反应详情

To a solution of tert-butyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-formyl-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 (0.1 g, 0.167 mmol) in DCE (2 ml) was added acetic acid (1M in DCM) (0.167 ml, 0.167 mmol) and 2-(2-pyridyl)ethylamine (0.024 ml, 0.200 mmol). The mixture was stirred for 15 minutes at rt and sodium triacetoxyborohydride (0.071 g, 0.334 mmol) was added. The mixture was stirred at rt for 1.5 h then an additional 0.1 g of sodium triacetoxyborohydride was added to the mixture and it was stirred for 23 h. To the mixture was added additional acetic acid (1M in DCM) (0.167 ml, 0.167 mmol), 2-(2-pyridyl)ethylamine (0.024 ml, 0.200 mmol), and sodium triacetoxyborohydride (0.071 g, 0.334 mmol). The mixture was stirred at rt for an additional 19 h, was diluted with 7 ml of sat. NaHCO3 and was extracted with dichloromethane (3×7 ml). The combined organic layers were dried with Na2SO4, the drying agent was removed by filtration and the filtrate was concentrated under reduced pressure. The mixture was purified by flash chromatography using a 0-10% MeOH in dichloromethane gradient. The fractions containing the expected product were combined and concentrated under reduced pressure to afford the title compound. LCMS: m/e 705.4 (M+H)+, 2.90 min (method 6).

1. stirringThe mixture was stirred at rt for 1.5 h
2. stirringwas stirred for 23 h
3. stirringThe mixture was stirred at rt for an additional 19 h
4. extractionwas extracted with dichloromethane (3×7 ml)
5. dry with materialThe combined organic layers were dried with Na2SO4
6. customthe drying agent was removed by filtration
7. concentrationthe filtrate was concentrated under reduced pressure
8. customThe mixture was purified by flash chromatography
9. additionThe fractions containing the expected product
10. concentrationconcentrated under reduced pressure