N,N-Dimethylethylenediamine → methyl 4-((1S,3aS,5aR,5bR,7aS,9S,11aS,11bR,13aR,13bR)-3a-(2-(dimethylamino)ethylcarbamoyl)-1-isopropyl-5a,5b,8,8,11a-pentamethylicosahydro-1H-cyclopenta[a]chrysen-9-yl)benzoate

Participants

Reaction Steps

To a flask containing methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(chlorocarbonyl)-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 (77 mg, 0.13 mmol) in DCE (2 mL) was added Hunig's base (0.068 mL, 0.390 mmol), DMAP (1 mg, 8.19 mmol), and N,N-dimethylethylenediamine (0.029 mL, 0.260 mmol). The mixture was stirred for two hours at rt. The reaction was quenched with 5 mL of water and was extracted with dichloromethane (3×5 mL). The combined organic layers were dried with Na2SO4. The drying agent was removed by filtration and the filtrate was concentrated under reduced pressure and was purified by Biotage flash chromatography using a 0-10% MeOH in dichloromethane gradient. The fractions containing the expected product were combined and concentrated under reduced pressure to give methyl 4-((1S,3aS,5aR,5bR,7aS,9S,11aS,11bR,13aR,13bR)-3a-(2-(dimethylamino)ethylcarbamoyl)-1-isopropyl-5a,5b,8,8,11a-pentamethylicosahydro-1H-cyclopenta[a]chrysen-9-yl)benzoate as a white foam (37 mg, 44% yield). LCMS: m/e 647.7 (M+H)+, 3.09 min (method 3).

Provenance & Evidence