Reaction Steps
To a solution of 3-(((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-5a,5b,8,8,11a-pentamethyl-3a-((2-(4-(methylsulfonyl)piperidin-1-yl)ethyl)amino)-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)methylene)cyclobutanecarbonitrile (30 mg, 0.043 mmol) in ethanol (2 mL) was added potassium hydroxide (1 mL, 0.043 mmol). A white precipitate was formed. The mixture became clear after warming up to 76° C. The reaction solution was stirred at 76° C. for 7 h. The crude product was purified without further work up by prep HPLC (method 4) to give 3-(((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-5a,5b,8,8,11a-pentamethyl-3a-((2-(4-(methylsulfonyl)piperidin-1-yl)ethyl)amino)-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)methylene)cyclobutanecarboxylic acid as a white solid (9 mg, 29.2%). MS: m/e 709.55 (M+H)+, 2.54 min (method 4). 1H NMR (400 MHz, METHANOL-d4) δ 5.72 (br. s., 1H), 5.38 (d, J=5.5 Hz, 1H), 4.78 (s, 1H), 4.68 (s, 1H), 3.28-2.75 (m, 14H), 2.96 (s, 3H), 2.65-2.52 (m, 1H), 2.42-2.27 (m, 1H), 2.23-1.80 (m, 11H), 1.75 (s, 3H), 1.69-1.27 (m, 14H), 1.22 (s, 3H), 1.10 (br. s., 3H), 1.01 (br. s., 3H), 0.96-0.93 (m, 3H), 0.90-0.87 (m, 3H).
