作者:Hamish McNab、James Montgomery、Simon Parsons、David G. Tredgett
DOI:10.1039/c0ob00116c
日期:——
Pyrrolizine-1,3-dione 4 was made by oxidation of the alcohol 2 using pyridinium chlorochromate. The dione 4 shows ketone properties (e.g. formation of DNP derivative 11) and, in common with other pyrrolizinones, the lactam unit is readily ring-opened by methanol under basic conditions. The active methylene unit of 4 couples readily with diazonium salts to provide the hydrazone 15 whose structure was confirmed by X-ray crystallography. The ‘Meldrumsated’ derivative 18 exists exclusively as the tautomer 18F; flash vacuum pyrolysis (FVP) of 18 at 700 °C gives the pyronopyrrolizine 20 exclusively. Reaction of 4 with DMF acetal gives the dimethylaminomethylene derivative 22 which exists as a mixture of rotamers at room temperature.
吡咯烷-1,3-二酮 4 是通过使用氯铬酸吡啶鎓氧化醇 2 制得的。二酮 4 具有酮的特性(如形成 DNP 衍生物 11),与其他吡咯烷酮一样,内酰胺单元在碱性条件下容易被甲醇开环。4 的活性亚甲基单元很容易与重氮盐偶联生成腙 15,腙 15 的结构已通过 X 射线晶体学证实。Meldrumsated "衍生物 18 只存在同分异构体 18F;在 700 °C 下对 18 进行闪速真空热解(FVP),只得到吡咯烷酮 20。将 4 与 DMF 乙缩醛反应,可得到二甲氨基亚甲基衍生物 22,该衍生物在室温下以转 子的混合物形式存在。