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Acta Crystallogr Sect E Struct Rep Online. 2009 April 1; 65(Pt 4): o867–o868.
Published online 2009 March 25. doi:  10.1107/S160053680900926X
PMCID: PMC2969092

1-(2-Fluoro­phen­yl)-6,7-dimethoxy­isochroman

Abstract

In the title compound, C17H17FO3, the benzene ring of the isochroman unit is inclined at 84.96 (7)° to the fluoro­benzene ring plane, and the pyran ring adopts a half-boat conformation. In the crystal structure, C—H(...)O hydrogen bonds link mol­ecules into rows along the c axis, while C—H(...)O inter­actions and C—H(...)F hydrogen bonds to the fluorine acceptor stack the mol­ecules down the b axis. In addition, the crystal structure exhibits a weak C—H(...)π inter­action between a methyl H atom of the meth­oxy group and the dimethoxy­benzene ring of an adjacent mol­ecule.

Related literature

For details of naturally occurring isochromans, see: Imamura et al. (2000 [triangle]); Ogawa et al. (2004 [triangle]); Peng et al. (1999 [triangle]); Kunesch et al. (1987 [triangle]). For the biological activity of isochromans, see: Zhang et al. (2008 [triangle]); Lorenz et al. (2005 [triangle]); Togna et al. (2003 [triangle]); Bianchi et al. (2004 [triangle]); Cutler et al. (1997 [triangle]); Liu et al. (2005 [triangle]); TenBrink et al. (1996 [triangle]); Frater et al. (1999 [triangle]); Dobson & Humber (1975 [triangle]); Yamato et al. (1985 [triangle]); McCall et al. (1982 [triangle]). For the synthesis of isochromans, see: Guiso et al. (2001 [triangle]). For related structures, see: Saeed & Flörke (2006a [triangle],b [triangle]). For ring puckering analysis, see: Cremer & Pople (1975 [triangle]); and for reference structural data, see: Allen et al. (1987 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-65-0o867-scheme1.jpg

Experimental

Crystal data

  • C17H17FO3
  • M r = 288.31
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-0o867-efi5.jpg
  • a = 15.730 (2) Å
  • b = 5.2328 (8) Å
  • c = 16.477 (2) Å
  • β = 93.108 (8)°
  • V = 1354.3 (3) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.11 mm−1
  • T = 89 K
  • 0.29 × 0.22 × 0.13 mm

Data collection

  • Bruker APEXII CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2006 [triangle]) T min = 0.789, T max = 0.986
  • 13466 measured reflections
  • 2371 independent reflections
  • 1864 reflections with I > 2σ(I)
  • R int = 0.072

Refinement

  • R[F 2 > 2σ(F 2)] = 0.074
  • wR(F 2) = 0.261
  • S = 1.28
  • 2371 reflections
  • 193 parameters
  • H-atom parameters constrained
  • Δρmax = 0.45 e Å−3
  • Δρmin = −0.37 e Å−3

Data collection: APEX2 (Bruker, 2006 [triangle]); cell refinement: APEX2 and SAINT (Bruker, 2006 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]) and TITAN2000 (Hunter & Simpson, 1999 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]) and Mercury (Macrae et al., 2006 [triangle]); software used to prepare material for publication: SHELXL97, enCIFer (Allen et al., 2004 [triangle]), PLATON (Spek, 2009 [triangle]) and publCIF (Westrip, 2009 [triangle]).

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053680900926X/lx2092sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053680900926X/lx2092Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors thank the University of Otago for the purchase of the diffractometer.

supplementary crystallographic information

Comment

Isochroman is a common structural motif found in many natural products. For example 1,6,8-trihydroxy-3-heptyl-7-carboxyisochroman, is an antibiotic and topoisomerase II inhibitor from Penicillum sp. (Imamura et al., 2000), pseudodeflectusin is a selective human cancer cytotoxin from Aspergillus pseudodeflectus, (Ogawa et al., 2004), in softwood lignin (Peng et al., 1999) and in the male wing gland pheromone of Aphomia sociella (Kunesch et al., 1987). A novel isochroman derivative inhibited apoptosis in vascular endothelial cells by depressing the levels of integrin 4, p53 and ROS (Zhang et al., 2008). 1-Phenyl- and 1-(3-methoxy-4-hydroxy)phenyl-6,7-dihydroxyisochromans identified in extra-virgin olive oil exhibit beneficial antioxidant effects (Lorenz et al., 2005) and antiplatelet activity (Togna et al., 2003). Isochroman derivatives also show plant-growth regulatory and herbicidal activities (Bianchi et al., 2004; Cutler et al., 1997), these are oestrogen receptors (Liu et al., 2005), dopamine receptor ligands (TenBrink et al., 1996), and fragrances, such as galaxolide (Frater et al., 1999). 1-Aryl-6,7-dimethoxyisochromans are known to demonstrate analgesic, muscle relaxant, antidepressant, antiinflammatory, antihistaminic and anticoagulant activity and are adrenergic antagonists (Dobson & Humber 1975; Yamato et al., 1985; McCall et al., 1982). The title dimethoxyisochroman derivative (I), Fig. 1, was prepared by the oxa-Pictet–Spengler reaction for the preparation of isochromans (Guiso et al., 2001) using 2-(3,4-dimethoxyphenyl)ethanol and 2-fluorobenzaldehyde.

The pyran ring of (I) adopts a half-boat conformation (Cremer & Pople, 1975) with the O1 atom 0.639 (3) Å from the least-squares plane through atoms C1–C3, C8, C9. The r.m.s. deviation from this plane was 0.083 Å. The benzene ring of the isochroman unit is inclined at 84.96 (7) ° to the fluorobenzene ring plane. Both the C and O atoms of the two methoxy substituents lie close to the aromatic ring plane (maximum deviation 0.310 (5) Å for C16).

In the molecular packing (Fig. 2), C17—H17B···O1 hydrogen bonds link the molecules into rows along the c axis (Fig. 2 and Table 1; symmetry codes as in Fig. 2). The F1 atom acts as an acceptor in a C7—H7···F1 hydrogen bond that, together with C1—H1B···O2 interactions, stacks molecules from individual rows down the the b axis (Fig. 2, Fig 3 and Table 1; symmetry codes as in Fig. 2). Additionally, a weak C—H···π interaction in the structure was observed between a methyl H atom of the methoxy group and the dimethoxybenzene ring of an adjacent molecule, with a C17—H17A···Cgi separation of 2.70 Å (Table 1 and Fig. 2; Cg is the centroid of the C3–C8 benzene ring, symmetry codes as in Fig. 2).)

Experimental

A homogenized mixture of 2-(3,4-dimethoxyphenyl)ethanol (0.18g, 1 mmol) and 4-fluorobenzaldehyde (0.12g 1 mmol) and a catalytic amount of p-toluenesulfonic acid monohydrate was irradiated for 1.3 min. The product was purified by thin layer chromatography using petroleum ether and ethyl acetate (7:2 v:v) to afford the title compound (0.91 mmol, 91%) which was recrystallized from ethyl acetate. Analysis calculated for C17H17O3F: C, 70.82%, H, 5.94% found, 70.69%, H, 5.97%.

Refinement

All H-atoms were positioned geometrically and refined using a riding model with d(C—H) = 0.95 Å, Uiso=1.2Ueq (C) for aromatic 1.00 Å, Uiso = 1.2Ueq (C) for CH, 0.99 Å, Uiso = 1.2Ueq (C) for CH2 and 0.98 Å, Uiso = 1.5Ueq (C) for CH3 hydrogen atoms.

Figures

Fig. 1.
The molecular structure of the title compound, showing displacement ellipsoids drawn at the 50% probability level.
Fig. 2.
C—H···F, C—H···O (dashed lines) and C—H···π interactions (dotted lines) in the title compound. The yellow spheres denote the ring centroids [symmetry ...
Fig. 3.
Crystal packing for (I) viewed down the b axis with hydrogen bonds drawn as dashed lines and H atoms on atoms not involved in hydrogen bonding omitted.

Crystal data

C17H17FO3F(000) = 608
Mr = 288.31Dx = 1.414 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3061 reflections
a = 15.730 (2) Åθ = 2.5–28.7°
b = 5.2328 (8) ŵ = 0.11 mm1
c = 16.477 (2) ÅT = 89 K
β = 93.108 (8)°Irregular fragment, colourless
V = 1354.3 (3) Å30.29 × 0.22 × 0.13 mm
Z = 4

Data collection

Bruker APEXII CCD area-detector diffractometer2371 independent reflections
Radiation source: fine-focus sealed tube1864 reflections with I > 2σ(I)
graphiteRint = 0.072
Detector resolution: 10.0 pixels mm-1θmax = 25.0°, θmin = 2.6°
ω' scansh = −17→18
Absorption correction: multi-scan (SADABS; Bruker, 2006)k = −6→5
Tmin = 0.789, Tmax = 0.986l = −19→19
13466 measured reflections

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.074H-atom parameters constrained
wR(F2) = 0.261w = 1/[σ2(Fo2) + (0.1483P)2 + 0.6898P] where P = (Fo2 + 2Fc2)/3
S = 1.28(Δ/σ)max < 0.001
2371 reflectionsΔρmax = 0.45 e Å3
193 parametersΔρmin = −0.37 e Å3
0 restraintsExtinction correction: SHELXS97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.021 (8)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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)

xyzUiso*/Ueq
O10.23025 (15)0.7414 (5)0.31621 (15)0.0181 (7)
C10.3182 (2)0.7001 (7)0.3030 (2)0.0203 (9)
H1A0.34250.85510.27870.024*
H1B0.32400.55680.26440.024*
C20.3667 (2)0.6388 (7)0.3826 (2)0.0177 (9)
H2A0.35240.46350.39990.021*
H2B0.42870.64550.37490.021*
C30.3445 (2)0.8270 (7)0.4478 (2)0.0151 (8)
C40.3972 (2)0.8448 (6)0.5191 (2)0.0149 (8)
H40.44580.73730.52570.018*
C50.3797 (2)1.0161 (6)0.5799 (2)0.0140 (8)
O20.42783 (15)1.0436 (5)0.65158 (15)0.0173 (7)
C160.4888 (2)0.8446 (7)0.6690 (2)0.0199 (9)
H16A0.46080.67790.66260.030*
H16B0.51240.86270.72500.030*
H16C0.53480.85710.63140.030*
C60.3085 (2)1.1783 (6)0.5699 (2)0.0143 (8)
O30.29623 (15)1.3416 (5)0.63316 (15)0.0167 (7)
C170.2271 (2)1.5183 (7)0.6224 (2)0.0167 (8)
H17A0.23531.62450.57450.025*
H17B0.22511.62750.67060.025*
H17C0.17341.42380.61480.025*
C70.2562 (2)1.1589 (6)0.4993 (2)0.0143 (8)
H70.20781.26650.49220.017*
C80.2740 (2)0.9841 (6)0.4389 (2)0.0143 (8)
C90.2186 (2)0.9759 (7)0.3601 (2)0.0154 (8)
H90.23681.11960.32500.019*
C100.1238 (2)1.0018 (6)0.3687 (2)0.0146 (8)
C110.0776 (2)0.8291 (6)0.4129 (2)0.0145 (8)
F10.12090 (13)0.6419 (4)0.45485 (12)0.0202 (6)
C12−0.0089 (2)0.8363 (6)0.4168 (2)0.0164 (8)
H12−0.03780.71400.44790.020*
C13−0.0540 (2)1.0280 (7)0.3740 (2)0.0185 (9)
H13−0.11421.03580.37500.022*
C14−0.0104 (2)1.2076 (7)0.3300 (2)0.0193 (9)
H14−0.04091.33940.30140.023*
C150.0770 (2)1.1947 (7)0.3276 (2)0.0162 (8)
H150.10611.31900.29750.019*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0232 (14)0.0159 (14)0.0156 (14)−0.0003 (10)0.0048 (10)−0.0068 (11)
C10.0219 (19)0.021 (2)0.018 (2)0.0006 (15)0.0063 (14)−0.0041 (16)
C20.0219 (19)0.0131 (18)0.019 (2)−0.0007 (14)0.0067 (14)−0.0015 (15)
C30.0200 (18)0.0126 (18)0.0135 (19)−0.0019 (13)0.0069 (13)0.0019 (14)
C40.0190 (18)0.0121 (18)0.0139 (19)0.0019 (13)0.0034 (13)0.0016 (14)
C50.0183 (18)0.0131 (17)0.0106 (18)−0.0022 (13)0.0020 (13)0.0020 (14)
O20.0204 (13)0.0169 (13)0.0145 (14)0.0043 (10)−0.0012 (9)−0.0007 (11)
C160.0218 (19)0.0155 (19)0.022 (2)0.0026 (14)−0.0017 (14)0.0030 (16)
C60.0232 (19)0.0093 (17)0.0111 (18)−0.0017 (13)0.0061 (13)−0.0018 (13)
O30.0233 (14)0.0151 (14)0.0116 (13)0.0065 (10)−0.0012 (9)−0.0042 (10)
C170.0215 (18)0.0127 (18)0.0159 (19)0.0030 (14)0.0013 (13)−0.0051 (14)
C70.0188 (18)0.0094 (17)0.0148 (19)0.0014 (13)0.0023 (13)0.0026 (14)
C80.0222 (19)0.0108 (17)0.0104 (18)−0.0027 (13)0.0047 (13)0.0012 (14)
C90.0247 (19)0.0114 (17)0.0105 (18)−0.0005 (14)0.0040 (13)−0.0022 (14)
C100.0238 (19)0.0103 (17)0.0096 (18)−0.0011 (13)0.0004 (13)−0.0041 (14)
C110.026 (2)0.0077 (17)0.0091 (18)0.0035 (13)−0.0024 (13)−0.0006 (13)
F10.0249 (12)0.0154 (12)0.0202 (12)0.0025 (8)0.0001 (8)0.0071 (9)
C120.029 (2)0.0109 (18)0.0099 (19)−0.0009 (14)0.0029 (14)−0.0023 (14)
C130.0215 (19)0.0170 (19)0.0169 (19)0.0021 (14)0.0009 (14)−0.0038 (15)
C140.030 (2)0.0125 (18)0.0148 (19)0.0064 (14)−0.0032 (14)−0.0016 (15)
C150.031 (2)0.0090 (16)0.0085 (18)−0.0008 (14)0.0011 (13)0.0015 (13)

Geometric parameters (Å, °)

O1—C11.429 (4)O3—C171.432 (4)
O1—C91.441 (4)C17—H17A0.9800
C1—C21.516 (5)C17—H17B0.9800
C1—H1A0.9900C17—H17C0.9800
C1—H1B0.9900C7—C81.391 (5)
C2—C31.512 (5)C7—H70.9500
C2—H2A0.9900C8—C91.525 (5)
C2—H2B0.9900C9—C101.511 (5)
C3—C81.382 (5)C9—H91.0000
C3—C41.404 (5)C10—C111.391 (5)
C4—C51.384 (5)C10—C151.401 (5)
C4—H40.9500C11—F11.360 (4)
C5—O21.375 (4)C11—C121.367 (5)
C5—C61.408 (5)C12—C131.397 (5)
O2—C161.434 (4)C12—H120.9500
C16—H16A0.9800C13—C141.391 (6)
C16—H16B0.9800C13—H130.9500
C16—H16C0.9800C14—C151.379 (5)
C6—O31.370 (4)C14—H140.9500
C6—C71.391 (5)C15—H150.9500
C1—O1—C9110.9 (3)H17A—C17—H17B109.5
O1—C1—C2110.2 (3)O3—C17—H17C109.5
O1—C1—H1A109.6H17A—C17—H17C109.5
C2—C1—H1A109.6H17B—C17—H17C109.5
O1—C1—H1B109.6C6—C7—C8120.9 (3)
C2—C1—H1B109.6C6—C7—H7119.5
H1A—C1—H1B108.1C8—C7—H7119.5
C3—C2—C1110.6 (3)C3—C8—C7120.4 (3)
C3—C2—H2A109.5C3—C8—C9119.5 (3)
C1—C2—H2A109.5C7—C8—C9120.0 (3)
C3—C2—H2B109.5O1—C9—C10106.1 (3)
C1—C2—H2B109.5O1—C9—C8111.6 (3)
H2A—C2—H2B108.1C10—C9—C8116.0 (3)
C8—C3—C4118.9 (3)O1—C9—H9107.6
C8—C3—C2121.8 (3)C10—C9—H9107.6
C4—C3—C2119.3 (3)C8—C9—H9107.6
C5—C4—C3121.2 (3)C11—C10—C15116.5 (3)
C5—C4—H4119.4C11—C10—C9122.5 (3)
C3—C4—H4119.4C15—C10—C9120.9 (3)
O2—C5—C4124.6 (3)F1—C11—C12117.9 (3)
O2—C5—C6115.8 (3)F1—C11—C10118.2 (3)
C4—C5—C6119.6 (3)C12—C11—C10123.8 (3)
C5—O2—C16115.3 (3)C11—C12—C13118.4 (3)
O2—C16—H16A109.5C11—C12—H12120.8
O2—C16—H16B109.5C13—C12—H12120.8
H16A—C16—H16B109.5C14—C13—C12119.9 (3)
O2—C16—H16C109.5C14—C13—H13120.1
H16A—C16—H16C109.5C12—C13—H13120.1
H16B—C16—H16C109.5C15—C14—C13120.1 (3)
O3—C6—C7125.5 (3)C15—C14—H14119.9
O3—C6—C5115.5 (3)C13—C14—H14119.9
C7—C6—C5119.0 (3)C14—C15—C10121.3 (3)
C6—O3—C17116.5 (3)C14—C15—H15119.4
O3—C17—H17A109.5C10—C15—H15119.4
O3—C17—H17B109.5
C9—O1—C1—C269.6 (4)C6—C7—C8—C9−176.7 (3)
O1—C1—C2—C3−47.7 (4)C1—O1—C9—C10178.8 (3)
C1—C2—C3—C815.5 (5)C1—O1—C9—C8−54.0 (4)
C1—C2—C3—C4−164.0 (3)C3—C8—C9—O120.5 (4)
C8—C3—C4—C5−0.1 (5)C7—C8—C9—O1−163.2 (3)
C2—C3—C4—C5179.4 (3)C3—C8—C9—C10142.2 (3)
C3—C4—C5—O2179.5 (3)C7—C8—C9—C10−41.5 (4)
C3—C4—C5—C6−0.9 (5)O1—C9—C10—C1164.0 (4)
C4—C5—O2—C16−13.0 (5)C8—C9—C10—C11−60.5 (4)
C6—C5—O2—C16167.4 (3)O1—C9—C10—C15−111.9 (3)
O2—C5—C6—O3−0.4 (4)C8—C9—C10—C15123.6 (3)
C4—C5—C6—O3−179.9 (3)C15—C10—C11—F1−178.8 (3)
O2—C5—C6—C7−179.2 (3)C9—C10—C11—F15.1 (5)
C4—C5—C6—C71.2 (5)C15—C10—C11—C121.1 (5)
C7—C6—O3—C17−4.7 (5)C9—C10—C11—C12−174.9 (3)
C5—C6—O3—C17176.6 (3)F1—C11—C12—C13179.9 (3)
O3—C6—C7—C8−179.3 (3)C10—C11—C12—C130.0 (5)
C5—C6—C7—C8−0.6 (5)C11—C12—C13—C14−1.0 (5)
C4—C3—C8—C70.8 (5)C12—C13—C14—C150.8 (5)
C2—C3—C8—C7−178.7 (3)C13—C14—C15—C100.3 (5)
C4—C3—C8—C9177.1 (3)C11—C10—C15—C14−1.3 (5)
C2—C3—C8—C9−2.4 (5)C9—C10—C15—C14174.8 (3)
C6—C7—C8—C3−0.5 (5)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C1—H1B···O2i0.992.593.360 (5)134
C7—H7···F1ii0.952.453.360 (4)160
C17—H17B···O1iii0.982.493.430 (4)160
C17—H17A···Cgii0.982.703.557 (3)146

Symmetry codes: (i) x, −y+3/2, z−1/2; (ii) x, y+1, z; (iii) x, −y+5/2, z+1/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LX2092).

References

  • Allen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst.37, 335–338.
  • Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.
  • Bianchi, D. A., Blanco, N. E., Carrillo, N. & Kaufman, T. S. (2004). J. Agric. Food. Chem.52, 1923–1927. [PubMed]
  • Bruker (2006). APEX2, SAINT and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc.97, 1354–1358.
  • Cutler, H. G., Majetich, G., Tian, X. & Spearing, P. (1997). J. Agric. Food Chem.45, 1422–1429.
  • Dobson, T. A. & Humber, L. G. (1975). J. Heterocycl. Chem.12, 591–594.
  • Frater, G., Muller, U. & Kraft, P. (1999). Helv. Chim. Acta, 82, 1656–1665.
  • Guiso, M., Marra, C. & Cavarischia, C. (2001). Tetrahedron Lett.42, 6531–6534.
  • Hunter, K. A. & Simpson, J. (1999). TITAN2000 University of Otago, New Zealand.
  • Imamura, N., Ishikawa, T., Ohtsuka, T., Yamamoto, K., Dekura, M., Fukami, H. & Nishida, R. (2000). Biosci. Biotechnol. Biochem.64, 2216–2217. [PubMed]
  • Kunesch, G., Zagatti, P., Pouverau, A. & Cassini, R. (1987). Z. Naturforsch.42, 657–659.
  • Liu, J., Birzin, E. T., Chan, W., Yang, Y. T., Pai, L. Y., DaSilva, C., Hayes, E. C., Mosley, R. T., DiNinno, F., Rohrer, S. P., Schaeer, J. M. & Hammonda, M. L. (2005). Bioorg. Med. Chem. Lett.15, 715–718. [PubMed]
  • Lorenz, P., Zeh, M., Lobenhoffer, J. M., Schmidt, H., Wolf, G. & Horn, T. F. W. (2005). Free Radic. Res.39, 535–545. [PubMed]
  • Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst.39, 453–457.
  • McCall, J. M., McCall, R. B., TenBrink, R. E., Kamdar, B. V., Humphrey, S. J., Sethy, V. H., Harris, D. W. & Daenzar, C. J. (1982). J. Med. Chem.25, 75–81. [PubMed]
  • Ogawa, A., Murakami, C., Kamisuki, S., Kuriyama, I., Yoshida, H., Sugawara, F. & Mizushina, Y. (2004). Bioorg. Med. Chem. Lett.14, 3539–3543. [PubMed]
  • Peng, J., Lu, F. & Ralph, J. (1999). Phytochemistry, 50, 659–666.
  • Saeed, A. & Flörke, U. (2006a). Acta Cryst. E62, o1598–o1600.
  • Saeed, A. & Flörke, U. (2006b). Acta Cryst. E62, o1819–o1821.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Spek, A. L. (2009). Acta Cryst. D65, 148–155. [PMC free article] [PubMed]
  • TenBrink, R. E., Bergh, C. L., Duncan, J. N., Harris, D. W., Huff, R. M., Lahti, R. A., Lawson, C. F., Lutzke, B. S., Martin, I. J., Rees, S. A., Schlachter, S. K., Sihr, J. C. & Smith, M. W. (1996). J. Med. Chem.39, 2435–2437. [PubMed]
  • Togna, G. I., Togna, A. R., Franconi, M., Marra, C. & Guiso, M. (2003). J. Nutr.133, 2532–2536. [PubMed]
  • Westrip, S. P. (2009). publCIF In preparation.
  • Yamato, M., Hashigaki, K., Ishikawa, S., Kokubu, N., Inoue, Y., Tsuruo, T. & Tashirot, T. (1985). J. Med. Chem.28, 1026–1031. [PubMed]
  • Zhang, L., Zhu, X., Zhao, B., Zhao, J., Zhang, Y., Zhang, S. L. & Miao, J. Y. (2008). Vasc. Pharmacol.48, 63–69. [PubMed]

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