Reaction Steps
To a solution of methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(3-(dimethylamino)propanamido)-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, TFA (87.9 mg, 0.116 mmol) in THF (5 mL) was added a solution of lithium hydroxide monohydrate (19.49 mg, 0.464 mmol) in water (1.00 mL). The reaction was stirred at 75° C. After 8 h, the reaction was concentrated to dryness. The crude material was dissolved in THF (1 mL) and MeOH (1.5 mL), filtered and purified by reverse phase preparative HPLC using HPLC method 1 to give the title compound (59.5 mg, 0.078 mmol, 67.6% yield) as a white solid. LCMS: m/e 629.4 (M+H)+, 4.17 min (method 8). 1H NMR (500 MHz, METHANOL-d4) δ=7.95 (d, J=8.2 Hz, 2H), 7.24 (d, J=8.2 Hz, 3H), 5.33 (dd, J=1.5, 6.1 Hz, 1H), 4.80 (d, J=1.5 Hz, 1H), 4.67 (s, 1H), 3.40 (t, J=6.6 Hz, 2H), 2.92 (s, 6H), 2.88-2.69 (m, 4H), 2.42 (dd, J=8.4, 12.4 Hz, 1H), 2.18 (dd, J=6.4, 17.1 Hz, 1H), 2.05-1.89 (m, 2H), 1.83 (d, J=11.3 Hz, 1H), 1.79-1.76 (m, 1H), 1.75 (s, 3H), 1.74-1.71 (m, 1H), 1.66-1.56 (m, 3H), 1.56-1.49 (m, 4H), 1.47-1.28 (m, 5H), 1.22-1.17 (m, 1H), 1.16 (s, 3H), 1.15-1.10 (m, 1H), 1.07 (s, 6H), 0.99 (s, 3H), 0.97 (s, 3H). 13C NMR (MeOD) δ ppm 14.5, 16.1, 16.8, 19.1, 20.6, 21.3, 22.1, 26.2, 28.2, 29.4, 29.7, 30.4, 34.5, 35.5, 37.1, 38.1, 38.2, 41.5, 42.5, 42.8, 43.2, 47.6, 49.3, 50.1, 50.5, 54.0, 55.1, 66.4, 110.4, 124.9, 129.5, 130.9, 147.4, 149.6, 150.8, 169.6, 171.0.
