3,4-Dimethoxy­benzohydrazide

The title compound, C₉H₁₂N₂O₃, is an important inter­mediate for the synthesis of biologically active heterocyclic compounds. The planar hydrazide group is oriented with respect to the benzene ring at a dihedral angle of 63.27 (3)°. In the crystal structure, inter­molecular N—H...O hydrogen bonds link the mol­ecules to form a supra­molecular structure.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.046
• wR factor = 0.094
• Data-to-parameter ratio = 15.7

checkCIF/PLATON results

No syntax errors found



Alert level C
REFLT03_ALERT_3_C  Reflection count < 95% complete
           From the CIF: _diffrn_reflns_theta_max           28.29
           From the CIF: _diffrn_reflns_theta_full          28.29
           From the CIF: _reflns_number_total               2148
           TEST2: Reflns within _diffrn_reflns_theta_max
           Count of symmetry unique reflns         2312
           Completeness (_total/calc)             92.91%
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 =          3

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Aromatic hydrazides are important intermediates in heterocyclic chemistry and have been used for the synthesis of various biologically active five-membered heterocycles such as 2,5-disubstituted-1,3,4-oxadiazoles (Zheng et al., 2003; Al-Talib et al., 1990) and 5-substituted-2-mercapto-1,3,4-oxadiazoles (Yousif et al., 1986; Ahmad et al., 2001; Al-Soud et al., 2004; El-Emam et al., 2004). In view of the versatility of these compounds, we have synthesized the title compound, (I), and reported its crystal structure.

In the molecule of the title compound, (I), (Fig. 1), the bond lengths and angles are within normal ranges (Allen et al., 1987). The dihedral angle between the planar hydrazidic group (C7/O1/N1/N2) and benzene ring (C1—C6) is 63.27 (3)°.

In the crystal structure, the intermolecular N—H···O hydrogen bonds (Table 1) link the molecules to form a supramolecular structure (Fig. 2).

Related literature

For general backgroud, see: Zheng et al. (2003); Al-Talib et al. (1990); Yousif et al. (1986); Ahmad et al. (2001); Al-Soud et al. (2004); El-Emam et al. (2004); Allen et al. (1987); Furniss et al. (1978).

S2. Experimental

The title compound, (I), is synthesized by the reaction of methyl ester of 3,4-dimethoxybenzoic acid with hdyrazine hydrate using the reported procedure (Furniss et al., 1978). For the preparation of (I), a mixture of methyl-3,4-dimethoxybenzoate (2.10 g, 10 mmol) and hydrazine hydrate (80%, 15 ml) in absolute ethanol (50 ml) was refluxed for 5 h at 413–423 K. The excess solvent was removed by distillation. The solid residue was filtered off, washed with water and recrystallized from ethanol (30%) to give the title compound (yield: 1.89 g, 90%, m.p. 391–392 K). Colorless single crystals of (I) were obtained by slow evaporation of an ethanol solution at room temperature.

S3. Refinement

H atoms of NH₂ group were located in difference syntheses and refined isotropically [N—H = 0.90 (2) and 0.95 (2) Å and U_iso(H) = 0.040 (7) and 0.053 (8) Ų]. The remaining H atoms were positioned geometrically, with N—H = 0.88 Å (for NH) and C—H = 0.95 and 0.98 Å for aromatic and methyl H atoms, 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.

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1999); 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 50% probability level.
	Fig. 2. A packing diagram for (I). Hydrogen bonds are shown as dashed lines.
	Fig. 3. The synthesis route for the formation of the title compound.

3,4-Dimethoxybenzohydrazide

Crystal data

C9H12N2O3	F(000) = 416
Mr = 196.21	Dx = 1.396 Mg m^−3 Dm = 1.375 Mg m^−3 Dm measured by not measured
Monoclinic, P21/c	Melting point: 391(1) K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 13.610 (3) Å	Cell parameters from 927 reflections
b = 8.9130 (19) Å	θ = 2.8–25.1°
c = 7.9780 (17) Å	µ = 0.11 mm^−1
β = 105.266 (4)°	T = 100 K
V = 933.6 (3) Å^3	Block, colourless
Z = 4	0.25 × 0.20 × 0.20 mm

Data collection

Bruker APEXII diffractometer	2148 independent reflections
Radiation source: fine-focus sealed tube	1279 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.064
φ and ω scans	θmax = 28.3°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −15→17
Tmin = 0.974, Tmax = 0.979	k = −7→11
5477 measured reflections	l = −10→10

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)] = 0.046	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.094	H atoms treated by a mixture of independent and constrained refinement
S = 0.83	w = 1/[σ^2(Fo^2) + (0.035P)^2] where P = (Fo^2 + 2Fc^2)/3
2148 reflections	(Δ/σ)max < 0.001
137 parameters	Δρmax = 0.29 e Å^−3
0 restraints	Δρmin = −0.23 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
C1	0.15181 (14)	0.9587 (2)	−0.0649 (2)	0.0184 (4)
C2	0.19359 (15)	0.9328 (2)	0.1130 (2)	0.0193 (4)
H2	0.1589	0.8700	0.1749	0.023*
C3	0.28501 (15)	0.9982 (2)	0.1984 (2)	0.0184 (4)
C4	0.33684 (14)	1.0898 (2)	0.1051 (3)	0.0193 (5)
C5	0.29693 (15)	1.1115 (2)	−0.0706 (3)	0.0210 (5)
H5	0.3329	1.1707	−0.1339	0.025*
C6	0.20398 (14)	1.0468 (2)	−0.1558 (3)	0.0205 (5)
H6	0.1763	1.0633	−0.2767	0.025*
C7	0.05527 (15)	0.8802 (2)	−0.1522 (2)	0.0188 (4)
C8	0.29096 (15)	0.8730 (2)	0.4659 (3)	0.0238 (5)
H8A	0.2210	0.9002	0.4646	0.036*
H8B	0.3330	0.8693	0.5862	0.036*
H8C	0.2912	0.7744	0.4117	0.036*
C9	0.48231 (15)	1.2419 (3)	0.1152 (3)	0.0315 (5)
H9A	0.5055	1.1820	0.0299	0.047*
H9B	0.5414	1.2842	0.2000	0.047*
H9C	0.4385	1.3235	0.0556	0.047*
N1	−0.00531 (12)	0.94684 (18)	−0.2911 (2)	0.0200 (4)
H1	0.0109	1.0367	−0.3209	0.024*
N2	−0.09501 (13)	0.8771 (2)	−0.3922 (2)	0.0229 (4)
O1	0.03265 (10)	0.75694 (15)	−0.09871 (17)	0.0232 (3)
O2	0.33148 (10)	0.98293 (14)	0.37109 (16)	0.0222 (3)
O3	0.42607 (10)	1.14850 (14)	0.20274 (17)	0.0235 (4)
H2A	−0.0736 (16)	0.802 (3)	−0.449 (3)	0.040 (7)*
H2B	−0.1309 (18)	0.845 (3)	−0.311 (3)	0.053 (8)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0218 (11)	0.0121 (10)	0.0222 (10)	0.0025 (8)	0.0076 (9)	−0.0011 (8)
C2	0.0239 (11)	0.0127 (10)	0.0231 (11)	0.0013 (8)	0.0091 (9)	0.0016 (8)
C3	0.0240 (11)	0.0141 (10)	0.0174 (10)	0.0032 (9)	0.0060 (9)	−0.0015 (8)
C4	0.0199 (11)	0.0129 (10)	0.0256 (11)	0.0001 (8)	0.0067 (9)	−0.0018 (8)
C5	0.0244 (11)	0.0158 (11)	0.0243 (11)	−0.0008 (9)	0.0088 (9)	0.0027 (9)
C6	0.0225 (11)	0.0179 (11)	0.0208 (10)	0.0030 (9)	0.0051 (9)	0.0008 (8)
C7	0.0224 (11)	0.0151 (11)	0.0208 (11)	0.0018 (9)	0.0093 (9)	−0.0024 (9)
C8	0.0267 (12)	0.0216 (12)	0.0232 (11)	−0.0002 (9)	0.0070 (9)	0.0061 (9)
C9	0.0248 (12)	0.0327 (13)	0.0353 (13)	−0.0076 (10)	0.0048 (10)	0.0095 (11)
N1	0.0202 (9)	0.0135 (9)	0.0250 (9)	−0.0036 (7)	0.0036 (8)	0.0005 (7)
N2	0.0212 (10)	0.0203 (10)	0.0263 (10)	−0.0020 (8)	0.0046 (8)	−0.0035 (8)
O1	0.0282 (8)	0.0133 (7)	0.0277 (8)	−0.0023 (6)	0.0064 (6)	0.0015 (6)
O2	0.0266 (8)	0.0201 (8)	0.0185 (8)	−0.0034 (6)	0.0036 (6)	0.0023 (6)
O3	0.0216 (8)	0.0220 (8)	0.0252 (8)	−0.0051 (6)	0.0031 (6)	0.0041 (6)

Geometric parameters (Å, º)

C1—C6	1.385 (3)	C7—N1	1.334 (2)
C1—C2	1.402 (2)	C8—O2	1.434 (2)
C1—C7	1.490 (3)	C8—H8A	0.9800
C2—C3	1.381 (3)	C8—H8B	0.9800
C2—H2	0.9500	C8—H8C	0.9800
C3—O2	1.363 (2)	C9—O3	1.431 (2)
C3—C4	1.413 (3)	C9—H9A	0.9800
C4—O3	1.363 (2)	C9—H9B	0.9800
C4—C5	1.377 (2)	C9—H9C	0.9800
C5—C6	1.393 (3)	N1—N2	1.417 (2)
C5—H5	0.9500	N1—H1	0.8800
C6—H6	0.9500	N2—H2A	0.90 (2)
C7—O1	1.247 (2)	N2—H2B	0.95 (2)
C6—C1—C2	119.75 (18)	O2—C8—H8A	109.5
C6—C1—C7	122.13 (18)	O2—C8—H8B	109.5
C2—C1—C7	117.97 (17)	H8A—C8—H8B	109.5
C3—C2—C1	120.18 (18)	O2—C8—H8C	109.5
C3—C2—H2	119.9	H8A—C8—H8C	109.5
C1—C2—H2	119.9	H8B—C8—H8C	109.5
O2—C3—C2	125.08 (17)	O3—C9—H9A	109.5
O2—C3—C4	115.31 (17)	O3—C9—H9B	109.5
C2—C3—C4	119.61 (18)	H9A—C9—H9B	109.5
O3—C4—C5	125.55 (17)	O3—C9—H9C	109.5
O3—C4—C3	114.45 (17)	H9A—C9—H9C	109.5
C5—C4—C3	119.99 (18)	H9B—C9—H9C	109.5
C4—C5—C6	120.17 (18)	C7—N1—N2	121.93 (17)
C4—C5—H5	119.9	C7—N1—H1	119.0
C6—C5—H5	119.9	N2—N1—H1	119.0
C1—C6—C5	120.27 (19)	N1—N2—H2A	105.5 (14)
C1—C6—H6	119.9	N1—N2—H2B	105.3 (14)
C5—C6—H6	119.9	H2A—N2—H2B	114.3 (19)
O1—C7—N1	121.50 (18)	C3—O2—C8	117.45 (14)
O1—C7—C1	121.37 (18)	C4—O3—C9	117.05 (15)
N1—C7—C1	117.13 (17)
C6—C1—C2—C3	1.8 (3)	C4—C5—C6—C1	−0.9 (3)
C7—C1—C2—C3	177.49 (17)	C6—C1—C7—O1	147.43 (18)
C1—C2—C3—O2	178.76 (16)	C2—C1—C7—O1	−28.1 (3)
C1—C2—C3—C4	−0.9 (3)	C6—C1—C7—N1	−31.9 (3)
O2—C3—C4—O3	0.3 (2)	C2—C1—C7—N1	152.58 (17)
C2—C3—C4—O3	179.92 (17)	O1—C7—N1—N2	−4.3 (3)
O2—C3—C4—C5	179.36 (16)	C1—C7—N1—N2	175.03 (17)
C2—C3—C4—C5	−1.0 (3)	C2—C3—O2—C8	10.0 (3)
O3—C4—C5—C6	−179.15 (18)	C4—C3—O2—C8	−170.31 (15)
C3—C4—C5—C6	1.9 (3)	C5—C4—O3—C9	0.7 (3)
C2—C1—C6—C5	−1.0 (3)	C3—C4—O3—C9	179.77 (16)
C7—C1—C6—C5	−176.43 (18)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1^i	0.88	2.10	2.894 (2)	150
N2—H2A···O1^ii	0.90 (2)	2.17 (2)	2.944 (2)	144.0 (18)

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