DIASTEREOISOMERS OF A PREDNISOLONE DERIVATIVE

The crystal and molecular structures of two synthetic corticosteroid d iastereoisomers were determined by X-ray diffraction methods. (22R)-21 -acetoxy-16 alpha,17 alpha-furfurylidenedioxy-11 beta-hydroxy-pregna-1 ,4-diene-3,20-dione, C28H32O8, crystallized in the orthorhombic syste m, space group P2(1)2(1)2(1), a = 6.346(1), b = 14.106(2), c = 27.901( 3) Angstrom, and Z = 4. (22S)-21-acetoxy-16 alpha, 17 alpha-furfurylid enedioxy-11 beta-hydroxy-5pregna-1,4-diene-3,20-dione ethanolate, C28H 32O8 . C2H5OH, crystallized in the monoclinic system, space group C2, a = 20.382(5), b = 8.331(1), 17.346(4) Angstrom, beta = 103.43(2)degre es, and Z = 4. A change of configuration at the C(22) chirality center has influence on the remote parts of the molecules. The long-range ef fects appear in the ability to form intermolecular hydrogen bonds by d ifferent atoms and consequently in the solvation of the (S) diastereoi somer.