Reaction Steps
To a solution of tert-butyl 4-(2-(((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-9-(4-(tert-butoxycarbonyl)phenyl)-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-3a-yl)methylamino)ethyl)piperazine-1-carboxylate (136 mg, 0.167 mmol) in DCM (1 ml) was added TFA (0.4 ml, 5.19 mmol). The mixture was stirred at rt for 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. HPLC showed some impurities were still present, so the reaction was repurified by prep. HPLC. The fractions were concentrated under reduced pressure to give the title compound as a white solid (18 mg, 0.027 mmol, 16.43% yield). LCMS: m/e 656.6 (M+H)+, 2.24 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), 3.50-3.67 (m, 6H), 3.40 (d, J=12.82 Hz, 1H), 3.22-3.29 (m, 6H), 2.99 (d, J=13.12 Hz, 1H), 2.49-2.58 (m, 1H), 1.76 (s, 3H), 1.19 (s, 3H), 1.16-2.23 (m, 22H), 1.10 (s, 3H), 1.08 (s, 3H), 1.02 (s, 3H), 1.00 (s, 3H).
