Acta Cryst. (2009). E65, o1233-o1234 [ doi:10.1107/S1600536809015487 ]
In the title compound, C11H14N2O4, all non-H atoms lie in a mirror plane except for one of the methyl groups which deviates from the mirror plane by 0.919 (3) Å and is twisted by a torsion angle of 62.9 (2)°. An intramolecular N-H
O hydrogen bond generates an S(6) ring motif. In the crystal packing, the molecules are linked together by O-HO hydrogen bonds, forming dimers with graph-set motif R22(8) which propagate along the a-axis direction. C-HO contacts link adjacent dimers with a graph-set motif C22(7), forming chains along b, and further consolidate the structure into a three-dimensional network. The crystal packing is further strengthened by short intermolecular OO=C [2.655 (4) Å] contacts.
Compound (I) was prepared by refluxing ethyl 4-(tert-butylamino)-3-nitrobenzoate (0.7 g, 0.0026 mol) (Mohd Maidin et al., 2008) and KOH (0.14 g, 0.0026 mol) in aqueous ethanol (10 ml) for 3 h. Ethanol was then removed in vacuo and the reaction mixture was diluted with water (15 ml). The aqueous layer was washed with dichloromethane (10 ml × 2) and acidified with concentrated hydrochloric acid to bring about the precipitation of the desired benzoic acid. Recrystallization of the precipitate with hot ethyl acetate afforded yellow crystals of the title compound (I).
H atoms were positioned geometrically [C–H = 0.93–0.96 Å] and refined using a riding model with Uiso(H) = 1.2Ueq(C) and 1.5Ueq(methyl C). A rotating–group model was used for the methyl groups. The O- and N-bound hydrogen atoms were located from the Fourier map and allowed to refine freely.
Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
![[Figure 1]](./tk2439fig1thm.gif)
| Fig. 1. The molecular structure of (I), showing 50% probability displacement ellipsoids and the atom numbering scheme. Intramolecular hydrogen bonding is shown as a dashed line. [Symmetry code used to generate methyl moiety C9A: x, -y + 1, z] |
![[Figure 2]](./tk2439fig2thm.gif)
| Fig. 2. The crystal packing of (I), viewed along the c axis. Dashed lines indicate the hydrogen bonding and C—H···O contacts. |
| C11H14N2O4 | F000 = 504 |
| Mr = 238.24 | Dx = 1.396 Mg m−3 |
| Monoclinic, C2/m | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: -C 2y | Cell parameters from 1829 reflections |
| a = 20.8125 (15) Å | θ = 3.2–30.6º |
| b = 6.7412 (5) Å | µ = 0.11 mm−1 |
| c = 8.0793 (5) Å | T = 100 K |
| β = 90.863 (6)º | Plate, yellow |
| V = 1133.41 (14) Å3 | 0.39 × 0.10 × 0.03 mm |
| Z = 4 |
| Bruker SMART APEXII CCD area-detector diffractometer | 1418 independent reflections |
| Radiation source: fine-focus sealed tube | 985 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.057 |
| T = 100 K | θmax = 27.5º |
| φ and ω scans | θmin = 2.0º |
| Absorption correction: multi-scan (SADABS; Bruker, 2005) | h = −26→26 |
| Tmin = 0.959, Tmax = 0.997 | k = −8→8 |
| 6267 measured reflections | l = −10→10 |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.065 | H atoms treated by a mixture of independent and constrained refinement |
| wR(F2) = 0.153 | w = 1/[σ2(Fo2) + (0.058P)2 + 2.3728P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.11 | (Δ/σ)max < 0.001 |
| 1418 reflections | Δρmax = 0.37 e Å−3 |
| 107 parameters | Δρmin = −0.31 e Å−3 |
| Primary atom site location: structure-invariant direct methods | Extinction correction: none |
| C11H14N2O4 | V = 1133.41 (14) Å3 |
| Mr = 238.24 | Z = 4 |
| Monoclinic, C2/m | Mo Kα |
| a = 20.8125 (15) Å | µ = 0.11 mm−1 |
| b = 6.7412 (5) Å | T = 100 K |
| c = 8.0793 (5) Å | 0.39 × 0.10 × 0.03 mm |
| β = 90.863 (6)º |
| Bruker SMART APEXII CCD area-detector diffractometer | 1418 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2005) | 985 reflections with I > 2σ(I) |
| Tmin = 0.959, Tmax = 0.997 | Rint = 0.057 |
| 6267 measured reflections |
| R[F2 > 2σ(F2)] = 0.065 | 107 parameters |
| wR(F2) = 0.153 | H atoms treated by a mixture of independent and constrained refinement |
| S = 1.11 | Δρmax = 0.37 e Å−3 |
| 1418 reflections | Δρmin = −0.31 e Å−3 |
Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
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 > 2sigma(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. |
| x | y | z | Uiso*/Ueq | ||
| O1 | 0.44372 (12) | 0.5000 | 0.3166 (3) | 0.0189 (6) | |
| O2 | 0.43314 (11) | 0.5000 | 0.5919 (3) | 0.0185 (6) | |
| O3 | 0.22447 (11) | 0.5000 | 0.8193 (3) | 0.0198 (6) | |
| O4 | 0.13560 (11) | 0.5000 | 0.6766 (3) | 0.0187 (6) | |
| N1 | 0.19540 (13) | 0.5000 | 0.6848 (3) | 0.0130 (6) | |
| N2 | 0.13842 (13) | 0.5000 | 0.3497 (4) | 0.0131 (6) | |
| C1 | 0.24626 (16) | 0.5000 | 0.2381 (4) | 0.0142 (7) | |
| H1A | 0.2298 | 0.5000 | 0.1304 | 0.017* | |
| C2 | 0.31116 (16) | 0.5000 | 0.2615 (4) | 0.0145 (7) | |
| H2A | 0.3377 | 0.5000 | 0.1700 | 0.017* | |
| C3 | 0.33894 (15) | 0.5000 | 0.4217 (4) | 0.0122 (7) | |
| C4 | 0.29869 (16) | 0.5000 | 0.5563 (4) | 0.0126 (7) | |
| H4A | 0.3163 | 0.5000 | 0.6628 | 0.015* | |
| C5 | 0.23216 (16) | 0.5000 | 0.5349 (4) | 0.0130 (7) | |
| C6 | 0.20244 (16) | 0.5000 | 0.3726 (4) | 0.0129 (7) | |
| C7 | 0.09935 (16) | 0.5000 | 0.1929 (4) | 0.0145 (7) | |
| C8 | 0.02967 (16) | 0.5000 | 0.2518 (4) | 0.0184 (8) | |
| H8B | 0.0008 | 0.5000 | 0.1581 | 0.028* | |
| H8C | 0.0228 | 0.3861 | 0.3206 | 0.028* | |
| C9 | 0.11138 (11) | 0.3105 (4) | 0.0926 (3) | 0.0169 (6) | |
| H9A | 0.1558 | 0.3044 | 0.0627 | 0.025* | |
| H9B | 0.0850 | 0.3120 | −0.0060 | 0.025* | |
| H9C | 0.1008 | 0.1966 | 0.1581 | 0.025* | |
| C10 | 0.40933 (15) | 0.5000 | 0.4522 (4) | 0.0132 (7) | |
| H1N2 | 0.1189 (18) | 0.5000 | 0.435 (5) | 0.015 (10)* | |
| H1O1 | 0.4804 (19) | 0.5000 | 0.341 (5) | 0.010 (10)* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| O1 | 0.0086 (13) | 0.0327 (15) | 0.0154 (14) | 0.000 | 0.0005 (10) | 0.000 |
| O2 | 0.0121 (12) | 0.0293 (14) | 0.0142 (13) | 0.000 | 0.0012 (10) | 0.000 |
| O3 | 0.0207 (13) | 0.0282 (14) | 0.0104 (12) | 0.000 | 0.0002 (10) | 0.000 |
| O4 | 0.0130 (13) | 0.0279 (14) | 0.0153 (13) | 0.000 | 0.0045 (10) | 0.000 |
| N1 | 0.0154 (15) | 0.0119 (14) | 0.0117 (15) | 0.000 | 0.0033 (11) | 0.000 |
| N2 | 0.0113 (15) | 0.0189 (15) | 0.0092 (15) | 0.000 | 0.0029 (12) | 0.000 |
| C1 | 0.0197 (18) | 0.0147 (17) | 0.0082 (17) | 0.000 | −0.0002 (14) | 0.000 |
| C2 | 0.0176 (18) | 0.0131 (16) | 0.0129 (18) | 0.000 | 0.0074 (14) | 0.000 |
| C3 | 0.0155 (17) | 0.0082 (15) | 0.0128 (17) | 0.000 | 0.0004 (13) | 0.000 |
| C4 | 0.0172 (17) | 0.0109 (16) | 0.0096 (17) | 0.000 | −0.0014 (13) | 0.000 |
| C5 | 0.0178 (18) | 0.0085 (15) | 0.0126 (17) | 0.000 | 0.0016 (13) | 0.000 |
| C6 | 0.0166 (17) | 0.0088 (15) | 0.0134 (17) | 0.000 | 0.0003 (14) | 0.000 |
| C7 | 0.0132 (17) | 0.0158 (17) | 0.0142 (17) | 0.000 | −0.0026 (13) | 0.000 |
| C8 | 0.0173 (18) | 0.0215 (18) | 0.0164 (18) | 0.000 | −0.0021 (14) | 0.000 |
| C9 | 0.0184 (12) | 0.0163 (12) | 0.0160 (12) | −0.0014 (10) | −0.0014 (10) | 0.0003 (10) |
| C10 | 0.0134 (17) | 0.0093 (16) | 0.0170 (18) | 0.000 | 0.0027 (14) | 0.000 |
| O1—C10 | 1.318 (4) | C3—C4 | 1.383 (5) |
| O1—H1O1 | 0.79 (4) | C3—C10 | 1.482 (5) |
| O2—C10 | 1.226 (4) | C4—C5 | 1.393 (5) |
| O3—N1 | 1.236 (4) | C4—H4A | 0.9300 |
| O4—N1 | 1.245 (4) | C5—C6 | 1.441 (5) |
| N1—C5 | 1.442 (4) | C7—C8 | 1.533 (5) |
| N2—C6 | 1.343 (4) | C7—C9 | 1.536 (3) |
| N2—C7 | 1.495 (4) | C7—C9i | 1.536 (3) |
| N2—H1N2 | 0.80 (4) | C8—H8B | 0.9595 |
| C1—C2 | 1.361 (5) | C8—H8C | 0.9600 |
| C1—C6 | 1.429 (5) | C9—H9A | 0.9600 |
| C1—H1A | 0.9300 | C9—H9B | 0.9600 |
| C2—C3 | 1.409 (5) | C9—H9C | 0.9600 |
| C2—H2A | 0.9300 | ||
| C10—O1—H1O1 | 109 (3) | N2—C6—C1 | 122.6 (3) |
| O3—N1—O4 | 121.5 (3) | N2—C6—C5 | 122.5 (3) |
| O3—N1—C5 | 118.6 (3) | C1—C6—C5 | 114.9 (3) |
| O4—N1—C5 | 119.9 (3) | N2—C7—C8 | 104.0 (3) |
| C6—N2—C7 | 130.0 (3) | N2—C7—C9 | 110.88 (17) |
| C6—N2—H1N2 | 113 (3) | C8—C7—C9 | 109.04 (18) |
| C7—N2—H1N2 | 117 (3) | N2—C7—C9i | 110.88 (17) |
| C2—C1—C6 | 122.5 (3) | C8—C7—C9i | 109.04 (18) |
| C2—C1—H1A | 118.7 | C9—C7—C9i | 112.6 (3) |
| C6—C1—H1A | 118.7 | C7—C8—H8B | 109.9 |
| C1—C2—C3 | 121.4 (3) | C7—C8—H8C | 109.3 |
| C1—C2—H2A | 119.3 | H8B—C8—H8C | 111.1 |
| C3—C2—H2A | 119.3 | C7—C9—H9A | 109.5 |
| C4—C3—C2 | 118.5 (3) | C7—C9—H9B | 109.5 |
| C4—C3—C10 | 118.5 (3) | H9A—C9—H9B | 109.5 |
| C2—C3—C10 | 122.9 (3) | C7—C9—H9C | 109.5 |
| C3—C4—C5 | 121.0 (3) | H9A—C9—H9C | 109.5 |
| C3—C4—H4A | 119.5 | H9B—C9—H9C | 109.5 |
| C5—C4—H4A | 119.5 | O2—C10—O1 | 123.3 (3) |
| C4—C5—C6 | 121.7 (3) | O2—C10—C3 | 122.6 (3) |
| C4—C5—N1 | 115.8 (3) | O1—C10—C3 | 114.2 (3) |
| C6—C5—N1 | 122.5 (3) | ||
| C6—C1—C2—C3 | 0.0 | C2—C1—C6—N2 | 180.0 |
| C1—C2—C3—C4 | 0.0 | C2—C1—C6—C5 | 0.0 |
| C1—C2—C3—C10 | 180.0 | C4—C5—C6—N2 | 180.0 |
| C2—C3—C4—C5 | 0.0 | N1—C5—C6—N2 | 0.0 |
| C10—C3—C4—C5 | 180.0 | C4—C5—C6—C1 | 0.0 |
| C3—C4—C5—C6 | 0.0 | N1—C5—C6—C1 | 180.0 |
| C3—C4—C5—N1 | 180.0 | C6—N2—C7—C8 | 180.0 |
| O3—N1—C5—C4 | 0.0 | C6—N2—C7—C9 | 62.9 (2) |
| O4—N1—C5—C4 | 180.0 | C6—N2—C7—C9i | −62.9 (2) |
| O3—N1—C5—C6 | 180.0 | C4—C3—C10—O2 | 0.0 |
| O4—N1—C5—C6 | 0.0 | C2—C3—C10—O2 | 180.0 |
| C7—N2—C6—C1 | 0.0 | C4—C3—C10—O1 | 180.0 |
| C7—N2—C6—C5 | 180.0 | C2—C3—C10—O1 | 0.0 |
| Symmetry codes: (i) x, −y+1, z. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O1—H1O1···O2ii | 0.82 (4) | 1.83 (4) | 2.655 (4) | 178 (4) |
| C1—H1A···O3iii | 0.93 | 2.52 | 3.407 (4) | 161 |
| N2—H1N2···O4 | 0.81 (4) | 1.97 (4) | 2.641 (4) | 139 (4) |
| C9—H9C···O2iv | 0.96 | 2.53 | 3.437 (3) | 158 |
| Symmetry codes: (ii) −x+1, y, −z+1; (iii) x, y, z−1; (iv) −x+1/2, y−1/2, −z+1. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O1—H1O1···O2i | 0.82 (4) | 1.83 (4) | 2.655 (4) | 178 (4) |
| C1—H1A···O3ii | 0.93 | 2.52 | 3.407 (4) | 161 |
| N2—H1N2···O4 | 0.81 (4) | 1.97 (4) | 2.641 (4) | 139 (4) |
| C9—H9C···O2iii | 0.96 | 2.53 | 3.437 (3) | 158 |
| Symmetry codes: (i) −x+1, y, −z+1; (ii) x, y, z−1; (iii) −x+1/2, y−1/2, −z+1. |
SNNB, ASAR and SAH are grateful to Universiti Sains Malaysia (USM) for funding the synthetic chemistry work under the University Research Grant (1001/PFARMASI/815026). SNNB thanks USM for a post–doctoral research fellowship. HKF and SRJ thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. SRJ thanks Universiti Sains Malaysia for a post–doctoral research fellowship. HKF also thanks Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012.
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Nitro benzoic acid derivatives are important intermediates for the synthesis of various heterocyclic compounds of pharmacological interest (Brouillette et al., 1999; Williams et al., 1995). As a part of our ongoing study on such compounds, in this paper, we present the crystal structure of the title compound (I) which was synthesized as an intermediate.
In the asymmetric unit of (I), all non-hydrogen atoms lie in a mirror plane except the methyl-C9A moiety, which is deviated from the mean plane by 0.919 (3) Å and twisted by a torsion angle C6–N2–C7–C9 of 62.9 (2) Å.
An intramolecular N—H···O hydrogen bond generates a ring of motif S(6) (Bernstein et al., 1995) (Fig. 1). In the crystal packing, the molecules are linked together by O—H···O hydrogen bonds to form dimers with the graph set motif R22(8) which propagate along the a-direction (Table 1). C—H···O contacts link adjacent dimers with a graph set motif C22(7) (Fig. 2) to form chains along the b-direction and further consolidate the structure into a 3D network. The crystal packing is further strengthened by short intermolecular O···Oi-ii = 2.655 (4)Å contacts; symmetry code: (i) 1-x, y, 1-z; (ii) 1-x, 1-y, 1-z.