2,4-Bis(3-methoxyphenyl)-3-azabicyclo[3.3.1]nonan-9-one

In the crystal structure, the title compound, C22H25NO3, exists in a twin-chair conformation with equatorial orientations of the meta-methoxyphenyl groups on both sides of the secondary amino group. The title compound is a positional isomer of 2,4-bis(2-methoxyphenyl)-3-azabicyclo[3.3.1]nonan-9-one and 2,4-bis(4-methoxyphenyl)-3-azabicyclo[3.3.1]nonan-9-one, which both also exhibit twin-chair conformations with equatorial dispositions of the anisyl rings on both sides of the secondary amino group. In the title compound, the meta-methoxyphenyl rings are orientated at an angle of 25.02 (3)° with respect to each other, whereas in the ortho and para isomers, the anisyl rings are orientated at dihedral angles of 33.86 (3) and 37.43 (4)°, respectively. The crystal packing is dominated by van der Waals interactions and by an intermolecular N—H⋯O hydrogen bond, whereas in the ortho isomer, an intermolecular N—H⋯π interaction (H⋯Cg = 2.75 Å) is found.

In the crystal structure, the title compound, C 22 H 25 NO 3 , exists in a twin-chair conformation with equatorial orientations of the meta-methoxyphenyl groups on both sides of the secondary amino group. The title compound is a positional isomer of 2,4-bis(2-methoxyphenyl)-3-azabicyclo[3.3.1]nonan-9-one and 2,4-bis(4-methoxyphenyl)-3-azabicyclo[3.3.1]nonan-9-one, which both also exhibit twin-chair conformations with equatorial dispositions of the anisyl rings on both sides of the secondary amino group. In the title compound, the meta-methoxyphenyl rings are orientated at an angle of 25.02 (3) with respect to each other, whereas in the ortho and para isomers, the anisyl rings are orientated at dihedral angles of 33.86 (3) and 37.43 (4) , respectively. The crystal packing is dominated by van der Waals interactions and by an intermolecular N-HÁ Á ÁO hydrogen bond, whereas in the ortho isomer, an intermolecular N-HÁ Á Á interaction (HÁ Á ÁCg = 2.75 Å ) is found.
alkaloids such as methyllycaconitine, elatine, nudicauline, delsoline, delcorine and so on, they act as potential nicotinic acetylcholine receptor antagonists (Hardick et al. 1996;Barker et al. 2005). However, the biological activity mainly depends on the stereochemistry of the molecule; hence, it is of immense help to establish the structures of the synthesized molecules.
The crystallographic analysis of the title compound shows that the piperidine ring adopts a near ideal chair conformation.
According to the crystallographic analysis, the cyclohexane ring slightly deviates from the ideal chair conformation.
Hence the title compound, C 22 H 25 NO 3 , exists in a chair-chair conformation with equatorial orientation of the meta-methoxyphenyl groups on both sides of the secondary amino group on the heterocycle. The title compound is a positional isomer of 2,4-bis(2-methoxyphenyl)-3-azabicyclo[3.3.1]nonan-9-one (Parthiban et al., 2009a) and 2,4-bis (4-methoxyphenyl)-3azabicyclo[3.3.1]nonan-9-one (Cox et al., 1985). Similar to the title compound the ortho as well as the para isomers also exhibit twin-chair conformations with equatorial disposition of the anisyl rings on both sides of the secondary amino group.
In the title compound, the meta-methoxyphenyl rings are orientated at an angle of 25.02 (3)° with respect to one another whereas in the ortho and para isomer, the phenyl rings are orientated at an angle of 33.86 (3)° and 37.43 (4)° respectively.
The crystal packing is dominated by shape recognition, by van der Waals interactions and is stabilized by an intermolecular N-H···O hydrogen bond (Table 1). In the ortho isomer, on the other hand, the crystal structure exhibits an intermolecular N-H···π interaction (N1-H1A···Cg1 = 2.75 Å).
The mixture was gently warmed on a hot plate with medium stirring and stirring was continued for about 15 h at a temperature of 303-308 K (30-35° C). After 12 h, the product formed was a spongy solid which was stirred for an additional 3 h until the reaction was complete as confirmed by the absence of aldehyde and cyclohexanone in the reaction mixture by TLC. After this, the crude compound was separated by filtration and washed with a 1:5 ethanol-ether mixture. X-ray diffraction quality crystals of 2,4-bis(3-methoxyphenyl)-3-azabicyclo[3.3.1]nonan-9-one were obtained by slow evaporation from ethanol.

Refinement
The nitrogen H atom was located in a difference Fourier map and refined isotropically. Other hydrogen atoms were fixed geometrically and allowed to ride on the parent carbon atoms with aromatic C-H = 0.93 Å, aliphatic C-H = 0.98 Å, methylene C-H = 0.97 Å and methyl C-H = 0.96 Å. The displacement parameters were set for phenyl, methylene and aliphatic H atoms at U iso (H) = 1.2U eq (C) and for methyl H atoms at U iso (H) = 1.5U eq (C) Figures   Fig. 1. Anistropic displacement representation of the molecule with atoms represented with 30% probability ellipsoids.   (17)