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-(2-(2-oxopyrrolidin-1-yl)ethylamino)-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 (0.025 g, 0.037 mmol) in 1,4-dioxane (1 mL) was added NaOH (1N) (0.5 mL, 0.500 mmol). The mixture was warmed to 60° C. for 15. 5 h then was cooled to rt and purified by prep HPLC. 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-(2-(2-oxopyrrolidin-1-yl)ethylamino)-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 (11 mg, 0.016 mmol, 42.2% yield) as a white solid. LCMS: m/e 659.5 (M+H)+, 1.77 min (method 2). 1H NMR (500 MHz, CHLOROFORM-d) δ 7.82 (t, J=6.9 Hz, 1H), 6.91 (d, J=6.1 Hz, 1H), 6.86 (d, J=11.9 Hz, 1H), 5.27 (d, J=4.6 Hz, 1H), 4.71 (s, 1H), 4.58 (s, 1H), 3.54-3.43 (m, 3H), 3.39-3.31 (m, 1H), 1.68 (s, 3H), 1.06 (s, 3H), 0.96 (s, 3H), 0.93 (s, 3H), 0.90 (s, 3H), 0.90 (s, 3H), 2.75-0.66 (m, 29H).
