Total synthesis of two novel 5,6,7,8-tetrahydroindolizine alkaloids, polygonatines A and B
作者:Andrew Dinsmore、Karen Mandy、Joseph P. Michael
DOI:10.1039/b517573a
日期:——
polygonatines A and B, two simple but structurally novel alkaloids, have been substantiated by synthesis. Cyclisation of 4-(1H-pyrrol-1-yl)butanoic acid or its ethyl ester produced 6,7-dihydroindolizin-8(5H)-one , formylation of which at C-3 followed by reduction afforded polygonatine A . Acetylation of this alkaloid followed by displacement of the acetate with ethanol yielded polygonatine B , possibly via
New pyrrole derivatives of cephalosporin compounds have been prepared which are useful as antibiotics.
已经制备了头孢菌素化合物的新吡咯衍生物,可用作抗生素。
US4148998A
申请人:——
公开号:US4148998A
公开(公告)日:1979-04-10
Total Syntheses of Bisdehydroneostemoninine and Bisdehydrostemoninine by Catalytic Carbonylative Spirolactonization
作者:Kaiqing Ma、Xianglin Yin、Mingji Dai
DOI:10.1002/anie.201809114
日期:2018.11.12
The first total syntheses of the stemona alkaloids bisdehydroneostemoninine and bisdehydrostemoninine in racemic forms have been achieved. The synthetic strategy features a novel palladium‐catalyzed carbonylative spirolactonization of a hydroxycyclopropanol to rapidly construct the oxaspirolactone moiety. It also features a Lewis acid promoted tandem Friedel–Crafts cyclization and lactonization to