Betapar,Parke Davis,US,1970
16β-Methylprednisone 21-acetate (0.5 g), when hydrolyzed by means of aqueous alcoholic potassium bicarbonate yields 16β-ethylprednisone. An alternative method of the preparation of the compound of this example is as follows. Bacillus sphaericus var. fusifermis (A.T.C.C. 7055) is incubated on a nutrient agar (composed of Bacto-beef extract, 3 g; Bacto-peptone, 5 9; sodium chloride, 8 9; agar, 15 g; and tap water, 1 liter) for 24 hours at 28°C.
To 100 ml of a sterile nutrient broth (composed of Bacto-beef extract, 3 9; Bacto-peptone, 5 9; per liter of tap water) in a 300 ml flask is added one loopful of the incubated culture and the broth mixture is further incubated for 24 hours at 28°C on a shaking machine. The broth culture so obtained is employed as an inoculum (1%). Into each of ten flasks containing 100 ml of sterile nutrient broth is added 1 ml of the inoculum. The flasks are agitated on a rotary shaker for 8 hours at 28°C at 240 strokes per minute. After this growth period, a solution of 25 mg of 16β-methylcortisonein 0.5 ml of methanol is aseptically added to each flask which in turn is reshaken and incubated for an additional 24 hours. The final pH is 7.8.
The contents of the flasks are then combined and extracted 3 times with two liters of chloroform per extraction. The combined chloroform extracts are evaporated to dryness yielding 310 mg of crude product. The crude steroid is purified by chromatography on a chromatographic system described by G.M. Shull, Abstracts of Papers of the 126th Meeting of the American Chemical Society, December 12-17, 1954, page 9a, paper No. 24. Chromatographic evaluation shows a quantitative conversion of the starting material to the diene when an authentic sample of the 16β-methylprednisone is used as a
control. Alternatively, the crude product is recrystallized from acetone
affording 225 mg of 16β-methylprednisone.
