4-Methoxy-N-(4-nitrobenzyl)aniline

In the title compound, C14H14N2O3, the nitro group is nearly coplanar with the benzene ring to which it is bonded [dihedral angle = 1.70 (2)°], and this ring is para-substituted by the aminomethylene group. The dihedral angle between the benzene rings is 57.8 (1)°. The crystal structure is stabilized by N—H⋯O and C—H⋯O hydrogen bonds and weak C—H⋯π interactions are also observed.


D-HÁ
Data collection: CrysAlis PRO (Oxford Diffraction, 2010); cell refinement: CrysAlis PRO; data reduction: CrysAlis RED (Oxford Diffraction, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: PLATON (Spek, 2009  In continuation of our project on the preparation of various aldimines from p-anisidine and aromatic aldehydes in refluxing methanol, the title compound has been prepared using the reductive amination method. In undergoing further applications of aldimines in various cycloaddition reactions (Rjosk & Neumann, 1971;Hillesheim et al., 1995), we observed that aldimines undergo a reductive amination with NaBH 4 in presence of catalytic amounts of AcOH in MeOH, to afford 4-methoxy-N-(4-nitrobenzyl)aniline as one of the products. We further tried to prepare this compound under similar conditions in a separate flask, and the title compound was obtained in high yield (> 90%) through reductive amination of p-nitrobenzaldehyde with p-anisidine.
The bond lengths in the molecule are within normal ranges (Allen et al., 1987) and comparable with those found in related molecules (Iwasaki et al., 1988). The nitro group is nearly coplanar to the benzene ring to which it is bonded, the dihedral angle being 1.70 (2)°. The 4-methoxy phenyl group is trans to the 4-nitro phenyl group about the C7-N8 bond.
The torsion angle C1-C7-N8-C9 is 178.22 (17) (Table 1, Fig. 2). On the other hand, C-H···π interactions (Cg1 is the centroid of the nitro-phenyl ring and Cg2 is the centroid of the methoxy-phenyl ring, Table 1) play important role in stabilizing the crystal structure.

Experimental
To a stirred solution of p-nitro-benzaldehyde (0.5 g, 3.3 mmol) in MeOH (10 ml) was added p-anisidine (0.41 g, 3.3 mmol) at room temperature and the mixture was refluxed for 4 h. The resulting reaction mixture was cooled to 273 K, which resulted in the precipitation of the corresponding aldimine intermediate. Few drops of AcOH were added, followed by NaBH 4 (0.09 g, 2.5 mmol), at the same temperature. The combined reaction mixture was stirred additionally for 2 h and quenched with sat. NaHCO 3 solution, extracted with EtOAc (2×15 ml), and concentrated under reduced pressure.

Refinement
Hydrogen atom H8 was found in a difference map and refined isotropically. All other H atoms were positioned geometrically and were treated as riding on their parent C atoms, with C-H distances of 0.93-0.97 Å and with U iso (H) = 1.2U eq (C) or 1.5U eq (methyl C). 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: PLATON (Spek, 2009).