Reaction Steps
To a solution of tert-butyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((2-acetamidoethylamino)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 (114 mg, 0.167 mmol) in DCM (1 ml) was added TFA (0.4 ml, 5.19 mmol). The mixture was stirred at rt for 3.5 h then was concentrated under reduced pressure. The residue was dissolved in dioxane and MeOH and was purified by pre. HPLC. The fractions containing the expected product were combined and concentrated under reduced pressure to afford the title compound as an off-white solid (40.7 mg, 0.065 mmol, 38.8% yield). LCMS: m/e 629.5 (M+H)+, 2.17 min (method 6). 1H NMR (500 MHz, Acetic) δ ppm 8.03 (d, J=8.24 Hz, 2H),7.30 (d, J=8.24 Hz, 2H), 5.37 (d, J=4.58 Hz, 1H), 4.79 (s, 1H), 4.68 (s, 1H), 3.61-3.70 (m, 2H), 3.40-3.53 (m, 2H), 3.37 (d, J=13.12 Hz, 1H), 2.98 (d, J=12.82 Hz, 1H), 2.49-2.57 (m, 1H), 2.09 (s, 3H), 1.75 (s, 3H), 1.19 (s, 3H), 1.14-2.24 (m, 22H), 1.10 (s, 3H), 1.07 (s, 3H), 1.02 (s, 3H), 1.00 (s, 3H).
