2,3,4-Trimeth­oxy-6-methyl­benzaldehyde

In the title compound, C₁₁H₁₄O₄, the aldehyde group and non-H atoms of the meth­oxy group at the para position are nearly coplanar with the benzene ring.

Key indicators

• Single-crystal X-ray study
• T = 294 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.041
• wR factor = 0.119
• Data-to-parameter ratio = 15.5

checkCIF/PLATON results

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S1. Comment

The crystal structure of the title compound, (I), has been determined in order to elucidate the molecular conformation.

The molecular structure of (I) is shown in Fig. 1, and selected geometric parameters in Table 1.

S2. Experimental

Compound (I) was prepared according to the method of Ishii et al. (1992). To a stirred solution of 3,4,5-trimethoxytoluene (18.2 g, 100 mmol) and dimethylformamide (7.3 g, 100 mmol) in chloroform (200 ml) at room temperature was added phosphorus oxychloride (16 g, 100 mmol). The mixture was stirred for 1 h. The chloroform layer was washed with water three times, dried over Na₂SO₄ and concentrated. Compound (I) was recrystallized from petroleum ether (m.p. 333 K). Spectroscopic analysis: IR (KBr, ν, cm⁻¹): 1680.

S3. Refinement

All H atoms were positioned geometrically and refined as riding (C—H = 0.93–0.96 Å). For the CH and CH₂ groups, U_iso(H) values were set equal to 1.2U_eq(C) and for the methyl groups they were set equal to 1.5U_eq(C).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); 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, 1997); software used to prepare material for publication: SHELXTL.

Figures

Fig. 1. A view of the molecule of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.

2,3,4-trimethoxy-6-methylbenzaldehyde

Crystal data

C11H14O4	Dx = 1.308 Mg m^−3
Mr = 210.22	Melting point: 333 K
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 9.239 (2) Å	Cell parameters from 1636 reflections
b = 7.3884 (15) Å	θ = 2.6–26.3°
c = 15.649 (3) Å	µ = 0.10 mm^−1
β = 92.329 (3)°	T = 294 K
V = 1067.3 (4) Å^3	Prism, colourless
Z = 4	0.20 × 0.14 × 0.12 mm
F(000) = 448

Data collection

Bruker SMART CCD area-detector diffractometer	2180 independent reflections
Radiation source: fine-focus sealed tube	1368 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
ϕ and ω scans	θmax = 26.4°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −11→11
Tmin = 0.972, Tmax = 0.988	k = −9→4
5806 measured reflections	l = −19→19

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.041	H-atom parameters constrained
wR(F^2) = 0.119	w = 1/[σ^2(Fo^2) + (0.0548P)^2 + 0.1632P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max = 0.002
2180 reflections	Δρmax = 0.18 e Å^−3
141 parameters	Δρmin = −0.14 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.019 (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
O1	0.9270 (2)	1.0152 (2)	0.77398 (10)	0.0831 (6)
O2	0.76757 (13)	1.30037 (15)	0.96232 (8)	0.0464 (4)
O3	0.68164 (13)	1.16631 (16)	1.11355 (8)	0.0450 (4)
O4	0.71589 (14)	0.80823 (16)	1.14992 (7)	0.0464 (4)
C1	0.84417 (18)	1.0060 (2)	0.91665 (10)	0.0360 (4)
C2	0.78117 (18)	1.1171 (2)	0.97772 (11)	0.0355 (4)
C3	0.73641 (18)	1.0493 (2)	1.05455 (10)	0.0347 (4)
C4	0.75796 (18)	0.8652 (2)	1.07244 (10)	0.0344 (4)
C5	0.82038 (18)	0.7543 (2)	1.01232 (10)	0.0360 (4)
H5	0.8334	0.6321	1.0246	0.043*
C6	0.86381 (17)	0.8208 (2)	0.93433 (11)	0.0362 (4)
C7	0.8869 (2)	1.0905 (3)	0.83628 (13)	0.0536 (5)
H7	0.8822	1.2161	0.8338	0.064*
C8	0.6294 (2)	1.3537 (3)	0.92771 (15)	0.0657 (6)
H8A	0.6117	1.2961	0.8733	0.099*
H8B	0.6274	1.4827	0.9204	0.099*
H8C	0.5559	1.3183	0.9660	0.099*
C9	0.5329 (2)	1.1366 (3)	1.13409 (13)	0.0569 (6)
H9A	0.4741	1.1285	1.0822	0.085*
H9B	0.5001	1.2356	1.1680	0.085*
H9C	0.5256	1.0259	1.1657	0.085*
C10	0.7364 (2)	0.6215 (3)	1.17200 (12)	0.0563 (6)
H10A	0.6881	0.5468	1.1295	0.084*
H10B	0.6969	0.5986	1.2268	0.084*
H10C	0.8381	0.5940	1.1745	0.084*
C11	0.9311 (2)	0.6907 (3)	0.87325 (12)	0.0526 (5)
H11A	0.9417	0.5742	0.9000	0.079*
H11B	1.0245	0.7349	0.8585	0.079*
H11C	0.8699	0.6800	0.8224	0.079*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.1234 (15)	0.0748 (12)	0.0537 (9)	0.0023 (10)	0.0356 (9)	0.0043 (8)
O2	0.0505 (8)	0.0289 (7)	0.0594 (8)	−0.0021 (5)	−0.0023 (6)	0.0041 (6)
O3	0.0481 (8)	0.0391 (7)	0.0482 (7)	−0.0006 (6)	0.0080 (6)	−0.0137 (6)
O4	0.0600 (9)	0.0414 (8)	0.0383 (7)	0.0038 (6)	0.0086 (6)	0.0053 (6)
C1	0.0352 (10)	0.0356 (10)	0.0371 (9)	−0.0056 (7)	0.0017 (8)	0.0011 (7)
C2	0.0355 (10)	0.0267 (9)	0.0438 (10)	−0.0039 (7)	−0.0026 (8)	0.0011 (8)
C3	0.0341 (9)	0.0326 (10)	0.0371 (9)	−0.0018 (7)	0.0009 (7)	−0.0070 (7)
C4	0.0351 (10)	0.0344 (10)	0.0336 (9)	−0.0025 (7)	−0.0009 (7)	0.0024 (7)
C5	0.0380 (10)	0.0274 (9)	0.0426 (10)	0.0016 (7)	0.0008 (8)	0.0018 (7)
C6	0.0320 (9)	0.0363 (10)	0.0403 (10)	−0.0020 (7)	0.0022 (7)	−0.0056 (8)
C7	0.0619 (14)	0.0480 (12)	0.0519 (12)	−0.0033 (10)	0.0133 (10)	0.0047 (10)
C8	0.0664 (15)	0.0439 (13)	0.0854 (16)	0.0065 (10)	−0.0135 (12)	0.0110 (11)
C9	0.0528 (14)	0.0591 (14)	0.0594 (13)	0.0078 (10)	0.0108 (10)	−0.0120 (10)
C10	0.0716 (15)	0.0469 (13)	0.0508 (11)	0.0065 (10)	0.0075 (10)	0.0184 (10)
C11	0.0587 (13)	0.0459 (12)	0.0543 (12)	0.0020 (9)	0.0142 (10)	−0.0077 (9)

Geometric parameters (Å, º)

O1—C7	1.194 (2)	C7—H7	0.9300
O2—C2	1.380 (2)	C8—H8A	0.9600
O2—C8	1.422 (2)	C8—H8B	0.9600
O3—C3	1.3760 (19)	C8—H8C	0.9600
O3—C9	1.440 (2)	C9—H9A	0.9600
O4—C4	1.3551 (19)	C9—H9B	0.9600
O4—C10	1.433 (2)	C9—H9C	0.9600
C1—C7	1.472 (2)	C10—H10A	0.9600
C2—C1	1.404 (2)	C10—H10B	0.9600
C3—C2	1.381 (2)	C10—H10C	0.9600
C4—C3	1.402 (2)	C11—C6	1.508 (2)
C5—C4	1.391 (2)	C11—H11A	0.9600
C5—H5	0.9300	C11—H11B	0.9600
C6—C5	1.390 (2)	C11—H11C	0.9600
C6—C1	1.406 (2)
C2—O2—C8	114.36 (14)	O2—C8—H8C	109.5
C3—O3—C9	115.72 (13)	O2—C8—H8A	109.5
C4—O4—C10	118.34 (14)	O2—C8—H8B	109.5
C2—C1—C6	119.24 (15)	H8A—C8—H8B	109.5
C2—C1—C7	117.82 (16)	H8A—C8—H8C	109.5
C6—C1—C7	122.93 (16)	H8B—C8—H8C	109.5
O2—C2—C3	118.64 (15)	O3—C9—H9A	109.5
O2—C2—C1	119.46 (15)	O3—C9—H9B	109.5
C3—C2—C1	121.86 (16)	O3—C9—H9C	109.5
O3—C3—C2	119.18 (15)	H9A—C9—H9B	109.5
O3—C3—C4	121.93 (15)	H9A—C9—H9C	109.5
C2—C3—C4	118.73 (15)	H9B—C9—H9C	109.5
O4—C4—C5	124.35 (15)	O4—C10—H10A	109.5
O4—C4—C3	115.89 (14)	O4—C10—H10B	109.5
C5—C4—C3	119.76 (15)	O4—C10—H10C	109.5
C6—C5—C4	121.88 (16)	H10A—C10—H10B	109.5
C6—C5—H5	119.1	H10A—C10—H10C	109.5
C4—C5—H5	119.1	H10B—C10—H10C	109.5
C5—C6—C1	118.51 (15)	C6—C11—H11A	109.5
C5—C6—C11	118.18 (16)	C6—C11—H11B	109.5
C1—C6—C11	123.31 (16)	C6—C11—H11C	109.5
O1—C7—C1	127.1 (2)	H11A—C11—H11B	109.5
O1—C7—H7	116.5	H11A—C11—H11C	109.5
C1—C7—H7	116.5	H11B—C11—H11C	109.5
C1—C6—C5—C4	0.3 (2)	O3—C3—C2—O2	−0.8 (2)
C11—C6—C5—C4	179.74 (16)	C4—C3—C2—O2	−176.28 (15)
C10—O4—C4—C5	−0.1 (2)	O3—C3—C2—C1	176.98 (15)
C10—O4—C4—C3	−179.49 (15)	C4—C3—C2—C1	1.5 (2)
C6—C5—C4—O4	−178.86 (15)	O2—C2—C1—C6	177.12 (15)
C6—C5—C4—C3	0.5 (2)	C3—C2—C1—C6	−0.7 (2)
C9—O3—C3—C2	117.23 (18)	O2—C2—C1—C7	−2.9 (2)
C9—O3—C3—C4	−67.5 (2)	C3—C2—C1—C7	179.34 (15)
O4—C4—C3—O3	2.7 (2)	C5—C6—C1—C2	−0.3 (2)
C5—C4—C3—O3	−176.77 (15)	C11—C6—C1—C2	−179.66 (16)
O4—C4—C3—C2	178.00 (14)	C5—C6—C1—C7	179.73 (16)
C5—C4—C3—C2	−1.4 (2)	C11—C6—C1—C7	0.3 (3)
C8—O2—C2—C3	−85.60 (19)	C2—C1—C7—O1	−171.3 (2)
C8—O2—C2—C1	96.55 (19)	C6—C1—C7—O1	8.7 (3)