Reaction Steps
To a stirred solution of (1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-3a-((1S,3R)-2,2-dimethyl-3-(pyrrolidine-1-carbonyl)cyclobutylcarbamoyl)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)icosahydro-1H-cyclopenta[a]chrysen-9-yl acetate (Example 13, 0.230 g, 0.340 mmol) in MeOH:THF (2:1) (9 ml) NaOH (2N, 3 ml) was added at about 0° C. and allowed to stir at room temperature for about 16 hours. After completion of the reaction (monitored by TLC), the volatiles were evaporated and the aqueous layer was extracted with ethyl acetate and the organic layer was washed with water, brine and dried with Na2SO4. The solvent was evaporated and purified by silica gel column (100-200 mesh, elution 15% EtOAc in hexane) to afford the title compound as an off white solid. Wt: 0.150 g: Yield: 69.5%; 1H NMR (300 MHz, CDCl3): δ 6.39 (d, 1H, J=8.4 Hz), 4.73 (s, 1H), 4.57 (s, 1H), 4.13-4.03 (m, 1H), 3.58-3.28 (m, 4H), 3.21-3.07 (m, 2H), 2.79 (t, 1H, J=7.2 Hz), 2.57-2.33 (m, 2H), 2.27-2.18 (m, 1H), 2.04-1.72 (m, 8H), 1.70-1.10 (m, 23H), 0.95, 0.92, 0.88, 0.83, 0.80, 0.75 (s, 21H); Mass: [M+1]+ 635 (100%), [M+Na]+ 657 (90%); IR (KBr, cm−1): 3489, 2947, 2869, 1637, 1615, 1441, 1376, 1357, 1250, 1194, 1050, 881, 717; M.R: 172.4° C.-173.8° C.; HPLC: 96.79%.
