Aristocort,Lederle,US,1959
To a solution of 16α,21-diacetoxy-11β,17α-dihydroxy-9α-fluoro-4-pregnene-
3,20-dione (1.0 g) in tertiary-butanol (160 ml) and glacial acetic acid (1.6 ml)
was added 600 mg of selenium dioxide, the mixture swept with nitrogen and
kept at 70°C for 24 hours, selenium dioxide (350 mg) added, and the mixture
swept with nitrogen and allowed to stand for another 24 hours. The reaction
mixture was filtered, and the filtrate was evaporated to dryness under reduced
pressure. The material so obtained was dissolved in ethyl acetate, washed
with saturated sodium bicarbonate, water, cold freshly prepared ammonium
sulfide solution, cold dilute ammonia water, cold dilute hydrochloric acid, and
finally with water. After treatment with anhydrous sodium sulfate and
activated charcoal, filtration through diatomaceous earth and evaporation to
dryness under reduced pressure, 850 mg of a tan glass was obtained. Paper
strip chromatographic analysis showed predominantly product plus a small
amount of starting material. The 850 mg was chromatographed on 320 g of
diatomaceous earth containing 160 ml of stationary phase of a solvent system
composed of 3,4,3,2-ethyl acetate-petroleum ether (boiling point 90°C to
100°C), methanol, and water, respectively. The column dimensions were 3.8
cm x 78 cm with 460 ml hold back volume. The fifth and sixth hold back
volumes were combined and evaporated under reduced pressure to 250 mg of
product which, after a single crystallization from acetone petroleum ether,
gave 173 mg, melting point 150°C to 190°C. Paper strip chromatography
showed a single spot having the same polarity as an authentic sample of
16α,21-diacetoxy-11β,17α-dihydroxy-9α-fluoro-1,4-pregnadiene-3,20-dione. A
further crystallization from the same solvent pair gave 134 mg, melting point
185°C to 189°C, bubbles to 230°C.
