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Acta Crystallogr Sect E Struct Rep Online. 2009 October 1; 65(Pt 10): o2446.
Published online 2009 September 12. doi:  10.1107/S160053680903596X
PMCID: PMC2970501

4-Bromo­methyl-7-methyl-6,8-dinitro­coumarin

Abstract

The crystal structure of the title compound, C11H7BrN2O6, establishes the substitution positions of the nitro groups from the nitration reaction of 7-methyl-4-bromo­methyl coumarin. The mean planes of the nitro groups form dihedral angles of 43.9 (8) and 52.7 (10)° with the essentially planar [maximum deviation 0.031 (6) Å] benzopyran ring system.

Related literature

For background information on the nitration of coumarin compounds, see: Kulkarni et al. (1983 [triangle]); Clayton et al. (1910 [triangle]). For a related structure, see: Vasudevan et al. (1990 [triangle]). For ab initio calculations on 6-methyl-4-bromo­methyl­coumarins, see: Sortur et al. (2006 [triangle]).

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Object name is e-65-o2446-scheme1.jpg

Experimental

Crystal data

  • C11H7BrN2O6
  • M r = 343.09
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-65-o2446-efi1.jpg
  • a = 8.122 (2) Å
  • b = 11.091 (4) Å
  • c = 27.723 (6) Å
  • V = 2497.3 (12) Å3
  • Z = 8
  • Mo Kα radiation
  • μ = 3.32 mm−1
  • T = 294 K
  • 0.2 × 0.2 × 0.1 mm

Data collection

  • Enraf–Nonius CAD-4 diffractometer
  • Absorption correction: ψ scan (North et al., 1968 [triangle]) T min = 0.520, T max = 0.72
  • 2196 measured reflections
  • 2196 independent reflections
  • 1148 reflections with I > 2σ(I)
  • 2 standard reflections frequency: 60 min intensity decay: none

Refinement

  • R[F 2 > 2σ(F 2)] = 0.060
  • wR(F 2) = 0.171
  • S = 1.05
  • 2196 reflections
  • 182 parameters
  • H-atom parameters constrained
  • Δρmax = 0.63 e Å−3
  • Δρmin = −0.82 e Å−3

Data collection: CAD-4 Software (Enraf–Nonius, 1989 [triangle]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995 [triangle]); program(s) used to solve structure: SIR92 (Altomare et al., 1994 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 [triangle]); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S160053680903596X/lh2864sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053680903596X/lh2864Isup2.hkl

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

Acknowledgments

KVAG gratefully thanks the DST for financial support through the SERC Fast Track Young Scientists Scheme and RG thanks MVJ College of Engineering Bangalore (Reasearch Center). The authors also thanks Professor T. N. Guru Row, Chairman, SSCU IISc, Bangalore, for the X-ray data collection.

supplementary crystallographic information

Comment

The molecular structure of the title compound is shown in Fig. 1. The bromomethyl group is twisted is out of the plane of the benzopyran ring as described by the torsion angle of 104.6 (7)° for C2-C3-C10-Br. This is in agreement with the ab initio calculations on 6-methyl-4- bromomethylcoumarins (Sortur et al., 2006). Positions C-6 and C-8 (refers to positions from systematic naming scheme) become activated due to the electron donating methyl group at C-7 and hence nitration occurs at C-6 and C-8 consistent with the title compound which is also in agreement with earlier reports (Clayton, 1910; Kulkarni et al., 1983).

Experimental

5.06 g of 7-methyl-4-bromomethyl coumarin (0.02 mol) was dissolved in conc. sulfuric acid (10 ml) and treated with a nitrating mixture 15 ml (10 ml H2SO4 + 5 ml HNO3) at ice bath temperatures (273-278K). The reaction mixture was then allowed to stand at room temperature for two hours and the reaction mixture was poured over crushed ice. The separated solid was washed with excess of water, dried and recrystallized from glacial acetic acid. Crystals suitable for diffraction studies were grown by slow evaporation of an ethanol solution of the title compound.

Refinement

Hydrogen atoms were positioned geometrically with C—H = 0.93-0.97 A° and included in the refinment in a riding-model approximation with Uiso(H) = 1.2 Ueq(C) or 1.5 Ueq(C) for methyl C atoms.

Figures

Fig. 1.
The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atomic numbering.

Crystal data

C11H7BrN2O6F(000) = 1360
Mr = 343.09Dx = 1.825 Mg m3
Orthorhombic, PbcaMo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ac 2abCell parameters from 25 reflections
a = 8.122 (2) Åθ = 10–15°
b = 11.091 (4) ŵ = 3.32 mm1
c = 27.723 (6) ÅT = 294 K
V = 2497.3 (12) Å3Plate, colourless
Z = 80.2 × 0.2 × 0.1 mm

Data collection

Enraf–Nonius CAD-4 diffractometer1148 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.0000
graphiteθmax = 25.0°, θmin = 2.9°
ω–2θ scansh = 0→9
Absorption correction: ψ scan (North et al., 1968)k = 0→13
Tmin = 0.520, Tmax = 0.72l = 0→32
2196 measured reflections2 standard reflections every 60 min
2196 independent reflections intensity decay: none

Refinement

Refinement on F20 restraints
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.060w = 1/[σ2(Fo2) + (0.0687P)2 + 11.8667P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.171(Δ/σ)max = 0.001
S = 1.05Δρmax = 0.63 e Å3
2196 reflectionsΔρmin = −0.82 e Å3
182 parameters

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*/Ueq
C10.7703 (11)0.2886 (7)0.6819 (3)0.047 (2)
C20.9438 (10)0.2873 (7)0.6922 (3)0.045 (2)
H30.98560.34470.71340.054*
C31.0484 (9)0.2073 (6)0.6727 (3)0.0380 (18)
C41.0779 (9)0.0341 (6)0.6146 (3)0.0364 (18)
H51.18980.02810.62130.044*
C51.0085 (9)−0.0431 (6)0.5812 (2)0.0348 (17)
C60.8400 (9)−0.0445 (6)0.5709 (3)0.0395 (19)
C70.7498 (9)0.0406 (6)0.5954 (2)0.0358 (16)
C80.9860 (8)0.1194 (6)0.6381 (3)0.0326 (17)
C90.8194 (9)0.1222 (6)0.6280 (3)0.0339 (17)
C101.2259 (10)0.2058 (7)0.6867 (3)0.049 (2)
H11A1.25420.28040.70300.059*
H11B1.29420.19870.65810.059*
C110.7574 (12)−0.1318 (7)0.5373 (3)0.057 (2)
H12A0.8385−0.18420.52340.085*
H12B0.7020−0.08820.51220.085*
H12C0.6787−0.17900.55500.085*
N11.1229 (9)−0.1278 (6)0.5564 (3)0.0483 (17)
N20.5699 (8)0.0459 (6)0.5897 (3)0.0477 (17)
O10.7146 (6)0.2044 (4)0.64815 (18)0.0406 (13)
O20.6689 (8)0.3553 (6)0.6980 (2)0.0649 (18)
O31.2252 (9)−0.1757 (6)0.5791 (3)0.085 (2)
O41.1032 (9)−0.1384 (6)0.5134 (3)0.079 (2)
O50.5137 (9)0.0940 (7)0.5564 (3)0.099 (3)
O60.4882 (8)0.0020 (9)0.6212 (3)0.113 (3)
Br1.26518 (11)0.06847 (7)0.72976 (3)0.0597 (4)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.061 (6)0.043 (4)0.037 (4)0.004 (5)−0.002 (5)−0.002 (4)
C20.060 (6)0.036 (4)0.040 (4)−0.001 (4)−0.002 (4)−0.006 (4)
C30.040 (4)0.039 (4)0.034 (4)−0.008 (4)−0.002 (3)0.004 (3)
C40.034 (4)0.038 (4)0.038 (4)0.000 (3)−0.004 (3)−0.001 (3)
C50.039 (4)0.036 (4)0.029 (4)0.007 (3)0.003 (3)−0.002 (3)
C60.045 (5)0.040 (4)0.034 (4)−0.003 (4)−0.009 (4)0.001 (3)
C70.030 (4)0.039 (4)0.039 (4)−0.002 (4)−0.002 (4)0.006 (3)
C80.028 (4)0.034 (4)0.036 (4)−0.004 (3)0.000 (3)−0.003 (3)
C90.033 (4)0.037 (4)0.032 (4)0.007 (3)0.004 (3)0.005 (3)
C100.056 (6)0.048 (4)0.044 (4)−0.013 (4)−0.004 (4)−0.001 (4)
C110.072 (6)0.040 (4)0.058 (5)−0.001 (5)−0.024 (5)−0.011 (4)
N10.049 (5)0.049 (4)0.045 (5)0.001 (4)0.001 (4)−0.001 (4)
N20.037 (4)0.046 (4)0.058 (5)0.001 (3)−0.012 (4)0.001 (4)
O10.031 (3)0.049 (3)0.042 (3)0.010 (2)−0.003 (2)−0.002 (3)
O20.071 (4)0.063 (4)0.061 (4)0.026 (4)0.003 (3)−0.013 (3)
O30.074 (5)0.092 (5)0.088 (5)0.039 (4)−0.010 (4)−0.023 (4)
O40.102 (6)0.076 (4)0.059 (5)0.023 (4)0.012 (4)−0.014 (4)
O50.060 (5)0.130 (7)0.108 (6)0.004 (4)−0.033 (5)0.048 (5)
O60.038 (4)0.160 (8)0.141 (8)−0.011 (5)−0.002 (5)0.073 (7)
Br0.0621 (6)0.0560 (5)0.0611 (6)0.0056 (5)−0.0181 (5)−0.0042 (4)

Geometric parameters (Å, °)

C1—O21.194 (9)C7—C91.397 (10)
C1—O11.398 (9)C7—N21.471 (10)
C1—C21.438 (11)C8—C91.382 (9)
C2—C31.342 (10)C9—O11.368 (8)
C2—H30.9300C10—H11A0.9700
C3—C81.458 (10)C10—H11B0.9700
C3—C101.494 (11)C11—H12A0.9600
C4—C81.370 (10)C11—H12B0.9600
C4—C51.383 (9)C11—H12C0.9600
C4—H50.9300N1—O31.169 (9)
C5—C61.398 (10)N1—O41.210 (9)
C5—N11.488 (10)N2—O51.160 (8)
C6—C71.375 (10)N2—O61.201 (9)
C6—C111.501 (10)
O2—C1—O1116.2 (8)C9—C8—C3117.3 (7)
O2—C1—C2127.4 (8)O1—C9—C8122.8 (7)
O1—C1—C2116.3 (7)O1—C9—C7116.4 (6)
C3—C2—C1123.1 (7)C8—C9—C7120.9 (7)
C3—C2—H3118.4C3—C10—Br108.9 (5)
C1—C2—H3118.4C3—C10—H11A109.9
C2—C3—C8119.2 (7)Br—C10—H11A109.9
C2—C3—C10120.9 (7)C3—C10—H11B109.9
C8—C3—C10120.0 (7)Br—C10—H11B109.9
C8—C4—C5121.6 (7)H11A—C10—H11B108.3
C8—C4—H5119.2C6—C11—H12A109.5
C5—C4—H5119.2C6—C11—H12B109.5
C4—C5—C6122.9 (7)H12A—C11—H12B109.5
C4—C5—N1116.5 (7)C6—C11—H12C109.5
C6—C5—N1120.7 (7)H12A—C11—H12C109.5
C7—C6—C5114.4 (7)H12B—C11—H12C109.5
C7—C6—C11120.8 (7)O3—N1—O4125.5 (8)
C5—C6—C11124.8 (7)O3—N1—C5118.9 (7)
C6—C7—C9123.3 (7)O4—N1—C5115.6 (7)
C6—C7—N2120.2 (7)O5—N2—O6123.2 (8)
C9—C7—N2116.5 (6)O5—N2—C7119.7 (8)
C4—C8—C9116.9 (7)O6—N2—C7117.0 (7)
C4—C8—C3125.8 (7)C9—O1—C1121.2 (6)
O2—C1—C2—C3179.1 (8)C3—C8—C9—O11.3 (10)
O1—C1—C2—C3−2.9 (11)C4—C8—C9—C70.4 (11)
C1—C2—C3—C82.1 (11)C3—C8—C9—C7−179.7 (6)
C1—C2—C3—C10−176.6 (7)C6—C7—C9—O1177.6 (6)
C8—C4—C5—C6−3.6 (11)N2—C7—C9—O1−4.9 (9)
C8—C4—C5—N1177.2 (7)C6—C7—C9—C8−1.5 (11)
C4—C5—C6—C72.5 (11)N2—C7—C9—C8176.0 (7)
N1—C5—C6—C7−178.4 (6)C2—C3—C10—Br104.6 (7)
C4—C5—C6—C11−175.8 (7)C8—C3—C10—Br−74.1 (7)
N1—C5—C6—C113.3 (11)C4—C5—N1—O341.9 (11)
C5—C6—C7—C90.0 (10)C6—C5—N1—O3−137.3 (8)
C11—C6—C7—C9178.4 (7)C4—C5—N1—O4−136.2 (8)
C5—C6—C7—N2−177.3 (6)C6—C5—N1—O444.6 (10)
C11—C6—C7—N21.0 (11)C6—C7—N2—O5−81.1 (10)
C5—C4—C8—C92.0 (11)C9—C7—N2—O5101.4 (9)
C5—C4—C8—C3−177.9 (7)C6—C7—N2—O6101.1 (10)
C2—C3—C8—C4178.7 (7)C9—C7—N2—O6−76.4 (10)
C10—C3—C8—C4−2.6 (11)C8—C9—O1—C1−2.2 (10)
C2—C3—C8—C9−1.2 (10)C7—C9—O1—C1178.7 (6)
C10—C3—C8—C9177.5 (7)O2—C1—O1—C9−178.9 (7)
C4—C8—C9—O1−178.6 (6)C2—C1—O1—C92.9 (10)

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH2864).

References

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