Reaction Steps
2-(trimethylsilyl)ethyl 4-((1S,3aS,5aR,5bR,7aS,11aS,11bR,13aR,13bR)-1-isopropyl-5a,5b,8,8,11a-pentamethyl-3a-(3-oxo-3-(2-(trimethylsilyl)ethoxy)propylcarbamoyl)icosahydro-1H-cyclopenta[a]chrysen-9-yl)benzoate (14 mg, 0.017 mmol) was dissolved in THF (Volume: 0.5 mL) and treated with TBAF (0.5 mL, 0.500 mmol). The mixture was stirred at rt for 1 h. The solvent was removed in vacuo and the residue was dissolved in DMF and purified using reverse phase prep HPLC to afford 4-((1S,3aS,5aR,5bR,7aS,11aS,11bR,13aR,13bR)-3a-(2-carboxyethylcarbamoyl)-1-isopropyl-5a,5b,8,8,11a-pentamethylicosahydro-1H-cyclopenta[a]chrysen-9-yl)benzoic acid (6 mg, 8.99 mmol, 53.6% yield) as a white solid. 1H NMR (400 MHz, DMSO-d6) δ ppm 7.82 (d, J=8.28 Hz, 2H), 7.56 (t, J=5.52 Hz, 1H), 7.29 (d, J=8.28 Hz, 2H), 3.37-3.11 (m, 2H), 2.65-2.56 (m, 1H), 2.47-2.39 (m, 1H), 2.39-2.31 (m, 2H), 2.28-2.18 (m, 1H), 2.18-2.08 (m, 2H), 1.84-0.97 (m, 22H), 0.94 (s, 6H), 0.91 (s, 3H), 0.83 (d, J=6.78 Hz, 3H), 0.74 (d, J=6.78 Hz, 3H), 0.72 (s, 3H), 0.67 (s, 3H).
