Reaction Steps
To a solution of (1S,4S)-tert-butyl 5-(2-(((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-9-(4-(methoxycarbonyl)phenyl)-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-3a-yl)amino)ethyl)-2,5-diazabicyclo[2.2.1]heptane-2-carboxylate (419 mg, 0.545 mmol) in DCM (10 mL) was added TFA (2 mL, 26.0 mmol) and the mixture was stirred at rt for 3 h. The reaction mixture was concentrated and dark brown viscous oil was dried to remove all TFA. The material was purified by reverse phase HPLC using HPLC method 6 and dried under vacuum to give methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((2-((1S,4S)-2,5-diazabicyclo[2.2.1]heptan-2-yl)ethyl)amino)-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, 3 TFA (75.2 mg, 12.28% yield) as a light brown solid. LC/MS: m/e 668.7 (M+H)+, 2.36 min (method 3). 1H NMR (400 MHz, CHLOROFORM-d) δ 9.77 (br. s., 1H), 9.49 (br. s., 1H), 7.92 (d, J=8.1 Hz, 2H), 7.19 (d, J=8.1 Hz, 2H), 5.28 (d, J=4.4 Hz, 1H), 4.76 (br. s., 1H), 4.69 (br. s., 1H), 4.31 (br. s., 1H), 3.96 (br. s., 1H), 3.90 (s, 3H), 3.66 (br. s., 1H), 3.40-3.10 (m, 5H), 3.09-2.89 (m, 2H), 2.81 (br. s., 1H), 2.23-2.06 (m, 4H), 2.05-1.91 (m, 3H), 1.85 (br. s., 1H), 1.78-1.73 (m, 1H), 1.69 (br. s., 3H), 1.65 (br. s., 1H), 1.62-1.30 (m, 11H), 1.26-1.17 (m, 2H), 1.11 (br. s., 3H), 1.05 (br. s., 3H), 0.99 (br. s., 3H), 0.93 (br. s., 6H). 13C NMR (101 MHz, CHLOROFORM-d) 167.2, 148.5, 147.1, 146.2, 130.0, 128.5, 127.9, 123.8, 114.8, 111.6, 77.24-77.18, 71.3, 65.8, 60.9, 57.7, 54.4, 52.7, 52.0, 49.2, 48.7, 48.62-48.49, 46.3, 45.0, 42.0, 41.6, 40.6, 37.4, 37.0, 36.2, 33.6, 32.5, 29.4, 28.0, 27.3, 25.8, 25.0, 20.9, 20.8, 19.5, 19.1, 16.3, 15.9, 15.2, 14.4.
