Reaction Steps
To a solution of methyl 2-fluoro-4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-5a,5b,8,8,11a-pentamethyl-3a-(3-(2-oxopyrrolidin-1-yl)propylamino)-1-(prop-1-en-2-yl)-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 (16 mg, 0.023 mmol) in 1,4-dioxane (1 mL) was added NaOH (1N) (0.25 mL, 0.250 mmol). The mixture was heated to 60° C. overnight for 15.25 h then was cooled to rt. The mixture was directly loaded onto the prep HPLC for purification. The fractions containing the expected product were combined and concentrated under reduced pressure to give 2-fluoro-4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-5a,5b,8,8,11a-pentamethyl-3a-(3-(2-oxopyrrolidin-1-yl)propylamino)-1-(prop-1-en-2-yl)-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 (6 mg, 8.02 mmol, 34.5% yield) as a clear, colorless film. LCMS: m/e 673.5 (M+H)+, 1.75 min (method 2). 1H NMR (500 MHz, Acetic acid d4) δ 7.96 (t, J=7.9 Hz, 1H), 7.09 (dd, J=7.9, 1.2 Hz, 1H), 7.03 (d, J=11.9 Hz, 1H), 5.42 (d, J=4.6 Hz, 1H), 4.86 (s, 1H), 4.74 (s, 1H), 3.58-3.40 (m, 4H), 3.26-3.16 (m, 2H), 2.94-2.85 (m, 1H), 2.56-2.48 (m, 2H), 1.76 (s, 3H), 1.22 (s, 3H), 1.13 (s, 3H), 1.08 (s, 3H), 1.04 (s, 3H), 1.01 (s, 3H), 2.29-0.85 (m, 26H).
