Structure and absolute configuration of a high affinity 5-HT3 receptor antagonist, (5aS,9aS)-N-[(3S)-1-azabicyclo[2.2.2]octan-3-yl]-2-chloro- 5a,6,7,8,9,9a-hexahydro-4-dibenzofurancarboxamide hydrochloride

• Published in: Acta crystallographica. Section C, Crystal structure communications Vol. 49 ( Pt 8); p. 1551
• Main Authors: Ammon, H L, Youssefyeh, R D, Airey, J E, Studt, W L, Campbell, H F, Powers, M R, Golec, F A
• Format: Journal Article
• Language: English
• Published: United States 15-08-1993
• Subjects: Amides - chemistry; Bridged Bicyclo Compounds - chemistry; Bridged Bicyclo Compounds, Heterocyclic; Molecular Conformation; Serotonin Antagonists - chemistry; Stereoisomerism
• ISSN: 0108-2701
• DOI: 10.1107/S0108270193000824

The absolute configuration was established as (S,S,S) by the R-factor test and by careful measurement of 197 enantiomorph-sensitive Friedel pairs of reflections. The determination also confirms the absolute stereochemistry of (-)-3-aminoquinuclidine, a compound used in the preparation of the title material. The cyclohexane/tetrahydrofuran ring fusion is cis. The quinuclidine moiety has almost perfect threefold symmetry; the front and rear halves are twisted about this axis by 15 degrees. Quinuclidine-N--H ... Cl- and amide-N--H ... Cl- hydrogen bonds link screw-dyad-related molecules along the b axis.