4-Meth­oxy-N-(4-nitro­benz­yl)aniline

Kamini Kapoor; Vivek K Gupta; Indresh Kumar; Nisar A Mir; Rajni Kant

doi:10.1107/S160053681200846X

. 2012 Mar 7;68(Pt 4):o988. doi: 10.1107/S160053681200846X

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

Kamini Kapoor ^a, Vivek K Gupta ^a, Indresh Kumar ^b, Nisar A Mir ^b, Rajni Kant ^a,^*

PMCID: PMC3343958 PMID: 22590039

Abstract

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.

Related literature

For related structures, see: Iwasaki et al. (1988 ▶). For the biological properties of aldimines, see: Rjosk & Neumann (1971 ▶); Hillesheim et al. (1995 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

C₁₄H₁₄N₂O₃
M _r = 258.27
Monoclinic,
a = 7.4993 (3) Å
b = 17.1516 (7) Å
c = 10.0048 (5) Å
β = 96.861 (4)°
V = 1277.65 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 293 K
0.3 × 0.2 × 0.1 mm

Data collection

Oxford Diffraction Xcalibur Sapphire3 diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2010 ▶) T _min = 0.955, T _max = 1.000
11435 measured reflections
2511 independent reflections
1692 reflections with I > 2σ(I)
R _int = 0.035

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.130
S = 1.05
2511 reflections
178 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.18 e Å⁻³
Δρ_min = −0.15 e Å⁻³

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 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S160053681200846X/bh2415sup1.cif

e-68-0o988-sup1.cif^{(20.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681200846X/bh2415Isup2.hkl

e-68-0o988-Isup2.hkl^{(120.8KB, hkl)}

Supplementary material file. DOI: 10.1107/S160053681200846X/bh2415Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

Cg1 and Cg2 are the centroids of the nitrophenyl (C1–C6) and methoxyphenyl (C9–C14) rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N8—H8⋯O1ⁱ	0.89 (2)	2.42 (3)	3.231 (2)	152.8 (19)
C16—H16B⋯O2ⁱⁱ	0.96	2.47	3.372 (3)	155
C3—H3⋯Cg2ⁱⁱⁱ	0.93	2.77	3.560 (2)	143
C6—H6⋯Cg2^iv	0.93	2.87	3.524 (2)	129
C16—H16A⋯Cg1^v	0.96	2.96	3.830 (2)	151

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) .

Acknowledgments

RK acknowledges the Department of Science & Technology for the single-crystal X-ray diffractometer sanctioned as a National Facility under project No. SR/S2/CMP-47/2003. He is also thankful to the University of Jammu (India) for financial support.

supplementary crystallographic information

Comment

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 NaBH₄ 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)°. Hydrogen H8 on atom N8 forms an intermolecular hydrogen bond with the nitro O atom O1 of a neighbouring centrosymmetrically related molecule. This interaction links the molecules into N—H···O hydrogen bonded dimers. Dimers are connected via C—H···O hydrogen bonds and form chains along the c-axis of the unit cell (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 NaBH₄ (0.09 g, 2.5 mmol), at the same temperature. The combined reaction mixture was stirred additionally for 2 h and quenched with sat. NaHCO₃ solution, extracted with EtOAc (2×15 ml), and concentrated under reduced pressure. The resulting crude amine compound was crystallized in hexane/EtOAc (2:1), to afford the title compound with 92% yield. ¹H-NMR: 3.68 (s, 3H), 4.38 (s, 2H), 6.40 (d, 2H), 6.72 (d, 2H), 7.65 (d, 2H), 8.10 (d, 2H).