4-Butyl­amino-3-nitro­benzoic acid

Shivanagere Nagojappa Narendra Babu; Aisyah Saad Abdul Rahim; Hasnah Osman; Samuel Robinson Jebas; Hoong-Kun Fun

doi:10.1107/S1600536809014780

. 2009 Apr 25;65(Pt 5):o1122–o1123. doi: 10.1107/S1600536809014780

4-Butylamino-3-nitrobenzoic acid

Shivanagere Nagojappa Narendra Babu ^a, Aisyah Saad Abdul Rahim ^a,^‡, Hasnah Osman ^b, Samuel Robinson Jebas ^c,^§, Hoong-Kun Fun ^c,^*,^¶

PMCID: PMC2977797 PMID: 21583933

Abstract

The asymmetric unit of the title compound, C₁₁H₁₄N₂O₄, comprises four crystallographically independent molecules (A, B, C and D) with similar geometries. In each molecule, the butylamino side chain is in an extended conformation, and the carboxyl and butylamino groups are almost coplanar with the attached benzene ring; the nitro group is slightly twisted away from the benzene ring. In the asymmetric unit, the benzene rings of molecules A, B and C are stacked parallel to one another, with a centroid–centroid distance of 3.6197 (11) or 3.6569 (11) Å, indicating π–π interactions. An intramolecular N—H⋯O hydrogen bond is observed in each independent molecule. In addition to the π–π interactions, the crystal packing is consolidated by intermolecular O—H⋯O and C—H⋯O hydrogen bonds and C—H⋯π interactions. The crystal studied was a non-merohedral twin. The minor twin component refined to a value of 0.290 (1).

Related literature

For the synthesis of nitrobenzoic acid derivatives, see: Ishida et al. (2006 ▶); Mohd Maidin et al. (2008 ▶). For bond-length data, see: Allen et al. (1987 ▶). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₁H₁₄N₂O₄
M _r = 238.24
Monoclinic,
a = 14.5188 (6) Å
b = 13.8801 (6) Å
c = 22.5694 (9) Å
β = 90.233 (2)°
V = 4548.2 (3) Å³
Z = 16
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 100 K
0.52 × 0.19 × 0.13 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.946, T _max = 0.986
137935 measured reflections
15056 independent reflections
11743 reflections with I > 2σ(I)
R _int = 0.066

Refinement

R[F ² > 2σ(F ²)] = 0.064
wR(F ²) = 0.163
S = 1.06
15056 reflections
622 parameters
H-atom parameters constrained
Δρ_max = 0.41 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809014780/ci2784sup1.cif

e-65-o1122-sup1.cif^{(37.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809014780/ci2784Isup2.hkl

e-65-o1122-Isup2.hkl^{(721.1KB, hkl)}

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
O2A—H2A⋯O1Aⁱ	0.82	1.80	2.613 (2)	168
O2B—H2B⋯O1Dⁱⁱ	0.82	1.81	2.624 (2)	172
O2C—H2C⋯O1Cⁱⁱⁱ	0.82	1.80	2.619 (2)	175
O2D—H2D⋯O1B^iv	0.82	1.80	2.612 (2)	173
C1A—H1AA⋯O3A^v	0.93	2.46	3.290 (2)	149
C1C—H1CA⋯O3C^vi	0.93	2.44	3.256 (2)	146
C1D—H1DA⋯O3B^vii	0.93	2.40	3.227 (2)	148
N2A—H2AB⋯O4A	0.86	2.02	2.656 (2)	130
N2B—H2BB⋯O4B	0.86	2.01	2.651 (2)	130
N2C—H2CB⋯O4C	0.86	2.02	2.649 (2)	129
N2D—H2DB⋯O4D	0.86	2.01	2.649 (2)	130
C1B—H1BA⋯O3D	0.93	2.49	3.311 (2)	147
C7D—H7DA⋯Cg1^v	0.97	2.81	3.584 (2)	137
C7C—H7CB⋯Cg2^viii	0.97	2.88	3.621 (2)	134

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) ; (viii) . Cg1 and Cg2 are the centroids of the C1A–C6A and C1D–C6D rings, respectively.

Acknowledgments

The synthetic chemistry work was funded by Universiti Sains Malaysia (USM) under University Research grant No. 1001/PFARMASI/815026. HKF and SRJ thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. HKF also thanks the Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012. SNNB and SRJ thank Universiti Sains Malaysia for a postdoctoral research fellowship.

supplementary crystallographic information

Comment

Synthesis of biologically active heterocyclic scaffolds can be accessed conveniently via nitro benzoic acid intermediates (Ishida et al., 2006). We synthesized the title compound as an intermediate, and herein we report its crystal structure.

The asymmetric unit of of the title compound (Fig.1) comprises of four crystallographically independent molecules (A, B, C & D) with similar geometries. The bond lengths (Allen et al., 1987) and angles have normal values. In each of these molecules, the butylamino side chain is in an extended conformation. The carboxyl and butylamino groups are almost coplanar with the attached bezene ring. The nitro group is slightly twisted away from the benzene ring, with the dihedral angle between them being 13.79 (10)° in molecule A [10.39 (10)° in B, 5.88 (10)° in C and 9.52 (10)° in D]. In the asymmetric unit, molecules A, B and C are stacked almost parallel to one another but the orientation of the molecule D is different. The benzene ring of molecule A forms dihedral angles of 2.93 (9) and 1.95 (9)°, respectively, with benzene rings of molecules B and C. The benzene ring of molecule D forms dihedral angles of 49.37 (9), 47.22 (9) and 47.73 (9)°, respectively, with benzene rings of molecules A, B and C.

An intramolecular N—H···O hydrogen bond is observed in each independent molecule. In the asymmetric unit, molecules B and D are linked via a C—H···O hydrogen bond. The crystal packing (Fig. 2) is consolidated by intermolecular O—H···O and C—H···O hydrogen bonds and intermolecular C—H···π interactions (Table 1). In addition, π-π interactions are observed between the benzene rings of molecules A, B and C, with Cg1···Cg2 and Cg2···Cg3 distances of 3.6197 (11) Å and 3.6569 (11) Å, respectively; Cg1, Cg2 and Cg3 are centroids of the C1A-C6A, C1B-C6B and C1C-C6B benzene rings, respectively.

Experimental

A mixture of ethyl 4-butylamino-3-nitro-benzoate (0.5 g, 0.0018 mol) (Mohd Maidin et al., 2008) and KOH (0.10 g, 0.0018 mol) was refluxed in aqueous ethanol (10 ml) for 3 h. After completion of the reaction, ethanol was distilled off and the reaction mixture was diluted with water (15 ml). The aqueous layer was washed with dichloromethane (5 × 2 ml) and acidified with concentrated hydrochloric acid to afford yellow precipitate as the crude product. Recrystallization of the crude product with hot ethyl acetate gave the title compound as yellow needles.