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Acta Crystallogr Sect E Struct Rep Online. 2009 December 1; 65(Pt 12): o3019.
Published online 2009 November 7. doi:  10.1107/S1600536809045668
PMCID: PMC2971974

1-(4-tert-Butyl­benz­yl)-2-(4-tert-butyl­phen­yl)-1H-benzimidazole

Abstract

In the mol­ecule of the title compound, C28H32N2, the benzimidazole ring system is almost planar [maximum deviation = 0.0221 (15) Å] and forms dihedral angles of 85.86 (4) and 32.09 (6)° with the benzene rings. In the crystal structure, mol­ecules are linked into chains running parallel to the a axis by inter­molecular C—H(...)N hydrogen bonds. The methyl groups of a tert-butyl group are rotationally disordered over two positions with refined site-occupancy factors of 0.636 (4) and 0.364 (4).

Related literature

For the biological and pharmaceutical properties of benzimidazole derivatives, see: Matsuno et al. (2000 [triangle]). Garuti et al. (1999 [triangle]). For reference structural data, see: Allen et al. (1987 [triangle]).

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Object name is e-65-o3019-scheme1.jpg

Experimental

Crystal data

  • C28H32N2
  • M r = 396.56
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-65-o3019-efi1.jpg
  • a = 6.2142 (5) Å
  • b = 21.1112 (13) Å
  • c = 17.4624 (12) Å
  • β = 92.869 (6)°
  • V = 2288.0 (3) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.07 mm−1
  • T = 293 K
  • 0.20 × 0.20 × 0.10 mm

Data collection

  • Rigaku SCXmini diffractometer
  • Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 [triangle]) T min = 0.987, T max = 0.993
  • 24819 measured reflections
  • 5239 independent reflections
  • 4315 reflections with I > 2σ(I)
  • R int = 0.047

Refinement

  • R[F 2 > 2σ(F 2)] = 0.061
  • wR(F 2) = 0.135
  • S = 1.09
  • 5239 reflections
  • 302 parameters
  • H-atom parameters constrained
  • Δρmax = 0.22 e Å−3
  • Δρmin = −0.18 e Å−3

Data collection: CrystalClear (Rigaku, 2005 [triangle]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXL97.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809045668/rz2378sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809045668/rz2378Isup2.hkl

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

Acknowledgments

This work was financially supported by the Jiangsu Provincial Key Laboratory of Pulp and Paper Science and Technology Fund (No. 200813).

supplementary crystallographic information

Comment

Imidazole and benzimidazole derivatives are important heteroaromatic compounds which have attracted great attention due to their biological and pharmaceutical activities (Matsuno et al., 2000; Garuti et al., 1999). These compounds have also played an important role in the development of coordination chemistry. In this paper, we report the crystal structure of the title compound.

The molecular structure of the title compound is shown in Fig. 1. Bond lengths (Allen et al., 1987) and angles are within normal ranges. The benzimidazole ring system is substantially planar, with a maximum displacement of 0.0221 (15) Å for atom C1. The dihedral angle it forms with the C8—C13 and C19—C24 benzene rings are 32.09 (6) and 85.86 (4) Å, respectively. The benzene rings are oriented perpendicularly to each other, forming a dihedral angle of 89.58 (5) °. In the crystal packing, the molecule are linked into chains running parallel to the a axis by intermolecular C—H···N hydrogen bonds (Table 1). The methyl groups of a tert-butyl group exhibits rotational disorder over two orientations with site occupation factors of 0.636 (4) and 0.364 (4) for the major and minor components of disorder, respectively.

Experimental

To a solution of o-phenylenediamine (0.432 g, 4 mmol) in ethanol(20 ml), 4-tert-butylbenzaldehyde (1.297 g, 8 mmol) was added. The mixture was heated to reflux with stirring for four hour, then cooled to room temperature. The resultant solution was filtered and allowed to evaporate slowly at room temperature. Colourless single crystals of the title compound suitable for X-ray diffraction study were obtained after several weeks.

Refinement

The C15, C16 and C17 methyl carbon atoms of a tert-butyl group are rotationally disordered over two position with refined site occupancy factors of 0.636 (4) and 0.364 (4). All H atoms were located geometrically and treated as riding atoms, with C—H = 0.93–0.97 Å, and with Uiso(H) = 1.2 Ueq(C) or 1.5 Ueq(C) for methyl H atoms.

Figures

Fig. 1.
The molecular structure of the title compound, showing the atomic numbering scheme. The displacement ellipsoids are drawn at the 30% probability level.

Crystal data

C28H32N2F(000) = 856
Mr = 396.56Dx = 1.151 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3426 reflections
a = 6.2142 (5) Åθ = 2.3–27.5°
b = 21.1112 (13) ŵ = 0.07 mm1
c = 17.4624 (12) ÅT = 293 K
β = 92.869 (6)°Block, colourless
V = 2288.0 (3) Å30.20 × 0.20 × 0.10 mm
Z = 4

Data collection

Rigaku SCXmini diffractometer5239 independent reflections
Radiation source: fine-focus sealed tube4315 reflections with I > 2σ(I)
graphiteRint = 0.047
Detector resolution: 13.6612 pixels mm-1θmax = 27.5°, θmin = 3.3°
ω scansh = −8→8
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)k = −27→27
Tmin = 0.987, Tmax = 0.993l = −22→22
24819 measured reflections

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.061Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.135H-atom parameters constrained
S = 1.09w = 1/[σ2(Fo2) + (0.0431P)2 + 0.936P] where P = (Fo2 + 2Fc2)/3
5239 reflections(Δ/σ)max < 0.001
302 parametersΔρmax = 0.22 e Å3
0 restraintsΔρmin = −0.18 e Å3

Special details

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)

xyzUiso*/UeqOcc. (<1)
N10.7010 (2)0.17678 (6)0.27399 (7)0.0256 (3)
N21.0343 (2)0.14275 (6)0.31033 (7)0.0298 (3)
C10.7112 (3)0.17535 (7)0.35346 (9)0.0270 (3)
C20.5570 (3)0.18846 (8)0.40650 (10)0.0346 (4)
H2B0.41920.20210.39130.041*
C30.6195 (3)0.18016 (9)0.48290 (10)0.0392 (4)
H3A0.52140.18840.52010.047*
C40.8268 (3)0.15961 (9)0.50544 (10)0.0382 (4)
H4A0.86320.15470.55740.046*
C50.9793 (3)0.14633 (8)0.45281 (10)0.0344 (4)
H5A1.11700.13280.46840.041*
C60.9185 (3)0.15411 (7)0.37498 (9)0.0282 (3)
C70.8992 (2)0.15635 (7)0.25137 (9)0.0258 (3)
C80.9583 (2)0.14654 (7)0.17169 (9)0.0272 (3)
C90.8876 (3)0.18418 (8)0.10959 (9)0.0310 (4)
H9A0.78870.21640.11680.037*
C100.9638 (3)0.17391 (9)0.03713 (10)0.0355 (4)
H10A0.91410.1995−0.00330.043*
C111.1119 (3)0.12648 (8)0.02342 (10)0.0344 (4)
C121.1810 (3)0.08896 (8)0.08579 (10)0.0370 (4)
H12A1.28020.05680.07850.044*
C131.1055 (3)0.09845 (8)0.15806 (10)0.0335 (4)
H13A1.15370.07230.19820.040*
C141.1974 (3)0.11519 (9)−0.05650 (10)0.0424 (5)
C151.4372 (5)0.1228 (2)−0.0550 (2)0.0569 (10)0.636 (4)
H15A1.47260.1670−0.05760.085*0.636 (4)
H15B1.49300.1011−0.09800.085*0.636 (4)
H15C1.49960.1051−0.00830.085*0.636 (4)
C161.1017 (6)0.16598 (17)−0.11722 (17)0.0508 (9)0.636 (4)
H16A0.94750.1625−0.12120.076*0.636 (4)
H16B1.15870.1580−0.16640.076*0.636 (4)
H16C1.14140.2079−0.10040.076*0.636 (4)
C171.1189 (8)0.0513 (2)−0.0846 (2)0.0687 (14)0.636 (4)
H17A0.96950.0541−0.10110.103*0.636 (4)
H17B1.13600.0209−0.04380.103*0.636 (4)
H17C1.20140.0381−0.12680.103*0.636 (4)
C16'1.3128 (12)0.1723 (4)−0.0785 (4)0.073 (2)0.364 (4)
H16D1.21280.2068−0.08510.109*0.364 (4)
H16E1.38110.1648−0.12580.109*0.364 (4)
H16F1.42010.1828−0.03910.109*0.364 (4)
C15'1.3773 (13)0.0576 (4)−0.0524 (3)0.077 (3)0.364 (4)
H15D1.31070.0193−0.03600.116*0.364 (4)
H15E1.49340.0688−0.01660.116*0.364 (4)
H15F1.43230.0514−0.10230.116*0.364 (4)
C17'1.0230 (11)0.0946 (4)−0.1102 (3)0.0593 (19)0.364 (4)
H17D0.91320.1266−0.11370.089*0.364 (4)
H17E0.96270.0558−0.09220.089*0.364 (4)
H17F1.07870.0879−0.15980.089*0.364 (4)
C180.5117 (2)0.19700 (7)0.22771 (9)0.0276 (3)
H18A0.38340.18450.25330.033*
H18B0.51000.17530.17870.033*
C190.5039 (2)0.26793 (7)0.21354 (8)0.0244 (3)
C200.6751 (3)0.30771 (8)0.23238 (10)0.0345 (4)
H20A0.79920.29120.25680.041*
C210.6647 (3)0.37210 (8)0.21545 (10)0.0354 (4)
H21A0.78230.39760.22920.042*
C220.4846 (2)0.39941 (7)0.17869 (9)0.0255 (3)
C230.3127 (3)0.35908 (8)0.16148 (11)0.0380 (4)
H23A0.18750.37560.13790.046*
C240.3214 (3)0.29478 (8)0.17827 (11)0.0370 (4)
H24A0.20260.26940.16560.044*
C250.4755 (3)0.47028 (7)0.15925 (10)0.0314 (4)
C260.6985 (3)0.49533 (9)0.14043 (12)0.0454 (5)
H26A0.74890.47290.09700.068*
H26B0.79740.48910.18380.068*
H26C0.68870.53970.12870.068*
C270.3234 (3)0.48367 (9)0.08955 (12)0.0474 (5)
H27A0.37230.46120.04590.071*
H27B0.32180.52830.07910.071*
H27C0.18060.46990.10000.071*
C280.3968 (4)0.50619 (9)0.22849 (12)0.0586 (6)
H28A0.25700.49090.24040.088*
H28B0.38820.55060.21680.088*
H28C0.49590.49970.27170.088*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
N10.0275 (7)0.0240 (6)0.0255 (7)0.0003 (5)0.0032 (5)0.0028 (5)
N20.0303 (7)0.0312 (7)0.0280 (7)0.0019 (5)0.0030 (6)0.0021 (6)
C10.0328 (8)0.0225 (7)0.0259 (8)−0.0023 (6)0.0048 (6)0.0025 (6)
C20.0335 (9)0.0364 (9)0.0344 (9)0.0014 (7)0.0075 (7)0.0009 (7)
C30.0449 (11)0.0425 (10)0.0311 (9)−0.0027 (8)0.0118 (8)−0.0010 (8)
C40.0482 (11)0.0403 (10)0.0263 (9)−0.0046 (8)0.0030 (7)0.0035 (7)
C50.0375 (9)0.0350 (9)0.0306 (9)−0.0009 (7)0.0007 (7)0.0044 (7)
C60.0321 (8)0.0255 (8)0.0271 (8)−0.0018 (6)0.0038 (6)0.0023 (6)
C70.0281 (8)0.0217 (7)0.0277 (8)−0.0012 (6)0.0038 (6)0.0016 (6)
C80.0281 (8)0.0261 (8)0.0276 (8)−0.0049 (6)0.0029 (6)−0.0006 (6)
C90.0323 (9)0.0304 (8)0.0303 (9)−0.0015 (7)0.0032 (7)0.0001 (7)
C100.0395 (10)0.0388 (9)0.0282 (9)−0.0057 (7)0.0023 (7)0.0015 (7)
C110.0351 (9)0.0387 (9)0.0300 (9)−0.0102 (7)0.0067 (7)−0.0082 (7)
C120.0371 (10)0.0354 (9)0.0391 (10)0.0023 (7)0.0076 (8)−0.0077 (8)
C130.0353 (9)0.0323 (9)0.0330 (9)0.0015 (7)0.0034 (7)−0.0003 (7)
C140.0468 (11)0.0484 (11)0.0333 (10)−0.0098 (9)0.0136 (8)−0.0078 (8)
C150.048 (2)0.078 (3)0.047 (2)0.0041 (18)0.0199 (15)0.0108 (18)
C160.056 (2)0.070 (2)0.0278 (15)−0.0027 (17)0.0097 (14)0.0037 (15)
C170.105 (4)0.059 (2)0.045 (2)−0.023 (2)0.032 (2)−0.0254 (19)
C16'0.081 (6)0.077 (5)0.063 (4)−0.019 (4)0.041 (4)−0.001 (4)
C15'0.095 (6)0.103 (6)0.036 (3)0.056 (5)0.024 (3)0.003 (4)
C17'0.069 (4)0.073 (5)0.036 (3)0.006 (3)0.002 (3)−0.015 (3)
C180.0254 (8)0.0258 (8)0.0316 (8)−0.0026 (6)−0.0001 (6)0.0012 (6)
C190.0251 (8)0.0247 (7)0.0236 (7)−0.0008 (6)0.0039 (6)−0.0004 (6)
C200.0289 (9)0.0296 (8)0.0437 (10)−0.0010 (6)−0.0107 (7)0.0043 (7)
C210.0303 (9)0.0272 (8)0.0476 (11)−0.0054 (6)−0.0080 (7)0.0018 (7)
C220.0273 (8)0.0250 (7)0.0243 (8)0.0017 (6)0.0041 (6)−0.0007 (6)
C230.0271 (9)0.0309 (9)0.0548 (11)0.0012 (7)−0.0097 (8)0.0059 (8)
C240.0260 (8)0.0303 (9)0.0538 (11)−0.0057 (7)−0.0074 (7)0.0032 (8)
C250.0382 (9)0.0248 (8)0.0316 (9)0.0022 (7)0.0056 (7)0.0022 (7)
C260.0454 (11)0.0331 (9)0.0576 (12)−0.0072 (8)0.0028 (9)0.0099 (9)
C270.0487 (12)0.0408 (10)0.0525 (12)0.0016 (9)−0.0011 (9)0.0176 (9)
C280.1005 (19)0.0285 (9)0.0493 (12)0.0113 (10)0.0287 (12)0.0019 (9)

Geometric parameters (Å, °)

N1—C71.3816 (19)C17—H17A0.9600
N1—C11.386 (2)C17—H17B0.9600
N1—C181.4571 (19)C17—H17C0.9600
N2—C71.327 (2)C16'—H16D0.9600
N2—C61.390 (2)C16'—H16E0.9600
C1—C21.393 (2)C16'—H16F0.9600
C1—C61.398 (2)C15'—H15D0.9600
C2—C31.382 (2)C15'—H15E0.9600
C2—H2B0.9300C15'—H15F0.9600
C3—C41.397 (3)C17'—H17D0.9600
C3—H3A0.9300C17'—H17E0.9600
C4—C51.381 (2)C17'—H17F0.9600
C4—H4A0.9300C18—C191.518 (2)
C5—C61.402 (2)C18—H18A0.9700
C5—H5A0.9300C18—H18B0.9700
C7—C81.471 (2)C19—C201.382 (2)
C8—C131.395 (2)C19—C241.385 (2)
C8—C91.397 (2)C20—C211.392 (2)
C9—C101.390 (2)C20—H20A0.9300
C9—H9A0.9300C21—C221.387 (2)
C10—C111.389 (2)C21—H21A0.9300
C10—H10A0.9300C22—C231.387 (2)
C11—C121.397 (3)C22—C251.535 (2)
C11—C141.536 (2)C23—C241.389 (2)
C12—C131.383 (2)C23—H23A0.9300
C12—H12A0.9300C24—H24A0.9300
C13—H13A0.9300C25—C281.528 (2)
C14—C17'1.463 (6)C25—C271.530 (2)
C14—C16'1.465 (7)C25—C261.534 (2)
C14—C151.498 (4)C26—H26A0.9600
C14—C171.508 (4)C26—H26B0.9600
C14—C161.601 (4)C26—H26C0.9600
C14—C15'1.650 (6)C27—H27A0.9600
C15—H15A0.9600C27—H27B0.9600
C15—H15B0.9600C27—H27C0.9600
C15—H15C0.9600C28—H28A0.9600
C16—H16A0.9600C28—H28B0.9600
C16—H16B0.9600C28—H28C0.9600
C16—H16C0.9600
C7—N1—C1106.40 (13)C14—C17—H17A109.5
C7—N1—C18129.74 (13)C14—C17—H17B109.5
C1—N1—C18123.86 (13)H17A—C17—H17B109.5
C7—N2—C6105.05 (13)C14—C17—H17C109.5
N1—C1—C2131.48 (15)H17A—C17—H17C109.5
N1—C1—C6105.77 (13)H17B—C17—H17C109.5
C2—C1—C6122.70 (15)C14—C16'—H16D109.5
C3—C2—C1116.56 (16)C14—C16'—H16E109.5
C3—C2—H2B121.7H16D—C16'—H16E109.5
C1—C2—H2B121.7C14—C16'—H16F109.5
C2—C3—C4121.47 (16)H16D—C16'—H16F109.5
C2—C3—H3A119.3H16E—C16'—H16F109.5
C4—C3—H3A119.3C14—C15'—H15D109.5
C5—C4—C3121.94 (16)C14—C15'—H15E109.5
C5—C4—H4A119.0H15D—C15'—H15E109.5
C3—C4—H4A119.0C14—C15'—H15F109.5
C4—C5—C6117.44 (16)H15D—C15'—H15F109.5
C4—C5—H5A121.3H15E—C15'—H15F109.5
C6—C5—H5A121.3C14—C17'—H17D109.5
N2—C6—C1110.16 (13)C14—C17'—H17E109.5
N2—C6—C5129.95 (15)H17D—C17'—H17E109.5
C1—C6—C5119.88 (15)C14—C17'—H17F109.5
N2—C7—N1112.61 (14)H17D—C17'—H17F109.5
N2—C7—C8121.68 (14)H17E—C17'—H17F109.5
N1—C7—C8125.63 (14)N1—C18—C19113.43 (12)
C13—C8—C9117.69 (15)N1—C18—H18A108.9
C13—C8—C7117.42 (14)C19—C18—H18A108.9
C9—C8—C7124.78 (14)N1—C18—H18B108.9
C10—C9—C8120.65 (16)C19—C18—H18B108.9
C10—C9—H9A119.7H18A—C18—H18B107.7
C8—C9—H9A119.7C20—C19—C24117.44 (14)
C11—C10—C9121.88 (16)C20—C19—C18122.86 (14)
C11—C10—H10A119.1C24—C19—C18119.67 (14)
C9—C10—H10A119.1C19—C20—C21121.05 (15)
C10—C11—C12117.05 (15)C19—C20—H20A119.5
C10—C11—C14122.04 (17)C21—C20—H20A119.5
C12—C11—C14120.91 (16)C22—C21—C20122.13 (15)
C13—C12—C11121.63 (16)C22—C21—H21A118.9
C13—C12—H12A119.2C20—C21—H21A118.9
C11—C12—H12A119.2C23—C22—C21116.09 (14)
C12—C13—C8121.10 (16)C23—C22—C25122.07 (14)
C12—C13—H13A119.5C21—C22—C25121.83 (14)
C8—C13—H13A119.5C22—C23—C24122.19 (15)
C17'—C14—C16'115.7 (5)C22—C23—H23A118.9
C17'—C14—C15138.4 (3)C24—C23—H23A118.9
C16'—C14—C1554.3 (4)C19—C24—C23121.07 (15)
C17'—C14—C1746.3 (3)C19—C24—H24A119.5
C16'—C14—C17143.7 (3)C23—C24—H24A119.5
C15—C14—C17114.0 (3)C28—C25—C27109.18 (16)
C17'—C14—C11110.5 (3)C28—C25—C26109.07 (16)
C16'—C14—C11107.9 (3)C27—C25—C26107.14 (15)
C15—C14—C11110.84 (19)C28—C25—C22108.57 (14)
C17—C14—C11108.26 (19)C27—C25—C22111.76 (14)
C17'—C14—C1662.4 (3)C26—C25—C22111.08 (14)
C16'—C14—C1656.3 (4)C25—C26—H26A109.5
C15—C14—C16106.1 (2)C25—C26—H26B109.5
C17—C14—C16106.3 (3)H26A—C26—H26B109.5
C11—C14—C16111.34 (18)C25—C26—H26C109.5
C17'—C14—C15'106.7 (4)H26A—C26—H26C109.5
C16'—C14—C15'106.2 (5)H26B—C26—H26C109.5
C15—C14—C15'53.6 (4)C25—C27—H27A109.5
C17—C14—C15'64.1 (4)C25—C27—H27B109.5
C11—C14—C15'109.8 (2)H27A—C27—H27B109.5
C16—C14—C15'138.6 (3)C25—C27—H27C109.5
C14—C15—H15A109.5H27A—C27—H27C109.5
C14—C15—H15B109.5H27B—C27—H27C109.5
H15A—C15—H15B109.5C25—C28—H28A109.5
C14—C15—H15C109.5C25—C28—H28B109.5
H15A—C15—H15C109.5H28A—C28—H28B109.5
H15B—C15—H15C109.5C25—C28—H28C109.5
C14—C16—H16A109.5H28A—C28—H28C109.5
C14—C16—H16B109.5H28B—C28—H28C109.5
C14—C16—H16C109.5

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C18—H18A···N2i0.972.593.553 (2)174

Symmetry codes: (i) x−1, y, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: RZ2378).

References

  • 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.
  • Garuti, L., Roberti, M. & Cermelli, C. (1999). Bioorg. Med. Chem. Lett. 9, 2525–2530. [PubMed]
  • Matsuno, T., Kato, M., Sasahara, H., Watanabe, T., Inaba, M., Takahashi, M., Yaguchi, S. I., Yoshioka, K., Sakato, M. & Kawashima, S. (2000). Chem. Pharm. Bull. 48, 1778–1781. [PubMed]
  • Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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