反应详情

温度

0 °C

To a suspension of ethyl 2-(diethoxyphosphoryl)propanoate (3.12 g, 13.09 mmol) in DMF (35 mL) stirred under nitrogen at 0° C. was added NaH (0.60 g, 80 wt %, 20 mmol) during 5 min and stirred for 10 mins. The solution was warmed to rt and stirred for 30 mins before (3aR,5aR,5bR,7aR,9S,11aR,11bR,13aS)-3a-formyl-1-isopropyl-5a,5b,8,8,11a-pentamethyl-2-oxo-3,3a,4,5,5a,5b,6,7,7a,8,9,10,11,11a,11b,12,13,13a-octadecahydro-2H-cyclopenta[a]chrysen-9-yl acetate (5.0 g, 10 mmol) was added to above mixture. After overnight, the reaction was quenched with water and washed with saturated NaHCO3 and water. The solid was solved into EtOAc, dried over Na2SO4, filtered and concentrated to remove the majority of solvent. The residue was recrystallized from petroleum ether/EtOAc (8:1), filtered and the filtrate was concentrated to give the residue, which was purified by silica gel eluting with petroleum ether/EtOAc (15:1-10:1) to obtain the product (E)-ethyl 3-((3aS,5aR,5bR,7aR,9S,11aR,11bR,13aS)-9-acetoxy-1-isopropyl-5a,5b,8,8,11a-pentamethyl-2-oxo-3,3a,4,5,5a,5b,6,7,7a,8,9,10,11,11a,11b,12,13,13a-octadecahydro-2H-cyclopenta[a]chrysen-3a-yl)-2-methylacrylate (1.0 g, 1.291 mmol, 12.82%) as a yellow solid.

1. stirringstirred for 10 mins
2. temperatureThe solution was warmed to rt
3. additionwas added to above mixture
4. customthe reaction was quenched with water
5. washwashed with saturated NaHCO3 and water
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated
9. customto remove the majority of solvent
10. customThe residue was recrystallized from petroleum ether/EtOAc (8:1)
11. filtrationfiltered
12. concentrationthe filtrate was concentrated
13. customto give the residue, which
14. customwas purified by silica gel eluting with petroleum ether/EtOAc (15:1-10:1)