Reaction Steps
To a solution of 1-tert-butyl 4-((3aS,5aR,5bR,7aR,9S,11aR,11bR,13aS)-1-isopropyl-5a,5b,8,8,11a-pentamethyl-2-oxo-3a-((E)-3-oxo-3-((1-(pyridin-2-yl)cyclopropyl)amino)prop-1-en-1-yl)-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 (460 mg, 0.577 mmol) in dichloromethane (6 mL) was added TFA (3 mL, 0.577 mmol). The reaction mixture was stirred at r.t for 2 hr and evaporated in vacuo to afford crude product, which was purified by preparative-HPLC (Mobile Phase: A=0.05% TFA/H2O, B=MeCN) to give the title compound, trifluoroacetic acid salt (30 mg, 0.033 mmol, 5.78%) as a white solid. 1H NMR (400 MHz, DMSO-d6) δ=12.16 (br. s., 1H), 8.80 (s, 1H), 8.42 (d, J=4.0 Hz, 1H), 7.66 (t, J=7.4 Hz, 1H), 7.29-7.06 (m, 2H), 6.69 (d, J=15.8 Hz, 1H), 5.97 (d, J=15.8 Hz, 1H), 4.40 (dd, J=4.6, 10.9 Hz, 1H), 3.27-3.13 (m, 1H), 3.02-2.87 (m, 1H), 2.80 (d, J=11.5 Hz, 1H), 2.59-2.52 (m, 1H), 2.30-0.73 (m, 51H); LC/MS: m/z calculated 740.5. Found 741.3 (M+1)+.
