Acta Cryst. (2008). E64, o546 [ doi:10.1107/S1600536808002948 ]
In the title molecule, C18H18O5, the two aromatic rings are connected by a flexible 3-oxapentane chain. The molecule has a crystallographic twofold rotation axis (C2) passing through the central O atom. An intramolecular C-H
O hydrogen bond is observed in the solid state.
A mixture of 2[2-(2-p-tolylsulfonyloxy)ethoxy]ethanol (1 g, 8.19 mmol), salicylic aldehyde (0.87 g, 2.10 mmol), and K2CO3 (0.47 g, 3.40 mmol) in dry MeCN (20 ml) was heated for 12 h under reflux. After the reaction mixture had cooled down to room temperature, it was filtered and the solvent removed under vacuum. The residue was purified by column chromatography (SiO2, Hexane:EtOAc 1:1) to give the desired product (0.55 g, 83%) as a yellow solid. A single-crystal was isolated after slow evaporation of the crystallization solvent (THF).
All hydrogen atoms were geometrically constrained using a riding model, with C—H distances of 0.93 Å for both benzene rings and the aldehyde moieties with Uiso(H) = 1.2Ueq(Csp2), and with C—H distances of 0.97 Å for the ethyl C atoms with Uiso(H) = 1.2Ueq(Csp3).
Data collection: COLLECT (Nonius, 1998); cell refinement: PHICHI (Duisenberg et al., 2000); data reduction: EVAL-14 (CCD) (Duisenberg et al., 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).
![[Figure 1]](./si2065fig1thm.gif)
| Fig. 1. ORTEP projection of the title molecule. Symmetry equivalent atoms are generated by the symmetry code [-x, 1 - y, z]. Intramolecular bonds are indicated by dashed lines. Thermal ellipsoids are shown at the 50% probability level. |
| C18H18O5 | F000 = 1328 |
| Mr = 314.32 | Dx = 1.292 Mg m−3 |
| Orthorhombic, Fdd2 | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: F 2 -2d | Cell parameters from 50 reflections |
| a = 27.613 (6) Å | θ = 1–27.5º |
| b = 26.404 (5) Å | µ = 0.09 mm−1 |
| c = 4.4313 (9) Å | T = 295 (2) K |
| V = 3230.8 (11) Å3 | Plate, yellow |
| Z = 8 | 0.25 × 0.08 × 0.05 mm |
| Nonius KappaCCD diffractometer | 480 reflections with I > 2σ(I) |
| Radiation source: fine-focus sealed tube | Rint = 0.134 |
| Monochromator: graphite | θmax = 27.5º |
| T = 295(2) K | θmin = 3.1º |
| φ and ω scans with κ offsets | h = −34→35 |
| Absorption correction: none | k = −34→34 |
| 4449 measured reflections | l = −5→5 |
| 1043 independent reflections |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
| R[F2 > 2σ(F2)] = 0.051 | H-atom parameters constrained |
| wR(F2) = 0.097 | w = 1/[σ2(Fo2) + (0.0377P)2] where P = (Fo2 + 2Fc2)/3 |
| S = 0.99 | (Δ/σ)max < 0.001 |
| 1043 reflections | Δρmax = 0.12 e Å−3 |
| 105 parameters | Δρmin = −0.14 e Å−3 |
| Primary atom site location: structure-invariant direct methods | Extinction correction: none |
| C18H18O5 | V = 3230.8 (11) Å3 |
| Mr = 314.32 | Z = 8 |
| Orthorhombic, Fdd2 | Mo Kα |
| a = 27.613 (6) Å | µ = 0.09 mm−1 |
| b = 26.404 (5) Å | T = 295 (2) K |
| c = 4.4313 (9) Å | 0.25 × 0.08 × 0.05 mm |
| Nonius KappaCCD diffractometer | 1043 independent reflections |
| Absorption correction: none | 480 reflections with I > 2σ(I) |
| 4449 measured reflections | Rint = 0.134 |
| R[F2 > 2σ(F2)] = 0.051 | Δρmax = 0.12 e Å−3 |
| wR(F2) = 0.097 | Δρmin = −0.14 e Å−3 |
| S = 0.99 | Absolute structure: ? |
| 1043 reflections | Flack parameter: ? |
| 105 parameters | Rogers parameter: ? |
| H-atom parameters constrained |
Experimental. The transformation of the unit cell axes and hkl intensity data were performed by using the matrix (00–1, 010, 100) in order to solve and refine the structure in the standard setting for space group Fdd2. |
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. |
| x | y | z | Uiso*/Ueq | ||
| C1 | 0.03242 (14) | 0.47183 (13) | 1.1699 (9) | 0.0683 (12) | |
| H1A | 0.0138 | 0.4508 | 1.3069 | 0.082* | |
| H1B | 0.0515 | 0.4951 | 1.2902 | 0.082* | |
| C2 | 0.06560 (13) | 0.43903 (12) | 0.9883 (9) | 0.0607 (10) | |
| H2A | 0.0831 | 0.4162 | 1.1207 | 0.073* | |
| H2B | 0.0469 | 0.4188 | 0.8472 | 0.073* | |
| C3 | 0.13695 (13) | 0.44746 (12) | 0.6829 (8) | 0.0495 (9) | |
| C4 | 0.14652 (13) | 0.39549 (12) | 0.6935 (9) | 0.0622 (11) | |
| H4 | 0.1263 | 0.3740 | 0.8015 | 0.075* | |
| C5 | 0.18651 (15) | 0.37623 (15) | 0.5414 (11) | 0.0773 (13) | |
| H5 | 0.1930 | 0.3417 | 0.5519 | 0.093* | |
| C6 | 0.21687 (15) | 0.40706 (15) | 0.3753 (10) | 0.0731 (13) | |
| H6 | 0.2433 | 0.3935 | 0.2739 | 0.088* | |
| C7 | 0.20743 (14) | 0.45820 (15) | 0.3617 (9) | 0.0677 (13) | |
| H7 | 0.2276 | 0.4791 | 0.2491 | 0.081* | |
| C8 | 0.16770 (12) | 0.47928 (12) | 0.5159 (10) | 0.0523 (10) | |
| C9 | 0.15870 (14) | 0.53391 (13) | 0.4966 (13) | 0.0834 (14) | |
| H9 | 0.1323 | 0.5466 | 0.6030 | 0.100* | |
| O1 | 0.0000 | 0.5000 | 0.9830 (7) | 0.0529 (9) | |
| O2 | 0.09910 (9) | 0.47057 (7) | 0.8266 (6) | 0.0563 (7) | |
| O3 | 0.18230 (10) | 0.56356 (10) | 0.3560 (9) | 0.1276 (15) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| C1 | 0.066 (3) | 0.085 (3) | 0.054 (3) | −0.002 (2) | −0.005 (3) | 0.018 (2) |
| C2 | 0.059 (2) | 0.061 (2) | 0.062 (3) | −0.007 (2) | −0.011 (2) | 0.023 (2) |
| C3 | 0.044 (2) | 0.045 (2) | 0.059 (3) | 0.0026 (19) | −0.018 (2) | 0.003 (2) |
| C4 | 0.060 (2) | 0.044 (2) | 0.083 (3) | −0.0005 (18) | −0.018 (3) | 0.0096 (19) |
| C5 | 0.075 (3) | 0.047 (2) | 0.110 (4) | 0.010 (2) | −0.029 (3) | −0.009 (3) |
| C6 | 0.069 (3) | 0.066 (3) | 0.084 (3) | 0.013 (2) | −0.012 (3) | −0.014 (3) |
| C7 | 0.051 (3) | 0.073 (3) | 0.079 (3) | 0.002 (2) | −0.006 (2) | 0.007 (2) |
| C8 | 0.0426 (19) | 0.049 (2) | 0.066 (2) | 0.0020 (18) | −0.014 (2) | 0.011 (2) |
| C9 | 0.059 (3) | 0.053 (3) | 0.138 (4) | 0.004 (2) | 0.011 (3) | 0.023 (3) |
| O1 | 0.0469 (17) | 0.066 (2) | 0.0457 (19) | −0.0031 (18) | 0.000 | 0.000 |
| O2 | 0.0481 (13) | 0.0462 (13) | 0.0746 (18) | −0.0005 (12) | 0.0020 (13) | 0.0170 (14) |
| O3 | 0.090 (2) | 0.0707 (18) | 0.222 (4) | 0.0013 (17) | 0.043 (3) | 0.068 (2) |
| C1—O1 | 1.429 (4) | C4—H4 | 0.9300 |
| C1—C2 | 1.496 (5) | C5—C6 | 1.381 (5) |
| C1—H1A | 0.9700 | C5—H5 | 0.9300 |
| C1—H1B | 0.9700 | C6—C7 | 1.377 (4) |
| C2—O2 | 1.436 (4) | C6—H6 | 0.9300 |
| C2—H2A | 0.9700 | C7—C8 | 1.407 (5) |
| C2—H2B | 0.9700 | C7—H7 | 0.9300 |
| C3—O2 | 1.368 (4) | C8—C9 | 1.466 (4) |
| C3—C4 | 1.398 (4) | C9—O3 | 1.194 (4) |
| C3—C8 | 1.405 (4) | C9—H9 | 0.9300 |
| C4—C5 | 1.390 (5) | O1—C1i | 1.429 (4) |
| O1—C1—C2 | 111.9 (3) | C6—C5—C4 | 121.7 (4) |
| O1—C1—H1A | 109.2 | C6—C5—H5 | 119.2 |
| C2—C1—H1A | 109.2 | C4—C5—H5 | 119.2 |
| O1—C1—H1B | 109.2 | C7—C6—C5 | 119.1 (4) |
| C2—C1—H1B | 109.2 | C7—C6—H6 | 120.4 |
| H1A—C1—H1B | 107.9 | C5—C6—H6 | 120.4 |
| O2—C2—C1 | 109.1 (3) | C6—C7—C8 | 121.0 (4) |
| O2—C2—H2A | 109.9 | C6—C7—H7 | 119.5 |
| C1—C2—H2A | 109.9 | C8—C7—H7 | 119.5 |
| O2—C2—H2B | 109.9 | C3—C8—C7 | 119.4 (3) |
| C1—C2—H2B | 109.9 | C3—C8—C9 | 121.1 (4) |
| H2A—C2—H2B | 108.3 | C7—C8—C9 | 119.5 (4) |
| O2—C3—C4 | 124.5 (3) | O3—C9—C8 | 125.7 (4) |
| O2—C3—C8 | 116.1 (3) | O3—C9—H9 | 117.2 |
| C4—C3—C8 | 119.4 (3) | C8—C9—H9 | 117.2 |
| C5—C4—C3 | 119.5 (3) | C1i—O1—C1 | 109.1 (4) |
| C5—C4—H4 | 120.2 | C3—O2—C2 | 117.8 (2) |
| C3—C4—H4 | 120.2 | ||
| O1—C1—C2—O2 | 69.3 (3) | C4—C3—C8—C9 | 179.4 (4) |
| O2—C3—C4—C5 | −179.1 (3) | C6—C7—C8—C3 | −0.8 (6) |
| C8—C3—C4—C5 | 0.7 (5) | C6—C7—C8—C9 | −180.0 (4) |
| C3—C4—C5—C6 | −1.0 (6) | C3—C8—C9—O3 | −178.5 (4) |
| C4—C5—C6—C7 | 0.5 (6) | C7—C8—C9—O3 | 0.6 (7) |
| C5—C6—C7—C8 | 0.4 (6) | C2—C1—O1—C1i | 176.7 (3) |
| O2—C3—C8—C7 | −180.0 (3) | C4—C3—O2—C2 | −3.0 (5) |
| C4—C3—C8—C7 | 0.2 (5) | C8—C3—O2—C2 | 177.2 (3) |
| O2—C3—C8—C9 | −0.8 (5) | C1—C2—O2—C3 | 170.5 (3) |
| Symmetry codes: (i) −x, −y+1, z. |
The X-ray diffraction measurements were performed in the Laboratório de Difração de Raios X from the Universidade Federal Fluminense (LDRX-UFF), Niterói, Brazil. The authors thank CAPES, CNPq and FAPERJ for financial support. The co-editor is thanked for the transformation of the space group F2dd to the standard setting Fdd2, and for help with the solution and refinement of the structure.
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The title molecule is generated by a symmetry operation according to the space group Fdd2. The symmetry operator (0, 1/2, z) applied to the equivalent atoms is a twofold rotation axis passing through the central atom O1 (Fig. 1). Bond lengths and angles are in the ranges reported for analogous structures (Biernat et al., 1992; Qi et al., 2005). The distances involving the C atoms in the central moiety are 1.496 (5) Å for C1—C2, 1.429 (4) Å for C1—O1, and 1.436 (4) Å for C2—O2.
The intramolecular C9—H9···O2 contact observed in the solid state (Fig. 1) is classificated as a non classical hydrogen bond (Jeffrey & Saenger, 1991). This secondary interaction does not affect the torsion angles in the 3-oxapentane chain. The torsion angle for the O2/C2/C1/O1 moiety is -69.3 (3)° and proves the flexibility of the 3-oxapentane chain. The hydrogen bonding geometry of the intramolecular contacts (Jeffrey & Saenger, 1991) with atom O2 as acceptor was calculated with PLATON (Spek, 2003): distances H9···O2 and C9···O2 are 2.42 and 2.764 (5) Å, respectively, and the angle at H9 is 102°.