Ethyl 3-nitro-4-(n-propyl­amino)benzoate

Abstract

In the mol­ecule of the title compound, C₁₂H₁₆N₂O₄, an intra­molecular N—H⋯O hydrogen bond results in the formation of a six-membered ring having an envelope conformation. In the crystal structure, a bifurcated intra/intermolecular N—H⋯(O,O) hydrogen bond generates inversion dimers.

Related literature

For bond-length data, see: Allen et al. (1987 ▶). For the synthesis, see: Ates-Alagoz & Buyukbingol (2001 ▶); Oezden et al. (2005 ▶).

Experimental

Crystal data

• C₁₂H₁₆N₂O₄

• M _r = 252.27

• Triclinic,

• a = 4.4400 (9) Å

• b = 12.606 (3) Å

• c = 13.209 (3) Å

• α = 61.710 (19)°

• β = 83.02 (3)°

• γ = 81.75 (3)°

• V = 643.1 (3) ų

• Z = 2

• Mo Kα radiation

• μ = 0.10 mm⁻¹

• T = 294 K

• 0.20 × 0.10 × 0.10 mm

Data collection

• Enraf–Nonius CAD-4 diffractometer

• Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.981, T _max = 0.990

• 2593 measured reflections

• 2281 independent reflections

• 924 reflections with I > 2σ(I)

• R _int = 0.083

• 3 standard reflections frequency: 120 min intensity decay: 1%

Refinement

• R[F ² > 2σ(F ²)] = 0.067

• wR(F ²) = 0.165

• S = 1.00

• 2281 reflections

• 157 parameters

• H-atom parameters constrained

• Δρ_max = 0.19 e Å⁻³

• Δρ_min = −0.14 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ▶); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 ▶); 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, 1997 ▶) and PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

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
N2—H2A⋯O4	0.86	2.02	2.635 (5)	128
N2—H2A⋯O4i	0.86	2.55	3.324 (6)	150

Symmetry code: (i) .

supplementary crystallographic information

Comment

Some derivatives of benzoic acid are important chemical materials. We report herein the crystal structure of the title compound.

In the molecule of the title compound (Fig 1), the bond lengths (Allen et al., 1987) and angles are within normal ranges. Ring A (C4-C9) is, of course, planar. Intramolecular N-H···O hydrogen bond (Table 1) results in the formation of a six-membered ring B (O4/N1/N2/C6/C7/H2A) having envelope conformation with atom O4 displaced by -0.116 (3) Å from the plane of the other ring atoms.

In the crystal structure, intra- and intermolecular N-H···O interactions (Table 1) link the molecules into centrosymmetric dimers (Fig. 2), in which they may be effective in the stabilization of the structure.

Experimental

For the preparation of the title compound, ethyl 4-chloro-3-nitrobenzoate (5.3 g, 23 mmol) was refluxed in n-propyl amine (25 ml) and tetrahydrofuran (50 ml) for 2 h. Then, solvents were evaporated and water was added to give yellow precipate, which was collected by filtration and washed with cold ethanol (2 × 15 ml) to afford the yellow solid (yield; 4.8 g). Crystals suitable for X-ray analysis were obtained by slow evaporation of an ethanol solution.

Refinement

H atoms were positioned geometrically, with N-H = 0.86 Å (for NH) and C-H = 0.93, 0.97 and 0.96 Å for aromatic, methylene and methyl H, respectively, and constrained to ride on their parent atoms, with U_iso(H) = xU_eq(C,N), where x = 1.5 for methyl H and x = 1.2 for all other H atoms.

Figures

Fig. 1.

The molecular structure of the title molecule, with the atom-numbering scheme. Hydrogen bond is shown as dashed line.

Fig. 2.

A partial packing diagram of the title compound. Hydrogen bonds are shown as dashed lines.

Crystal data

C12H16N2O4	Z = 2
Mr = 252.27	F(000) = 268
Triclinic, P1	Dx = 1.303 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.4400 (9) Å	Cell parameters from 25 reflections
b = 12.606 (3) Å	θ = 9–11°
c = 13.209 (3) Å	µ = 0.10 mm−1
α = 61.710 (19)°	T = 294 K
β = 83.02 (3)°	Block, colorless
γ = 81.75 (3)°	0.20 × 0.10 × 0.10 mm
V = 643.1 (3) Å3

Data collection

Enraf–Nonius CAD-4 diffractometer	924 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.083
graphite	θmax = 25.2°, θmin = 1.8°
ω/2θ scans	h = 0→5
Absorption correction: ψ scan (North et al., 1968)	k = −14→15
Tmin = 0.981, Tmax = 0.990	l = −15→15
2593 measured reflections	3 standard reflections every 120 min
2281 independent reflections	intensity decay: 1%

Refinement

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)] = 0.067	H-atom parameters constrained
wR(F2) = 0.165	w = 1/[σ2(Fo2) + (0.057P)2] where P = (Fo2 + 2Fc2)/3
S = 1.00	(Δ/σ)max < 0.001
2281 reflections	Δρmax = 0.19 e Å−3
157 parameters	Δρmin = −0.14 e Å−3
Primary atom site location: structure-invariant direct methods

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > 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 (Ų)

	x	y	z	Uiso*/Ueq
O1	−0.3870 (7)	−0.0274 (2)	0.8647 (2)	0.0865 (10)
O2	−0.2837 (8)	−0.1310 (3)	0.7632 (3)	0.1130 (12)
O3	−0.0492 (8)	0.3592 (2)	0.7202 (2)	0.1056 (12)
O4	0.2630 (7)	0.4310 (3)	0.5801 (2)	0.104
N1	0.1072 (8)	0.3526 (3)	0.6413 (3)	0.0706 (10)
N2	0.4396 (8)	0.3293 (3)	0.4457 (3)	0.0842 (11)
H2A	0.4491	0.3936	0.4521	0.101*
C1	−0.3968 (13)	−0.2145 (4)	1.0388 (4)	0.127 (2)
H1A	−0.5267	−0.2746	1.0918	0.190*
H1B	−0.3079	−0.1811	1.0788	0.190*
H1C	−0.2379	−0.2511	1.0058	0.190*
C2	−0.5738 (10)	−0.1193 (4)	0.9484 (4)	0.1006 (16)
H2B	−0.7339	−0.0825	0.9819	0.121*
H2C	−0.6696	−0.1538	0.9100	0.121*
C3	−0.2502 (11)	−0.0448 (4)	0.7781 (4)	0.0809 (13)
C4	−0.0655 (9)	0.0540 (3)	0.6944 (3)	0.0664 (11)
C5	−0.0537 (8)	0.1582 (3)	0.7019 (3)	0.0592 (10)
H5A	−0.1638	0.1678	0.7620	0.071*
C6	0.1163 (8)	0.2486 (3)	0.6230 (3)	0.0584 (10)
C7	0.2859 (8)	0.2413 (3)	0.5268 (3)	0.0588 (10)
C8	0.2554 (10)	0.1315 (4)	0.5233 (3)	0.0820 (13)
H8A	0.3503	0.1217	0.4612	0.098*
C9	0.1030 (11)	0.0445 (4)	0.6018 (4)	0.0834 (14)
H9A	0.1064	−0.0264	0.5961	0.100*
C10	0.5976 (13)	0.3193 (4)	0.3427 (4)	0.129 (2)
H10A	0.8040	0.2821	0.3610	0.155*
H10B	0.4927	0.2659	0.3281	0.155*
C11	0.6104 (14)	0.4292 (5)	0.2425 (4)	0.138 (2)
H11A	0.7199	0.4821	0.2561	0.165*
H11B	0.4046	0.4674	0.2246	0.165*
C12	0.7633 (11)	0.4158 (4)	0.1409 (3)	0.1116 (17)
H12A	0.7768	0.4944	0.0758	0.167*
H12B	0.6465	0.3692	0.1229	0.167*
H12C	0.9645	0.3752	0.1591	0.167*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.082 (2)	0.0819 (19)	0.0924 (19)	−0.0227 (18)	−0.0007 (18)	−0.0351 (17)
O2	0.149 (3)	0.0806 (19)	0.122 (2)	−0.028 (2)	−0.029 (2)	−0.0475 (19)
O3	0.128 (3)	0.103 (2)	0.104 (2)	−0.035 (2)	0.038 (2)	−0.0672 (19)
O4	0.123	0.115	0.097	−0.056	0.021	−0.063
N1	0.068 (2)	0.076 (2)	0.0711 (19)	−0.031 (2)	0.0100 (19)	−0.0344 (17)
N2	0.073 (3)	0.088 (2)	0.074 (2)	0.010 (2)	0.006 (2)	−0.0304 (18)
C1	0.133 (5)	0.088 (3)	0.104 (3)	0.007 (4)	0.004 (4)	−0.007 (3)
C2	0.070 (4)	0.089 (3)	0.126 (4)	−0.012 (3)	−0.017 (3)	−0.033 (3)
C3	0.079 (4)	0.063 (3)	0.094 (3)	0.001 (3)	−0.041 (3)	−0.025 (3)
C4	0.058 (3)	0.066 (2)	0.084 (3)	0.016 (2)	−0.030 (2)	−0.041 (2)
C5	0.050 (3)	0.065 (2)	0.067 (2)	0.002 (2)	−0.010 (2)	−0.034 (2)
C6	0.053 (3)	0.071 (2)	0.059 (2)	0.005 (2)	−0.013 (2)	−0.037 (2)
C7	0.043 (2)	0.064 (2)	0.054 (2)	0.021 (2)	−0.0114 (19)	−0.0212 (19)
C8	0.092 (4)	0.090 (3)	0.068 (3)	0.036 (3)	−0.019 (3)	−0.049 (2)
C9	0.104 (4)	0.069 (3)	0.089 (3)	0.014 (3)	−0.023 (3)	−0.048 (2)
C10	0.132 (4)	0.115 (4)	0.088 (3)	0.026 (3)	0.038 (3)	−0.026 (3)
C11	0.155 (5)	0.133 (4)	0.091 (3)	0.031 (4)	0.014 (4)	−0.041 (3)
C12	0.106 (4)	0.132 (4)	0.066 (2)	0.012 (3)	0.005 (3)	−0.030 (3)

Geometric parameters (Å, °)

O1—C3	1.326 (5)	C4—C9	1.400 (5)
O1—C2	1.446 (4)	C5—C6	1.373 (4)
O2—C3	1.223 (4)	C5—H5A	0.9300
O3—N1	1.211 (3)	C6—C7	1.432 (4)
O4—N1	1.188 (3)	C7—C8	1.432 (5)
N1—C6	1.436 (4)	C8—C9	1.304 (5)
N2—C7	1.326 (4)	C8—H8A	0.9300
N2—C10	1.505 (5)	C9—H9A	0.9300
N2—H2A	0.8600	C10—C11	1.393 (5)
C1—C2	1.443 (5)	C10—H10A	0.9700
C1—H1A	0.9600	C10—H10B	0.9700
C1—H1B	0.9600	C11—C12	1.500 (5)
C1—H1C	0.9600	C11—H11A	0.9700
C2—H2B	0.9700	C11—H11B	0.9700
C2—H2C	0.9700	C12—H12A	0.9600
C3—C4	1.488 (5)	C12—H12B	0.9600
C4—C5	1.372 (4)	C12—H12C	0.9600
C3—O1—C2	117.2 (3)	C5—C6—N1	115.8 (3)
O4—N1—O3	120.0 (3)	C7—C6—N1	121.9 (3)
O4—N1—C6	119.2 (3)	N2—C7—C6	123.9 (4)
O3—N1—C6	120.8 (3)	N2—C7—C8	123.4 (3)
C7—N2—C10	121.4 (4)	C6—C7—C8	112.6 (3)
C7—N2—H2A	119.3	C9—C8—C7	124.2 (4)
C10—N2—H2A	119.3	C9—C8—H8A	117.9
C2—C1—H1A	109.5	C7—C8—H8A	117.9
C2—C1—H1B	109.5	C8—C9—C4	122.3 (4)
H1A—C1—H1B	109.5	C8—C9—H9A	118.8
C2—C1—H1C	109.5	C4—C9—H9A	118.8
H1A—C1—H1C	109.5	C11—C10—N2	114.4 (4)
H1B—C1—H1C	109.5	C11—C10—H10A	108.7
C1—C2—O1	111.7 (4)	N2—C10—H10A	108.7
C1—C2—H2B	109.3	C11—C10—H10B	108.7
O1—C2—H2B	109.3	N2—C10—H10B	108.7
C1—C2—H2C	109.3	H10A—C10—H10B	107.6
O1—C2—H2C	109.3	C10—C11—C12	113.1 (4)
H2B—C2—H2C	107.9	C10—C11—H11A	109.0
O2—C3—O1	123.7 (4)	C12—C11—H11A	109.0
O2—C3—C4	121.8 (5)	C10—C11—H11B	109.0
O1—C3—C4	114.4 (4)	C12—C11—H11B	109.0
C5—C4—C9	116.8 (4)	H11A—C11—H11B	107.8
C5—C4—C3	122.8 (4)	C11—C12—H12A	109.5
C9—C4—C3	120.4 (4)	C11—C12—H12B	109.5
C4—C5—C6	121.8 (3)	H12A—C12—H12B	109.5
C4—C5—H5A	119.1	C11—C12—H12C	109.5
C6—C5—H5A	119.1	H12A—C12—H12C	109.5
C5—C6—C7	122.2 (3)	H12B—C12—H12C	109.5
C3—O1—C2—C1	87.3 (5)	C5—C6—C7—N2	176.3 (4)
C2—O1—C3—O2	3.0 (6)	N1—C6—C7—N2	−2.0 (6)
C2—O1—C3—C4	179.2 (3)	C5—C6—C7—C8	0.2 (5)
O2—C3—C4—C5	172.1 (4)	N1—C6—C7—C8	−178.1 (3)
O1—C3—C4—C5	−4.1 (6)	N2—C7—C8—C9	−179.4 (4)
O2—C3—C4—C9	−6.9 (7)	C6—C7—C8—C9	−3.2 (6)
O1—C3—C4—C9	176.9 (4)	C7—C8—C9—C4	4.6 (7)
C9—C4—C5—C6	−0.4 (6)	C5—C4—C9—C8	−2.6 (6)
C3—C4—C5—C6	−179.4 (4)	C3—C4—C9—C8	176.5 (4)
C4—C5—C6—C7	1.5 (6)	C7—N2—C10—C11	148.5 (5)
C4—C5—C6—N1	179.9 (3)	N2—C10—C11—C12	−178.8 (4)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O4	0.86	2.02	2.635 (5)	128
N2—H2A···O4i	0.86	2.55	3.324 (6)	150

Symmetry codes: (i) −x+1, −y+1, −z+1.