缩合。以β-酮酰胺侧链为特征的吡啶在10摩尔%TfOH的存在下进行环化,以高收率得到吡啶基取代的羟基内酰胺。已发现这些产物在各种条件下均能抵抗进一步的脱水,但是用亚硫酰氯处理引发了异常的脱水/氧化反应顺序。相反,与胺键合的脂族醛与吡啶的酸催化环化生成吡啶基取代的脱氢哌啶产物。相似地,