Water → (S)-2-tert-Butoxycarbonylamino-3-methylbutyric acid (RS)-1-[4-((8S,11R,-13S,14S,17S)-17-hydroxy-13-methyl-3-oxo-17-pentafluoroethyl-2,3,6,7,8,11,12,13,14,15,-16,17-dodecahydro-1H-cyclopenta[a]phenanthren-11-yl)phenyl]ethyl ester

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Reaction Conditions

Reaction Steps

The solution of 300 mg (0.59 mmol) of (8S,11R,13S,14S,17S)-17-hydroxy-11-[4-((RS)-1-hydroxyethyl)phenyl]-1 3-methyl-17-pentafluoroethyl-1,2,6,7,8,11,12,13,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-3-one in 3 ml of pyridine was admixed with 14 mg of 4-dimethylaminopyridine, 383 mg of (S)-2-tert-butoxycarbonylamino-3-methylbutanoic acid and 130 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and the mixture was stirred at 23° C. for 16 hours. The mixture was poured into water and extracted repeatedly with dichloromethane, and the combined organic extracts were washed with water and saturated sodium chloride solution and dried over sodium sulphate. The residue obtained after filtration and solvent removal was purified by chromatography. 314 mg (75%) of the title compounds were isolated as a colourless foam.

Provenance & Evidence