1-TRIHYDROXY-1,4-PREGNADIENE-3,20-DIONE-21-ACETATE (9-FLUOROPREDNISOLONE-21-ACETATE)

The synthetic steroid 9 alpha-fluoro-11 beta,17 alpha,21 -trihydroxy-1 ,4-pregnadiene-3,20-dione-21-acetate (9-fluoroprednisolone-21-acetate) , formula Cu23H29O6F, is related to substances which are potent induce rs of hepatic microsomal enzymes and anti-inflammatory agents. The str ucture was determined at 294 K from counter-collected data by direct m ethods. Crystals are tetragonal, space group P4(1)2(1)2, a, b = 9.214( 2), c = 49.452(39) Angstrom, V = 4198(4) Angstrom, D-x = 1.33 mu g/m(3 ) for Z = 8; R (on F) 0.063 for 915 independent intensities (I > 2 sig ma(l)). The structure shows H-bonding and packing of the mean molecula r plane approximately perpendicular to the crystallographic 4-fold axi s.