N 6-(4-Fluoro­benz­yl)-3-nitro­pyridine-2,6-diamine

Ji-long Ge; Xiao-min Qian

doi:10.1107/S1600536811018642

. 2011 May 20;67(Pt 6):o1481. doi: 10.1107/S1600536811018642

N ⁶-(4-Fluorobenzyl)-3-nitropyridine-2,6-diamine

Ji-long Ge ^a,^*, Xiao-min Qian ^b

PMCID: PMC3120364 PMID: 21754850

Abstract

In the title compound, C₁₂H₁₁FN₄O₂, the pyridine ring is connected to a benzene ring by a –CH₂—NH₂- chain. The nitro group is twisted out of the pyridine ring plane [torsion angle O—N—C—C = 10.41 (10)°]. An intramolecular N—H⋯O hydrogen bond occurs. The fluorobenzene ring is disordered over two positions [occupancy ratio = 0.59 (3):0.41 (3)]. Intermolecular N—H⋯O and N—H⋯N hydrogen bonds stabilize the crystal structure.

Related literature

The title compound is an intermediate in the synthesis of analgesic drugs. For the analgesic properties of flupirtine (systematic name ethyl{2-amino-6-[(4-fluorobenzyl)amino]pyridin-3-yl}carbamate), see: Klawe & Maschke (2009 ▶). For synthetic procedures, see: Gerhard & Ilia (2010 ▶). For a related structure, see: Wang (2009 ▶).

Experimental

Crystal data

C₁₂H₁₁FN₄O₂
M _r = 262.25
Monoclinic,
a = 14.8187 (14) Å
b = 5.9972 (6) Å
c = 14.8840 (15) Å
β = 109.827 (1)°
V = 1244.3 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 298 K
0.38 × 0.15 × 0.11 mm

Data collection

Rigaku SCXmini CCD diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T _min = 0.960, T _max = 0.988
5923 measured reflections
2184 independent reflections
1169 reflections with I > 2σ(I)
R _int = 0.056

Refinement

R[F ² > 2σ(F ²)] = 0.052
wR(F ²) = 0.140
S = 1.03
2184 reflections
227 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: CrystalClear (Rigaku, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811018642/pv2411sup1.cif

e-67-o1481-sup1.cif^{(19.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811018642/pv2411Isup2.hkl

e-67-o1481-Isup2.hkl^{(107.4KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811018642/pv2411Isup3.cml

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3B⋯O1	0.86	2.03	2.651 (3)	129
N3—H3A⋯N1ⁱ	0.86	2.17	3.028 (3)	174
N2—H2⋯O1ⁱⁱ	0.86	2.35	3.060 (3)	141

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Symmetry codes: (i) Inline graphic ; (ii) .

supplementary crystallographic information

Comment

Flupirtine, ethyl{2-amino-6-[(4-fluorobenzyl)amino]pyridin-3-yl}carbamate, is of great importance owing to its analgesic properties (Klawe & Maschke, 2009). In this article, we report the crystal structure of the title compound which is one of the key intermediates in the synthsis of analgesia drugs (Gerhard & Ilia, 2010).

In the title molecule (Fig. 1), a pyridine ring is connected with a benzene ring by –CH₂—NH₂- chain and the nitro group is twisted out of the pyridine ring plane [torsion angle O1—N4—C4—C5 = 10.41 (10)°]. The crystal structure is stabilized by intermolecular N—H···O and N—H···N hydrogen bonds (Figure 2 and Table 1).

Experimental

To a solution of 2-amino-3-nitro-6-chloropyridine (7.8 g, 45 mmol) in 2-propanol (50 ml) were added 4-fluorobenzylamine (5.63 g, 45 mmol) and triethylamine (6.45 g,64 mmol) (Gerhard & Ilia, 2010). Then another 30 ml 2-propanol was add to the above solution. The mixture was heated to backflow and stirred for 3 h. Then 100 ml water was add to the mixture to obtain the title compound which was recrystallized from ethanol by slow evaporation (yield 10.2 g, 91%).