Tetrahydrofuran → ethyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((2-(2-oxa-5-azabicyclo[2.2.1]heptan-5-yl)ethyl)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

Participants

Reaction Conditions

Reaction Steps

To a vial containing a suspension of 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 (0.05 g, 0.085 mmol) in THF (1 mL) was added N,N-diisopropylethylamine (0.089 mL, 0.510 mmol) followed by 2-oxa-5-azabicyclo[2.2.1]heptane, HCl (0.035 g, 0.255 mmol). The vial was sealed and the mixture was heated to 100° C. After 16 h of heating, the mixture was cooled to rt, was diluted with methanol and 1,4-dioxane and was purified by prep HPLC (method 8). The fractions containing the expected product were concentrated under reduced pressure to give ethyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((2-(2-oxa-5-azabicyclo[2.2.1]heptan-5-yl)ethyl)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 (0.0152 g, 0.022 mmol, 26.0% yield) as an off-white foam. LCMS: m/e 687.7 (M+H)+, 1.96 min (method 5).

Provenance & Evidence