supplementary materials


su2614 scheme

Acta Cryst. (2013). E69, o1155-o1156    [ doi:10.1107/S160053681301708X ]

Pallidol hexaacetate ethyl acetate monosolvate

Q. Mao, D. K. Taylor, S. W. Ng and E. R. T. Tiekink

Abstract top

The entire molecule of pallidol hexaacetate {systematic name: (±)-(4bR,5R,9bR,10R)-5,10-bis[4-(acetyloxy)phenyl]-4b,5,9b,10-tetrahydroindeno[2,1-a]indene-1,3,6,8-tetrayl tetraacetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate molecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009). Acta Cryst. D65, 148-155]; the crystallographic data take into account the presence of the solvent. In pallidol hexaacetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100 Å) is 54.73 (6)°, indicating a significant fold in the molecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70 (5)° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C-O(carboxy)-C-C torsion angles = -70.24 (14), -114.43 (10) and -72.54 (13)°]. In the crystal, a three-dimensional architecture is sustained by C-H...O interactions which encompass channels in which the disordered ethyl acetate molecules reside.

Comment top

The synthesis of pallidol hexaacetate was achieved by employing a modified procedure to that reported by Takaya et al. (2005) as outlined by Moss et al. (2013) which involved the oxidation of trans-resveratrol with K3Fe(CN)6. Herein, the crystal structure determination of pallidol hexaacetate, isolated as its ethylacetate solvate, (I), is described.

The pallidol hexaacetate molecule is disposed about a two-fold rotation axis, Fig. 1. The central five-membered ring is approximately planar with a r.m.s. deviation of 0.100 Å. The maximum deviations = 0.086 (1) Å for the C10 atom and -0.081 (1) Å for the C9 atom, indicating a small twist about the C9—C10 bond. The dihedral angle between the mean planes of the fused five-membered rings is 54.73 (6)°, indicating significant curvature in the molecule. The pendent benzene ring is nearly perpendicular to the mean plane of the five-membered ring to which it is attached, forming a dihedral angle of 80.70 (5)°. None of the acetate residues are co-planar with the benzene ring to which they are attached as seen in the values of the C2—O1—C3—C4 [-70.24 (14)°], C17—O3—C16—C11 [-114.43 (10)°] and C19—O5—C14—C13 [-72.54 (13)°] torsion angles.

In the crystal, molecules assemble into a three-dimensional architecture via C—H···O interactions, Fig. 2 and Table 1. In so doing, they define channels in which, presumably, reside the disordered ethylacetate molecules.

Related literature top

For synthetic protocols, see: Takaya et al. (2005); Moss et al. (2013). For the spectroscopic characteristics of pallidol hexaacetate, see: Khan et al. (1986).

Experimental top

To a stirred solution of trans-resveratrol (500 mg) and K2CO3 (245 mg) in MeOH (120 ml) at ambient temperature was slowly added an aqueous solution of K3Fe(CN)6 (575 mg in 10 ml) over 5 minutes and the mixture stirred for a further 30 minutes. The mixture was then concentrated in vacuo and loaded directly onto a flash chromatography column and the organics eluted with EtOAc. The fraction containing the crude dimers was concentrated in vacuo and then dissolved in CH2Cl2 (60 ml) and DMSO (10 ml). Ac2O (0.83 ml) and Et3N (1.23 ml) were then added and the reaction mixture kept at ambient temperature for 24 h. The reaction was then quenched with NaHCO3 (30 ml) and the organics extracted with EtOAc (3 x 30 ml). The combined organics were washed with water (20 ml), dried (MgSO4) and the volatiles removed in vacuo. The acetates were then separated by flash column chromatography (increasing polarity from 20% to 50% ethylacetate in petroleum spirit) to afford pallidol hexaacetate (150 mg) along with several other dimers identified as trans-ε-viniferin pentaacetate and trans-δ-viniferin pentaacetate (120 mg, 1:2). Recrystallization of the pallidol hexaacetate from neat EtOAc afforded pure material as a colourless crystalline solid. Melting point 486.0–488.4 K; 1H NMR (600 MHz, CDCl3): δ 7.15 (4H, d, J = 8.4 Hz), 7.05 (4H, d, J = 8.4 Hz), 6.88 (2H, d, J = 1.8 Hz), 6.76 (2H, d, J = 1.8 Hz), 4.45 (2H, dd, J = 3.0, 3.0 Hz), 4.17 (2H, dd, J = 3.0, 3.0 Hz), 2.30 (6H, 2 x OAc), 2.28 (6H, 2 x OAc), 1.69 (6H, 2 x OAc). 13C NMR (600 MHz, CDCl3): δ 169.46, 169.01 and 167.82 (3 x COCH3), 150.9, 149.5, 147.9, 147.4, 140.6, 133.6, 128.7, 121.8, 115.4, 115.1, 61.2, 55.7, 21.11, 21.09 and 19.95 (3 x COCH3). All other spectral data are identical to those previously reported by Khan et al. (1986).

Refinement top

C-bound H-atoms were placed in calculated positions and were included in the refinement in the riding model approximation: C—H = 0.95 to 0.98 Å, with Uiso(H) =1.5Ueq(C-methyl) and = 1.2Ueq(C) for other H atoms. The heavily disordered ethyl acetate molecule, lying on a 2-fold rotation axis, was removed by using the SQUEEZE option in PLATON (Spek, 2009).

Computing details top

Data collection: CrysAlis PRO (Agilent, 2013); cell refinement: CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis PRO (Agilent, 2013); 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, 2012) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level. Unlabelled atoms are related by the symmetry operation 1 - x, y, 1/2 - z. The disordered ethylacetate molecule is omitted.
[Figure 2] Fig. 2. A view in projection down the c axis of the unit-cell contents of (I). The C—H···O interactions are shown as blue dashed lines. The disordered ethylacetate molecules are omitted but, presumably lie in the occupied channels.
(±)-(4bR,5R,9bR,10R)-5,10-Bis[4-(acetyloxy)phenyl]-4b,5,9b,10-tetrahydroindeno[2,1-a]indene-1,3,6,8-tetrayl tetraacetate ethyl acetate monosolvate top
Crystal data top
C40H34O12·C4H8O2F(000) = 1672
Mr = 794.78Dx = 1.321 Mg m3
Monoclinic, C2/cCu Kα radiation, λ = 1.54184 Å
Hall symbol: -C 2ycCell parameters from 19786 reflections
a = 13.1495 (1) Åθ = 3.7–74.3°
b = 12.7439 (1) ŵ = 0.83 mm1
c = 24.0386 (2) ÅT = 100 K
β = 97.186 (1)°Prism, colourless
V = 3996.65 (5) Å30.30 × 0.10 × 0.10 mm
Z = 4
Data collection top
Agilent SuperNova Dual
diffractometer with an Atlas detector
4029 independent reflections
Radiation source: SuperNova (Cu) X-ray Source3714 reflections with I > 2σ(I)
Mirror monochromatorRint = 0.022
Detector resolution: 10.4041 pixels mm-1θmax = 74.4°, θmin = 3.7°
ω scanh = 1615
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2013)
k = 015
Tmin = 0.790, Tmax = 0.922l = 029
27173 measured reflections
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)] = 0.036Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.095H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0505P)2 + 2.699P]
where P = (Fo2 + 2Fc2)/3
4029 reflections(Δ/σ)max = 0.001
238 parametersΔρmax = 0.21 e Å3
0 restraintsΔρmin = 0.22 e Å3
Crystal data top
C40H34O12·C4H8O2V = 3996.65 (5) Å3
Mr = 794.78Z = 4
Monoclinic, C2/cCu Kα radiation
a = 13.1495 (1) ŵ = 0.83 mm1
b = 12.7439 (1) ÅT = 100 K
c = 24.0386 (2) Å0.30 × 0.10 × 0.10 mm
β = 97.186 (1)°
Data collection top
Agilent SuperNova Dual
diffractometer with an Atlas detector
4029 independent reflections
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2013)
3714 reflections with I > 2σ(I)
Tmin = 0.790, Tmax = 0.922Rint = 0.022
27173 measured reflectionsθmax = 74.4°
Refinement top
R[F2 > 2σ(F2)] = 0.036H-atom parameters constrained
wR(F2) = 0.095Δρmax = 0.21 e Å3
S = 1.02Δρmin = 0.22 e Å3
4029 reflectionsAbsolute structure: ?
238 parametersAbsolute structure parameter: ?
0 restraintsRogers 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.23221 (6)0.46511 (7)0.48061 (3)0.0295 (2)
O20.35408 (8)0.41673 (8)0.54965 (4)0.0408 (2)
O30.56127 (6)0.19610 (6)0.42147 (3)0.02298 (17)
O40.63350 (6)0.31813 (7)0.48240 (3)0.02886 (19)
O50.88454 (6)0.23900 (7)0.35088 (3)0.02608 (19)
O60.86993 (7)0.10847 (7)0.28727 (4)0.0331 (2)
C10.20807 (11)0.51331 (11)0.57260 (5)0.0374 (3)
H1A0.24410.51650.61080.056*
H1B0.14420.47370.57270.056*
H1C0.19240.58460.55890.056*
C20.27454 (9)0.46003 (9)0.53515 (5)0.0287 (3)
C30.28958 (8)0.41950 (9)0.44109 (4)0.0244 (2)
C40.37948 (8)0.46632 (9)0.42947 (4)0.0238 (2)
H40.40480.52780.44890.029*
C50.43189 (8)0.42139 (8)0.38878 (4)0.0215 (2)
H50.49390.45260.38050.026*
C60.39535 (8)0.33136 (8)0.35982 (4)0.0194 (2)
C70.30498 (8)0.28622 (9)0.37288 (4)0.0238 (2)
H70.27930.22480.35360.029*
C80.25172 (8)0.32971 (10)0.41377 (5)0.0270 (2)
H80.19040.29820.42270.032*
C90.45295 (8)0.28440 (8)0.31499 (4)0.0184 (2)
H90.42400.21320.30520.022*
C100.44581 (7)0.35182 (8)0.25998 (4)0.0185 (2)
H100.42470.42520.26780.022*
C110.56755 (8)0.27379 (8)0.33139 (4)0.0188 (2)
C120.62362 (8)0.30738 (8)0.28902 (4)0.0191 (2)
C130.72954 (8)0.29618 (8)0.29446 (4)0.0218 (2)
H130.76790.31920.26580.026*
C140.77742 (8)0.25032 (9)0.34309 (4)0.0220 (2)
C150.72490 (8)0.21823 (8)0.38658 (4)0.0218 (2)
H150.75990.18800.41970.026*
C160.61939 (8)0.23177 (8)0.38003 (4)0.0207 (2)
C170.57259 (8)0.24896 (9)0.47149 (4)0.0229 (2)
C180.49717 (9)0.20992 (11)0.50834 (5)0.0318 (3)
H18A0.52420.22170.54770.048*
H18B0.48560.13470.50190.048*
H18C0.43220.24770.49960.048*
C190.92348 (9)0.16363 (9)0.31875 (4)0.0255 (2)
C201.03744 (9)0.16233 (11)0.32956 (5)0.0334 (3)
H20A1.06410.10740.30680.050*
H20B1.05890.14800.36940.050*
H20C1.06430.23060.31970.050*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0263 (4)0.0399 (5)0.0223 (4)0.0058 (3)0.0037 (3)0.0057 (3)
O20.0498 (6)0.0482 (6)0.0237 (4)0.0166 (5)0.0015 (4)0.0032 (4)
O30.0252 (4)0.0263 (4)0.0168 (3)0.0011 (3)0.0004 (3)0.0028 (3)
O40.0302 (4)0.0337 (4)0.0223 (4)0.0028 (3)0.0017 (3)0.0036 (3)
O50.0180 (4)0.0374 (5)0.0217 (4)0.0034 (3)0.0021 (3)0.0062 (3)
O60.0350 (5)0.0312 (4)0.0323 (4)0.0066 (4)0.0001 (3)0.0058 (4)
C10.0450 (7)0.0404 (7)0.0289 (6)0.0006 (6)0.0127 (5)0.0086 (5)
C20.0362 (6)0.0282 (6)0.0221 (5)0.0005 (5)0.0055 (5)0.0006 (4)
C30.0235 (5)0.0311 (6)0.0185 (5)0.0061 (4)0.0020 (4)0.0013 (4)
C40.0260 (5)0.0242 (5)0.0201 (5)0.0012 (4)0.0013 (4)0.0026 (4)
C50.0219 (5)0.0220 (5)0.0202 (5)0.0012 (4)0.0013 (4)0.0008 (4)
C60.0195 (5)0.0219 (5)0.0159 (5)0.0017 (4)0.0015 (4)0.0018 (4)
C70.0221 (5)0.0264 (5)0.0222 (5)0.0031 (4)0.0004 (4)0.0031 (4)
C80.0203 (5)0.0359 (6)0.0247 (5)0.0022 (4)0.0025 (4)0.0012 (5)
C90.0205 (5)0.0173 (5)0.0167 (5)0.0008 (4)0.0009 (4)0.0004 (4)
C100.0205 (5)0.0172 (5)0.0172 (5)0.0009 (4)0.0003 (4)0.0005 (4)
C110.0206 (5)0.0165 (5)0.0186 (5)0.0005 (4)0.0002 (4)0.0015 (4)
C120.0215 (5)0.0182 (5)0.0167 (5)0.0010 (4)0.0011 (4)0.0023 (4)
C130.0223 (5)0.0251 (5)0.0179 (5)0.0013 (4)0.0017 (4)0.0034 (4)
C140.0179 (5)0.0260 (5)0.0209 (5)0.0014 (4)0.0023 (4)0.0058 (4)
C150.0242 (5)0.0227 (5)0.0172 (5)0.0032 (4)0.0025 (4)0.0024 (4)
C160.0241 (5)0.0202 (5)0.0172 (5)0.0003 (4)0.0012 (4)0.0005 (4)
C170.0240 (5)0.0270 (5)0.0166 (5)0.0054 (4)0.0014 (4)0.0028 (4)
C180.0305 (6)0.0432 (7)0.0220 (5)0.0002 (5)0.0043 (4)0.0066 (5)
C190.0282 (6)0.0289 (6)0.0193 (5)0.0082 (4)0.0026 (4)0.0045 (4)
C200.0254 (6)0.0429 (7)0.0321 (6)0.0093 (5)0.0044 (5)0.0073 (5)
Geometric parameters (Å, º) top
O1—C21.3603 (14)C9—C111.5152 (14)
O1—C31.4103 (13)C9—C101.5697 (13)
O2—C21.1953 (15)C9—H91.0000
O3—C171.3700 (13)C10—C12i1.5076 (14)
O3—C161.4049 (13)C10—C10i1.560 (2)
O4—C171.1978 (14)C10—H101.0000
O5—C191.3712 (13)C11—C161.3854 (14)
O5—C141.4050 (13)C11—C121.3972 (14)
O6—C191.1955 (14)C12—C131.3900 (15)
C1—C21.4941 (16)C12—C10i1.5076 (13)
C1—H1A0.9800C13—C141.3857 (15)
C1—H1B0.9800C13—H130.9500
C1—H1C0.9800C14—C151.3849 (15)
C3—C81.3807 (16)C15—C161.3873 (15)
C3—C41.3835 (16)C15—H150.9500
C4—C51.3886 (15)C17—C181.4951 (15)
C4—H40.9500C18—H18A0.9800
C5—C61.3957 (15)C18—H18B0.9800
C5—H50.9500C18—H18C0.9800
C6—C71.3910 (15)C19—C201.4886 (16)
C6—C91.5158 (14)C20—H20A0.9800
C7—C81.3915 (15)C20—H20B0.9800
C7—H70.9500C20—H20C0.9800
C8—H80.9500
C2—O1—C3116.15 (9)C12i—C10—H10110.1
C17—O3—C16117.01 (8)C10i—C10—H10110.1
C19—O5—C14115.82 (8)C9—C10—H10110.1
C2—C1—H1A109.5C16—C11—C12119.00 (9)
C2—C1—H1B109.5C16—C11—C9128.50 (9)
H1A—C1—H1B109.5C12—C11—C9112.41 (9)
C2—C1—H1C109.5C13—C12—C11120.93 (9)
H1A—C1—H1C109.5C13—C12—C10i127.87 (9)
H1B—C1—H1C109.5C11—C12—C10i111.20 (9)
O2—C2—O1122.74 (11)C14—C13—C12117.83 (10)
O2—C2—C1126.19 (11)C14—C13—H13121.1
O1—C2—C1111.06 (10)C12—C13—H13121.1
C8—C3—C4121.86 (10)C15—C14—C13122.99 (10)
C8—C3—O1118.07 (10)C15—C14—O5117.09 (9)
C4—C3—O1120.05 (10)C13—C14—O5119.86 (10)
C3—C4—C5118.44 (10)C14—C15—C16117.63 (10)
C3—C4—H4120.8C14—C15—H15121.2
C5—C4—H4120.8C16—C15—H15121.2
C4—C5—C6121.34 (10)C11—C16—C15121.55 (10)
C4—C5—H5119.3C11—C16—O3118.01 (9)
C6—C5—H5119.3C15—C16—O3120.29 (9)
C7—C6—C5118.55 (10)O4—C17—O3123.38 (10)
C7—C6—C9120.94 (9)O4—C17—C18126.17 (10)
C5—C6—C9120.51 (9)O3—C17—C18110.43 (10)
C6—C7—C8120.95 (10)C17—C18—H18A109.5
C6—C7—H7119.5C17—C18—H18B109.5
C8—C7—H7119.5H18A—C18—H18B109.5
C3—C8—C7118.86 (10)C17—C18—H18C109.5
C3—C8—H8120.6H18A—C18—H18C109.5
C7—C8—H8120.6H18B—C18—H18C109.5
C11—C9—C6114.79 (8)O6—C19—O5122.45 (10)
C11—C9—C10102.76 (8)O6—C19—C20127.18 (11)
C6—C9—C10113.59 (8)O5—C19—C20110.37 (10)
C11—C9—H9108.5C19—C20—H20A109.5
C6—C9—H9108.5C19—C20—H20B109.5
C10—C9—H9108.5H20A—C20—H20B109.5
C12i—C10—C10i104.29 (9)C19—C20—H20C109.5
C12i—C10—C9114.78 (8)H20A—C20—H20C109.5
C10i—C10—C9107.37 (8)H20B—C20—H20C109.5
C3—O1—C2—O22.36 (17)C10—C9—C11—C1211.21 (11)
C3—O1—C2—C1178.50 (10)C16—C11—C12—C131.96 (15)
C2—O1—C3—C8111.57 (12)C9—C11—C12—C13174.97 (9)
C2—O1—C3—C470.24 (14)C16—C11—C12—C10i179.25 (9)
C8—C3—C4—C50.54 (17)C9—C11—C12—C10i3.83 (12)
O1—C3—C4—C5177.59 (9)C11—C12—C13—C140.27 (15)
C3—C4—C5—C60.24 (16)C10i—C12—C13—C14178.31 (10)
C4—C5—C6—C70.59 (15)C12—C13—C14—C151.81 (16)
C4—C5—C6—C9179.16 (9)C12—C13—C14—O5178.90 (9)
C5—C6—C7—C80.18 (16)C19—O5—C14—C15110.20 (11)
C9—C6—C7—C8179.57 (9)C19—O5—C14—C1372.54 (13)
C4—C3—C8—C70.94 (17)C13—C14—C15—C161.04 (16)
O1—C3—C8—C7177.22 (10)O5—C14—C15—C16178.20 (9)
C6—C7—C8—C30.57 (17)C12—C11—C16—C152.79 (15)
C7—C6—C9—C11133.77 (10)C9—C11—C16—C15173.58 (10)
C5—C6—C9—C1146.49 (13)C12—C11—C16—O3178.43 (9)
C7—C6—C9—C10108.39 (11)C9—C11—C16—O32.06 (16)
C5—C6—C9—C1071.36 (12)C14—C15—C16—C111.32 (16)
C11—C9—C10—C12i129.45 (9)C14—C15—C16—O3176.87 (9)
C6—C9—C10—C12i105.94 (10)C17—O3—C16—C11114.43 (10)
C11—C9—C10—C10i14.02 (9)C17—O3—C16—C1569.87 (13)
C6—C9—C10—C10i138.64 (8)C16—O3—C17—O45.04 (15)
C6—C9—C11—C1648.41 (14)C16—O3—C17—C18173.34 (9)
C10—C9—C11—C16172.23 (10)C14—O5—C19—O62.25 (15)
C6—C9—C11—C12135.02 (9)C14—O5—C19—C20178.01 (9)
Symmetry code: (i) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C10—H10···O6ii1.002.513.5053 (14)179
C15—H15···O4iii0.952.593.4834 (12)158
C20—H20A···O6iv0.982.523.2708 (15)133
C20—H20B···O2iii0.982.283.2318 (16)162
Symmetry codes: (ii) x1/2, y+1/2, z; (iii) x+3/2, y+1/2, z+1; (iv) x+2, y, z+1/2.

Experimental details

Crystal data
Chemical formulaC40H34O12·C4H8O2
Mr794.78
Crystal system, space groupMonoclinic, C2/c
Temperature (K)100
a, b, c (Å)13.1495 (1), 12.7439 (1), 24.0386 (2)
β (°) 97.186 (1)
V3)3996.65 (5)
Z4
Radiation typeCu Kα
µ (mm1)0.83
Crystal size (mm)0.30 × 0.10 × 0.10
Data collection
DiffractometerAgilent SuperNova Dual
diffractometer with an Atlas detector
Absorption correctionMulti-scan
(CrysAlis PRO; Agilent, 2013)
Tmin, Tmax0.790, 0.922
No. of measured, independent and
observed [I > 2σ(I)] reflections
27173, 4029, 3714
Rint0.022
(sin θ/λ)max1)0.625
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.095, 1.02
No. of reflections4029
No. of parameters238
No. of restraints0
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.21, 0.22

Computer programs: CrysAlis PRO (Agilent, 2013), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C10—H10···O6i1.002.513.5053 (14)179
C15—H15···O4ii0.952.593.4834 (12)158
C20—H20A···O6iii0.982.523.2708 (15)133
C20—H20B···O2ii0.982.283.2318 (16)162
Symmetry codes: (i) x1/2, y+1/2, z; (ii) x+3/2, y+1/2, z+1; (iii) x+2, y, z+1/2.
Acknowledgements top

This project was supported in part by the School of Agriculture, Food and Wine, The University of Adelaide, and by Australia's grape-growers and winemakers through their investment body, the Grape and Wine Research and Development Corporation, with matching funds from the Australian Government. QM thanks the Faculty of Science for a PhD scholarship. The authors also thank the Ministry of Higher Education (Malaysia) for funding structural studies through the High-Impact Research scheme (UM.C/HIR-MOHE/SC/03).

references
References top

Agilent (2013). CrysAlis PRO. Agilent Technologies Inc., Santa Clara, CA, USA.

Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.

Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.

Khan, M. A., Nabi, S. G., Prakash, S. & Zaman, A. (1986). Phytochemistry, 25, 1945–1948.

Moss, R., Mao, Q., Taylor, D. K. & Saucier, C. (2013). Rapid Commun. Mass Spectrom. DOI: 10.1002/rcm.6636.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Spek, A. L. (2009). Acta Cryst. D65, 148–155.

Takaya, Y., Terashima, K., Ito, J., He, Y.-H., Tateoka, M., Yamaguchi, N. & Niwa, M. (2005). Tetrahedron, 61, 10285–10290.

Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.