N-(olean-3β-hydroxy-11-oxo-12-en-30-oyl)-L-leucine 、
2,2-二甲基琥珀酸酐 在
吡啶 、
4-二甲氨基吡啶 作用下,
反应 12.0h,
以65%的产率得到2,2-Dimethyl-succinic acid 4-[(3S,4aR,6aR,6bS,8aS,11S,12aR,14aR,14bS)-11-((S)-1-carboxy-3-methyl-butylcarbamoyl)-4,4,6a,6b,8a,11,14b-heptamethyl-14-oxo-1,2,3,4,4a,5,6,6a,6b,7,8,8a,9,10,11,12,12a,14,14a,14b-icosahydro-picen-3-yl] ester