Di-tert-butyl dicarbonate → (3aR,5aR,5bR,7aR,9S,11aR,11bR,13aS)-3a-(3-(1-(5-chloropyrimidin-2-yl)cyclopropyl)-2-oxooxazolidin-5-yl)-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

Participants

Reaction Steps

To a solution of (3aR,5aR,5bR,7aR,9S,11aR,11bR,13aS)-3a-(2-((1-(5-chloropyrimidin-2-yl)cyclopropyl)amino)-1-hydroxyethyl)-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 (106) (400 mg, 0.588 mmol) in dichloromethane (15 ml) stirred at rt was added BOC2O (1.365 ml, 5.88 mmol). The reaction mixture was stirred at rt overnight then evaporated under reduced pressure and the residue was subjected to a silica gel chromatography with petroleum ether/EtOAc (6:1 to 3:1) to give (3aR,5aR,5bR,7aR,9S,11aR,11bR,13aS)-3a-(3-(1-(5-chloropyrimidin-2-yl)cyclopropyl)-2-oxooxazolidin-5-yl)-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 (107) (350 mg, 0.496 mmol, 84% yield) as a white solid.

Provenance & Evidence