Manufacturing Process
The preparation of dexamethasone acetate is described in US Patent
3,007,923 as follows. 1.5 cc of dimethylformamide and 1.5 cc of anhydrous
hydrofluoric acid are admixed and treated with 480 mg of 9β,11β-epoxy-17αhydroxy-21-acetoxy-16α-methyl-?1,4-pregnadiene-3,20-dione (prepared
according to E.P. Oliveto et al, J. Am. Chem. Soc., 80, 44331, 1958). The
steroid dissolves in about 15 minutes. The reaction mixture is shaken for two
hours at a temperature between 0 and +5°C, and then poured into 75 cc of
water containing in suspension, 7.5 grams of sodium bicarbonate. The mixture
is vacuum filtered, the filter cake washed and then dried at 100°C, yielding
460 mg of crude hexadecadrol contaminated with a small amount of the
starting material. A single recrystallization from methylene chloride yields 370
mg of the pure product having a melting point of 170°C and 229°C. The
mother liquor yields 62 mg of the starting material, and a remainder
constituting a mixture of starting and final materials with little other
contamination.
Therapeutic Function
9-Fluoro-11β,17-dihydroxy-21-acetoxy-16α-methylpregna1,4-diene-3,20-dione
Purification Methods
Dexamethasone 21-acetate is purified on neutral Al2O3 using CHCl3 as eluent, the fractions are evaporated, and the residue is recrystallised from CHCl3. It has max at 239nm. [Oliveto et al. J Am Chem Soc 8 0 4431 1958]. [Beilstein 8 IV 3501.]
