Corphos,Tilden Yates,US,1959
21-iodo-11β:17α-dihydroxypregn-4-ene-3,20-dione (5.0 g) in pure acetonitrile
(125 ml) was mixed with a solution of 90% phosphoric acid (2.5 ml) and
triethylamine (7.5 ml) in acetonitrile (125 ml) and boiled under reflux for 4
hours. The solvent was removed in vacuo and the residue, dissolved in
ethanol (20 ml) and water (80 ml), was passed down a column of Zeo-Karb
225 (H+form) (60 g) made up in 20% alcohol. Elution was continued with
20% alcohol (50 ml), 50% alcohol (50 ml) and alcohol (150 ml). The eluate
was at first cloudy, but by the end of the elution it was clear and nonacid.
The eluate was titrated to pH 7 with 0.972N NaOH (63 ml). Removal of
solvent left a gum, which was boiled with methanol (400 ml) for 20 minutes.
The solid insoluble inorganic phosphate was filtered off and washed with
methanol (200 ml). The slightly cloudy filtrate was filtered again, and
evaporated to dryness in vacuo. The residual gum dissolved readily in water
(40 ml) and on addition of acetone (600 ml) to the solution a mixture of
sodium salts of hydrocortisone 21-phosphate separated as a white solid. This
was collected after 2 days, washed with acetone and dried at 100°C/0.l mm/2
hr to constant weight. Yield 4.45 g.
