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

Guo, W.; Liao, X.-J.; Li, G.-Q.; Xu, S.-H.

doi:10.1107/S1600536811015182

organic compounds

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Volume 67| Part 6| June 2011| Page o1511

doi:10.1107/S1600536811015182

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

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

^aDepartment of Chemistry, Jinan University, Guangzhou 510632, People's Republic of China
^*Correspondence e-mail: txush@jnu.edu.cn

(Received 5 April 2011; accepted 22 April 2011; online 25 May 2011)

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, P 2₁ /n
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 $[Oxford Diffraction (2010). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.]$ ) 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[F² > 2σ(F²)] = 0.049
wR(F²) = 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

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)
Symmetry code: (i) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ .

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 $[Oxford Diffraction (2010). CrysAlis PRO. Oxford Diffraction Ltd, Yarnton, England.]$ ); 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.

Supporting information

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

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

Supporting information file. DOI: 10.1107/S1600536811015182/zs2108Isup3.cml

checkCIF report

Comment top

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.

Related literature top

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 top

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.

Computing details top

Data collection: CrysAlis PRO (Oxford Diffraction, 2010); cell refinement: CrysAlis PRO (Oxford Diffraction, 2010); data reduction: CrysAlis PRO (Oxford Diffraction, 2010); 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 (Dolomanov et al., 2009).

Figures top

Fig. 1. The molecular structure of the title compound showing the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

methyl 2-amino-3,4,5,6-tetrafluorobenzoate top

Crystal data top

C₈H₅F₄NO₂	F(000) = 448
M_r = 223.0	D_x = 1.758 Mg m⁻³
Monoclinic, P2₁/n	Cu Kα radiation, λ = 1.5418 Å
a = 4.5246 (2) Å	Cell parameters from 1857 reflections
b = 9.6484 (4) Å	θ = 4.6–63.3°
c = 19.3133 (9) Å	µ = 1.66 mm⁻¹
β = 91.324 (4)°	T = 295 K
V = 842.90 (6) Å³	Prism, colourless
Z = 4	0.62 × 0.22 × 0.17 mm

Data collection top

Oxford Diffraction Xcalibur Sapphire3 Gemini Ultra CCD diffractometer	1332 independent reflections
Radiation source: Enhance Ultra (Cu) X-ray Source	1185 reflections with I > 2σ(I)
Mirror monochromator	R_int = 0.018
Detector resolution: 16.0288 pixels mm^-1	θ_max = 63.4°, θ_min = 4.6°
ω scans	h = −5→4
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2010)	k = −10→10
T_min = 0.622, T_max = 1.000	l = −22→21
2513 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.049	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.140	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ²(F_o²) + (0.0959P)² + 0.1931P] where P = (F_o² + 2F_c²)/3
1332 reflections	(Δ/σ)_max = 0.001
145 parameters	Δρ_max = 0.17 e Å⁻³
4 restraints	Δρ_min = −0.20 e Å⁻³

Crystal data top

C₈H₅F₄NO₂	V = 842.90 (6) Å³
M_r = 223.0	Z = 4
Monoclinic, P2₁/n	Cu Kα radiation
a = 4.5246 (2) Å	µ = 1.66 mm⁻¹
b = 9.6484 (4) Å	T = 295 K
c = 19.3133 (9) Å	0.62 × 0.22 × 0.17 mm
β = 91.324 (4)°

Data collection top

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

Refinement top

R[F² > 2σ(F²)] = 0.049	4 restraints
wR(F²) = 0.140	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	Δρ_max = 0.17 e Å⁻³
1332 reflections	Δρ_min = −0.20 e Å⁻³
145 parameters

Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
F1	−0.0308 (3)	0.34475 (14)	0.54384 (7)	0.0577 (5)
F2	0.3821 (3)	−0.06985 (13)	0.70892 (7)	0.0608 (5)
F4	−0.2509 (3)	0.09206 (15)	0.52989 (7)	0.0614 (5)
F7	−0.0460 (3)	−0.11671 (14)	0.61192 (8)	0.0691 (6)
O3	0.6161 (4)	0.44489 (16)	0.68851 (8)	0.0594 (6)
O5	0.3628 (4)	0.50208 (16)	0.59299 (9)	0.0614 (6)
N12	0.6013 (4)	0.1837 (2)	0.73274 (10)	0.0507 (7)
C6	0.3985 (4)	0.1679 (2)	0.68073 (10)	0.0394 (6)
C8	0.3010 (4)	0.2775 (2)	0.63623 (9)	0.0380 (6)
C9	0.0669 (5)	0.0104 (2)	0.61966 (11)	0.0474 (7)
C10	0.4398 (4)	0.4146 (2)	0.64304 (10)	0.0408 (6)
C11	0.0806 (4)	0.2464 (2)	0.58597 (9)	0.0404 (6)
C13	0.2801 (5)	0.0359 (2)	0.66907 (10)	0.0434 (6)
C14	−0.0354 (5)	0.1169 (2)	0.57774 (11)	0.0458 (6)
C15	0.5115 (7)	0.6350 (3)	0.59424 (16)	0.0759 (10)
H12A	0.661 (7)	0.115 (3)	0.7566 (16)	0.075 (9)*
H12B	0.678 (6)	0.267 (3)	0.7397 (14)	0.070 (8)*
H15A	0.44700	0.68880	0.55490	0.1140*
H15B	0.72120	0.62090	0.59260	0.1140*
H15C	0.46470	0.68340	0.63600	0.1140*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
F1	0.0617 (8)	0.0530 (8)	0.0572 (8)	−0.0006 (6)	−0.0233 (6)	0.0059 (6)
F2	0.0727 (9)	0.0404 (7)	0.0690 (9)	0.0027 (6)	−0.0032 (7)	0.0116 (6)
F4	0.0540 (8)	0.0700 (9)	0.0594 (8)	−0.0116 (6)	−0.0146 (6)	−0.0162 (6)
F7	0.0748 (10)	0.0441 (8)	0.0882 (11)	−0.0209 (6)	−0.0010 (8)	−0.0080 (7)
O3	0.0744 (11)	0.0454 (9)	0.0571 (10)	−0.0116 (7)	−0.0273 (8)	0.0005 (7)
O5	0.0716 (11)	0.0408 (9)	0.0704 (10)	−0.0096 (7)	−0.0279 (8)	0.0127 (7)
N12	0.0606 (12)	0.0402 (11)	0.0505 (11)	0.0041 (9)	−0.0178 (9)	0.0033 (8)
C6	0.0413 (10)	0.0378 (10)	0.0392 (10)	0.0040 (8)	0.0008 (8)	−0.0016 (8)
C8	0.0397 (10)	0.0356 (10)	0.0385 (10)	0.0021 (8)	−0.0039 (8)	−0.0026 (8)
C9	0.0493 (12)	0.0379 (11)	0.0553 (12)	−0.0065 (9)	0.0079 (10)	−0.0071 (9)
C10	0.0433 (11)	0.0354 (10)	0.0433 (11)	0.0041 (8)	−0.0049 (8)	−0.0013 (8)
C11	0.0414 (10)	0.0402 (11)	0.0395 (10)	0.0040 (8)	−0.0039 (8)	−0.0015 (8)
C13	0.0487 (11)	0.0341 (10)	0.0476 (11)	0.0025 (8)	0.0036 (9)	0.0022 (8)
C14	0.0409 (10)	0.0520 (12)	0.0442 (11)	−0.0050 (9)	−0.0038 (8)	−0.0104 (9)
C15	0.095 (2)	0.0390 (13)	0.092 (2)	−0.0168 (13)	−0.0328 (16)	0.0158 (12)

Geometric parameters (Å, º) top

F1—C11	1.341 (2)	C6—C13	1.398 (3)
F2—C13	1.353 (2)	C6—C8	1.426 (3)
F4—C14	1.349 (3)	C8—C11	1.408 (3)
F7—C9	1.336 (2)	C8—C10	1.469 (3)
O3—C10	1.209 (3)	C9—C13	1.364 (3)
O5—C10	1.324 (3)	C9—C14	1.381 (3)
O5—C15	1.448 (3)	C11—C14	1.363 (3)
N12—C6	1.353 (3)	C15—H15A	0.9600
N12—H12A	0.85 (3)	C15—H15B	0.9600
N12—H12B	0.88 (3)	C15—H15C	0.9600

C10—O5—C15	115.98 (19)	F1—C11—C8	121.20 (17)
C6—N12—H12B	118.2 (18)	F1—C11—C14	116.08 (17)
H12A—N12—H12B	121 (3)	C8—C11—C14	122.72 (18)
C6—N12—H12A	121 (2)	C6—C13—C9	122.65 (18)
C8—C6—C13	117.80 (17)	F2—C13—C6	118.11 (18)
N12—C6—C8	123.97 (18)	F2—C13—C9	119.25 (17)
N12—C6—C13	118.22 (18)	F4—C14—C9	119.76 (18)
C6—C8—C10	119.22 (16)	F4—C14—C11	120.86 (18)
C6—C8—C11	117.50 (17)	C9—C14—C11	119.4 (2)
C10—C8—C11	123.25 (17)	O5—C15—H15A	109.00
C13—C9—C14	119.87 (19)	O5—C15—H15B	109.00
F7—C9—C13	120.44 (18)	O5—C15—H15C	109.00
F7—C9—C14	119.69 (19)	H15A—C15—H15B	109.00
O3—C10—C8	123.81 (18)	H15A—C15—H15C	109.00
O3—C10—O5	122.31 (18)	H15B—C15—H15C	110.00
O5—C10—C8	113.83 (16)

C15—O5—C10—O3	2.4 (3)	C6—C8—C11—C14	−1.4 (3)
C15—O5—C10—C8	−175.26 (19)	C10—C8—C11—F1	−4.7 (3)
N12—C6—C8—C10	4.4 (3)	C10—C8—C11—C14	176.41 (19)
N12—C6—C8—C11	−177.73 (18)	F7—C9—C13—F2	1.8 (3)
C13—C6—C8—C10	−174.65 (17)	F7—C9—C13—C6	−177.89 (19)
C13—C6—C8—C11	3.3 (3)	C14—C9—C13—F2	−178.81 (19)
N12—C6—C13—F2	−2.2 (3)	C14—C9—C13—C6	1.5 (3)
N12—C6—C13—C9	177.5 (2)	F7—C9—C14—F4	0.8 (3)
C8—C6—C13—F2	176.87 (17)	F7—C9—C14—C11	179.94 (19)
C8—C6—C13—C9	−3.4 (3)	C13—C9—C14—F4	−178.57 (19)
C6—C8—C10—O3	−6.8 (3)	C13—C9—C14—C11	0.6 (3)
C6—C8—C10—O5	170.78 (17)	F1—C11—C14—F4	−0.4 (3)
C11—C8—C10—O3	175.38 (19)	F1—C11—C14—C9	−179.53 (18)
C11—C8—C10—O5	−7.0 (3)	C8—C11—C14—F4	178.59 (18)
C6—C8—C11—F1	177.52 (16)	C8—C11—C14—C9	−0.6 (3)

Hydrogen-bond geometry (Å, º) top

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)
N12—H12A···F2	0.85 (3)	2.36 (3)	2.676 (2)	103 (2)

Symmetry code: (i) −x+3/2, y−1/2, −z+3/2.

Experimental details

Crystal data
Chemical formula	C₈H₅F₄NO₂
M_r	223.0
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	295
a, b, c (Å)	4.5246 (2), 9.6484 (4), 19.3133 (9)
β (°)	91.324 (4)
V (Å³)	842.90 (6)
Z	4
Radiation type	Cu Kα
µ (mm⁻¹)	1.66
Crystal size (mm)	0.62 × 0.22 × 0.17

Data collection
Diffractometer	Oxford Diffraction Xcalibur Sapphire3 Gemini Ultra CCD diffractometer
Absorption correction	Multi-scan (CrysAlis PRO; Oxford Diffraction, 2010)
T_min, T_max	0.622, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	2513, 1332, 1185
R_int	0.018
(sin θ/λ)_max (Å⁻¹)	0.580

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.049, 0.140, 1.03
No. of reflections	1332
No. of parameters	145
No. of restraints	4
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.17, −0.20

Computer programs: CrysAlis PRO (Oxford Diffraction, 2010), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), OLEX2 (Dolomanov et al., 2009).

Hydrogen-bond geometry (Å, º) top

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)

Symmetry code: (i) −x+3/2, y−1/2, −z+3/2.

Acknowledgements

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).

References

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