Diastereoisomers of a prednisolone derivative

The crystal and molecular structures of two synthetic corticosteroid diastereoisomers were determined by X-ray diffraction methods. (22R)-21-acetoxy-16,17-furfurylidenedioxy-11-hydroxy-pregna-1,4-diene-3,20-dione, C₂₈H₃₂O₈, crystallized in the orthorhombic system, space group P2₁2₁2₁,a=6.346(1),b=14.106(2),c=27.901(3) Å, andZ=4. (22S)-21-acetoxy-16, 17-furfurylidenedioxy-11-hydroxy-5 pregna-1,4-diene-3,20-dione ethanolate, C₂₈H₃₂O₈ ·C₂H₅OH, crystallized in the monoclinic system, space group C2,a=20.382(5),b=8.331(1),c=17.346(4)Å, =103.43(2)°, andZ=4. A change of configuration at the C(22) chirality center has influence on the remote parts of the molecules. The long-range effects appear in the ability to form intermolecular hydrogen bonds by different atoms and consequently in the solvation of the (S) diastereoisomer.