Old reagents, new results: Aromatization of Hantzsch 1,4-dihydropyridines with manganese dioxide and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone
作者:Jean Jacques Vanden Eynde、Florence Delfosse、Annie Mayence、Yves Van Haverbeke
DOI:10.1016/0040-4020(95)00318-3
日期:1995.6
Hantzsch 1,4-dihydropyridines are readily oxidized by manganese dioxide or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in dichloromethane at room temperature. With manganese dioxide loss of the 4-substituent, in addition to aromatization, occurs when it is a secondary alkyl or a benzylic group and sonication significantly reduces the reaction times. In contrast, loss of the 4-substituent is never
Hantzsch 1,4-dihydropyridines在室温下很容易被二氧化锰或2,3-dichloro-5,6-dicyano-1,4-苯醌(DDQ)氧化在二氯甲烷中。除二氧化锰外,当其为仲烷基或苄基时,除芳香化外还会发生4-取代基的损失,超声处理可显着缩短反应时间。相反,当DDQ为氧化性物质时,从未观察到4-取代基的损失。