organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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

aDepartment of Physics, Goverment College for Women, Kolar 563 101, Karnataka, India, bDepartment of Chemistry, Karnatak University, Dharwad 580 003, Karnataka, India, and cDepartment of Physics, Goverment First Grade College, K.R. Pura, Bangalore 560 036, Karnataka, India
*Correspondence e-mail: arjunagowda@indiainfo.com

(Received 12 July 2009; accepted 5 September 2009; online 12 September 2009)

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[Kulkarni, M. V., Pujar, B. G. & Patil, V. D. (1983). Arch. Pharm. 316, 15-21.]); Clayton et al. (1910[Clayton, A. (1910). J. Chem. Soc. 97, 1397-1408.]). For a related structure, see: Vasudevan et al. (1990[Vasudevan, K. T., Puttaraja & Kulkarni, M. V. (1990). Acta Cryst. C46, 2129-2131.]). For ab initio calculations on 6-methyl-4-bromo­methyl­coumarins, see: Sortur et al. (2006[Sortur, V., Yenagi, J., Tonannavar, J., Jadhav, V. B. & Kulkarni, M. V. (2006). Spectrochim. Acta A, 64, 301-307.]).

[Scheme 1]

Experimental

Crystal data
  • C11H7BrN2O6

  • Mr = 343.09

  • Orthorhombic, P b c a

  • 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[North, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351-359.]) Tmin = 0.520, Tmax = 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[F2 > 2σ(F2)] = 0.060

  • wR(F2) = 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[Enraf-Nonius (1989). CAD-4 Software. Enraf-Nonius, Delft, The Netherlands.]); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]); program(s) used to solve structure: SIR92 (Altomare et al., 1994[Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

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).

Related literature top

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

Experimental top

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 top

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.

Computing details top

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

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atomic numbering.
4-Bromomethyl-7-methyl-6,8-dinitrocoumarin top
Crystal data top
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 top
Enraf–Nonius CAD-4
diffractometer
1148 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.000
Graphite monochromatorθmax = 25.0°, θmin = 2.9°
ω–2θ scansh = 09
Absorption correction: ψ scan
(North et al., 1968)
k = 013
Tmin = 0.520, Tmax = 0.72l = 032
2196 measured reflections2 standard reflections every 60 min
2196 independent reflections intensity decay: none
Refinement top
Refinement on F20 restraints
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.060 w = 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
Crystal data top
C11H7BrN2O6V = 2497.3 (12) Å3
Mr = 343.09Z = 8
Orthorhombic, PbcaMo Kα radiation
a = 8.122 (2) ŵ = 3.32 mm1
b = 11.091 (4) ÅT = 294 K
c = 27.723 (6) Å0.2 × 0.2 × 0.1 mm
Data collection top
Enraf–Nonius CAD-4
diffractometer
1148 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.000
Tmin = 0.520, Tmax = 0.722 standard reflections every 60 min
2196 measured reflections intensity decay: none
2196 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0600 restraints
wR(F2) = 0.171H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.0687P)2 + 11.8667P]
where P = (Fo2 + 2Fc2)/3
2196 reflectionsΔρmax = 0.63 e Å3
182 parametersΔρmin = 0.82 e Å3
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
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)
H12A0.83850.18420.52340.085*
H12B0.70200.08820.51220.085*
H12C0.67870.17900.55500.085*
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) top
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, º) top
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—C32.9 (11)C4—C8—C9—C70.4 (11)
C1—C2—C3—C82.1 (11)C3—C8—C9—C7179.7 (6)
C1—C2—C3—C10176.6 (7)C6—C7—C9—O1177.6 (6)
C8—C4—C5—C63.6 (11)N2—C7—C9—O14.9 (9)
C8—C4—C5—N1177.2 (7)C6—C7—C9—C81.5 (11)
C4—C5—C6—C72.5 (11)N2—C7—C9—C8176.0 (7)
N1—C5—C6—C7178.4 (6)C2—C3—C10—Br104.6 (7)
C4—C5—C6—C11175.8 (7)C8—C3—C10—Br74.1 (7)
N1—C5—C6—C113.3 (11)C4—C5—N1—O341.9 (11)
C5—C6—C7—C90.0 (10)C6—C5—N1—O3137.3 (8)
C11—C6—C7—C9178.4 (7)C4—C5—N1—O4136.2 (8)
C5—C6—C7—N2177.3 (6)C6—C5—N1—O444.6 (10)
C11—C6—C7—N21.0 (11)C6—C7—N2—O581.1 (10)
C5—C4—C8—C92.0 (11)C9—C7—N2—O5101.4 (9)
C5—C4—C8—C3177.9 (7)C6—C7—N2—O6101.1 (10)
C2—C3—C8—C4178.7 (7)C9—C7—N2—O676.4 (10)
C10—C3—C8—C42.6 (11)C8—C9—O1—C12.2 (10)
C2—C3—C8—C91.2 (10)C7—C9—O1—C1178.7 (6)
C10—C3—C8—C9177.5 (7)O2—C1—O1—C9178.9 (7)
C4—C8—C9—O1178.6 (6)C2—C1—O1—C92.9 (10)

Experimental details

Crystal data
Chemical formulaC11H7BrN2O6
Mr343.09
Crystal system, space groupOrthorhombic, Pbca
Temperature (K)294
a, b, c (Å)8.122 (2), 11.091 (4), 27.723 (6)
V3)2497.3 (12)
Z8
Radiation typeMo Kα
µ (mm1)3.32
Crystal size (mm)0.2 × 0.2 × 0.1
Data collection
DiffractometerEnraf–Nonius CAD-4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.520, 0.72
No. of measured, independent and
observed [I > 2σ(I)] reflections
2196, 2196, 1148
Rint0.000
(sin θ/λ)max1)0.594
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.060, 0.171, 1.05
No. of reflections2196
No. of parameters182
H-atom treatmentH-atom parameters constrained
w = 1/[σ2(Fo2) + (0.0687P)2 + 11.8667P]
where P = (Fo2 + 2Fc2)/3
Δρmax, Δρmin (e Å3)0.63, 0.82

Computer programs: CAD-4 Software (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), SIR92 (Altomare et al., 1994), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997).

 

Acknowledgements

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.

References

First citationAltomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.  CrossRef Web of Science IUCr Journals Google Scholar
First citationClayton, A. (1910). J. Chem. Soc. 97, 1397–1408.  Google Scholar
First citationEnraf–Nonius (1989). CAD-4 Software. Enraf–Nonius, Delft, The Netherlands.  Google Scholar
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals Google Scholar
First citationHarms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.  Google Scholar
First citationKulkarni, M. V., Pujar, B. G. & Patil, V. D. (1983). Arch. Pharm. 316, 15–21.  CrossRef CAS Web of Science Google Scholar
First citationNorth, A. C. T., Phillips, D. C. & Mathews, F. S. (1968). Acta Cryst. A24, 351–359.  CrossRef IUCr Journals Web of Science Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSortur, V., Yenagi, J., Tonannavar, J., Jadhav, V. B. & Kulkarni, M. V. (2006). Spectrochim. Acta A, 64, 301–307.  CrossRef Google Scholar
First citationVasudevan, K. T., Puttaraja & Kulkarni, M. V. (1990). Acta Cryst. C46, 2129–2131.  Google Scholar

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