Reaction Steps
To a solution of methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(2,2-dimethoxyethylamino)-5a,5b,8,8,11a-pentamethyl-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, 0.040 mmol) in 1,4-dioxane (1 mL) was added NaOH (1N) (0.198 mL, 0.198 mmol). The mixture was heated to 85° C. After 6 h of heating, the mixture was cooled to rt, the reaction mixture was diluted with MeOH and was purified by prep HPLC. The fractions containing the expected product were combined and were concentrated under reduced pressure to give the title compound (17 mg, 0.026 mmol, 66.1% yield) as a clear film. LCMS: m/e 618.8 (M+H)+, 2.28 min (method 11). 1H NMR (500 MHz, CHLOROFORM-d) d ppm 7.99 (d, J=7.93 Hz, 2H), 7.20 (d, J=7.93 Hz, 2H), 5.28 (d, J=4.88 Hz, 1H), 5.12 (br. s., 1H), 4.72 (s, 1H), 4.58 (s, 1H), 4.53 (t, J=5.49 Hz, 1H), 3.44 (s, 3H), 3.41 (s, 3H), 2.64-2.74 (m, 2H), 2.60 (dd, J=11.44, 6.56 Hz, 1H), 1.97-2.13 (m, 2H), 1.86-1.95 (m, 2H), 1.81 (dd, J=12.51, 8.24 Hz, 1H), 1.68 (s, 3H), 1.11 (s, 3H), 0.98 (s, 3H), 0.97 (br. s., 3H), 0.95-1.72 (m, 17H), 0.93 (br. s., 6H).
