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The title compound, C19H14O6, is a derivative of 2,3-dioxo-2,3-di­hydro­furan. The furan ring is essentially planar and the phenyl rings in the methoxy­phenyl and methoxy­benzoyl groups are not parallel to each other. The furan and phenyl rings are not coplanar. In the crystal, there are two weak C—H...O-type intermolecular interactions.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801020669/wn6074sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801020669/wn6074Isup2.hkl
Contains datablock I

CCDC reference: 180535

Key indicators

  • Single-crystal X-ray study
  • T = 293 K
  • Mean [sigma](C-C) = 0.005 Å
  • R factor = 0.045
  • wR factor = 0.116
  • Data-to-parameter ratio = 10.2

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Yellow Alert Alert Level C:
THETM_01 Alert C The value of sine(theta_max)/wavelength is less than 0.590 Calculated sin(theta_max)/wavelength = 0.5768 PLAT_369 Alert C Long C(sp2)-C(sp2) Bond C(1) - C(2) = 1.53 Ang.
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
2 Alert Level C = Please check

Comment top

Recently, reactions of cyclic oxalyl compounds have been reported to give substituted heterocyclic compounds (Kollenz et al., 1991). The reactions of substituted 2,3-furandiones with various dienophiles (Akçamur & Kollenz, 1987; Kollenz et al., 1984, 1991) or nucleophiles (Akçamur et al., 1997) in different solvents and at various temperatures have also been studied. A convenient method for the synthesis, together with mechanisms of reactions and calculations on the interaction of 2,3-dioxo-2,3-dihydrofurans with several semicarbazones, ureas and their thio-analogues have been reported recently (Altural et al., 1989; Yıldırım et al., 1995).

Thermal decomposition of 2,3-dioxo-2,3-dihydrofurans leads to the formation of reactive α-oxoketene (acylketene) intermediates (Kollenz et al., 1972; Ziegler et al., 1977). α-Oxoketenes are highly reactive molecules which can be trapped by nucleophiles to give β-ketocarboxylic acid derivatives (Yıldırım & Ílhan, 1997) or alternatively undergo cycloaddition reactions (Sarıpınar et al., 2001; Kollenz et al., 1977; Ziegler et al., 1977).

Fig. 1 shows the title compound, (I), with the atomic numbering. The bond lengths and angles are in accordance with other reported values. The furan ring is almostly planar [C1—C2—C3—C4 = -3.3 (3)°], due to strong overlap of the p-orbitals.

An examination of the deviations from the least-squares planes through the individual rings shows that rings A(O1/C1–C4), B(C6–C11) and C(C13–C18) are nearly planar with maximum deviations for atoms C2 [-0.019 (4) Å], C9 [-0.021 (4) Å] and C16 [-0.019 (3) Å]. The phenyl rings in the 4-methoxybenzoyl and 4-methoxyphenyl groups are not parallel to each other, the angle between these rings being 79.9 (1)°. The dihedral angles between the phenyl rings and the furan ring are A/B = 77.5 (1)° and A/C = 6.3 (1)°.

The coplanarity of methoxy carbon with the phenyl rings [0.280 (4) Å for C12 and 0.063 (4) Å for C19] results in a close approach between C9 and C10 [1.379 (4) Å] and between C15 and C16 [1.384 (4) Å] and this causes widening of C10—C9—O5 [124.5 (3)°] and C15—C16—O6 [124.8 (3)°] and narrowing of C8—C9—O5 [115.8 (3)°] and C17—C16—O6 [115.8 (3)°] from 120°. Atoms O2 and O3 are nearly coplanar with the furan ring [O1—C1—C2—O3 = -177.9 (3)°, O2—C1—C2—C3 = -177.2 (4)°].

A quantum-chemical calculation using the AM1 technique showed that the charges on atoms C1 and C2 are 0.334 and 0.187 e-, respectively, whereas the charges on atoms C3 and C4 are -0.360 and 0.230 e-, respectively. Atoms O2 and O3 have charges of -0.210 and -0.203 e-, respectively (Yılmaz, 2000).

The molecules in the crystal structure are bonded by van der Waals interactions. As can be seen from the packing diagram (Fig. 2), there are two intermolecular hydrogen bonds involving O3 atoms [(C12)H12C···O3(1 + x, y, z) = 2.494 Å and (C19)H19A···O3(1 + x, -1 + y, z) = 2.577 Å] and one intramolecular hydrogen bond [(C18)H18···O1 = 2.395 Å].

Experimental top

3.0 g (10.6 mmol) of p,p'-dimethoxydibenzoylmethane was dissolved in 100 ml of dry diethyl ether, 1 ml (11.7 mmol) of oxalyl chloride was added and the mixture kept at room temperature for 48 h. The liquid phase was pipetted from the yellow crystals. It was washed several times with dry diethylether; yield 2.4 g (67%), m.p. 428 K. Solvents were dried by refluxing with the appropriate drying agent and distilled before use. Melting points were determined on the Electrothermal 9200 apparatus and uncorrected. Elemental analysis was performed with the Carlo Erba Elemental Analyzer, 1108. IR spectra were recorded on a Shimadzu 435 V-04 apparatus, using potassium bromide tablets. The 1H and 13C NMR spectra were obtained on a Gemini-Varian 200 instrument. The chemical shifts are reported in p.p.m. from tetramethylsilane and given in d units. IR (KBr): ν =1810 cm-1 (C2O); 1720 (C3 O); 1645 (Ar—CO); 1600 (CC). 1H-NMR (CDCl3): δ = 3.87 p.p.m. (3H, CH3O); 3.88 (3H, CH3O); 6.92 (2H, Ar—H); 6.94 (2H, Ar—H); 6.97 (2Ar-H); 7.90 (2H, Ar—H); 13C NMR (CDCl3): δ = 187.81 p.p.m. (C6); 176.46 (C3); 175.84 (C5); 154.53 (C2); 118.2 (C4); 166.62–114.74 (aromatic C); 56.35 (CH3O); 56.11 (CH3O). Found: C 67.62; H 4.13%; calculated for C19H14O6: C 67.45; H 4.17%.

Refinement top

H atoms were placed geometrically and refined using the usual riding model.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; 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: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. An ORTEPII (Johnson, 1976) drawing of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. Packing diagram for the title compound. Hydrogen bonds are shown as dotted lines.
(I) top
Crystal data top
C19H14O6F(000) = 704
Mr = 338.3Dx = 1.433 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 25 reflections
a = 8.3574 (10) Åθ = 10–18°
b = 9.5422 (10) ŵ = 0.11 mm1
c = 19.775 (2) ÅT = 293 K
β = 96.197 (8)°Rod-shaped, colorless
V = 1567.8 (3) Å30.3 × 0.25 × 0.2 mm
Z = 4
Data collection top
Enraf-Nonius Turbo-CAD-4
diffractometer
Rint = 0.019
non–profiled ω/2θ scansθmax = 24.2°, θmin = 2.4°
Absorption correction: ψ scan
(MolEN; Fair, 1990)
h = 99
Tmin = 0.968, Tmax = 0.979k = 1111
2479 measured reflectionsl = 2222
2395 independent reflections3 standard reflections every 120 min
1188 reflections with I > 2σ(I) intensity decay: none
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.045 w = 1/[σ2(Fo2) + (0.0507P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.116(Δ/σ)max = 0.001
S = 0.98Δρmax = 0.15 e Å3
2300 reflectionsΔρmin = 0.22 e Å3
226 parameters
Crystal data top
C19H14O6V = 1567.8 (3) Å3
Mr = 338.3Z = 4
Monoclinic, P21/nMo Kα radiation
a = 8.3574 (10) ŵ = 0.11 mm1
b = 9.5422 (10) ÅT = 293 K
c = 19.775 (2) Å0.3 × 0.25 × 0.2 mm
β = 96.197 (8)°
Data collection top
Enraf-Nonius Turbo-CAD-4
diffractometer
1188 reflections with I > 2σ(I)
Absorption correction: ψ scan
(MolEN; Fair, 1990)
Rint = 0.019
Tmin = 0.968, Tmax = 0.9793 standard reflections every 120 min
2479 measured reflections intensity decay: none
2395 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0450 restraints
wR(F2) = 0.116H-atom parameters constrained
S = 0.98Δρmax = 0.15 e Å3
2300 reflectionsΔρmin = 0.22 e Å3
226 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O60.5005 (3)0.2114 (2)1.00187 (13)0.0570 (7)
C190.5758 (5)0.1314 (4)1.0580 (2)0.0733 (13)
H19A0.63880.05761.04120.11*
H19B0.49460.09161.0830.11*
H19C0.64440.19141.08740.11*
O10.0380 (3)0.7298 (2)0.98265 (11)0.0437 (6)
O20.1373 (3)0.9064 (2)0.95772 (12)0.0523 (7)
O50.7175 (3)0.8604 (3)1.30417 (11)0.0635 (8)
C160.4062 (4)0.3205 (4)1.01637 (18)0.0427 (9)
O30.1266 (3)0.9238 (3)1.10754 (12)0.0622 (7)
C40.1114 (4)0.6713 (3)1.04403 (17)0.0393 (9)
C130.2095 (4)0.5512 (3)1.03394 (17)0.0377 (8)
C10.0614 (4)0.8368 (4)0.99964 (18)0.0417 (9)
C60.2749 (4)0.7437 (3)1.20470 (16)0.0404 (9)
C30.0671 (4)0.7371 (3)1.09969 (17)0.0389 (9)
C180.2406 (4)0.5086 (3)0.96916 (17)0.0415 (9)
H180.19580.55840.93130.05*
C150.3731 (4)0.3577 (4)1.08106 (18)0.0466 (9)
H150.41560.3061.11860.056*
C170.3358 (4)0.3950 (4)0.96036 (18)0.0449 (9)
H170.35350.36730.91670.054*
C140.2769 (4)0.4716 (3)1.08922 (17)0.0443 (9)
H140.25590.49671.13280.053*
C100.5311 (4)0.8602 (4)1.20126 (16)0.0522 (10)
H100.60040.91181.17720.063*
C110.3825 (4)0.8196 (4)1.17067 (16)0.0481 (10)
H110.35330.8441.12550.058*
O40.0099 (3)0.6634 (3)1.20688 (13)0.0735 (9)
C50.1131 (5)0.7083 (3)1.17384 (17)0.0466 (10)
C20.0492 (4)0.8425 (4)1.07723 (18)0.0456 (9)
C90.5758 (4)0.8234 (4)1.26806 (17)0.0487 (10)
C80.4738 (5)0.7415 (4)1.30239 (17)0.0576 (11)
H80.50590.71271.34670.069*
C70.3262 (5)0.7030 (4)1.27137 (17)0.0555 (10)
H70.25870.64861.29510.067*
C120.8156 (5)0.9598 (4)1.27410 (19)0.0679 (12)
H12A0.91170.97671.30420.102*
H12B0.75731.0461.26620.102*
H12C0.8440.92371.23170.102*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O60.0611 (16)0.0399 (15)0.0703 (17)0.0112 (14)0.0088 (14)0.0005 (13)
C190.069 (3)0.054 (3)0.093 (3)0.019 (2)0.014 (2)0.001 (2)
O10.0492 (16)0.0385 (14)0.0422 (14)0.0032 (12)0.0003 (12)0.0006 (11)
O20.0505 (17)0.0456 (16)0.0578 (16)0.0004 (13)0.0072 (13)0.0074 (14)
O50.0648 (19)0.078 (2)0.0438 (15)0.0049 (16)0.0133 (14)0.0031 (14)
C160.043 (2)0.029 (2)0.058 (3)0.0048 (19)0.0098 (19)0.0016 (19)
O30.0638 (18)0.0582 (17)0.0661 (18)0.0129 (15)0.0143 (14)0.0044 (14)
C40.038 (2)0.036 (2)0.044 (2)0.0069 (19)0.0000 (18)0.0050 (19)
C130.034 (2)0.032 (2)0.047 (2)0.0006 (18)0.0039 (17)0.0014 (18)
C10.037 (2)0.035 (2)0.053 (2)0.0046 (19)0.0046 (19)0.000 (2)
C60.050 (2)0.040 (2)0.031 (2)0.0002 (19)0.0060 (18)0.0019 (17)
C30.039 (2)0.035 (2)0.043 (2)0.0013 (17)0.0051 (17)0.0001 (18)
C180.044 (2)0.037 (2)0.044 (2)0.0024 (18)0.0020 (18)0.0069 (17)
C150.052 (2)0.039 (2)0.047 (2)0.001 (2)0.0020 (19)0.0080 (18)
C170.049 (2)0.040 (2)0.047 (2)0.0061 (19)0.0087 (19)0.0005 (19)
C140.049 (2)0.041 (2)0.042 (2)0.002 (2)0.0010 (18)0.0046 (18)
C100.058 (3)0.060 (3)0.037 (2)0.013 (2)0.0001 (19)0.0059 (19)
C110.056 (3)0.056 (2)0.032 (2)0.007 (2)0.0009 (19)0.0061 (18)
O40.063 (2)0.093 (2)0.0685 (18)0.0066 (17)0.0221 (15)0.0247 (16)
C50.058 (3)0.040 (2)0.044 (2)0.002 (2)0.015 (2)0.0023 (18)
C20.053 (3)0.034 (2)0.051 (2)0.005 (2)0.010 (2)0.0031 (19)
C90.056 (3)0.053 (2)0.035 (2)0.001 (2)0.002 (2)0.003 (2)
C80.075 (3)0.069 (3)0.028 (2)0.004 (2)0.001 (2)0.009 (2)
C70.072 (3)0.057 (2)0.040 (2)0.001 (2)0.014 (2)0.006 (2)
C120.055 (3)0.088 (3)0.058 (3)0.008 (3)0.005 (2)0.008 (2)
Geometric parameters (Å, º) top
C19—H19A0.96C6—C111.384 (4)
C19—H19B0.96C6—C71.397 (4)
C19—H19C0.96C6—C51.462 (5)
O1—C11.381 (4)C18—C171.367 (4)
O1—C41.414 (4)C18—H180.93
O2—C11.191 (4)C15—C141.372 (4)
O4—C51.215 (4)C15—H150.93
O5—C91.362 (4)C17—H170.93
O5—C121.425 (4)C14—H140.93
O6—C161.355 (4)C10—C111.377 (4)
O6—C191.436 (4)C10—C91.379 (4)
C16—C151.384 (4)C10—H100.93
C16—C171.392 (4)C11—H110.93
O3—C21.210 (4)C9—C81.387 (5)
C1—C21.528 (5)C8—C71.368 (5)
C3—C21.436 (5)C8—H80.93
C3—C51.501 (5)C7—H70.93
C4—C31.353 (4)C12—H12A0.96
C4—C131.435 (4)C12—H12B0.96
C13—C181.395 (4)C12—H12C0.96
C13—C141.399 (4)
O6—C19—H19A109.5C17—C18—C13121.1 (3)
O6—C19—H19B109.5C17—C18—H18119.4
H19A—C19—H19B109.5C13—C18—H18119.4
O6—C19—H19C109.5C14—C15—C16119.3 (3)
H19A—C19—H19C109.5C14—C15—H15120.3
H19B—C19—H19C109.5C16—C15—H15120.3
C1—O1—C4107.4 (3)C18—C17—C16120.4 (3)
C9—O5—C12117.4 (3)C18—C17—H17119.8
C16—O6—C19117.5 (3)C16—C17—H17119.8
O2—C1—C2130.7 (3)C15—C14—C13122.0 (3)
O1—C1—C2107.1 (3)C15—C14—H14119
O3—C2—C3132.6 (3)C13—C14—H14119
C3—C2—C1104.8 (3)C11—C10—C9119.2 (3)
C4—C3—C2108.0 (3)C11—C10—H10120.4
C4—C3—C5130.3 (3)C9—C10—H10120.4
C3—C4—O1112.6 (3)C10—C11—C6122.4 (3)
C3—C4—C13133.9 (3)C10—C11—H11118.8
O1—C4—C13113.4 (3)C6—C11—H11118.8
O4—C5—C6122.4 (3)O3—C2—C1122.6 (3)
O4—C5—C3117.9 (3)O5—C9—C8115.8 (3)
C6—C5—C3119.6 (3)C10—C9—C8119.7 (4)
C7—C6—C5120.4 (3)C7—C8—C9120.3 (3)
O5—C9—C10124.5 (3)C7—C8—H8119.9
O6—C16—C15124.8 (3)C9—C8—H8119.9
O6—C16—C17115.4 (3)C8—C7—C6121.3 (3)
C15—C16—C17119.7 (3)C8—C7—H7119.4
C18—C13—C14117.4 (3)C6—C7—H7119.4
C18—C13—C4121.7 (3)O5—C12—H12A109.5
C14—C13—C4120.9 (3)O5—C12—H12B109.5
O2—C1—O1122.2 (3)H12A—C12—H12B109.5
C11—C6—C7117.0 (3)O5—C12—H12C109.5
C11—C6—C5122.6 (3)H12A—C12—H12C109.5
C2—C3—C5121.6 (3)H12B—C12—H12C109.5
C1—O1—C4—C31.3 (3)C11—C6—C5—O4167.1 (3)
C1—O1—C4—C13175.6 (2)C7—C6—C5—O411.9 (5)
C3—C4—C13—C18177.5 (3)C11—C6—C5—C38.6 (5)
O1—C4—C13—C186.5 (4)C7—C6—C5—C3172.5 (3)
C3—C4—C13—C143.0 (6)C4—C3—C5—O4111.2 (4)
O1—C4—C13—C14173.1 (3)C4—C3—C5—C673.0 (5)
C4—O1—C1—O2178.9 (3)C2—C3—C5—C6111.7 (4)
C4—O1—C1—C20.8 (3)C4—C3—C2—O3177.2 (4)
C2—C3—C5—O464.2 (4)C5—C3—C2—O30.9 (6)
O1—C4—C3—C23.0 (4)C4—C3—C2—C13.3 (3)
C13—C4—C3—C2173.1 (3)C5—C3—C2—C1179.5 (3)
O1—C4—C3—C5178.8 (3)O2—C1—C2—O32.4 (6)
C13—C4—C3—C52.7 (6)O1—C1—C2—O3177.9 (3)
C14—C13—C18—C171.2 (5)O2—C1—C2—C3177.2 (4)
C4—C13—C18—C17179.2 (3)O1—C1—C2—C32.5 (3)
O6—C16—C15—C14179.3 (3)C12—O5—C9—C109.3 (5)
C17—C16—C15—C142.9 (5)C12—O5—C9—C8171.6 (3)
C13—C18—C17—C161.1 (5)C11—C10—C9—O5178.3 (3)
O6—C16—C17—C18178.9 (3)C11—C10—C9—C82.7 (5)
C15—C16—C17—C183.2 (5)O5—C9—C8—C7177.7 (3)
C16—C15—C14—C130.6 (5)C10—C9—C8—C73.2 (5)
C18—C13—C14—C151.5 (5)C9—C8—C7—C60.5 (6)
C4—C13—C14—C15179.0 (3)C11—C6—C7—C82.6 (5)
C9—C10—C11—C60.5 (5)C5—C6—C7—C8176.4 (3)
C7—C6—C11—C103.1 (5)C19—O6—C16—C152.2 (5)
C5—C6—C11—C10175.9 (3)C19—O6—C16—C17180.0 (3)

Experimental details

Crystal data
Chemical formulaC19H14O6
Mr338.3
Crystal system, space groupMonoclinic, P21/n
Temperature (K)293
a, b, c (Å)8.3574 (10), 9.5422 (10), 19.775 (2)
β (°) 96.197 (8)
V3)1567.8 (3)
Z4
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.3 × 0.25 × 0.2
Data collection
DiffractometerEnraf-Nonius Turbo-CAD-4
diffractometer
Absorption correctionψ scan
(MolEN; Fair, 1990)
Tmin, Tmax0.968, 0.979
No. of measured, independent and
observed [I > 2σ(I)] reflections
2479, 2395, 1188
Rint0.019
(sin θ/λ)max1)0.577
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.116, 0.98
No. of reflections2300
No. of parameters226
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.15, 0.22

Computer programs: CAD-4 EXPRESS (Enraf-Nonius, 1994), CAD-4 EXPRESS, XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEPII (Johnson, 1976), SHELXL97.

Selected geometric parameters (Å, º) top
O1—C11.381 (4)O6—C191.436 (4)
O1—C41.414 (4)C1—C21.528 (5)
O2—C11.191 (4)C3—C21.436 (5)
O4—C51.215 (4)C3—C51.501 (5)
O5—C91.362 (4)C4—C31.353 (4)
O5—C121.425 (4)C4—C131.435 (4)
O6—C161.355 (4)C6—C51.462 (5)
C1—O1—C4107.4 (3)C3—C4—C13133.9 (3)
C9—O5—C12117.4 (3)O1—C4—C13113.4 (3)
C16—O6—C19117.5 (3)O4—C5—C6122.4 (3)
O2—C1—C2130.7 (3)O4—C5—C3117.9 (3)
O1—C1—C2107.1 (3)C6—C5—C3119.6 (3)
O3—C2—C3132.6 (3)C7—C6—C5120.4 (3)
C3—C2—C1104.8 (3)O5—C9—C10124.5 (3)
C4—C3—C2108.0 (3)O6—C16—C15124.8 (3)
C4—C3—C5130.3 (3)O6—C16—C17115.4 (3)
C3—C4—O1112.6 (3)C15—C16—C17119.7 (3)
C2—C3—C5—O464.2 (4)C12—O5—C9—C8171.6 (3)
C11—C6—C5—O4167.1 (3)C19—O6—C16—C152.2 (5)
C11—C6—C5—C38.6 (5)C19—O6—C16—C17180.0 (3)
C12—O5—C9—C109.3 (5)
 

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