supplementary materials
2,2-Dibromo-1-(4-hydroxy-3-methoxyphenyl)ethanone
To a stirred solution of acetovanillone (5 g, 0.03 mol) in anhydrous CHCl3,
bromine (3.1 ml, 0.06 mol) was added dropwise under nitrogen over 2 h at 273 K.
The reaction mixture was kept at 273k for 1 h.
The reaction mixture was diluted with ether and washed with ice-cold water
and brine.
The solution was dried over anhydrous Na2SO4 and concentrated to dryness
in vacuo.
The crude crystalline product was purified by column chromatography to obtain
a pure white solid, (I).
Colourless single crystals were grown by slow evaporation of an ethyl acetate
solution of (I).
H atoms were placed in calculated positions and treated using a riding model,
with C—H = 0.93–0.98 Å and O—H = 0.85 Å, and with
Uiso(H) = 1.2Ueq(C, O) or 1.5Ueq(C) for
methyl-H atoms.
Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
Crystal data top
| C9H8Br2O3 | F(000) = 624 |
| Mr = 323.97 | Dx = 2.065 Mg m−3 |
| Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
| Hall symbol: -P 2yn | Cell parameters from 25 reflections |
| a = 7.0370 (14) Å | θ = 10–13° |
| b = 10.805 (2) Å | µ = 7.76 mm−1 |
| c = 13.871 (3) Å | T = 295 K |
| β = 98.80 (3)° | Needle, colourless |
| V = 1042.3 (4) Å3 | 0.10 × 0.05 × 0.05 mm |
| Z = 4 | |
Data collection top
Enraf–Nonius CAD-4
diffractometer | 894 reflections with I > 2σ(I) |
| Radiation source: fine-focus sealed tube | Rint = 0.041 |
| graphite | θmax = 25.3°, θmin = 2.4° |
| ω/2θ scans | h = 0→8 |
Absorption correction: ψ scan
(North et al., 1968) | k = 0→12 |
| Tmin = 0.511, Tmax = 0.698 | l = −16→16 |
| 2060 measured reflections | 3 standard reflections every 200 reflections |
| 1900 independent reflections | intensity decay: 1% |
Refinement top
| Refinement on F2 | Primary atom site location: structure-invariant direct methods |
| Least-squares matrix: full | Secondary atom site location: difference Fourier map |
| R[F2 > 2σ(F2)] = 0.067 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.159 | H-atom parameters constrained |
| S = 0.96 | w = 1/[σ2(Fo2) + (0.0723P)2]
where P = (Fo2 + 2Fc2)/3 |
| 1900 reflections | (Δ/σ)max < 0.001 |
| 127 parameters | Δρmax = 0.56 e Å−3 |
| 61 restraints | Δρmin = −0.65 e Å−3 |
Crystal data top
| C9H8Br2O3 | V = 1042.3 (4) Å3 |
| Mr = 323.97 | Z = 4 |
| Monoclinic, P21/n | Mo Kα radiation |
| a = 7.0370 (14) Å | µ = 7.76 mm−1 |
| b = 10.805 (2) Å | T = 295 K |
| c = 13.871 (3) Å | 0.10 × 0.05 × 0.05 mm |
| β = 98.80 (3)° | |
Data collection top
Enraf–Nonius CAD-4
diffractometer | 894 reflections with I > 2σ(I) |
Absorption correction: ψ scan
(North et al., 1968) | Rint = 0.041 |
| Tmin = 0.511, Tmax = 0.698 | θmax = 25.3° |
| 2060 measured reflections | 3 standard reflections every 200 reflections |
| 1900 independent reflections | intensity decay: 1% |
Refinement top
| R[F2 > 2σ(F2)] = 0.067 | H-atom parameters constrained |
| wR(F2) = 0.159 | Δρmax = 0.56 e Å−3 |
| S = 0.96 | Δρmin = −0.65 e Å−3 |
| 1900 reflections | Absolute structure: ? |
| 127 parameters | Flack parameter: ? |
| 61 restraints | Rogers parameter: ? |
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| | x | y | z | Uiso*/Ueq | |
| Br1 | 0.08467 (19) | 0.97920 (12) | 0.38634 (8) | 0.0775 (5) | |
| Br2 | 0.51183 (19) | 0.91674 (13) | 0.35768 (10) | 0.0890 (5) | |
| O1 | 0.1990 (9) | 1.1174 (7) | −0.1321 (4) | 0.0521 (17) | |
| O2 | 0.2770 (9) | 0.8866 (7) | −0.1677 (4) | 0.062 (2) | |
| H2A | 0.2526 | 0.9407 | −0.2123 | 0.074* | |
| O3 | 0.2364 (10) | 1.1382 (6) | 0.2363 (4) | 0.0578 (19) | |
| C1 | 0.1731 (15) | 1.2472 (10) | −0.1180 (7) | 0.065 (3) | |
| H1A | 0.1408 | 1.2869 | −0.1802 | 0.097* | |
| H1B | 0.2900 | 1.2820 | −0.0840 | 0.097* | |
| H1C | 0.0712 | 1.2596 | −0.0802 | 0.097* | |
| C2 | 0.2291 (13) | 1.0450 (8) | −0.0514 (6) | 0.041 (2) | |
| C3 | 0.2247 (12) | 1.0754 (8) | 0.0407 (5) | 0.036 (2) | |
| H3A | 0.2002 | 1.1572 | 0.0554 | 0.043* | |
| C4 | 0.2555 (12) | 0.9894 (8) | 0.1168 (5) | 0.0303 (19) | |
| C5 | 0.2965 (12) | 0.8669 (8) | 0.0924 (5) | 0.037 (2) | |
| H5A | 0.3198 | 0.8071 | 0.1410 | 0.045* | |
| C6 | 0.3021 (13) | 0.8348 (9) | −0.0047 (6) | 0.043 (2) | |
| H6A | 0.3279 | 0.7536 | −0.0208 | 0.052* | |
| C7 | 0.2714 (13) | 0.9187 (9) | −0.0728 (6) | 0.044 (2) | |
| C8 | 0.2469 (13) | 1.0318 (9) | 0.2175 (6) | 0.039 (2) | |
| C9 | 0.2485 (13) | 0.9338 (9) | 0.2920 (6) | 0.048 (2) | |
| H9A | 0.2046 | 0.8555 | 0.2606 | 0.057* | |
Atomic displacement parameters (Å2) top| | U11 | U22 | U33 | U12 | U13 | U23 |
| Br1 | 0.0952 (10) | 0.0694 (9) | 0.0809 (7) | 0.0149 (8) | 0.0546 (7) | 0.0129 (7) |
| Br2 | 0.0631 (8) | 0.0828 (11) | 0.1166 (10) | 0.0081 (8) | −0.0004 (7) | 0.0338 (8) |
| O1 | 0.051 (4) | 0.059 (5) | 0.046 (3) | −0.001 (4) | 0.008 (3) | 0.009 (3) |
| O2 | 0.065 (5) | 0.072 (5) | 0.055 (4) | 0.001 (4) | 0.030 (3) | −0.003 (4) |
| O3 | 0.105 (6) | 0.018 (4) | 0.058 (4) | 0.001 (4) | 0.037 (4) | −0.001 (3) |
| C1 | 0.072 (8) | 0.055 (8) | 0.068 (7) | −0.007 (7) | 0.017 (6) | 0.020 (6) |
| C2 | 0.044 (5) | 0.035 (5) | 0.045 (4) | −0.001 (4) | 0.009 (4) | 0.003 (4) |
| C3 | 0.041 (5) | 0.020 (4) | 0.048 (4) | −0.006 (4) | 0.013 (4) | 0.000 (3) |
| C4 | 0.027 (4) | 0.024 (4) | 0.040 (3) | −0.003 (4) | 0.006 (3) | 0.000 (3) |
| C5 | 0.038 (5) | 0.031 (4) | 0.041 (4) | 0.004 (4) | −0.002 (4) | 0.001 (4) |
| C6 | 0.046 (5) | 0.034 (5) | 0.052 (4) | 0.000 (4) | 0.015 (4) | −0.005 (4) |
| C7 | 0.046 (5) | 0.048 (5) | 0.045 (4) | 0.002 (5) | 0.025 (4) | −0.005 (4) |
| C8 | 0.042 (5) | 0.025 (5) | 0.053 (4) | 0.004 (4) | 0.019 (4) | 0.001 (4) |
| C9 | 0.049 (5) | 0.033 (5) | 0.064 (5) | −0.002 (5) | 0.015 (4) | 0.004 (4) |
Geometric parameters (Å, °) top
| Br1—C9 | 1.935 (9) | C2—C7 | 1.437 (12) |
| Br2—C9 | 1.945 (9) | C3—C4 | 1.398 (10) |
| O1—C2 | 1.355 (10) | C3—H3A | 0.9300 |
| O1—C1 | 1.431 (12) | C4—C5 | 1.407 (11) |
| O2—C7 | 1.369 (9) | C4—C8 | 1.481 (11) |
| O2—H2A | 0.8500 | C5—C6 | 1.398 (11) |
| O3—C8 | 1.184 (10) | C5—H5A | 0.9300 |
| C1—H1A | 0.9600 | C6—C7 | 1.302 (11) |
| C1—H1B | 0.9600 | C6—H6A | 0.9300 |
| C1—H1C | 0.9600 | C8—C9 | 1.478 (12) |
| C2—C3 | 1.324 (11) | C9—H9A | 0.9800 |
| | | |
| C2—O1—C1 | 117.4 (7) | C6—C5—H5A | 119.9 |
| C7—O2—H2A | 119.6 | C4—C5—H5A | 119.9 |
| O1—C1—H1A | 109.5 | C7—C6—C5 | 120.0 (9) |
| O1—C1—H1B | 109.5 | C7—C6—H6A | 120.0 |
| H1A—C1—H1B | 109.5 | C5—C6—H6A | 120.0 |
| O1—C1—H1C | 109.5 | C6—C7—O2 | 119.7 (9) |
| H1A—C1—H1C | 109.5 | C6—C7—C2 | 121.9 (8) |
| H1B—C1—H1C | 109.5 | O2—C7—C2 | 118.4 (8) |
| C3—C2—O1 | 129.0 (9) | O3—C8—C9 | 122.4 (8) |
| C3—C2—C7 | 118.0 (8) | O3—C8—C4 | 121.4 (8) |
| O1—C2—C7 | 112.9 (7) | C9—C8—C4 | 116.2 (8) |
| C2—C3—C4 | 122.7 (8) | C8—C9—Br1 | 110.5 (6) |
| C2—C3—H3A | 118.7 | C8—C9—Br2 | 107.5 (6) |
| C4—C3—H3A | 118.7 | Br1—C9—Br2 | 109.3 (4) |
| C3—C4—C5 | 117.2 (7) | C8—C9—H9A | 109.8 |
| C3—C4—C8 | 118.9 (7) | Br1—C9—H9A | 109.8 |
| C5—C4—C8 | 123.9 (7) | Br2—C9—H9A | 109.8 |
| C6—C5—C4 | 120.1 (8) | | |
| | | |
| C1—O1—C2—C3 | 5.5 (14) | O1—C2—C7—C6 | −179.1 (8) |
| C1—O1—C2—C7 | −174.4 (8) | C3—C2—C7—O2 | −179.7 (9) |
| O1—C2—C3—C4 | 178.7 (8) | O1—C2—C7—O2 | 0.2 (12) |
| C7—C2—C3—C4 | −1.3 (13) | C3—C4—C8—O3 | −8.6 (13) |
| C2—C3—C4—C5 | 1.4 (13) | C5—C4—C8—O3 | 170.2 (9) |
| C2—C3—C4—C8 | −179.7 (9) | C3—C4—C8—C9 | 170.2 (8) |
| C3—C4—C5—C6 | −1.0 (12) | C5—C4—C8—C9 | −10.9 (12) |
| C8—C4—C5—C6 | −179.8 (8) | O3—C8—C9—Br1 | 35.2 (12) |
| C4—C5—C6—C7 | 0.7 (14) | C4—C8—C9—Br1 | −143.6 (7) |
| C5—C6—C7—O2 | −179.9 (8) | O3—C8—C9—Br2 | −84.0 (10) |
| C5—C6—C7—C2 | −0.7 (14) | C4—C8—C9—Br2 | 97.2 (8) |
| C3—C2—C7—C6 | 1.0 (14) | | |
Hydrogen-bond geometry (Å, °) top
| D—H···A | D—H | H···A | D···A | D—H···A |
| O2—H2A···O1 | 0.85 | 2.27 | 2.617 (11) | 105 |
| C1—H1A···O2i | 0.96 | 2.51 | 3.398 (11) | 153 |
| C5—H5A···O3ii | 0.93 | 2.57 | 3.460 (10) | 161 |
| C9—H9A···O3ii | 0.98 | 2.38 | 3.222 (11) | 143 |
| Symmetry codes: (i) −x+1/2, y+1/2, −z−1/2; (ii) −x+1/2, y−1/2, −z+1/2. |
Table 1
Hydrogen-bond geometry (Å, °) top
| D—H···A | D—H | H···A | D···A | D—H···A |
| O2—H2A···O1 | 0.85 | 2.27 | 2.617 (11) | 105 |
| C1—H1A···O2i | 0.96 | 2.51 | 3.398 (11) | 153 |
| C5—H5A···O3ii | 0.93 | 2.57 | 3.460 (10) | 161 |
| C9—H9A···O3ii | 0.98 | 2.38 | 3.222 (11) | 143 |
| Symmetry codes: (i) −x+1/2, y+1/2, −z−1/2; (ii) −x+1/2, y−1/2, −z+1/2. |
The authors thank the Natural Science Foundation of Shandong Province (grant
No. Y2005B04) for support.
Cathala, B., Saake, B., Faix, O. & Monties, B. (2003). J. Chromatogr. A, 1020, 229–239.
Enraf–Nonius (1994). CAD-4 EXPRESS. Enraf–Nonius, Delft, The Netherlands.
Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.
Kishimoto, T., Uraki, Y. & Ubukata, M. (2005). Org. Biomol. Chem. 3, 1067–1073.
North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
O interaction. Intermolecular C-H![[pi]](/logos/entities/pi_rmgif.gif)
-![[Figure 1]](./tk2463fig1thm.gif)
Lignin is natural polymer occurring in plant cell walls and is considered to be the second most abundant biopolymer after cellulose. The beta-O-4 structure is the most abundant substructure in lignin (Cathala et al., 2003). In order to prepare well defined linear polymers composed of the β-O-4 structure and in attempt to develop new utilization methods of lignins (Kishimoto et al., 2005), a new compound, 2,2-dibromo-1-(4-hydroxy-3-methoxyphenyl)ethanone, (I), was synthesized and its structure determined using single-crystal X-ray methods.
The molecular conformation of (I), Fig. 1, is stabilized by an intramolecular O—H···O interaction formed between the hydroxyl-H and methoxy-O atoms (H···O = 2.27 Å). The molecules are connected into a 2-D array via C-H···O interactions in the bc-plane (Table 1). Connections between the layers are afforded by π-π stacking interactions, with the shortest centroid···centroid distance being 3.596 (5)Å.