title: Relative configuration, absolute configuration and absolute structure of three isomeric 8-benzyl-2-[(4-bromophenyl)(hydroxy)methyl]-8-azabicyclo[3.2.1]octan-3-ones.
abstract: The title compounds, C21H22BrNO2, are isomeric 8-benzyl-2-[(4-bromophenyl)(hydroxy)methyl]-8-azabicyclo[3.2.1]octan-3-ones. Compound (I), the (±)-exo,syn-(1RS,2SR,5SR,9SR) isomer, crystallizes in the hexagonal space group R-3, while compounds (II) [the (+)-exo,anti-(1R,2S,5S,9R) isomer] and (III) [the (±)-exo,anti-(1RS,2SR,5SR,9RS) isomer] crystallize in the orthorhombic space groups P212121 and Pna21, respectively. The absolute configuration was determined for enantiomerically pure (II). For the noncentrosymmetric crystal of (III), its absolute structure was established. In the crystal structures of (I) and (II), an intramolecular hydrogen bond is formed between the hydroxy group and the heterocyclic N atom. In the crystal structure of racemic (III), hydrogen-bonded chains of molecules are formed via intermolecular O-H...O interactions. Additionally, face-to-edge π-π interactions are present in the crystal structures of (I) and (II). In all three structures, the piperidinone rings adopt chair conformations and the N-benzyl substituents occupy the equatorial positions.
authors: Institute of Chemistry, University of Bialystok, Hurtowa 1, 15-399 Bialystok, Poland. k.brzezinski@uwb.edu.pl
authors: Krzysztof
authors: K
authors: Brzezinski
authors: Ryszard
authors: R
authors: Lazny
authors: Aneta
authors: A
authors: Nodzewska
authors: Katarzyna
authors: K
authors: Sidorowicz
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D007536:Isomerism; D007659:Ketones / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure
chemical_list: D001372:Aza Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007659:Ketones