Trifluoroacetic acid → 4-[[(3aR,5aR,5bR,7aR,9S,11aR,11bR,13aS)-3a-[(E)-3-[[(1S)-1-(3-chlorophenyl)ethyl]amino]-3-oxo-prop-1-enyl]-1-isopropyl-5a,5b,8,8,11a-pentamethyl-2,3,4,5,6,7,7a,9,10,11,11b,12,13,13a-tetradecahydrocyclopenta[a]chrysen-9-yl]oxy]-2,2-dimethyl-4-oxo-butanoic acid

Participants

Reaction Steps

To a solution of 1-tert-butyl 4-((3aR,5aR,5bR,7aR,9S,11aR,11bR,13aS)-3a-((E)-3-(((S)-1-(3-chlorophenyl)ethyl)amino)-3-oxoprop-1-en-1-yl)-1-isopropyl-5a,5b,8,8,11a-pentamethyl-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 (1556 mg, 1.934 mmol) in DCM (12 mL) stirred at room temp was added TFA (4 mL, 51.9 mmol). The reaction mixture was stirred at rt for 2 h. The mixture was evaporated to dryness, then diluted with 200 ml DCM. The organic phase was washed with saturated NaHCO3 solution (200 mL*3), water and brine. The organics were dried and concentrated under reduced pressure to afford the crude product which was purified by preparative-HPLC to give the title compound (550 mg, 38%) as a white solid. 1H NMR (400 MHz, CHLOROFORM-d) δ=7.40-7.17 (m, 4H), 6.85 (d, J=15.3 Hz, 1H), 5.72-5.49 (m, 2H), 5.18 (t, J=7.2 Hz, 1H), 4.50 (dd, J=5.6, 10.7 Hz, 1H), 3.28-3.10 (m, 1H), 2.74-2.62 (m, 1H), 2.62-2.50 (m, 1H), 2.24 (br. s., 3H), 2.08-1.92 (m, 2H), 1.89-0.70 (m, 49H); LC/MS: m/z calculated 747.5. Found 748.2 (M+1)+.

Provenance & Evidence