2-Amino-5-fluoro­benzoic acid

S Sreenivasa; KE ManojKumar; PA Suchetan; B S Palakshamurthy; K Gunasekaran

doi:10.1107/S160053681300408X

. 2013 Feb 16;69(Pt 3):o387. doi: 10.1107/S160053681300408X

2-Amino-5-fluorobenzoic acid

S Sreenivasa ^a,^*, KE ManojKumar ^a, PA Suchetan ^b, B S Palakshamurthy ^c, K Gunasekaran ^d

PMCID: PMC3588531 PMID: 23476572

Abstract

In the title compound, C₇H₆FNO₂, the molecule is almost planar (r.m.s. deviation for the non-H atoms = 0.015 Å) and an intramolecular N—H⋯O hydrogen bond closes an S(6) ring. In the crystal, inversion dimers linked by pairs of O—H⋯O hydrogen bonds generate R ₂ ²(8) loops. Weak N—H⋯F hydrogen bonds, short F⋯F contacts [2.763 (2) Å] and aromatic π–π stacking interactions [centroid–centroid separation = 3.5570 (11) Å] are also observed in the crystal structure.

Related literature

For the applications of the title compound in the field of genetics, see: Toyn et al. (2000 ▶).

Experimental

Crystal data

C₇H₆FNO₂
M _r = 155.13
Monoclinic,
a = 4.9346 (2) Å
b = 11.7542 (6) Å
c = 11.9727 (5) Å
β = 96.782 (3)°
V = 689.58 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 293 K
0.43 × 0.37 × 0.25 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.947, T _max = 0.969
5184 measured reflections
1207 independent reflections
1057 reflections with I > 2σ(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.100
S = 1.09
1207 reflections
108 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.11 e Å⁻³
Δρ_min = −0.18 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶);; cell refinement: SAINT-Plus (Bruker, 2004 ▶); data reduction: SAINT-Plus; 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, 2012 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Click here for additional data file.^{(16.8KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S160053681300408X/hb7040sup1.cif

e-69-0o387-sup1.cif^{(16.8KB, cif)}

Click here for additional data file.^{(59.7KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681300408X/hb7040Isup2.hkl

e-69-0o387-Isup2.hkl^{(59.7KB, hkl)}

Click here for additional data file.^{(2.7KB, cml)}

Supplementary material file. DOI: 10.1107/S160053681300408X/hb7040Isup3.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
N1—H1B⋯O1	0.901 (19)	2.044 (19)	2.6959 (17)	128.2 (16)
N1—H1A⋯F1ⁱ	0.91 (2)	2.55 (2)	3.3646 (17)	149.8 (14)
O2—H2⋯O1ⁱⁱ	0.82	1.81	2.6279 (12)	175

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

Acknowledgments

The authors thank Dr S. C. Sharma, Vice Chancellor, Tumkur University, Tumkur, for his constant encouragement. BSPM thanks Dr H. C. Devarajegowda, Department of Physics Yuvarajas College (Constituent), University of Mysore, for his guidance.

supplementary crystallographic information

Comment

2-Amino-5-fluorobenzoic acid is used for the counterselection of TRP1, a commonly used genetic marker in the yeast Saccharomyces cerevisiae (Toyn et al., 2000). The ability to counterselect, as well as to select for, a genetic marker has numerous applications in microbial genetics. Keeping this in mind, the structure of the title compound is discussed here.

In the crystal structure of the title compound, C₇H₆FNO₂, the molecules are linked through O2—H2···O1 hydrogen bonds into inversion related dimers. N1—H1A···F1 hydrogen bonds and short F1···F1 contacts [2.763 (2) Å] are also observed in the crystal structure. Further, the structure features an intra molecular hydrogen bond between the amino proton and the adjacent carboxylic oxygen atom.

Experimental

4-Fluoroaniline (0.01 mmol), aluminium chloride (0.05 mmol) and trichloroacetyl chloride(0.03 mmol) were taken in dichloro methane (DCM) (20 ml) at 00 C under nitrogen atmosphere. The reaction mixture was refluxed for 16 h. The mixture was poured into ice-water carefully and the pH was adjusted to 2. The organic layer was separated and the aqueous layer was extracted with DCM. The combined extract was concentrated to get dark oily 1-(2-amino-5-fluorophenyl)-2,2,2-trichloroethanone. This compound (0.01 mmol) was dissolved in methanol. To this solution sodium methoxide (25% w/t in methanol) was added at 0 °C. The mixture was stirred for 1 h, the pH was adjusted to 6. The resulting solution was extracted with DCM and concentrated to get a brown solid methyl-2-amino-5-fluorobenzoate. To a solution of methyl-2-amino-5-fluorobenzoate (0.01 mmol) in tetrahydrofuran (10 ml),1 N Lithium hydroxide (0.03 mmol) was added at room temperature and stirred at 60 °C for 6 h. The reaction mixture was cooled to 0 °C and pH was adjusted to 5, the precipitate obtained was collected and dried in vacuum to get the title compound. Colourless prisms were obtained by slow evaporation of the solution of the compound in a mixture of DCM and methanol.