Reaction Steps
The title compound was prepared in 14% yield from methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-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 following the same procedure as described for the preparation of 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(3-(dimethylamino)propanamido)-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)benzoic acid, except 2-pyrazine acetic acid was used instead of 3-(dimethylamino)propionic acid hydrochloride in Step 1. LCMS: m/e 650.6 (M+H)+, 2.12 min (method 6). 1H NMR (500 MHz, 1:1 CDCl3:MeOD) δ=8.68-8.50 (m, 3H), 7.92 (d, J=8.2 Hz, 2H), 7.20 (d, J=8.2 Hz, 3H), 5.29 (dd, J=1.7, 6.0 Hz, 1H), 4.76 (s, 1H), 3.79 (q, J=14.3 Hz, 2H), 2.66-2.53 (m, 2H), 2.42-2.31 (m, 1H), 2.12 (dd, J=6.4, 17.1 Hz, 1H), 1.91-1.74 (m, 3H), 1.72 (br. s., 1H), 1.71 (s, 2H), 1.67 (d, J=11.9 Hz, 2H), 1.57-1.18 (m, 13H), 1.17-1.02 (m, 3H), 1.00 (br. s., 3H), 1.00 (br. s., 3H), 0.94 (s, 3H), 0.92 (br. s., 3H), 0.92 (br. s., 3H).
