Reaction Steps
To a solution of tert-butyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((2-(dimethylamino)-2-(pyridin-3-yl)ethylamino)methyl)-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 (125 mg, 0.167 mmol) in DCM (1 ml) was added TFA (0.4 ml, 5.19 mmol). The mixture was stirred at rt for 4.5 h then was concentrated under reduced pressure. The residue was dissolved in dioxane and MeOH and was purified by prep HPLC. The fractions containing the expected product were combined and concentrated under reduced pressure. Impurities were still present so the residue was purified again by prep HPLC. The fractions containing the expected product were combined and concentrated under reduced pressure to give the title compound as an off-white solid (16 mg, 13.8%). LCMS: m/e 692.5 (M+H)+, 2.30 min (method 6). 1H NMR (500 MHz, Acetic Acid) δ ppm 8.83-8.98 (m, 2H), 8.27-8.42 (m, 1H), 7.99-8.11 (m, 2H), 7.71-7.84 (m, 1H), 7.27-7.35 (m, 2H), 5.33-5.42 (m, 1H), 5.22-5.30 (m, 1H), 4.79 (d, J=14.34 Hz, 1H), 4.67 (d, J=12.82 Hz, 1H), 4.21-4.38 (m, 2H), 3.34-3.52 (m, 1H), 2.97-3.15 (m, 1H), 2.83 (br. s., 3H), 2.82 (br. s., 3H), 2.43-2.58 (m, 1H), 0.88-2.23 (m, 40H).
