Diisopropylethylamine → tert-butyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((tert-butoxycarbonyl(2-hydroxyethyl)amino)methyl)-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)benzoate

Participants

Reaction Conditions

Reaction Steps

tert-butyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((2-hydroxyethylamino)methyl)-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)benzoate (600 mg, 0.932 mmol) was dissolved in CH2Cl2 (10 mL), BOC2O (0.260 mL, 1.118 mmol) was added followed by Hunig's Base (0.163 mL, 0.932 mmol) to form a colorless solution that was stirred at 0° C. for 6 hrs. LCMS indicated formation of desired product (M+23=767). The solvent was removed in vacuo and the resultant white solid was used as is in the next step.

Provenance & Evidence