Diisopropylethylamine → ethyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-5a,5b,8,8,11a-pentamethyl-3a-((2-(4-(methylsulfonyl)piperidin-1-yl)ethyl)amino)-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 flask containing a suspension of the crude ethyl 4-((1R,3 aS,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 (0.055 g, 0.094 mmol) in 1,4-dioxane (2 mL) was added Hunig's base (0.098 mL, 0.561 mmol) followed by 4-(methylsulfonyl)piperidine (0.076 g, 0.468 mmol). The mixture was heated to 100° C. for 20.5 h then was cooled to rt and was purified by flash chromatography using a 20-80% ethyl acetate in hexanes gradient and a 12 g silica gel column. The fractions containing the expected product were combined and were concentrated under reduced pressure to give ethyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-5a,5b,8,8,11a-pentamethyl-3a-((2-(4-(methylsulfonyl)piperidin-1-yl)ethyl)amino)-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 (0.036 g, 0.048 mmol, 51.2% yield) as an off-white solid. LCMS: m/e 751.7 (M+H)+, 2.29 min (method 1).

Provenance & Evidence