Methyl 2-amino-3,4,5,6-tetra­fluoro­benzoate

Wei Guo; Xiao-Jian Liao; Guo-Qiang Li; Shi-Hai Xu

doi:10.1107/S1600536811015182

. 2011 May 25;67(Pt 6):o1511. doi: 10.1107/S1600536811015182

Methyl 2-amino-3,4,5,6-tetrafluorobenzoate

Wei Guo ^a, Xiao-Jian Liao ^a, Guo-Qiang Li ^a, Shi-Hai Xu ^a,^*

PMCID: PMC3120311 PMID: 21754876

Abstract

In the title compound, C₈H₅F₄NO₂, synthesized by esterification of 2,3,4,5-tetrafluoroanthranilic acid with methanol, an intramolecular amine N—H⋯O_carbonyl hydrogen bond is present, while intermolecular N—H⋯O hydrogen bonds produce chains in the crystal, which extend along the b-axis direction.

Related literature

For general background to this compound and its synthesis, see: Cai et al. (1992 ▶); Liao et al. (2007 ▶); Xu et al. (2008 ▶); Li et al. (1999 ▶).

Experimental

Crystal data

C₈H₅F₄NO₂
M _r = 223.0
Monoclinic,
a = 4.5246 (2) Å
b = 9.6484 (4) Å
c = 19.3133 (9) Å
β = 91.324 (4)°
V = 842.90 (6) Å³
Z = 4
Cu Kα radiation
μ = 1.66 mm⁻¹
T = 295 K
0.62 × 0.22 × 0.17 mm

Data collection

Oxford Diffraction Xcalibur Sapphire3 Gemini Ultra CCD diffractometer
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010 ▶) T _min = 0.622, T _max = 1.000
2513 measured reflections
1332 independent reflections
1185 reflections with I > 2σ(I)
R _int = 0.018

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.140
S = 1.03
1332 reflections
145 parameters
4 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.17 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: OLEX2 (Dolomanov et al., 2009 ▶); software used to prepare material for publication: OLEX2.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811015182/zs2108sup1.cif

e-67-o1511-sup1.cif^{(15.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811015182/zs2108Isup2.hkl

e-67-o1511-Isup2.hkl^{(64.4KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811015182/zs2108Isup3.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
N12—H12A⋯O3ⁱ	0.85 (3)	2.19 (3)	3.028 (2)	171 (3)
N12—H12B⋯O3	0.88 (3)	2.00 (3)	2.662 (2)	131 (2)

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Symmetry code: (i) Inline graphic .

Acknowledgments

This work was supported by grants from the National High Technology Development Project (863 Project; Nos. 2006 A A09Z408 GDSFC 06025194, 2005 A30503001, and 2006Z3E4041) and the National Natural Science Fund (No. 20772048).

supplementary crystallographic information

Comment

The title compound C₈H₅F₄NO₂ (I) (Fig. 1) was prepared by the esterification of 2,3,4,5-tetrafluoroanthranilic acid with methanol (Cai et al., 1992), and is an intermediate product in the synthesis of a coupling reagent (Li et al., 1999; Liao et al., 2007; Xu et al., 2008). In (I), the bond lengths and angles are unexceptional. In the molecule, an intramolecular amine N—H···O_carbonyl hydrogen bond is present while intermolecular N—H···O hydrogen bonds give one-dimensional chain structures which extend along the b cell direction.

Experimental

2,3,4,5-Tetrafluoroanthranilic acid (10 mmol) in 50 ml of methanol was cooled in an ice-water bath and 5 ml SOCl₂ was added dropwise. After 15 min, the mixture was removed and allowed to stand at room temperature for 30 min, and then was refluxed for 8 h. The cooled mixture was washed with 5% Na₂C03 (1 x 10 ml) and water (2 x 10 ml) and then dried and evaporated to leave 1.71 g (76%) of the title compound as colorless crystals. Crystals suitable for X-ray analysis grew over a period of a week when a solution in methanol was allowed to evaporate in air at room temperature.