Trifluoroacetic acid → 4-[(1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-[[2-dimethylaminoethyl-(4-hydroxy-4-oxo-butanoyl)amino]methyl]-1-isopropenyl-5a,5b,8,8,11a-pentamethyl-1,2,3,4,5,6,7,7a,11,11b,12,13,13a,13b-tetradecahydrocyclopenta[a]chrysen-9-yl]benzoic acid

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Reaction Steps

To a solution of 4-((((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-9-(4-(tert-butoxycarbonyl)phenyl)-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-3a-yl)methyl)(2-(dimethylamino)ethyl)amino)-4-oxobutanoic acid (47 mg, 0.061 mmol) in DCM (1 ml) was added TFA (0.25 ml, 3.24 mmol). The mixture was stirred at rt. After 1.75 h, The mixture was concentrated under reduced pressure, was diluted with dioxane and MeOH and was purified by prep HPLC to afford 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-((3-carboxy-N-(2-(dimethylamino)ethyl)propanamido)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)benzoic acid as a white solid (25 mg, 0.035 mmol, 57.4% yield. LCMS: m/e 715.4 (M+H)+, 2.16 min (method 6).

Provenance & Evidence