Reaction Steps
To a solution of methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-3a-((3,3,3-trifluoropropyl)amino)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)benzoate (0.032 g, 0.050 mmol) in 1,4-dioxane (1 mL) was added NaOH (1N) (0.2 mL, 0.200 mmol). The mixture was heated to 75° C. for 22.5 h then was cooled to rt. The mixture was diluted with methanol, was filtered through a plug of glass wool and was purified by Prep HPLC. The fractions containing the expected product were combined and concentrated under reduced pressure to give 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-3a-((3,3,3-trifluoropropyl)amino)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)benzoic acid (0.022 g, 0.033 mmol, 66.8% yield) as a white solid. LCMS: m/e 626.6 (M+H)+, 1.87 min (method 2). 1H NMR (400 MHz, Acetic acid d4) 67.99 (d, J=8.28 Hz, 2H), 7.25 (d, J=8.28 Hz, 2H), 5.33 (d, J=4.77 Hz, 1H), 4.82 (s, 1H), 4.70 (s, 1H), 3.36-3.51 (m, 2H), 2.81-2.97 (m, 3H), 2.12-2.28 (m, 4H), 1.72 (s, 3H), 1.17 (s, 3H), 1.09 (s, 3H), 1.05 (s, 3H), 0.98 (s, 3H), 0.96 (s, 3H), 0.82-2.11 (m, 18H).
