Citric Acid → Methyl (5Z)-(9R,11R,13RS,14RS,15S)-9-chloro-11,15-dihydroxy-16,16-dimethyl-13,14-epoxy-5-prostenoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

4.7 mL of titanium(IV) isopropoxide are added dropwise to a solution of 6.52 g of methyl (5Z,13E)-(9R,11R,15R)-9-chloro-11,15-dihydroxy-16,16-dimethyl-5,13-prostadienoate in 33 mL of methylene chloride at −20° C. under nitrogen, and the mixture is stirred at −20° C. for 30 min. Six mL of tert-butyl hydroperoxide are then added to the reaction mixture. A solution of 10 g of iron sulphate and 20 g of citric acid in 100 mL of water is subsequently added, and the mixture is extracted 3× with methylene chloride. The combined organic phases are washed 1× with saturated sodium chloride solution, dried over sodium sulphate and concentrated in vacuo. Chromatography on silica gel with methylene chloride/ethyl acetate (0-40%) results in 3.55 g of the epoxide as a colourless oil.

Herkunft & Nachweise