Phosphoric Acid → ethyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(aziridin-1-yl)-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)cyclohex-3-enecarboxylate

Participants

Reaction Conditions

Reaction Steps

To a sealable vial was added ethyl 4-((1R,3 aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-amino-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)cyclohex-3-enecarboxylate (0.2 g, 0.356 mmol), 1-bromo-2-chloroethane (0.295 mL, 3.56 mmol) and phosphoric acid, potassium salt (0.378 g, 1.780 mmol). The mixture was diluted with acetonitrile (5 mL), was flushed with nitrogen, then sealed and heated to 120° C. After 24 h of heating, the mixture was cooled to rt. The reaction mixture was filtered to remove solids, then the solids were washed with dichloromethane and the filtrate was concentrated under reduced pressure to give the title compound (0.21 g, 0.357 mmol, 100% yield) as an off-white solid. LCMS: m/e 588.7 (M+H)+, 2.21 min (method 5).

Provenance & Evidence