Acta Crystallographica Section B

Structural Science

Volume 55, Part 5 (October 1999)

research papers

Acta Cryst. (1999). B55, 793-798 [ doi:10.1107/S0108768199005273 ]

Molecular structures and conformations of three 3-azabicyclononanes

D. Kumaran, M. N. Ponnuswamy, G. Shanmugam, S. Ponnuswamy, R. Jeyaraman, K. Shivakumar and H. K. Fun

Abstract: The structure, conformation, molecular geometry and the mode of packing of 7-tert-butyl-N-methyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonane (C₂₅H₃₃N; MTABN), N-acetyl-2,4-diphenyl-3-azabicyclo[3.3.1]nonane (C₂₂H₂₅NO; AABN) and N-methyl-2,4-bis(2-methylphenyl)-3-azabicyclo[3.3.1]nonan-9-ol (C₂₃H₂₉NO; MHABN) are presented. The compounds MTABN and MHABN crystallize in monoclinic space groups, whereas AABN is orthorhombic. In each of the three structures, the bicyclic ring system adopts a chair-chair conformation and the phenyl rings are in equatorial orientation with respect to the piperidine ring. In AABN, apart from the van der Waals forces, weak intermolecular C-HO type interactions are involved in the packing.