反応手順
To a mixture of propane-2-sulfonamide (18.46 mg, 0.150 mmol), DMAP (0.915 mg, 7.49 μmol) and Hunig's Base (0.065 mL, 0.375 mmol) in DME (2 mL) was added (1R,3aS,5aR,5bR,7aR,11aS,13aR,13bR)-benzyl 9-(4-(chlorocarbonyl)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]chrysene-3a-carboxylate (50 mg, 0.075 mmol). The reaction mixture was stirred for 16 hours. LCMS indicated the formation of the desired product. The reaction mixture was quenched with distilled water, extracted with ethyl acetate and concentrated under reduced pressure to give crude intermediate (1R,3aS,5aR,5bR,7aR,11aS,13aR,13bR)-benzyl 9-(4-(isopropylsulfonylcarbamoyl)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]chrysene-3a-carboxylate as a yellow solid. LCMS: m/e 754.60 (M+H)+, 2.36 min (method 7). To this intermediate (50 mg, 0.066 mmol) in EtOAc (2 mL) and MeOH (2.00 mL) was added 10% Pd/C (21.17 mg, 0.020 mmol). The reaction mixture was hydrogentated using a Parr shaker at 40 Psi for 17 hours. LCMS indicated the reaction was completed. The reaction mixture was filtered through a pad of celite and concentrated under reduced. The residue was purified by prep HPLC to provide the desired product, (1R,3aS,5aR,5bR,7aR,11aS,13aR,13bR)-9-(4-(isopropylsulfonylcarbamoyl)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]chrysene-3a-carboxylic acid, as a white solid (12 mg, 26%). LCMS: m/e 664.48 (M+H)+, 2.18 min (method 7). 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 0.91 (s, 6H), 0.96 (s, 3H), 1.00 (d, J=4.27 Hz, 6H), 1.18-1.27 (m, 8H), 1.35-1.55 (m, 13H), 1.60-1.75 (m, 5H), 1.94-2.03 (m, 2H), 2.07-2.14 (m, 1H), 2.22-2.31 (m, 2H), 2.97-3.07 (m, 1H), 3.98-4.08 (m, 1H), 4.61 (s, 1H), 4.74 (s, 1H), 5.28 (d, J=4.88 Hz, 1H), 7.23-7.25 (m, 2H), 7.74 (d, J=8.24 Hz, 2H).
