Reaction Steps
A mixture of (1R,3aS,5aR,5bR,7aR,9S,11aR,11bR,13aR,13bR)-3a-((2-(1,1-dioxido-4-thiomorpholinyl)ethyl)amino)-1-isopropenyl-5a,5b,8,8,11a-pentamethylicosahydro-1H-cyclopenta[a]chrysen-9-ol (100 mg, 0.170 mmol), 3,3-dimethyldihydrofuran-2,5-dione (436 mg, 3.4 mmol) and DMAP (208 mg, 1.7 mmol) in pyridine (1 mL) was heated up at 150° C. for 37 h. The reaction mixture was filtered and purified by prep. HPLC to provide the title compounds 4-(((1R,3aS,5aR,5bR,7aR,9S,11aR,13aR,13bR)-3a-((2-(1,1-dioxido-4-thiomorpholinyl)ethyl)amino)-1-isopropenyl-5a,5b,8,8,11a-pentamethylicosahydro-1H-cyclopenta[a]chrysen-9-yl)oxy)-3,3-dimethyl-4-oxobutanoic acid, example 1, as a white solid (17 mg, 13%). LCMS: m/e 717.51 (M+H)+, 2.39 min (method 1). 1H NMR (500 MHz, Acetic) δ 4.83 (s, 1H), 4.75 (s, 1H), 4.51 (dd, J=10.8, 5.6 Hz, 1H), 3.41-3.11 (m, 11H), 3.10-2.99 (m, 1H), 2.82 (td, J=10.8, 5.5 Hz, 1H), 2.75-2.63 (m, 2H), 2.27-1.04 (m, 24H), 1.76 (s, 3H), 1.31 (s, 6H), 1.19 (s, 3H), 1.13 (s, 3H), 0.95 (s, 3H), 0.92 (s, 3H), 0.92 (s, 3H) and 4-(((1R,3aS,5aR,5bR,7aR,9S,11aR,13aR,13bR)-3a-((2-(1,1-dioxido-4-thiomorpholinyl)ethyl)amino)-1-isopropenyl-5a,5b,8,8,11a-pentamethylicosahydro-1H-cyclopenta[a]chrysen-9-yl)oxy)-2,2-dimethyl-4-oxobutanoic acid, example 2, as a white solid (60 mg, 47%). LCMS: m/e 717.51 (M+H)+, 2.44 min (method 1). 1H NMR (500 MHz, Acetic) δ 4.82 (s, 1H), 4.72 (s, 1H), 4.57 (dd, J=10.2, 6.0 Hz, 1H), 3.44 (d, J=12.5 Hz, 1H), 3.35-3.20 (m, 6H), 3.19-3.09 (m, 3H), 3.05 (d, J=4.6 Hz, 2H), 2.97-2.85 (m, 1H), 2.81-2.58 (m, 2H), 2.32-2.13 (m, 2H), 1.79-1.05 (m, 22H), 1.75 (s, 3H), 1.33 (s, 3H), 1.31 (s, 3H), 1.23 (s, 3H), 1.11 (s, 3H), 0.96 (s, 3H), 0.90 (s, 3H), 0.89 (s, 3H).
