Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801020669/wn6074sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801020669/wn6074Isup2.hkl |
CCDC reference: 180535
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 (C2═O); 1720 (C3═ O); 1645 (Ar—C═O); 1600 (C═C). 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%.
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.
C19H14O6 | F(000) = 704 |
Mr = 338.3 | Dx = 1.433 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 25 reflections |
a = 8.3574 (10) Å | θ = 10–18° |
b = 9.5422 (10) Å | µ = 0.11 mm−1 |
c = 19.775 (2) Å | T = 293 K |
β = 96.197 (8)° | Rod-shaped, colorless |
V = 1567.8 (3) Å3 | 0.3 × 0.25 × 0.2 mm |
Z = 4 |
Enraf-Nonius Turbo-CAD-4 diffractometer | Rint = 0.019 |
non–profiled ω/2θ scans | θmax = 24.2°, θmin = 2.4° |
Absorption correction: ψ scan (MolEN; Fair, 1990) | h = −9→9 |
Tmin = 0.968, Tmax = 0.979 | k = −11→11 |
2479 measured reflections | l = −22→22 |
2395 independent reflections | 3 standard reflections every 120 min |
1188 reflections with I > 2σ(I) | intensity decay: none |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | H-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 = 0.98 | Δρmax = 0.15 e Å−3 |
2300 reflections | Δρmin = −0.22 e Å−3 |
226 parameters |
C19H14O6 | V = 1567.8 (3) Å3 |
Mr = 338.3 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 8.3574 (10) Å | µ = 0.11 mm−1 |
b = 9.5422 (10) Å | T = 293 K |
c = 19.775 (2) Å | 0.3 × 0.25 × 0.2 mm |
β = 96.197 (8)° |
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 = 0.979 | 3 standard reflections every 120 min |
2479 measured reflections | intensity decay: none |
2395 independent reflections |
R[F2 > 2σ(F2)] = 0.045 | 0 restraints |
wR(F2) = 0.116 | H-atom parameters constrained |
S = 0.98 | Δρmax = 0.15 e Å−3 |
2300 reflections | Δρmin = −0.22 e Å−3 |
226 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
O6 | 0.5005 (3) | 0.2114 (2) | 1.00187 (13) | 0.0570 (7) | |
C19 | 0.5758 (5) | 0.1314 (4) | 1.0580 (2) | 0.0733 (13) | |
H19A | 0.6388 | 0.0576 | 1.0412 | 0.11* | |
H19B | 0.4946 | 0.0916 | 1.083 | 0.11* | |
H19C | 0.6444 | 0.1914 | 1.0874 | 0.11* | |
O1 | 0.0380 (3) | 0.7298 (2) | 0.98265 (11) | 0.0437 (6) | |
O2 | −0.1373 (3) | 0.9064 (2) | 0.95772 (12) | 0.0523 (7) | |
O5 | 0.7175 (3) | 0.8604 (3) | 1.30417 (11) | 0.0635 (8) | |
C16 | 0.4062 (4) | 0.3205 (4) | 1.01637 (18) | 0.0427 (9) | |
O3 | −0.1266 (3) | 0.9238 (3) | 1.10754 (12) | 0.0622 (7) | |
C4 | 0.1114 (4) | 0.6713 (3) | 1.04403 (17) | 0.0393 (9) | |
C13 | 0.2095 (4) | 0.5512 (3) | 1.03394 (17) | 0.0377 (8) | |
C1 | −0.0614 (4) | 0.8368 (4) | 0.99964 (18) | 0.0417 (9) | |
C6 | 0.2749 (4) | 0.7437 (3) | 1.20470 (16) | 0.0404 (9) | |
C3 | 0.0671 (4) | 0.7371 (3) | 1.09969 (17) | 0.0389 (9) | |
C18 | 0.2406 (4) | 0.5086 (3) | 0.96916 (17) | 0.0415 (9) | |
H18 | 0.1958 | 0.5584 | 0.9313 | 0.05* | |
C15 | 0.3731 (4) | 0.3577 (4) | 1.08106 (18) | 0.0466 (9) | |
H15 | 0.4156 | 0.306 | 1.1186 | 0.056* | |
C17 | 0.3358 (4) | 0.3950 (4) | 0.96036 (18) | 0.0449 (9) | |
H17 | 0.3535 | 0.3673 | 0.9167 | 0.054* | |
C14 | 0.2769 (4) | 0.4716 (3) | 1.08922 (17) | 0.0443 (9) | |
H14 | 0.2559 | 0.4967 | 1.1328 | 0.053* | |
C10 | 0.5311 (4) | 0.8602 (4) | 1.20126 (16) | 0.0522 (10) | |
H10 | 0.6004 | 0.9118 | 1.1772 | 0.063* | |
C11 | 0.3825 (4) | 0.8196 (4) | 1.17067 (16) | 0.0481 (10) | |
H11 | 0.3533 | 0.844 | 1.1255 | 0.058* | |
O4 | 0.0099 (3) | 0.6634 (3) | 1.20688 (13) | 0.0735 (9) | |
C5 | 0.1131 (5) | 0.7083 (3) | 1.17384 (17) | 0.0466 (10) | |
C2 | −0.0492 (4) | 0.8425 (4) | 1.07723 (18) | 0.0456 (9) | |
C9 | 0.5758 (4) | 0.8234 (4) | 1.26806 (17) | 0.0487 (10) | |
C8 | 0.4738 (5) | 0.7415 (4) | 1.30239 (17) | 0.0576 (11) | |
H8 | 0.5059 | 0.7127 | 1.3467 | 0.069* | |
C7 | 0.3262 (5) | 0.7030 (4) | 1.27137 (17) | 0.0555 (10) | |
H7 | 0.2587 | 0.6486 | 1.2951 | 0.067* | |
C12 | 0.8156 (5) | 0.9598 (4) | 1.27410 (19) | 0.0679 (12) | |
H12A | 0.9117 | 0.9767 | 1.3042 | 0.102* | |
H12B | 0.7573 | 1.046 | 1.2662 | 0.102* | |
H12C | 0.844 | 0.9237 | 1.2317 | 0.102* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O6 | 0.0611 (16) | 0.0399 (15) | 0.0703 (17) | 0.0112 (14) | 0.0088 (14) | −0.0005 (13) |
C19 | 0.069 (3) | 0.054 (3) | 0.093 (3) | 0.019 (2) | −0.014 (2) | 0.001 (2) |
O1 | 0.0492 (16) | 0.0385 (14) | 0.0422 (14) | 0.0032 (12) | −0.0003 (12) | 0.0006 (11) |
O2 | 0.0505 (17) | 0.0456 (16) | 0.0578 (16) | −0.0004 (13) | −0.0072 (13) | 0.0074 (14) |
O5 | 0.0648 (19) | 0.078 (2) | 0.0438 (15) | −0.0049 (16) | −0.0133 (14) | 0.0031 (14) |
C16 | 0.043 (2) | 0.029 (2) | 0.058 (3) | −0.0048 (19) | 0.0098 (19) | −0.0016 (19) |
O3 | 0.0638 (18) | 0.0582 (17) | 0.0661 (18) | 0.0129 (15) | 0.0143 (14) | −0.0044 (14) |
C4 | 0.038 (2) | 0.036 (2) | 0.044 (2) | −0.0069 (19) | 0.0000 (18) | 0.0050 (19) |
C13 | 0.034 (2) | 0.032 (2) | 0.047 (2) | −0.0006 (18) | 0.0039 (17) | 0.0014 (18) |
C1 | 0.037 (2) | 0.035 (2) | 0.053 (2) | −0.0046 (19) | 0.0046 (19) | 0.000 (2) |
C6 | 0.050 (2) | 0.040 (2) | 0.031 (2) | 0.0002 (19) | 0.0060 (18) | −0.0019 (17) |
C3 | 0.039 (2) | 0.035 (2) | 0.043 (2) | −0.0013 (17) | 0.0051 (17) | 0.0001 (18) |
C18 | 0.044 (2) | 0.037 (2) | 0.044 (2) | −0.0024 (18) | 0.0020 (18) | 0.0069 (17) |
C15 | 0.052 (2) | 0.039 (2) | 0.047 (2) | 0.001 (2) | −0.0020 (19) | 0.0080 (18) |
C17 | 0.049 (2) | 0.040 (2) | 0.047 (2) | −0.0061 (19) | 0.0087 (19) | −0.0005 (19) |
C14 | 0.049 (2) | 0.041 (2) | 0.042 (2) | −0.002 (2) | 0.0010 (18) | −0.0046 (18) |
C10 | 0.058 (3) | 0.060 (3) | 0.037 (2) | −0.013 (2) | −0.0001 (19) | 0.0059 (19) |
C11 | 0.056 (3) | 0.056 (2) | 0.032 (2) | −0.007 (2) | 0.0009 (19) | 0.0061 (18) |
O4 | 0.063 (2) | 0.093 (2) | 0.0685 (18) | −0.0066 (17) | 0.0221 (15) | 0.0247 (16) |
C5 | 0.058 (3) | 0.040 (2) | 0.044 (2) | 0.002 (2) | 0.015 (2) | 0.0023 (18) |
C2 | 0.053 (3) | 0.034 (2) | 0.051 (2) | −0.005 (2) | 0.010 (2) | −0.0031 (19) |
C9 | 0.056 (3) | 0.053 (2) | 0.035 (2) | 0.001 (2) | −0.002 (2) | −0.003 (2) |
C8 | 0.075 (3) | 0.069 (3) | 0.028 (2) | 0.004 (2) | −0.001 (2) | 0.009 (2) |
C7 | 0.072 (3) | 0.057 (2) | 0.040 (2) | −0.001 (2) | 0.014 (2) | 0.006 (2) |
C12 | 0.055 (3) | 0.088 (3) | 0.058 (3) | −0.008 (3) | −0.005 (2) | −0.008 (2) |
C19—H19A | 0.96 | C6—C11 | 1.384 (4) |
C19—H19B | 0.96 | C6—C7 | 1.397 (4) |
C19—H19C | 0.96 | C6—C5 | 1.462 (5) |
O1—C1 | 1.381 (4) | C18—C17 | 1.367 (4) |
O1—C4 | 1.414 (4) | C18—H18 | 0.93 |
O2—C1 | 1.191 (4) | C15—C14 | 1.372 (4) |
O4—C5 | 1.215 (4) | C15—H15 | 0.93 |
O5—C9 | 1.362 (4) | C17—H17 | 0.93 |
O5—C12 | 1.425 (4) | C14—H14 | 0.93 |
O6—C16 | 1.355 (4) | C10—C11 | 1.377 (4) |
O6—C19 | 1.436 (4) | C10—C9 | 1.379 (4) |
C16—C15 | 1.384 (4) | C10—H10 | 0.93 |
C16—C17 | 1.392 (4) | C11—H11 | 0.93 |
O3—C2 | 1.210 (4) | C9—C8 | 1.387 (5) |
C1—C2 | 1.528 (5) | C8—C7 | 1.368 (5) |
C3—C2 | 1.436 (5) | C8—H8 | 0.93 |
C3—C5 | 1.501 (5) | C7—H7 | 0.93 |
C4—C3 | 1.353 (4) | C12—H12A | 0.96 |
C4—C13 | 1.435 (4) | C12—H12B | 0.96 |
C13—C18 | 1.395 (4) | C12—H12C | 0.96 |
C13—C14 | 1.399 (4) | ||
O6—C19—H19A | 109.5 | C17—C18—C13 | 121.1 (3) |
O6—C19—H19B | 109.5 | C17—C18—H18 | 119.4 |
H19A—C19—H19B | 109.5 | C13—C18—H18 | 119.4 |
O6—C19—H19C | 109.5 | C14—C15—C16 | 119.3 (3) |
H19A—C19—H19C | 109.5 | C14—C15—H15 | 120.3 |
H19B—C19—H19C | 109.5 | C16—C15—H15 | 120.3 |
C1—O1—C4 | 107.4 (3) | C18—C17—C16 | 120.4 (3) |
C9—O5—C12 | 117.4 (3) | C18—C17—H17 | 119.8 |
C16—O6—C19 | 117.5 (3) | C16—C17—H17 | 119.8 |
O2—C1—C2 | 130.7 (3) | C15—C14—C13 | 122.0 (3) |
O1—C1—C2 | 107.1 (3) | C15—C14—H14 | 119 |
O3—C2—C3 | 132.6 (3) | C13—C14—H14 | 119 |
C3—C2—C1 | 104.8 (3) | C11—C10—C9 | 119.2 (3) |
C4—C3—C2 | 108.0 (3) | C11—C10—H10 | 120.4 |
C4—C3—C5 | 130.3 (3) | C9—C10—H10 | 120.4 |
C3—C4—O1 | 112.6 (3) | C10—C11—C6 | 122.4 (3) |
C3—C4—C13 | 133.9 (3) | C10—C11—H11 | 118.8 |
O1—C4—C13 | 113.4 (3) | C6—C11—H11 | 118.8 |
O4—C5—C6 | 122.4 (3) | O3—C2—C1 | 122.6 (3) |
O4—C5—C3 | 117.9 (3) | O5—C9—C8 | 115.8 (3) |
C6—C5—C3 | 119.6 (3) | C10—C9—C8 | 119.7 (4) |
C7—C6—C5 | 120.4 (3) | C7—C8—C9 | 120.3 (3) |
O5—C9—C10 | 124.5 (3) | C7—C8—H8 | 119.9 |
O6—C16—C15 | 124.8 (3) | C9—C8—H8 | 119.9 |
O6—C16—C17 | 115.4 (3) | C8—C7—C6 | 121.3 (3) |
C15—C16—C17 | 119.7 (3) | C8—C7—H7 | 119.4 |
C18—C13—C14 | 117.4 (3) | C6—C7—H7 | 119.4 |
C18—C13—C4 | 121.7 (3) | O5—C12—H12A | 109.5 |
C14—C13—C4 | 120.9 (3) | O5—C12—H12B | 109.5 |
O2—C1—O1 | 122.2 (3) | H12A—C12—H12B | 109.5 |
C11—C6—C7 | 117.0 (3) | O5—C12—H12C | 109.5 |
C11—C6—C5 | 122.6 (3) | H12A—C12—H12C | 109.5 |
C2—C3—C5 | 121.6 (3) | H12B—C12—H12C | 109.5 |
C1—O1—C4—C3 | −1.3 (3) | C11—C6—C5—O4 | −167.1 (3) |
C1—O1—C4—C13 | 175.6 (2) | C7—C6—C5—O4 | 11.9 (5) |
C3—C4—C13—C18 | −177.5 (3) | C11—C6—C5—C3 | 8.6 (5) |
O1—C4—C13—C18 | 6.5 (4) | C7—C6—C5—C3 | −172.5 (3) |
C3—C4—C13—C14 | 3.0 (6) | C4—C3—C5—O4 | −111.2 (4) |
O1—C4—C13—C14 | −173.1 (3) | C4—C3—C5—C6 | 73.0 (5) |
C4—O1—C1—O2 | 178.9 (3) | C2—C3—C5—C6 | −111.7 (4) |
C4—O1—C1—C2 | −0.8 (3) | C4—C3—C2—O3 | 177.2 (4) |
C2—C3—C5—O4 | 64.2 (4) | C5—C3—C2—O3 | 0.9 (6) |
O1—C4—C3—C2 | 3.0 (4) | C4—C3—C2—C1 | −3.3 (3) |
C13—C4—C3—C2 | −173.1 (3) | C5—C3—C2—C1 | −179.5 (3) |
O1—C4—C3—C5 | 178.8 (3) | O2—C1—C2—O3 | 2.4 (6) |
C13—C4—C3—C5 | 2.7 (6) | O1—C1—C2—O3 | −177.9 (3) |
C14—C13—C18—C17 | −1.2 (5) | O2—C1—C2—C3 | −177.2 (4) |
C4—C13—C18—C17 | 179.2 (3) | O1—C1—C2—C3 | 2.5 (3) |
O6—C16—C15—C14 | 179.3 (3) | C12—O5—C9—C10 | 9.3 (5) |
C17—C16—C15—C14 | −2.9 (5) | C12—O5—C9—C8 | −171.6 (3) |
C13—C18—C17—C16 | −1.1 (5) | C11—C10—C9—O5 | −178.3 (3) |
O6—C16—C17—C18 | −178.9 (3) | C11—C10—C9—C8 | 2.7 (5) |
C15—C16—C17—C18 | 3.2 (5) | O5—C9—C8—C7 | 177.7 (3) |
C16—C15—C14—C13 | 0.6 (5) | C10—C9—C8—C7 | −3.2 (5) |
C18—C13—C14—C15 | 1.5 (5) | C9—C8—C7—C6 | 0.5 (6) |
C4—C13—C14—C15 | −179.0 (3) | C11—C6—C7—C8 | 2.6 (5) |
C9—C10—C11—C6 | 0.5 (5) | C5—C6—C7—C8 | −176.4 (3) |
C7—C6—C11—C10 | −3.1 (5) | C19—O6—C16—C15 | −2.2 (5) |
C5—C6—C11—C10 | 175.9 (3) | C19—O6—C16—C17 | 180.0 (3) |
Experimental details
Crystal data | |
Chemical formula | C19H14O6 |
Mr | 338.3 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 293 |
a, b, c (Å) | 8.3574 (10), 9.5422 (10), 19.775 (2) |
β (°) | 96.197 (8) |
V (Å3) | 1567.8 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.11 |
Crystal size (mm) | 0.3 × 0.25 × 0.2 |
Data collection | |
Diffractometer | Enraf-Nonius Turbo-CAD-4 diffractometer |
Absorption correction | ψ scan (MolEN; Fair, 1990) |
Tmin, Tmax | 0.968, 0.979 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2479, 2395, 1188 |
Rint | 0.019 |
(sin θ/λ)max (Å−1) | 0.577 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.116, 0.98 |
No. of reflections | 2300 |
No. of parameters | 226 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 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.
O1—C1 | 1.381 (4) | O6—C19 | 1.436 (4) |
O1—C4 | 1.414 (4) | C1—C2 | 1.528 (5) |
O2—C1 | 1.191 (4) | C3—C2 | 1.436 (5) |
O4—C5 | 1.215 (4) | C3—C5 | 1.501 (5) |
O5—C9 | 1.362 (4) | C4—C3 | 1.353 (4) |
O5—C12 | 1.425 (4) | C4—C13 | 1.435 (4) |
O6—C16 | 1.355 (4) | C6—C5 | 1.462 (5) |
C1—O1—C4 | 107.4 (3) | C3—C4—C13 | 133.9 (3) |
C9—O5—C12 | 117.4 (3) | O1—C4—C13 | 113.4 (3) |
C16—O6—C19 | 117.5 (3) | O4—C5—C6 | 122.4 (3) |
O2—C1—C2 | 130.7 (3) | O4—C5—C3 | 117.9 (3) |
O1—C1—C2 | 107.1 (3) | C6—C5—C3 | 119.6 (3) |
O3—C2—C3 | 132.6 (3) | C7—C6—C5 | 120.4 (3) |
C3—C2—C1 | 104.8 (3) | O5—C9—C10 | 124.5 (3) |
C4—C3—C2 | 108.0 (3) | O6—C16—C15 | 124.8 (3) |
C4—C3—C5 | 130.3 (3) | O6—C16—C17 | 115.4 (3) |
C3—C4—O1 | 112.6 (3) | C15—C16—C17 | 119.7 (3) |
C2—C3—C5—O4 | 64.2 (4) | C12—O5—C9—C8 | −171.6 (3) |
C11—C6—C5—O4 | −167.1 (3) | C19—O6—C16—C15 | −2.2 (5) |
C11—C6—C5—C3 | 8.6 (5) | C19—O6—C16—C17 | 180.0 (3) |
C12—O5—C9—C10 | 9.3 (5) |
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].