Crystal Research and Technology · 1994 · 16 citations · 3 references
Natural SciencesChemistryMedicinal ChemistryCrystal StructureSteroid BiochemistryStructural BiologyCrystal ChemistryCrystal SystemsCrystallographySteroid StructureStructure DeterminationX-ray CrystallographyCrystal Structure RefinementSteroid Conformational AnalysisSteroid CrystallographySteroid Ring ConformationUnit Cell ParametersX-ray Structure Determination
Abstract The crystal structure of 4‐Pregnen‐11α‐ol‐3,20‐dione has been determined by X‐ray structure analysis. The compound crystallizes in the orthorhombic space group P2 1 2 1 2 1 with cell parameters a = 8.4415(4), b = 10.6884(3), c = 20.1273(5) Å. The structure has been solved by direct methods and refined to R = 0.050. Ring A exists in half‐chair conformation. Rings B and C adopt a chair conformation, and ring D is a 13α‐envelope. The A/B ring junction is quasi ‐ trans , whilst ring systems B/C and C/D are trans fused about the bonds C(8)–C(9) and C(13)–C(14). Molecules are held together by hydrogen bonds.
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Conformation of non-aromatic ring Compounds—XXV
C. Altona, H. J. Geise, C. Romers · Tetrahedron · 1968 · 379 citations