2-Methyl-N-(3,4,5-trimethoxy­benzyl­idene)aniline N-oxide

In the crystal structure of the title compound, C₁₇H₁₉NO₄, the geometry about the C=N double bond is Z. The structure is stabilized by weak inter­molecular C—H...O hydrogen bonds, linking the mol­ecules into chains.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.038
• wR factor = 0.100
• Data-to-parameter ratio = 7.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97
PLAT089_ALERT_3_C Poor Data / Parameter Ratio (Zmax .LT. 18) .....       7.20

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           25.02
           From the CIF: _reflns_number_total               1461
           Count of symmetry unique reflns         1507
           Completeness (_total/calc)             96.95%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no

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

   0 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
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check


checkCIF publication errors

Alert level A
PUBL022_ALERT_1_A There is a mismatched ~ on line 122
              In the crystal structure of the title compound, C~17~H~19~N~O~4~, the geometry
              If you require a ~ then it should be escaped
              with a \, i.e. \~
              Otherwise there must be a matching closing ~, e.g. C~2~H~4~

   1 ALERT level A = Data missing that is essential or data in wrong format
   0 ALERT level G = General alerts. Data that may be required is missing

---

Computing details

Data collection: XPRESS (MacScience, 2002); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003), ORTEPIII (Burnett & Johnson, 1996) and ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

2-Methyl-N-(3,4,5-trimethoxybenzylidene)aniline N-oxide

Crystal data

C17H19NO4	F(000) = 320
Mr = 301.33	Dx = 1.258 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 2564 reflections
a = 7.532 (8) Å	θ = 2.9–25.0°
b = 8.256 (9) Å	µ = 0.09 mm^−1
c = 12.872 (13) Å	T = 295 K
β = 96.283 (4)°	Block, pale yellow
V = 795.6 (15) Å^3	0.25 × 0.20 × 0.20 mm
Z = 2

Data collection

MacScience DIPLabo 32001 diffractometer	1375 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.029
Graphite monochromator	θmax = 25.0°, θmin = 2.9°
Detector resolution: 10.0 pixels mm^-1	h = −8→8
ω scans	k = −9→9
2564 measured reflections	l = −15→15
1461 independent reflections

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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.100	H-atom parameters constrained
S = 1.11	w = 1/[σ^2(Fo^2) + (0.0501P)^2 + 0.1017P] where P = (Fo^2 + 2Fc^2)/3
1461 reflections	(Δ/σ)max = 0.006
203 parameters	Δρmax = 0.12 e Å^−3
1 restraint	Δρmin = −0.15 e Å^−3

Special details

Experimental. The melting points were determined on SELACO-650 hot stage apparatus and are uncorrected. Infrared (IR) spectra were recorded using a Shimadzu 8300 spectrophotometer. ¹ HNMR, ¹³C NMR spectra were recorded on a Bruker AMX-500 MHz s pectrometer and chemical shifts are expressed in (p.p.m., for δ) relative to tetramethyl silane as internal standard. Spin multiplets are given as s (singlet), d (doublet), dd (doublet of doublets), t(triplet), q(quartet), and m(multiplet). Coupling constant (J) are given in hertz (Hz). ¹³C NMR spectra were acquired using the J modulated spin-echo technique where methyl and methane carbons appear as positive peaks and methylene and quaternary carbon resonance appear as negative peaks. Elemental analysis (C, H, N) was obtained on vario-EL Column and the results were within the acceptable limits of 0.4% of calculated values. Silica gel column chromatography was performed using Merck 7734 silica gel (60–130 mesh) and pre-coated silica gel plates.

¹ HNMR ((500 MHz, CDCl₃): δ 3.92 (S, 9H, OCH₃) 7.25–7.55 (m, 6H ArH), 7.72(S, 1H CH=N).

¹³C NMR (CDCl₃): δ 151.1, 141.0, 143.1, 130.1, 129.2, 128.6, 125.9, 124.2, 110.7, 56.8, 54.2, 16.4.

IR (KBr Cm^-1): 3061, 3018, 2976, 2874, 1608, 1540, 1266, 1150, 1041, 820, 720, 624.

Anal. calcd. for C₁₇H₁₉N_O4~: C, 67.76; H, 6.36; N, 4.65. Found: C, 67.72; H, 6.38; N, 4.69.

MS (ESI + ion): m/z = 303.16 [M+H]⁺.

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All e.s.d.'s are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F^2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F^2, conventional R-factors R are based on F, with F set to zero for negative F^2. The observed criterion of F^2 > σ(F^2) is used only for calculating -R-factor-obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2 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
O15	0.0908 (3)	0.2076 (3)	0.66639 (16)	0.0719 (8)
O17	0.0575 (3)	0.2440 (3)	0.45840 (16)	0.0669 (7)
O19	0.2675 (3)	0.4408 (3)	0.36540 (14)	0.0627 (7)
O21	0.5946 (3)	0.4713 (4)	0.86252 (17)	0.0883 (9)
N7	0.6720 (3)	0.5561 (3)	0.79473 (16)	0.0551 (7)
C1	0.9697 (4)	0.8324 (4)	0.9605 (2)	0.0639 (10)
C2	1.1336 (4)	0.7961 (5)	0.9288 (2)	0.0636 (10)
C3	1.1450 (3)	0.6857 (4)	0.8494 (2)	0.0625 (10)
C4	0.9927 (3)	0.6106 (4)	0.8033 (2)	0.0568 (8)
C5	0.8298 (3)	0.6452 (4)	0.83919 (19)	0.0507 (8)
C6	0.8129 (3)	0.7579 (4)	0.91742 (19)	0.0584 (9)
C8	0.6216 (3)	0.5638 (3)	0.6954 (2)	0.0508 (8)
C9	0.4709 (3)	0.4805 (3)	0.63900 (19)	0.0484 (8)
C10	0.4455 (3)	0.5023 (3)	0.5305 (2)	0.0503 (8)
C11	0.3041 (3)	0.4276 (3)	0.47091 (19)	0.0490 (8)
C12	0.1887 (3)	0.3276 (3)	0.5194 (2)	0.0514 (8)
C13	0.2132 (3)	0.3058 (3)	0.6269 (2)	0.0516 (8)
C14	0.3534 (3)	0.3821 (4)	0.6877 (2)	0.0520 (8)
C16	0.1207 (5)	0.1574 (5)	0.7710 (3)	0.0826 (14)
C18	−0.1131 (4)	0.3202 (5)	0.4492 (3)	0.0828 (11)
C20	0.3716 (5)	0.5488 (6)	0.3129 (3)	0.0899 (15)
C22	0.6358 (4)	0.8031 (6)	0.9538 (3)	0.0862 (13)
H1	0.96330	0.90960	1.01270	0.0770*
H2	1.23620	0.84570	0.96070	0.0760*
H3	1.25530	0.66190	0.82690	0.0750*
H4	0.99910	0.53770	0.74880	0.0680*
H8	0.68890	0.62960	0.65600	0.0610*
H10	0.52400	0.56730	0.49810	0.0600*
H14	0.36870	0.36760	0.75970	0.0620*
H16A	0.23760	0.11050	0.78390	0.1240*
H16B	0.03260	0.07840	0.78450	0.1240*
H16C	0.11220	0.24910	0.81610	0.1240*
H18A	−0.15660	0.32390	0.51660	0.1240*
H18B	−0.19490	0.25960	0.40170	0.1240*
H18C	−0.10280	0.42840	0.42330	0.1240*
H20A	0.36550	0.65500	0.34280	0.1350*
H20B	0.32680	0.55250	0.24020	0.1350*
H20C	0.49340	0.51260	0.32010	0.1350*
H22A	0.55140	0.82660	0.89430	0.1300*
H22B	0.65070	0.89700	0.99790	0.1300*
H22C	0.59250	0.71460	0.99230	0.1300*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O15	0.0739 (12)	0.0750 (15)	0.0673 (12)	−0.0275 (12)	0.0104 (9)	0.0046 (12)
O17	0.0667 (12)	0.0603 (13)	0.0726 (12)	−0.0183 (11)	0.0028 (9)	−0.0159 (10)
O19	0.0714 (12)	0.0649 (13)	0.0511 (10)	−0.0146 (11)	0.0040 (8)	−0.0059 (9)
O21	0.0778 (13)	0.119 (2)	0.0660 (13)	−0.0364 (16)	−0.0018 (10)	0.0233 (14)
N7	0.0469 (10)	0.0640 (14)	0.0539 (12)	−0.0072 (11)	0.0033 (9)	0.0077 (11)
C1	0.0606 (15)	0.077 (2)	0.0532 (14)	−0.0048 (16)	0.0023 (11)	−0.0129 (15)
C2	0.0480 (13)	0.079 (2)	0.0626 (16)	−0.0103 (15)	0.0000 (11)	0.0002 (16)
C3	0.0430 (13)	0.074 (2)	0.0705 (17)	−0.0005 (14)	0.0061 (11)	−0.0012 (16)
C4	0.0512 (14)	0.0607 (16)	0.0585 (14)	0.0022 (14)	0.0066 (11)	−0.0026 (14)
C5	0.0425 (12)	0.0602 (16)	0.0481 (13)	−0.0003 (12)	−0.0004 (9)	0.0063 (12)
C6	0.0498 (13)	0.078 (2)	0.0471 (13)	0.0031 (15)	0.0046 (10)	−0.0028 (14)
C8	0.0487 (13)	0.0492 (14)	0.0540 (14)	−0.0021 (12)	0.0035 (10)	0.0011 (12)
C9	0.0458 (12)	0.0441 (14)	0.0554 (14)	0.0010 (12)	0.0056 (10)	−0.0024 (12)
C10	0.0504 (13)	0.0445 (14)	0.0565 (13)	−0.0039 (12)	0.0076 (10)	−0.0029 (11)
C11	0.0542 (13)	0.0417 (14)	0.0513 (13)	−0.0003 (12)	0.0066 (10)	−0.0059 (11)
C12	0.0529 (13)	0.0432 (14)	0.0582 (14)	−0.0036 (12)	0.0060 (10)	−0.0094 (11)
C13	0.0502 (13)	0.0429 (14)	0.0629 (15)	−0.0038 (12)	0.0113 (11)	−0.0041 (12)
C14	0.0554 (14)	0.0474 (14)	0.0535 (13)	0.0009 (13)	0.0075 (11)	−0.0016 (12)
C16	0.084 (2)	0.085 (3)	0.081 (2)	−0.016 (2)	0.0191 (17)	0.018 (2)
C18	0.0625 (17)	0.081 (2)	0.100 (2)	−0.0145 (18)	−0.0130 (15)	0.005 (2)
C20	0.106 (3)	0.108 (3)	0.0558 (16)	−0.036 (3)	0.0095 (17)	0.008 (2)
C22	0.0565 (16)	0.124 (3)	0.080 (2)	0.002 (2)	0.0164 (14)	−0.028 (2)

Geometric parameters (Å, º)

O15—C13	1.367 (4)	C12—C13	1.388 (4)
O15—C16	1.403 (5)	C13—C14	1.394 (4)
O17—C12	1.378 (4)	C1—H1	0.9312
O17—C18	1.424 (4)	C2—H2	0.9295
O19—C11	1.360 (3)	C3—H3	0.9302
O19—C20	1.408 (5)	C4—H4	0.9296
O21—N7	1.305 (4)	C8—H8	0.9303
N7—C5	1.460 (4)	C10—H10	0.9303
N7—C8	1.295 (4)	C14—H14	0.9291
C1—C2	1.375 (5)	C16—H16A	0.9596
C1—C6	1.392 (4)	C16—H16B	0.9598
C2—C3	1.379 (5)	C16—H16C	0.9604
C3—C4	1.380 (4)	C18—H18A	0.9608
C4—C5	1.387 (4)	C18—H18B	0.9598
C5—C6	1.387 (4)	C18—H18C	0.9596
C6—C22	1.508 (4)	C20—H20A	0.9607
C8—C9	1.452 (4)	C20—H20B	0.9599
C9—C10	1.400 (4)	C20—H20C	0.9596
C9—C14	1.399 (4)	C22—H22A	0.9601
C10—C11	1.387 (4)	C22—H22B	0.9601
C11—C12	1.395 (4)	C22—H22C	0.9598
O15···O17	2.678 (4)	C16···H14	2.5654
O15···C18	3.178 (6)	C20···H10	2.5348
O17···O19	2.644 (4)	C22···H2^ix	3.0412
O17···O15	2.678 (4)	H1···H22B	2.3436
O19···C8^i	3.338 (5)	H1···C3^x	3.0544
O19···O17	2.644 (4)	H1···C4^x	2.8812
O19···C18	3.324 (5)	H1···C5^x	3.0325
O21···C22	2.983 (7)	H2···C22^xi	3.0412
O21···C22^ii	3.381 (6)	H2···O21^x	2.6912
O21···C14	2.831 (5)	H3···C14^xi	3.0631
O15···H18C^iii	2.5840	H4···C8	2.8593
O15···H18A	2.7065	H4···C13^xi	3.0466
O17···H8^i	2.7064	H8···C4	2.8117
O19···H8^i	2.6086	H8···H10	2.3207
O21···H14	2.2106	H8···O17^v	2.7064
O21···H22C	2.6137	H8···O19^v	2.6086
O21···H2^iv	2.6912	H8···C11^v	2.9569
O21···H22B^ii	2.7829	H8···C12^v	3.0125
N7···H14	2.7602	H10···C20	2.5348
N7···H22A	2.7767	H10···H8	2.3207
C8···O19^v	3.338 (5)	H10···H20A	2.3288
C14···C20^i	3.445 (7)	H10···H20C	2.3219
C14···O21	2.831 (5)	H10···C12^v	3.0755
C18···O19	3.324 (5)	H14···O21	2.2106
C18···O15	3.178 (6)	H14···N7	2.7602
C20···C14^v	3.445 (7)	H14···C16	2.5654
C22···O21	2.983 (7)	H14···H16A	2.3759
C22···O21^vi	3.381 (6)	H14···H16C	2.3502
C1···H16C^vi	3.0840	H16A···C14	2.7493
C2···H16B^vii	3.0251	H16A···H14	2.3759
C3···H1^iv	3.0544	H16B···C2^xii	3.0251
C4···H1^iv	2.8812	H16C···C14	2.8098
C4···H8	2.8117	H16C···H14	2.3502
C5···H1^iv	3.0325	H16C···C1^ii	3.0840
C8···H4	2.8593	H18A···O15	2.7065
C9···H20A^i	2.9550	H18A···C13	2.9884
C10···H20A	2.7333	H18B···C10^iii	3.0327
C10···H18B^viii	3.0327	H18C···C11	3.0590
C10···H20C	2.7724	H18C···O15^viii	2.5840
C11···H8^i	2.9569	H20A···C10	2.7333
C11···H18C	3.0590	H20A···H10	2.3288
C12···H8^i	3.0125	H20A···C9^v	2.9550
C12···H10^i	3.0755	H20A···C14^v	2.8869
C13···H18A	2.9884	H20C···C10	2.7724
C13···H4^ix	3.0466	H20C···H10	2.3219
C14···H16A	2.7493	H22A···N7	2.7767
C14···H20A^i	2.8869	H22B···H1	2.3436
C14···H16C	2.8098	H22B···O21^vi	2.7829
C14···H3^ix	3.0631	H22C···O21	2.6137
C13—O15—C16	119.2 (2)	C2—C3—H3	120.03
C12—O17—C18	114.2 (2)	C4—C3—H3	120.00
C11—O19—C20	117.9 (2)	C3—C4—H4	120.41
O21—N7—C5	114.3 (2)	C5—C4—H4	120.36
O21—N7—C8	125.6 (2)	N7—C8—H8	116.65
C5—N7—C8	120.0 (2)	C9—C8—H8	116.54
C2—C1—C6	122.4 (3)	C9—C10—H10	119.81
C1—C2—C3	119.7 (3)	C11—C10—H10	119.72
C2—C3—C4	120.0 (2)	C9—C14—H14	120.42
C3—C4—C5	119.2 (3)	C13—C14—H14	120.36
N7—C5—C4	118.5 (2)	O15—C16—H16A	109.46
N7—C5—C6	119.1 (2)	O15—C16—H16B	109.44
C4—C5—C6	122.3 (2)	O15—C16—H16C	109.44
C1—C6—C5	116.4 (2)	H16A—C16—H16B	109.51
C1—C6—C22	120.5 (3)	H16A—C16—H16C	109.52
C5—C6—C22	123.1 (3)	H16B—C16—H16C	109.46
N7—C8—C9	126.8 (2)	O17—C18—H18A	109.44
C8—C9—C10	116.9 (2)	O17—C18—H18B	109.46
C8—C9—C14	123.3 (2)	O17—C18—H18C	109.49
C10—C9—C14	119.8 (2)	H18A—C18—H18B	109.46
C9—C10—C11	120.5 (2)	H18A—C18—H18C	109.43
O19—C11—C10	125.2 (2)	H18B—C18—H18C	109.55
O19—C11—C12	115.2 (2)	O19—C20—H20A	109.40
C10—C11—C12	119.6 (2)	O19—C20—H20B	109.47
O17—C12—C11	119.0 (2)	O19—C20—H20C	109.46
O17—C12—C13	120.8 (2)	H20A—C20—H20B	109.54
C11—C12—C13	120.1 (2)	H20A—C20—H20C	109.43
O15—C13—C12	115.2 (2)	H20B—C20—H20C	109.54
O15—C13—C14	124.0 (2)	C6—C22—H22A	109.46
C12—C13—C14	120.7 (2)	C6—C22—H22B	109.46
C9—C14—C13	119.2 (2)	C6—C22—H22C	109.51
C2—C1—H1	118.84	H22A—C22—H22B	109.44
C6—C1—H1	118.77	H22A—C22—H22C	109.45
C1—C2—H2	120.19	H22B—C22—H22C	109.50
C3—C2—H2	120.16
C16—O15—C13—C14	−10.8 (4)	N7—C5—C6—C22	−4.8 (5)
C16—O15—C13—C12	169.8 (3)	C4—C5—C6—C22	176.9 (3)
C18—O17—C12—C13	86.4 (3)	N7—C8—C9—C14	2.4 (4)
C18—O17—C12—C11	−97.4 (3)	N7—C8—C9—C10	−177.7 (2)
C20—O19—C11—C10	−5.5 (4)	C8—C9—C10—C11	−179.7 (2)
C20—O19—C11—C12	175.7 (3)	C8—C9—C14—C13	−179.4 (2)
C8—N7—C5—C4	−59.8 (4)	C10—C9—C14—C13	0.6 (4)
C5—N7—C8—C9	178.7 (2)	C14—C9—C10—C11	0.3 (4)
O21—N7—C8—C9	−0.3 (4)	C9—C10—C11—O19	180.0 (2)
O21—N7—C5—C6	−59.0 (4)	C9—C10—C11—C12	−1.3 (4)
C8—N7—C5—C6	121.9 (3)	O19—C11—C12—C13	−179.8 (2)
O21—N7—C5—C4	119.3 (3)	C10—C11—C12—O17	−174.9 (2)
C2—C1—C6—C5	−0.7 (4)	O19—C11—C12—O17	4.0 (3)
C2—C1—C6—C22	−179.3 (3)	C10—C11—C12—C13	1.3 (4)
C6—C1—C2—C3	2.0 (5)	C11—C12—C13—O15	179.0 (2)
C1—C2—C3—C4	−1.0 (5)	C11—C12—C13—C14	−0.5 (4)
C2—C3—C4—C5	−1.3 (5)	O17—C12—C13—O15	−4.9 (3)
C3—C4—C5—N7	−175.7 (3)	O17—C12—C13—C14	175.7 (2)
C3—C4—C5—C6	2.6 (5)	O15—C13—C14—C9	−179.9 (2)
C4—C5—C6—C1	−1.6 (4)	C12—C13—C14—C9	−0.5 (4)
N7—C5—C6—C1	176.6 (3)

Symmetry codes: (i) −x+1, y−1/2, −z+1; (ii) −x+1, y−1/2, −z+2; (iii) −x, y−1/2, −z+1; (iv) −x+2, y−1/2, −z+2; (v) −x+1, y+1/2, −z+1; (vi) −x+1, y+1/2, −z+2; (vii) x+1, y+1, z; (viii) −x, y+1/2, −z+1; (ix) x−1, y, z; (x) −x+2, y+1/2, −z+2; (xi) x+1, y, z; (xii) x−1, y−1, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C14—H14···O21	0.93	2.21	2.831 (5)	123
C18—H18C···O15^viii	0.96	2.58	3.539 (6)	174

Symmetry code: (viii) −x, y+1/2, −z+1.