2-Methyl-amino-5-nitro-benzoic acid.

The title compound, C(8)H(8)N(2)O(4), is almost planar (r.m.s. deviation = 0.037 Å) and an intra-molecular N-H⋯O hydrogen bond generates an S(6) ring. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate R(2) (2)(8) loops. Inter-molecular N-H⋯O hydrogen bonds (involving the same H atom that forms the intra-molecular hydrogen bond) link the dimers into infinite sheets lying parallel to (102).

Related literature

For background to the medicinal properties of benzodiazepines, see: Blank et al. (2009 ▶); Kamal et al. (2010 ▶). For a related structure, see: Dhaneshwar & Pant (1972 ▶). For graph-set theory, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C8H8N2O4

M = 196.16

Monoclinic,

a = 7.2541 (12) Å

b = 14.037 (2) Å

c = 8.5972 (14) Å

β = 103.673 (6)°

V = 850.6 (2) Å3

Z = 4

Mo Kα radiation

μ = 0.13 mm−1

T = 296 K

0.34 × 0.12 × 0.10 mm

Data collection

Bruker Kappa APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T min = 0.979, T max = 0.988

6739 measured reflections

1667 independent reflections

931 reflections with I > 2σ(I)

R int = 0.051

Refinement

R[F 2 > 2σ(F 2)] = 0.051

wR(F 2) = 0.156

S = 0.95

1667 reflections

129 parameters

H-atom parameters constrained

Δρmax = 0.25 e Å−3

Δρmin = −0.27 e Å−3

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; 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: WinGX (Farrugia, 1999 ▶) and PLATON.

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053681001946X/hb5463sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053681001946X/hb5463Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C8H8N2O4	F(000) = 408
Mr = 196.16	Dx = 1.532 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 931 reflections
a = 7.2541 (12) Å	θ = 2.8–26.0°
b = 14.037 (2) Å	µ = 0.13 mm−1
c = 8.5972 (14) Å	T = 296 K
β = 103.673 (6)°	Needle, colorless
V = 850.6 (2) Å3	0.34 × 0.12 × 0.10 mm
Z = 4

Bruker Kappa APEXII CCD diffractometer	1667 independent reflections
Radiation source: fine-focus sealed tube	931 reflections with I > 2σ(I)
graphite	Rint = 0.051
Detector resolution: 7.50 pixels mm-1	θmax = 26.0°, θmin = 2.8°
ω scans	h = −8→8
Absorption correction: multi-scan (SADABS; Bruker, 2005)	k = −17→12
Tmin = 0.979, Tmax = 0.988	l = −10→10
6739 measured reflections

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)] = 0.051	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.156	H-atom parameters constrained
S = 0.95	w = 1/[σ2(Fo2) + (0.0901P)2] where P = (Fo2 + 2Fc2)/3
1667 reflections	(Δ/σ)max < 0.001
129 parameters	Δρmax = 0.25 e Å−3
0 restraints	Δρmin = −0.27 e Å−3

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.

	x	y	z	Uiso*/Ueq
O1	0.5419 (3)	0.38658 (12)	0.5049 (2)	0.0518 (7)
O2	0.7127 (3)	0.49628 (11)	0.4158 (3)	0.0573 (8)
O3	1.2269 (3)	0.42409 (14)	0.1896 (3)	0.0729 (9)
O4	1.3096 (3)	0.27893 (14)	0.1606 (3)	0.0672 (8)
N1	0.6259 (3)	0.20268 (13)	0.4642 (3)	0.0468 (8)
N2	1.2080 (3)	0.33798 (16)	0.2050 (3)	0.0520 (9)
C1	0.7967 (3)	0.33700 (15)	0.3914 (3)	0.0356 (8)
C2	0.7635 (3)	0.23711 (16)	0.4028 (3)	0.0380 (8)
C3	0.8868 (3)	0.17368 (17)	0.3470 (3)	0.0421 (9)
C4	1.0304 (4)	0.20647 (17)	0.2851 (3)	0.0445 (9)
C5	1.0588 (3)	0.30381 (17)	0.2745 (3)	0.0412 (9)
C6	0.9435 (4)	0.36766 (16)	0.3270 (3)	0.0405 (8)
C7	0.6728 (4)	0.40694 (16)	0.4424 (3)	0.0404 (9)
C8	0.5800 (4)	0.10286 (17)	0.4683 (4)	0.0530 (11)
H1	0.55963	0.24247	0.50427	0.0562*
H2	0.63612	0.53160	0.44325	0.0859*
H3	0.86864	0.10833	0.35312	0.0505*
H4	1.10970	0.16375	0.24988	0.0534*
H6	0.96473	0.43263	0.31904	0.0486*
H8A	0.68822	0.06878	0.52857	0.0796*
H8B	0.54575	0.07839	0.36101	0.0796*
H8C	0.47552	0.09499	0.51789	0.0796*

	U11	U22	U33	U12	U13	U23
O1	0.0570 (13)	0.0296 (10)	0.0792 (14)	0.0016 (8)	0.0367 (11)	0.0003 (9)
O2	0.0657 (13)	0.0256 (11)	0.0921 (16)	0.0005 (9)	0.0418 (12)	−0.0015 (9)
O3	0.0793 (16)	0.0436 (12)	0.1119 (19)	−0.0089 (10)	0.0550 (14)	0.0108 (12)
O4	0.0582 (13)	0.0610 (13)	0.0958 (17)	0.0082 (10)	0.0448 (12)	0.0052 (12)
N1	0.0541 (14)	0.0254 (11)	0.0716 (16)	−0.0034 (10)	0.0363 (13)	−0.0040 (10)
N2	0.0497 (15)	0.0443 (14)	0.0687 (17)	0.0010 (12)	0.0273 (13)	0.0050 (12)
C1	0.0406 (15)	0.0224 (12)	0.0464 (16)	0.0003 (10)	0.0156 (12)	−0.0020 (10)
C2	0.0416 (15)	0.0307 (13)	0.0447 (15)	−0.0026 (11)	0.0160 (13)	−0.0013 (11)
C3	0.0464 (16)	0.0261 (12)	0.0584 (17)	0.0005 (11)	0.0216 (14)	−0.0032 (12)
C4	0.0461 (16)	0.0333 (15)	0.0586 (18)	0.0050 (12)	0.0212 (14)	−0.0029 (12)
C5	0.0414 (15)	0.0366 (15)	0.0497 (16)	−0.0023 (11)	0.0190 (13)	0.0030 (12)
C6	0.0438 (15)	0.0288 (13)	0.0502 (16)	−0.0012 (11)	0.0137 (13)	−0.0003 (11)
C7	0.0467 (16)	0.0264 (14)	0.0494 (16)	−0.0001 (11)	0.0141 (14)	−0.0006 (12)
C8	0.069 (2)	0.0257 (14)	0.076 (2)	−0.0092 (12)	0.0404 (16)	−0.0070 (13)

O1—C7	1.230 (4)	C1—C6	1.380 (4)
O2—C7	1.319 (3)	C2—C3	1.423 (3)
O3—N2	1.227 (3)	C3—C4	1.357 (4)
O4—N2	1.228 (3)	C4—C5	1.388 (3)
O2—H2	0.8200	C5—C6	1.373 (4)
N1—C8	1.443 (3)	C3—H3	0.9300
N1—C2	1.326 (3)	C4—H4	0.9300
N2—C5	1.437 (3)	C6—H6	0.9300
N1—H1	0.8600	C8—H8A	0.9600
C1—C7	1.466 (3)	C8—H8B	0.9600
C1—C2	1.430 (3)	C8—H8C	0.9600
C7—O2—H2	109.00	N2—C5—C6	119.7 (2)
C2—N1—C8	124.3 (2)	C1—C6—C5	121.1 (2)
O3—N2—C5	119.2 (2)	O1—C7—O2	121.4 (2)
O4—N2—C5	118.1 (2)	O1—C7—C1	124.5 (2)
O3—N2—O4	122.7 (2)	O2—C7—C1	114.2 (2)
C2—N1—H1	118.00	C2—C3—H3	119.00
C8—N1—H1	118.00	C4—C3—H3	119.00
C6—C1—C7	119.8 (2)	C3—C4—H4	120.00
C2—C1—C6	119.5 (2)	C5—C4—H4	120.00
C2—C1—C7	120.7 (2)	C1—C6—H6	119.00
N1—C2—C3	119.9 (2)	C5—C6—H6	119.00
N1—C2—C1	122.7 (2)	N1—C8—H8A	109.00
C1—C2—C3	117.4 (2)	N1—C8—H8B	109.00
C2—C3—C4	121.5 (2)	N1—C8—H8C	109.00
C3—C4—C5	119.9 (2)	H8A—C8—H8B	109.00
C4—C5—C6	120.6 (2)	H8A—C8—H8C	110.00
N2—C5—C4	119.6 (2)	H8B—C8—H8C	109.00
C8—N1—C2—C1	175.8 (3)	C2—C1—C7—O1	4.1 (4)
C8—N1—C2—C3	−5.1 (4)	C2—C1—C7—O2	−175.9 (2)
O3—N2—C5—C4	176.8 (3)	C6—C1—C7—O1	−178.0 (2)
O3—N2—C5—C6	−2.0 (4)	C6—C1—C7—O2	2.0 (4)
O4—N2—C5—C4	−1.9 (4)	N1—C2—C3—C4	−179.3 (2)
O4—N2—C5—C6	179.4 (3)	C1—C2—C3—C4	−0.1 (4)
C6—C1—C2—N1	179.6 (2)	C2—C3—C4—C5	−0.3 (4)
C6—C1—C2—C3	0.4 (4)	C3—C4—C5—N2	−178.4 (2)
C7—C1—C2—N1	−2.5 (4)	C3—C4—C5—C6	0.4 (4)
C7—C1—C2—C3	178.4 (2)	N2—C5—C6—C1	178.7 (2)
C2—C1—C6—C5	−0.4 (4)	C4—C5—C6—C1	0.0 (4)
C7—C1—C6—C5	−178.3 (2)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1	0.86	2.03	2.694 (3)	134
N1—H1···O4i	0.86	2.52	3.165 (3)	133
O2—H2···O1ii	0.82	1.86	2.679 (3)	177

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1	0.86	2.03	2.694 (3)	134
N1—H1⋯O4i	0.86	2.52	3.165 (3)	133
O2—H2⋯O1ii	0.82	1.86	2.679 (3)	177

Symmetry codes: (i) ; (ii) .