3,5-Dimethoxy­benzamide oxime

In the crystal structure of the title compound, C₉H₁₂N₂O₃, inter­molecular N—H...O and O—H...N hydrogen bonds link the mol­ecules. There is also an intra­molecular N—H...O hydrogen bond. The oxime group has an E configuration.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.057
• wR factor = 0.180
• Data-to-parameter ratio = 14.8

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CELLV02_ALERT_1_C  The supplied cell volume s.u. differs from that
            calculated from the cell parameter s.u.'s by > 2
            Calculated cell volume su =      19.71
            Cell volume su given      =      17.00
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S1. Comment

The oxime (–C=N—OH) moiety is a functional group that is amphiprotic with a slightly basic N atom and a mildly acidic hydroxyl group. Oxime groups possess stronger hydrogen-bonding capabilities than in alcohols, phenols, and carboxylic acids (Marsman et al., 1999), in which intermolecular hydrogen bonding combines moderate strenght and directionality (Karle et al., 1996) in linking the molecules to form supramolecular structures; this has received considerable attention with respect to directional non-covalent intermolecular interactions (Etter et al., 1990).

The hydrogen-bond systems in the crystal structures of oximes have been analysed and a correlation between a pattern of hydrogen bonding and N—O bond lengths has been suggested (Bertolasi et al., 1982). In general, oxime derivatives are very important compounds in the chemical industry and medicine (Sevagapandian et al., 2000). We report here the crystal structure of the title compound, (I).

In the molecule of the title compound, (I), (Fig. 1), the bond lengths and angles are generally within normal ranges (Allen et al., 1987). In the oxime moiety, the N1—O3 [1.422 (3) Å], N1—C9 [1.282 (4) Å], C9—C4 [1.479 (4) Å] bonds and N1—C9—C4 [116.0 (3)°] and O3—N1—C9 [111.2 (3)°] angles present no unusual features and are similar to those found in other similar compounds (Hökelek, Batı et al., 2001; Hökelek, Zülfikaroğlu et al., 2001; Hökelek, Büyükgüngör et al., 2004a,b; Hökelek, Taş et al., 2004; Büyükgüngör et al., 2003).

The oxime moiety has an E configuration [C4—C9—N1—O3 = -177.7 (3)°; Chertanova et al., 1994]. In this configuration, the oxime group is involved as a donor in intermolecular hydrogen bonding (Table 1). The rings A (C2—C7) and B (N1/N2/O3/C9/H2A) are, of course, planar and the dihedral angle between them is A/B = 37.5 (2)°.

In the crystal structure, intramolecular N—H···O and intermolecular N—H···O and O—H···N hydrogen bonds (Table 1) link the molecules, in which they seem to be effective in the stabilization of the structure.

Related literature

For general background, see: Marsman et al. (1999); Karle et al. (1996); Etter et al. (1990); Bertolasi et al. (1982); Sevagapandian et al. (2000); Allen et al. (1987). For related structures, see: Hökelek, Batı et al. (2001); Hökelek, Zülfikaroğlu et al. (2001); Hökelek, Büyükgüngör et al. (2004a,b); Hökelek, Taş et al. (2004); Büyükgüngör et al. (2003). For related literature, see: Chertanova et al. (1994).

S2. Experimental

For the preparation of the title compound, a mixture of 3,5-dimethoxy -benzonitrile (20 mmol) in ethanol (8 ml), hydroxylamine hydrochloride (20 mmol) in ethanol (6 ml) and potassium carbonate (10 mmol) in water (10 ml) was refluxed for 24 h. After cooling and filtrating, compound (I) was obtained. Crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of an ethanol solution.

S3. Refinement

H atoms were positioned geometrically, with N—H = 0.86 Å (for NH), O—H = 0.82 Å (for OH) and C—H = 0.93 and 0.96 Å for aromatic and methyl H atoms, and constrained to ride on their parent atoms, with U_iso(H) = xU_eq(C,N,O), where x = 1.5 for methyl and OH H, and x = 1.2 for all other H atoms.

Computing details

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, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1996); software used to prepare material for publication: SHELXTL.

Figures

Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Intramolecular hydrogen bond is shown as dashed line.

3,5-Dimethoxybenzamide oxime

Crystal data

C9H12N2O3	Z = 2
Mr = 196.21	F(000) = 208
Triclinic, P1	Dx = 1.351 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.4390 (13) Å	Cell parameters from 25 reflections
b = 8.0840 (16) Å	θ = 10–14°
c = 10.188 (2) Å	µ = 0.10 mm^−1
α = 71.29 (3)°	T = 294 K
β = 81.60 (3)°	Block, colorless
γ = 74.21 (3)°	0.30 × 0.20 × 0.20 mm
V = 482.33 (17) Å^3

Data collection

Enraf–Nonius CAD-4 diffractometer	1378 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.028
Graphite monochromator	θmax = 26.0°, θmin = 2.1°
ω/2θ scans	h = −7→7
Absorption correction: ψ scan (North et al., 1968)	k = −9→9
Tmin = 0.970, Tmax = 0.980	l = 0→12
2059 measured reflections	3 standard reflections every 120 min
1880 independent reflections	intensity decay: none

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.180	H-atom parameters constrained
S = 1.11	w = 1/[σ^2(Fo^2) + (0.04P)^2 + 0.9P] where P = (Fo^2 + 2Fc^2)/3
1880 reflections	(Δ/σ)max < 0.001
127 parameters	Δρmax = 0.40 e Å^−3
0 restraints	Δρmin = −0.36 e Å^−3

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
N1	1.0788 (4)	0.1642 (4)	0.9438 (3)	0.0451 (7)
O1	1.0049 (5)	0.8092 (4)	0.4557 (3)	0.0641 (8)
C1	1.2181 (7)	0.7582 (6)	0.3939 (4)	0.0601 (11)
H1B	1.2331	0.8433	0.3044	0.090*
H1C	1.2407	0.6406	0.3834	0.090*
H1D	1.3231	0.7565	0.4524	0.090*
O2	0.4585 (4)	0.7003 (3)	0.8199 (3)	0.0522 (7)
C2	0.9512 (5)	0.7037 (4)	0.5843 (3)	0.0435 (8)
N2	1.3735 (4)	0.2953 (4)	0.8772 (3)	0.0529 (8)
H2A	1.4608	0.2016	0.9251	0.063*
H2B	1.4198	0.3887	0.8296	0.063*
O3	1.2317 (4)	0.0190 (3)	1.0254 (3)	0.0537 (7)
H3A	1.1736	−0.0635	1.0674	0.081*
C3	1.0923 (5)	0.5541 (4)	0.6617 (3)	0.0414 (8)
H3B	1.2341	0.5181	0.6278	0.050*
C4	1.0177 (5)	0.4578 (4)	0.7923 (3)	0.0359 (7)
C5	0.8059 (5)	0.5116 (4)	0.8431 (3)	0.0392 (7)
H5A	0.7575	0.4478	0.9303	0.047*
C6	0.6679 (5)	0.6608 (4)	0.7627 (3)	0.0411 (8)
C7	0.7402 (6)	0.7582 (5)	0.6338 (4)	0.0454 (8)
H7A	0.6473	0.8597	0.5809	0.055*
C8	0.3158 (6)	0.8628 (5)	0.7501 (4)	0.0551 (10)
H8A	0.1769	0.8740	0.8004	0.083*
H8B	0.3006	0.8616	0.6581	0.083*
H8C	0.3731	0.9629	0.7447	0.083*
C9	1.1641 (5)	0.2958 (4)	0.8768 (3)	0.0369 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0325 (14)	0.0394 (15)	0.0496 (17)	−0.0041 (12)	−0.0096 (12)	0.0048 (13)
O1	0.0639 (17)	0.0624 (17)	0.0438 (15)	−0.0107 (14)	0.0047 (13)	0.0071 (13)
C1	0.068 (3)	0.068 (3)	0.045 (2)	−0.035 (2)	0.0086 (18)	−0.0075 (19)
O2	0.0359 (13)	0.0527 (15)	0.0506 (15)	−0.0005 (11)	0.0003 (11)	−0.0015 (12)
C2	0.0449 (19)	0.0402 (18)	0.0390 (18)	−0.0099 (15)	0.0006 (14)	−0.0047 (14)
N2	0.0359 (15)	0.0523 (18)	0.060 (2)	−0.0132 (13)	−0.0112 (14)	0.0030 (15)
O3	0.0338 (13)	0.0464 (14)	0.0616 (16)	−0.0019 (10)	−0.0133 (11)	0.0084 (12)
C3	0.0340 (16)	0.0419 (18)	0.0446 (19)	−0.0070 (14)	0.0002 (14)	−0.0109 (15)
C4	0.0302 (15)	0.0356 (16)	0.0384 (17)	−0.0061 (13)	−0.0038 (13)	−0.0071 (13)
C5	0.0341 (16)	0.0375 (17)	0.0411 (18)	−0.0076 (13)	−0.0016 (13)	−0.0059 (14)
C6	0.0337 (16)	0.0416 (18)	0.0445 (19)	−0.0059 (14)	−0.0027 (14)	−0.0105 (15)
C7	0.0436 (19)	0.0382 (18)	0.0428 (19)	−0.0020 (15)	−0.0077 (15)	−0.0005 (15)
C8	0.049 (2)	0.049 (2)	0.055 (2)	0.0023 (17)	−0.0046 (17)	−0.0100 (18)
C9	0.0306 (15)	0.0404 (17)	0.0371 (17)	−0.0077 (13)	−0.0030 (13)	−0.0085 (14)

Geometric parameters (Å, º)

N1—C9	1.282 (4)	N2—H2B	0.8600
N1—O3	1.422 (3)	O3—H3A	0.8200
O1—C2	1.369 (4)	C3—C4	1.400 (4)
O1—C1	1.434 (5)	C3—H3B	0.9300
C1—H1B	0.9600	C4—C5	1.390 (4)
C1—H1C	0.9600	C4—C9	1.479 (4)
C1—H1D	0.9600	C5—C6	1.382 (4)
O2—C6	1.384 (4)	C5—H5A	0.9300
O2—C8	1.418 (4)	C6—C7	1.385 (5)
C2—C7	1.382 (5)	C7—H7A	0.9300
C2—C3	1.382 (5)	C8—H8A	0.9600
N2—C9	1.347 (4)	C8—H8B	0.9600
N2—H2A	0.8600	C8—H8C	0.9600
C9—N1—O3	111.2 (3)	C5—C4—C9	119.5 (3)
C2—O1—C1	118.4 (3)	C3—C4—C9	119.9 (3)
O1—C1—H1B	109.5	C6—C5—C4	119.4 (3)
O1—C1—H1C	109.5	C6—C5—H5A	120.3
H1B—C1—H1C	109.5	C4—C5—H5A	120.3
O1—C1—H1D	109.5	C5—C6—O2	115.2 (3)
H1B—C1—H1D	109.5	C5—C6—C7	120.6 (3)
H1C—C1—H1D	109.5	O2—C6—C7	124.2 (3)
C6—O2—C8	117.9 (3)	C2—C7—C6	119.6 (3)
O1—C2—C7	114.7 (3)	C2—C7—H7A	120.2
O1—C2—C3	124.2 (3)	C6—C7—H7A	120.2
C7—C2—C3	121.1 (3)	O2—C8—H8A	109.5
C9—N2—H2A	120.0	O2—C8—H8B	109.5
C9—N2—H2B	120.0	H8A—C8—H8B	109.5
H2A—N2—H2B	120.0	O2—C8—H8C	109.5
N1—O3—H3A	109.5	H8A—C8—H8C	109.5
C2—C3—C4	118.7 (3)	H8B—C8—H8C	109.5
C2—C3—H3B	120.7	N1—C9—N2	125.0 (3)
C4—C3—H3B	120.7	N1—C9—C4	116.0 (3)
C5—C4—C3	120.7 (3)	N2—C9—C4	119.0 (3)
C1—O1—C2—C7	−177.5 (3)	C8—O2—C6—C7	−7.9 (5)
C1—O1—C2—C3	2.7 (6)	O1—C2—C7—C6	179.7 (3)
O1—C2—C3—C4	179.7 (3)	C3—C2—C7—C6	−0.5 (6)
C7—C2—C3—C4	0.0 (5)	C5—C6—C7—C2	1.1 (5)
C2—C3—C4—C5	0.0 (5)	O2—C6—C7—C2	−177.9 (3)
C2—C3—C4—C9	179.2 (3)	O3—N1—C9—N2	3.0 (5)
C3—C4—C5—C6	0.6 (5)	O3—N1—C9—C4	−177.7 (3)
C9—C4—C5—C6	−178.6 (3)	C5—C4—C9—N1	38.3 (5)
C4—C5—C6—O2	177.9 (3)	C3—C4—C9—N1	−141.0 (3)
C4—C5—C6—C7	−1.2 (5)	C5—C4—C9—N2	−142.4 (3)
C8—O2—C6—C5	173.0 (3)	C3—C4—C9—N2	38.4 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O3	0.86	2.28	2.578 (4)	101
N2—H2A···O3^i	0.86	2.27	3.083 (4)	158
N2—H2B···O2^ii	0.86	2.57	3.319 (4)	147
O3—H3A···N1^iii	0.82	2.04	2.724 (4)	141

Symmetry codes: (i) −x+3, −y, −z+2; (ii) x+1, y, z; (iii) −x+2, −y, −z+2.