supplementary materials


zl2545 scheme

Acta Cryst. (2013). E69, o877    [ doi:10.1107/S160053681301221X ]

6,8-Dibromo-3-nitro-2-phenyl-2H-chromene

L.-J. Yan and S.-Y. Zhang

Abstract top

In the title compound, C15H9Br2NO3, the chromene unit is not quite planar (r.m.s. deviation from planarity = 0.0888 Å). The dihydropyran ring adopts an envelope conformation with the phenyl-substituted C atom fused to the dihydropyran ring as the flap. The dihedral angle between the plane defined by this C atom and the adjacent C and O atoms and the mean plane of the dihydropyran ring excluding the phenyl-substituted C atom is 25.1 (3)°. The dihedral angle between the mean plane of the chromene unit and the phenyl ring is 85.7 (1)°. The crystal structure features C-H...O hydrogen bonds and Br...O contacts [3.289 (3) Å] involving the nitro O atoms.

Comment top

3-Nitro-2H-chromene derivatives are important intermediates for synthesis of (-)-epigallocatechin gallate (EGCG) which is a promising candidate for drug development for its cancer preventive, antiviral, and other important bioactivities and is a major constituent of green tea extract (Furuta et al., 2007). In addition, 3-nitro-2-phenyl-2H-chromene derivatives were used for synthesis of the 1, 2, 3-triazole heterocycles which are reported to posses several biological activities, including anti-HIV, anti-allergic, anti-fungal, anti-viral, and anti-microbial (Pateliya et al., 2009). The title compound, oxa-6,8-dibromo-3-nitro-2-phenyl-2H-chromene, is such a 3-nitro-2H-chromene derivative. It has been synthesized by tandem oxa-Henry-Michael reaction of 4,5-dibromo-2-hydroxy-benzaldehyde with (2-nitro-vinyl)-benzene (Yan et al., 2001).

In the title compound, C15H9Br2NO3, the chromene unit is not quite planar. The r.m.s. deviation from planarity is 0.0888 Å (fitted atoms are C1, C2, C3, C4, C5, C6, C7, C8, C9 and O3). The dihydropyran ring adopts an envelope conformation (with atom C9 as the flap). The dihedral angle between the plane defined by C8, C9 and O3 and the least-squares plane defined by C1, C6, C7, C8 and O3 is 25.1 (3)°. The dihedral angle between the phenyl ring and the overall average plane of the chromene unit (defined by atoms C1, C2, C3, C4, C5, C6, C7, C8, C9 and O3) is 85.7 (1)°. The structure is stabilized by intermolecular C5—H5···O2 and C7—H7···O2 hydrogen bonds and a C4—Br2···O1 halogen bond (Fig. 2), with the nitro O atoms acceptors for the C—H and C—Br groups.

Related literature top

For the preparation of analogs of the title compound, see: Yan et al. (2001); Pateliya et al. (2009). For synthetic use of the analogs and bioactive derivatives of the title compound, see: Furuta et al. (2007); Pateliya et al. (2009).

Experimental top

In a 100 ml Schlenk tube were placed 4,5-dibromo-2-hydroxy-benzaldehyde (2.26 g, 5.5 mmol), (2-nitro-vinyl)-benzene (0.75 g, 5 mmol), and 1,4-diazabicyclo[2.2.2]octane (DABCO) (0.56 g, 5 mmol), and the flask was evacuated and filled with N2 three times, anhydrous toluene (20 ml, degassed) was added to the tube. The reaction mixture was stirred for 1.5 h at 80 °C under N2. The solvent was removed under reduced pressure to give the crude product as a brown oil. The crude product was purified by a flash column chromatography with the elution of n-hexane/ethyl acetate (20/1) to yield the title compound (Rf = 0.65) as a light yellow powder (76%). 1H NMR (CDCl3, 500 MHz): δ 8.15 (s, 1H), 7.50 (s, 1H), 7.35–7.32 (m, 2H), 7.1 (s, 2H), 7.04–6.99 (m, 2H), 6.8 (d, 1H).

Single crystals of the compound were obtained from dry CH2Cl2.

Refinement top

All H atoms were placed in calculated positions and refined as riding, with C—H distances of 0.93 Å and 0.98 Å, and with Uiso(H) = 1.2Ueq(C) for aromatic and methylidyne H atoms.

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); 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).

Figures top
[Figure 1] Fig. 1. Figure 1 The molecular structure of the title compound, showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 2] Fig. 2. Figure 2 Crystal packing in the title compound where molecules are linked via C–H···O hydrogen bonds and C—Br···O bond (dashed lines). Except for those involved in hydrogen-bonding interactions, H atoms have been omitted for clarity.
6,8-Dibromo-3-nitro-2-phenyl-2H-chromene top
Crystal data top
C15H9Br2NO3F(000) = 400
Mr = 411.05Dx = 1.873 Mg m3
Triclinic, P1Melting point: 358 K
a = 8.2249 (19) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.886 (2) ÅCell parameters from 1256 reflections
c = 10.814 (3) Åθ = 2.6–23.4°
α = 73.503 (4)°µ = 5.57 mm1
β = 75.633 (4)°T = 296 K
γ = 79.579 (4)°Block, yellow
V = 728.8 (3) Å30.37 × 0.24 × 0.14 mm
Z = 2
Data collection top
Bruker APEXII CCD
diffractometer
2563 independent reflections
Radiation source: fine-focus sealed tube1856 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.029
φ and ω scansθmax = 25.1°, θmin = 2.4°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
h = 99
Tmin = 0.232, Tmax = 0.505k = 108
3687 measured reflectionsl = 129
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)] = 0.041Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.105H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0459P)2]
where P = (Fo2 + 2Fc2)/3
2563 reflections(Δ/σ)max = 0.001
190 parametersΔρmax = 0.54 e Å3
0 restraintsΔρmin = 0.56 e Å3
Crystal data top
C15H9Br2NO3γ = 79.579 (4)°
Mr = 411.05V = 728.8 (3) Å3
Triclinic, P1Z = 2
a = 8.2249 (19) ÅMo Kα radiation
b = 8.886 (2) ŵ = 5.57 mm1
c = 10.814 (3) ÅT = 296 K
α = 73.503 (4)°0.37 × 0.24 × 0.14 mm
β = 75.633 (4)°
Data collection top
Bruker APEXII CCD
diffractometer
2563 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
1856 reflections with I > 2σ(I)
Tmin = 0.232, Tmax = 0.505Rint = 0.029
3687 measured reflectionsθmax = 25.1°
Refinement top
R[F2 > 2σ(F2)] = 0.041H-atom parameters constrained
wR(F2) = 0.105Δρmax = 0.54 e Å3
S = 1.04Δρmin = 0.56 e Å3
2563 reflectionsAbsolute structure: ?
190 parametersFlack 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.

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
xyzUiso*/Ueq
Br11.27050 (6)0.90953 (6)0.84090 (5)0.0643 (2)
Br20.93397 (8)0.62857 (8)1.35367 (5)0.0800 (2)
N10.6350 (4)0.6139 (4)0.7380 (4)0.0480 (9)
O10.6475 (4)0.6655 (5)0.6195 (3)0.0686 (10)
O20.5354 (4)0.5232 (4)0.8073 (3)0.0699 (10)
O31.0007 (3)0.7836 (3)0.7672 (3)0.0431 (7)
C10.9785 (5)0.7523 (5)0.8998 (4)0.0377 (9)
C21.0929 (5)0.7996 (5)0.9515 (4)0.0441 (10)
C31.0787 (5)0.7621 (5)1.0868 (4)0.0521 (12)
H31.15580.79351.12160.063*
C40.9514 (5)0.6788 (5)1.1700 (4)0.0494 (11)
C50.8386 (5)0.6283 (5)1.1199 (4)0.0449 (10)
H50.75450.56941.17630.054*
C60.8516 (5)0.6659 (5)0.9847 (4)0.0390 (10)
C70.7392 (5)0.6132 (5)0.9260 (4)0.0409 (10)
H70.66350.54230.97760.049*
C80.7458 (5)0.6672 (5)0.7984 (4)0.0382 (9)
C90.8570 (5)0.7858 (5)0.7090 (4)0.0375 (9)
H90.90150.75410.62610.045*
C100.7659 (5)0.9503 (5)0.6771 (4)0.0396 (10)
C110.7715 (6)1.0345 (6)0.5490 (5)0.0570 (12)
H110.83300.98930.48120.068*
C120.6882 (7)1.1838 (7)0.5188 (5)0.0702 (15)
H120.69301.23910.43110.084*
C130.5985 (6)1.2509 (6)0.6174 (6)0.0680 (15)
H130.54221.35260.59720.082*
C140.5908 (6)1.1686 (6)0.7473 (5)0.0576 (13)
H140.52931.21440.81480.069*
C150.6736 (5)1.0198 (5)0.7763 (4)0.0447 (10)
H150.66800.96430.86400.054*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.0462 (3)0.0659 (4)0.0820 (4)0.0181 (2)0.0097 (2)0.0162 (3)
Br20.0990 (4)0.0991 (5)0.0454 (3)0.0001 (4)0.0277 (3)0.0197 (3)
N10.046 (2)0.050 (2)0.052 (3)0.0092 (18)0.0085 (19)0.020 (2)
O10.076 (2)0.092 (3)0.046 (2)0.024 (2)0.0183 (18)0.0163 (19)
O20.071 (2)0.085 (3)0.066 (2)0.045 (2)0.0055 (18)0.023 (2)
O30.0343 (14)0.0536 (18)0.0381 (17)0.0051 (13)0.0062 (12)0.0077 (14)
C10.034 (2)0.037 (2)0.041 (3)0.0003 (18)0.0100 (18)0.0078 (19)
C20.036 (2)0.041 (2)0.056 (3)0.0031 (19)0.012 (2)0.015 (2)
C30.050 (3)0.056 (3)0.059 (3)0.003 (2)0.022 (2)0.024 (3)
C40.050 (3)0.053 (3)0.044 (3)0.007 (2)0.014 (2)0.016 (2)
C50.043 (2)0.045 (3)0.041 (3)0.001 (2)0.008 (2)0.006 (2)
C60.041 (2)0.038 (2)0.038 (2)0.0024 (18)0.0117 (19)0.0065 (19)
C70.040 (2)0.036 (2)0.045 (3)0.0062 (18)0.0043 (19)0.011 (2)
C80.036 (2)0.040 (2)0.040 (3)0.0041 (18)0.0053 (19)0.015 (2)
C90.037 (2)0.046 (3)0.032 (2)0.0069 (18)0.0066 (18)0.0113 (19)
C100.036 (2)0.044 (2)0.041 (3)0.0084 (19)0.0094 (19)0.010 (2)
C110.060 (3)0.060 (3)0.043 (3)0.002 (2)0.010 (2)0.005 (2)
C120.076 (3)0.070 (4)0.053 (3)0.004 (3)0.019 (3)0.001 (3)
C130.063 (3)0.046 (3)0.090 (5)0.003 (3)0.032 (3)0.001 (3)
C140.055 (3)0.050 (3)0.073 (4)0.001 (2)0.016 (3)0.024 (3)
C150.044 (2)0.043 (3)0.048 (3)0.007 (2)0.010 (2)0.011 (2)
Geometric parameters (Å, º) top
Br1—C21.872 (4)C7—C81.316 (5)
Br2—C41.882 (4)C7—H70.9300
N1—O21.214 (4)C8—C91.487 (6)
N1—O11.217 (4)C9—C101.504 (5)
N1—C81.453 (5)C9—H90.9800
O3—C11.352 (5)C10—C111.369 (6)
O3—C91.465 (4)C10—C151.382 (6)
C1—C21.384 (6)C11—C121.368 (7)
C1—C61.391 (6)C11—H110.9300
C2—C31.385 (6)C12—C131.360 (7)
C3—C41.373 (6)C12—H120.9300
C3—H30.9300C13—C141.380 (6)
C4—C51.376 (6)C13—H130.9300
C5—C61.385 (5)C14—C151.362 (6)
C5—H50.9300C14—H140.9300
C6—C71.447 (6)C15—H150.9300
O2—N1—O1124.0 (4)C7—C8—C9124.5 (4)
O2—N1—C8119.0 (4)N1—C8—C9116.0 (4)
O1—N1—C8116.9 (4)O3—C9—C8109.5 (3)
C1—O3—C9119.2 (3)O3—C9—C10110.4 (3)
O3—C1—C2118.3 (4)C8—C9—C10113.3 (3)
O3—C1—C6122.2 (3)O3—C9—H9107.8
C2—C1—C6119.4 (4)C8—C9—H9107.8
C1—C2—C3119.7 (4)C10—C9—H9107.8
C1—C2—Br1120.9 (3)C11—C10—C15118.4 (4)
C3—C2—Br1119.4 (3)C11—C10—C9120.7 (4)
C4—C3—C2120.5 (4)C15—C10—C9120.9 (4)
C4—C3—H3119.7C10—C11—C12121.3 (5)
C2—C3—H3119.7C10—C11—H11119.4
C3—C4—C5120.5 (4)C12—C11—H11119.4
C3—C4—Br2120.0 (3)C13—C12—C11119.7 (5)
C5—C4—Br2119.6 (4)C13—C12—H12120.1
C4—C5—C6119.4 (4)C11—C12—H12120.1
C4—C5—H5120.3C12—C13—C14120.1 (5)
C6—C5—H5120.3C12—C13—H13119.9
C5—C6—C1120.6 (4)C14—C13—H13119.9
C5—C6—C7121.9 (4)C15—C14—C13119.7 (5)
C1—C6—C7117.4 (4)C15—C14—H14120.2
C8—C7—C6118.9 (4)C13—C14—H14120.2
C8—C7—H7120.6C14—C15—C10120.8 (4)
C6—C7—H7120.6C14—C15—H15119.6
C7—C8—N1119.4 (4)C10—C15—H15119.6
C9—O3—C1—C2159.3 (3)O2—N1—C8—C71.8 (6)
C9—O3—C1—C624.9 (5)O1—N1—C8—C7179.0 (4)
O3—C1—C2—C3176.7 (3)O2—N1—C8—C9176.3 (3)
C6—C1—C2—C30.7 (6)O1—N1—C8—C92.8 (5)
O3—C1—C2—Br11.8 (5)C1—O3—C9—C833.4 (5)
C6—C1—C2—Br1177.7 (3)C1—O3—C9—C1092.0 (4)
C1—C2—C3—C40.3 (6)C7—C8—C9—O323.2 (5)
Br1—C2—C3—C4178.7 (3)N1—C8—C9—O3158.8 (3)
C2—C3—C4—C51.5 (6)C7—C8—C9—C10100.6 (4)
C2—C3—C4—Br2179.9 (3)N1—C8—C9—C1077.5 (4)
C3—C4—C5—C61.8 (6)O3—C9—C10—C11110.8 (4)
Br2—C4—C5—C6179.8 (3)C8—C9—C10—C11126.0 (4)
C4—C5—C6—C10.8 (6)O3—C9—C10—C1569.7 (5)
C4—C5—C6—C7178.6 (4)C8—C9—C10—C1553.5 (5)
O3—C1—C6—C5176.3 (3)C15—C10—C11—C120.0 (7)
C2—C1—C6—C50.4 (6)C9—C10—C11—C12179.5 (5)
O3—C1—C6—C71.6 (5)C10—C11—C12—C130.2 (8)
C2—C1—C6—C7177.4 (4)C11—C12—C13—C140.3 (8)
C5—C6—C7—C8172.6 (4)C12—C13—C14—C150.1 (7)
C1—C6—C7—C89.6 (6)C13—C14—C15—C100.2 (7)
C6—C7—C8—N1179.3 (3)C11—C10—C15—C140.3 (6)
C6—C7—C8—C92.7 (6)C9—C10—C15—C14179.8 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C5—H5···O2i0.932.613.404144
C7—H7···O2i0.932.473.265143
Symmetry code: (i) x+1, y+1, z+2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C5—H5···O2i0.932.613.404143.73
C7—H7···O2i0.932.473.265143.15
Symmetry code: (i) x+1, y+1, z+2.
Acknowledgements top

We thank the Natural Science Foundation of China (grant No. 21172262) for financial support.

references
References top

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

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