Reaction Steps
To a solution of 1-tert-butyl 4-((3aS,5aR,5bR,7aR,9S,11aR,11bR,13aS)-3a-((E)-3-(((S)-1-(2-chlorophenyl)ethyl)amino)-3-oxoprop-1-en-1-yl)-1-isopropyl-5a,5b,8,8,11a-pentamethyl-2-oxo-3,3a,4,5,5a,5b,6,7,7a,8,9,10,11,11a,11b,12,13,13a-octadecahydro-2H-cyclopenta[a]chrysen-9-yl) 2,2-dimethylsuccinate (150 mg, 0.183 mmol), trifluoroacetic acid (1 mL, 12.98 mmol) in dichloromethane (4 mL) stirred at rt. The reaction mixture was stirred at rt for 2 h. The reaction mixture was evaporated and then purified by preparative-HPLC (Mobile Phase A: Water (0.05% TFA), B: ACN; Gradient 89-89% B in 0-7.5 min, stop at 12 min; Flow Rate (ml/min) 30.00; Retention Time (min) 7.0) to give the title compound (70 mg, 0.092 mmol, 50.1%) as a white solid. 1H NMR (400 MHz, METHANOL-d4) δ=7.43-7.32 (m, 2H), 7.32-7.18 (m, 2H), 6.81 (d, J=15.8 Hz, 1H), 6.01 (d, J=15.8 Hz, 1H), 5.41 (q, J=6.9 Hz, 1H), 4.48 (dd, J=5.1, 11.2 Hz, 1H), 3.30-3.24 (m, 1H), 2.94-2.81 (m, 1H), 2.72-2.49 (m, 2H), 2.30-0.75 (m, 50H); LC/MS: m/z calculated 761.4. Found 762.3 (M+1)+.
