Reaction Steps
To a stirred solution of (1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-N-((1R,3S)-2,2-dimethyl-3-(piperidine-1-carbonyl)cyclobutyl)-9-hydroxy-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysene-3a-carboxamide (Example 47, 0.190 g, 0.293 mmol) 2,2-Dimethylsuccinic anhydride (0.375 g, 2.932 mmol) and DMAP (0.071 g, 0.586 mmol) in pyridine (10 ml) were added at room temperature and refluxed for about 24 hours. After completion of the reaction (monitored by TLC), the reaction mixture was diluted with EtOAc, washed with aqueous 1N HCl, then water and brine, and dried over Na2SO4 then the solvent was evaporated and purified by silica gel column (100-200 mesh, elution 20% EtOAc in hexane) to afford the title compound as an off white solid. Wt: 0.090 g; Yield: 39.6%; 1H NMR (300 MHz, CDCl3): δ 5.96 (d, 111, J=8.1 Hz), 4.72 (s, 1H), 4.58 (s, 1H), 4.52-4.44 (m, 1H), 4.16-4.07 (m, 1H), 3.79-3.58 (m, 1H), 3.50-3.31 (m, 3H), 3.18-3.07 (m, 1H), 2.91-2.87 (m, 1H), 2.71-2.56 (m, 2H), 2.56-2.37 (m, 2H), 2.30-2.19 (m, 1H), 2.01-1.81 (m, 3H), 1.80-1.10 (m, 35H), 0.95, 0.93, 0.88, 0.87 (s, 21H); Mass: [M+1]+ 777 (30%), [M+Na]+ 799 (100%); IR (KBr, cm−1): 3400, 2947, 2868, 1733, 1622, 1456, 1390, 1369, 1320, 1252, 1231, 1192, 1150, 1021, 978, 881; HPLC: 97.37%; M.R: 168.5° C.-176.9° C.
