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The mol­ecule of the title compound, C22H30O8, contains a crystallographic inversion centre located at the middle of the benzene ring.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536805028126/hg6241sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536805028126/hg6241Isup2.hkl
Contains datablock I

CCDC reference: 287596

Key indicators

  • Single-crystal X-ray study
  • T = 292 K
  • Mean [sigma](C-C) = 0.004 Å
  • Disorder in main residue
  • R factor = 0.066
  • wR factor = 0.197
  • Data-to-parameter ratio = 13.6

checkCIF/PLATON results

No syntax errors found



Alert level C PLAT220_ALERT_2_C Large Non-Solvent C Ueq(max)/Ueq(min) ... 2.76 Ratio PLAT222_ALERT_3_C Large Non-Solvent H Ueq(max)/Ueq(min) ... 3.43 Ratio PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C6 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C9 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C10 PLAT242_ALERT_2_C Check Low Ueq as Compared to Neighbors for C10' PLAT301_ALERT_3_C Main Residue Disorder ......................... 12.00 Perc.
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 7 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 5 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

Comment top

β-keto esters are multicoupling reagents with electrophilic and nucleophilic sites that have proven to be valuable tools in the synthesis of a wide variety of molecular systems (Benetti et al., 1995). In the present paper, we report the crystal structure of the title compound, (I). The molecule of (I) lies on a crystallographic inversion center located in the middle of the central benzene ring. Selected bond distances and angles are given in Table 1. One pair of symmetrically related ethyl groups are found to be disordered over two orientations (Fig. 1). The occupancies of the disordered positions C10/C10' and C11/C11' were refined to 0.736 (18)/0.264 (18); C10a/C10a' and C11a/C11a' were also refined to 0.736 (18)/0.264 (18). The molecular structure is stabilized by C—H···π intermolecular interactions (Fig. 2).

Experimental top

A mixture of 1,4-bis(bromomethyl)benzene (1.32 g, 5 mmol), ethyl malonate (1.53 ml, 10 mmol), potassium carbonate (1.38 g, 10 mmol) and acetone (25 ml) was stirred and refluxed for 8 h (Morenomanas et al., 1993). The solvent was evaporated on a rotary evaporator and the resulting oil was chromatographed on a silica-gel column, yielding the title compound (1.37 g, 65%). Crystals appropriate for data collection were obtained by slow evaporation from acetone solution at 283 K. M.p. 326–319 K. 1H NMR (CDCl3, 400 MHz, p.p.m.): δ 7.26 (s, 4H), 4.15 (q, 2H, J = 7.2 Hz), 3.60 (t, 1H, J = 7.6 Hz), 3.17 (d, 2H, J = 7.6 Hz), 1.23 (t, 3H, J = 7.2 Hz). MS: 423 (M+1,100), 348 (80.99), 274 (90.56), 262 (62.24), 189 (67.31).

Refinement top

One pair of symmetrically related ethyl groups are found to be disordered over two orientations. The occupancies of the disordered positions C10/C10' and C11/C11' were refined to 0.736 (18)/0.264 (18); C10a/C10a' and C11a/C11a' were also refined to 0.736 (18)/0.264 (18). All H atoms were refined as riding; C—H (methyl H) = 0.96 Å, C—H (methylene H) = 0.97 Å, C—H (methene H) = 0.98 Å and C—H (aromatic H) = 0.93 Å. The constraint Uiso(H) = 1.2Ueq(C) or 1.5Ueq(methyl C) was applied.

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SMART; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2001); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. View of the molecule of (I), showing the atom-labelling scheme. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level. H atoms are represented by circles of arbitrary size. [Symmetry code: (a) 1 − x, −y, 1 - z.]
[Figure 2] Fig. 2. C—H···π intermolecular interactions in the crystal structure. H atoms have been omitted.
Tetraethyl 2,2'-(p-phenylenedimethylene)dimalonate top
Crystal data top
C22H30O8F(000) = 452
Mr = 422.46Dx = 1.213 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 1926 reflections
a = 9.461 (2) Åθ = 2.4–21.4°
b = 8.3944 (17) ŵ = 0.09 mm1
c = 14.601 (3) ÅT = 292 K
β = 94.069 (4)°Block, colorless
V = 1156.8 (4) Å30.20 × 0.20 × 0.20 mm
Z = 2
Data collection top
Bruker SMART CCD area-detector
diffractometer
1518 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.025
Graphite monochromatorθmax = 25.0°, θmin = 2.5°
ϕ and ω scansh = 1011
5515 measured reflectionsk = 99
1991 independent reflectionsl = 1317
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.066Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.197H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.1046P)2 + 0.3206P]
where P = (Fo2 + 2Fc2)/3
1991 reflections(Δ/σ)max < 0.001
146 parametersΔρmax = 0.42 e Å3
3 restraintsΔρmin = 0.22 e Å3
Crystal data top
C22H30O8V = 1156.8 (4) Å3
Mr = 422.46Z = 2
Monoclinic, P21/nMo Kα radiation
a = 9.461 (2) ŵ = 0.09 mm1
b = 8.3944 (17) ÅT = 292 K
c = 14.601 (3) Å0.20 × 0.20 × 0.20 mm
β = 94.069 (4)°
Data collection top
Bruker SMART CCD area-detector
diffractometer
1518 reflections with I > 2σ(I)
5515 measured reflectionsRint = 0.025
1991 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0663 restraints
wR(F2) = 0.197H-atom parameters constrained
S = 1.04Δρmax = 0.42 e Å3
1991 reflectionsΔρmin = 0.22 e Å3
146 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.

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 (Å2) top
xyzUiso*/UeqOcc. (<1)
C10.6168 (3)0.0600 (3)0.46213 (18)0.0754 (8)
H10.69650.10220.43730.090*
C20.5309 (3)0.0454 (3)0.41066 (15)0.0612 (6)
C30.4140 (3)0.1034 (3)0.45040 (17)0.0707 (7)
H30.35400.17380.41740.085*
C40.5649 (3)0.1023 (3)0.31665 (17)0.0707 (7)
H4A0.48160.15430.28790.085*
H4B0.63950.18140.32390.085*
C60.4968 (3)0.1520 (3)0.23399 (16)0.0652 (6)
C70.4511 (5)0.4295 (5)0.2205 (3)0.1228 (14)
H7A0.35460.40010.23150.147*
H7B0.47650.52270.25740.147*
C80.4606 (5)0.4662 (6)0.1240 (4)0.148 (2)
H8A0.55690.49180.11310.223*
H8B0.40070.55550.10750.223*
H8C0.43050.37560.08750.223*
C90.6466 (3)0.0445 (3)0.16142 (17)0.0682 (7)
C10'0.780 (3)0.022 (3)0.0280 (14)0.108 (2)0.264 (18)
H10C0.76350.08530.00450.129*0.264 (18)
H10D0.88040.04110.04140.129*0.264 (18)
C11'0.704 (4)0.1531 (19)0.032 (2)0.169 (5)0.264 (18)
H11D0.70300.12340.09550.254*0.264 (18)
H11E0.75370.25220.02270.254*0.264 (18)
H11F0.60850.16500.01490.254*0.264 (18)
C100.7133 (13)0.0081 (9)0.0115 (4)0.108 (2)0.736 (18)
H10A0.77440.08480.01480.129*0.736 (18)
H10B0.62310.02280.01920.129*0.736 (18)
C110.7742 (16)0.1262 (12)0.0386 (5)0.169 (5)0.736 (18)
H11A0.72710.22560.02930.254*0.736 (18)
H11B0.76500.09910.10260.254*0.736 (18)
H11C0.87270.13600.01870.254*0.736 (18)
C50.6115 (3)0.0279 (3)0.25239 (15)0.0618 (6)
H50.69640.08000.28070.074*
O10.3770 (2)0.1213 (3)0.21006 (16)0.0949 (7)
O20.5466 (2)0.2984 (2)0.24678 (14)0.0871 (7)
O30.6350 (2)0.1816 (2)0.14195 (14)0.0923 (7)
O40.6906 (3)0.0642 (3)0.10625 (14)0.1075 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0767 (17)0.0800 (17)0.0717 (16)0.0140 (13)0.0215 (12)0.0021 (13)
C20.0760 (15)0.0508 (12)0.0576 (13)0.0035 (11)0.0096 (11)0.0099 (10)
C30.0783 (17)0.0673 (15)0.0670 (15)0.0116 (12)0.0080 (12)0.0009 (12)
C40.0907 (18)0.0579 (13)0.0653 (15)0.0008 (12)0.0171 (12)0.0030 (11)
C60.0723 (16)0.0686 (15)0.0552 (13)0.0015 (12)0.0079 (11)0.0012 (11)
C70.136 (3)0.078 (2)0.149 (4)0.026 (2)0.024 (3)0.002 (2)
C80.131 (4)0.123 (3)0.185 (5)0.014 (3)0.036 (3)0.072 (3)
C90.0760 (16)0.0683 (16)0.0619 (14)0.0024 (12)0.0146 (11)0.0046 (12)
C10'0.147 (7)0.112 (3)0.069 (3)0.050 (4)0.040 (4)0.029 (2)
C11'0.231 (13)0.190 (6)0.097 (3)0.098 (7)0.089 (5)0.054 (4)
C100.147 (7)0.112 (3)0.069 (3)0.050 (4)0.040 (4)0.029 (2)
C110.231 (13)0.190 (6)0.097 (3)0.098 (7)0.089 (5)0.054 (4)
C50.0717 (15)0.0589 (13)0.0554 (13)0.0002 (11)0.0085 (10)0.0017 (10)
O10.0750 (14)0.0930 (15)0.1155 (17)0.0003 (11)0.0013 (11)0.0012 (12)
O20.0980 (15)0.0606 (11)0.1008 (15)0.0076 (9)0.0068 (11)0.0003 (9)
O30.1199 (17)0.0748 (13)0.0849 (13)0.0007 (11)0.0250 (11)0.0181 (10)
O40.172 (2)0.0874 (14)0.0686 (12)0.0267 (14)0.0473 (13)0.0132 (10)
Geometric parameters (Å, º) top
C1—C3i1.379 (4)C8—H8C0.9600
C1—C21.386 (4)C9—O31.189 (3)
C1—H10.9300C9—O41.304 (3)
C2—C31.374 (4)C9—C51.519 (3)
C2—C41.509 (3)C10'—O41.512 (9)
C3—C1i1.379 (4)C10'—C11'1.55 (4)
C3—H30.9300C10'—H10C0.9700
C4—C51.526 (3)C10'—H10D0.9700
C4—H4A0.9700C11'—H11D0.9600
C4—H4B0.9700C11'—H11E0.9600
C6—O11.190 (3)C11'—H11F0.9600
C6—O21.325 (3)C10—C111.383 (10)
C6—C51.514 (4)C10—O41.491 (4)
C7—C81.452 (6)C10—H10A0.9700
C7—O21.458 (4)C10—H10B0.9700
C7—H7A0.9700C11—H11A0.9600
C7—H7B0.9700C11—H11B0.9600
C8—H8A0.9600C11—H11C0.9600
C8—H8B0.9600C5—H50.9800
C3i—C1—C2121.1 (2)O3—C9—O4123.9 (2)
C3i—C1—H1119.5O3—C9—C5125.1 (2)
C2—C1—H1119.5O4—C9—C5111.1 (2)
C3—C2—C1117.1 (2)O4—C10'—C11'89.9 (17)
C3—C2—C4120.1 (2)O4—C10'—H10C113.7
C1—C2—C4122.7 (2)C11'—C10'—H10C113.7
C2—C3—C1i121.8 (2)O4—C10'—H10D113.7
C2—C3—H3119.1C11'—C10'—H10D113.7
C1i—C3—H3119.1H10C—C10'—H10D110.9
C2—C4—C5115.0 (2)C10'—C11'—H11D109.5
C2—C4—H4A108.5C10'—C11'—H11E109.5
C5—C4—H4A108.5H11D—C11'—H11E109.5
C2—C4—H4B108.5C10'—C11'—H11F109.5
C5—C4—H4B108.5H11D—C11'—H11F109.5
H4A—C4—H4B107.5H11E—C11'—H11F109.5
O1—C6—O2124.3 (3)C11—C10—O4110.9 (5)
O1—C6—C5124.0 (2)C11—C10—H10A109.4
O2—C6—C5111.7 (2)O4—C10—H10A109.4
C8—C7—O2109.6 (4)C11—C10—H10B109.4
C8—C7—H7A109.8O4—C10—H10B109.4
O2—C7—H7A109.8H10A—C10—H10B108.0
C8—C7—H7B109.8C6—C5—C9108.56 (19)
O2—C7—H7B109.8C6—C5—C4111.5 (2)
H7A—C7—H7B108.2C9—C5—C4110.0 (2)
C7—C8—H8A109.5C6—C5—H5108.9
C7—C8—H8B109.5C9—C5—H5108.9
H8A—C8—H8B109.5C4—C5—H5108.9
C7—C8—H8C109.5C6—O2—C7117.1 (3)
H8A—C8—H8C109.5C9—O4—C10115.2 (4)
H8B—C8—H8C109.5C9—O4—C10'121.5 (10)
C3i—C1—C2—C30.4 (4)C2—C4—C5—C661.1 (3)
C3i—C1—C2—C4176.8 (2)C2—C4—C5—C9178.4 (2)
C1—C2—C3—C1i0.4 (4)O1—C6—O2—C76.6 (4)
C4—C2—C3—C1i176.9 (2)C5—C6—O2—C7172.7 (3)
C3—C2—C4—C5137.5 (2)C8—C7—O2—C686.8 (4)
C1—C2—C4—C545.3 (3)O3—C9—O4—C105.7 (7)
O1—C6—C5—C970.8 (3)C5—C9—O4—C10173.8 (6)
O2—C6—C5—C9108.5 (2)O3—C9—O4—C10'22.8 (14)
O1—C6—C5—C450.5 (3)C5—C9—O4—C10'157.7 (14)
O2—C6—C5—C4130.2 (2)C11—C10—O4—C9173.5 (11)
O3—C9—C5—C6120.0 (3)C11—C10—O4—C10'63 (3)
O4—C9—C5—C659.5 (3)C11'—C10'—O4—C9144.1 (15)
O3—C9—C5—C42.3 (4)C11'—C10'—O4—C1061 (3)
O4—C9—C5—C4178.2 (2)
Symmetry code: (i) x+1, y, z+1.

Experimental details

Crystal data
Chemical formulaC22H30O8
Mr422.46
Crystal system, space groupMonoclinic, P21/n
Temperature (K)292
a, b, c (Å)9.461 (2), 8.3944 (17), 14.601 (3)
β (°) 94.069 (4)
V3)1156.8 (4)
Z2
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.20 × 0.20 × 0.20
Data collection
DiffractometerBruker SMART CCD area-detector
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
5515, 1991, 1518
Rint0.025
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.066, 0.197, 1.04
No. of reflections1991
No. of parameters146
No. of restraints3
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.42, 0.22

Computer programs: SMART (Bruker, 1997), SMART, SAINT (Bruker, 1999), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 2001), SHELXTL.

Selected geometric parameters (Å, º) top
C2—C41.509 (3)C9—O31.189 (3)
C4—C51.526 (3)C9—O41.304 (3)
C6—O11.190 (3)C9—C51.519 (3)
C6—O21.325 (3)C10'—O41.512 (9)
C6—C51.514 (4)C10'—C11'1.55 (4)
C7—C81.452 (6)C10—C111.383 (10)
C7—O21.458 (4)C10—O41.491 (4)
C3—C2—C4120.1 (2)O4—C9—C5111.1 (2)
C1—C2—C4122.7 (2)O4—C10'—C11'89.9 (17)
C2—C4—C5115.0 (2)C11—C10—O4110.9 (5)
O1—C6—O2124.3 (3)C6—C5—C9108.56 (19)
O1—C6—C5124.0 (2)C6—C5—C4111.5 (2)
O2—C6—C5111.7 (2)C9—C5—C4110.0 (2)
C8—C7—O2109.6 (4)C6—O2—C7117.1 (3)
O3—C9—O4123.9 (2)C9—O4—C10115.2 (4)
O3—C9—C5125.1 (2)C9—O4—C10'121.5 (10)
 

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