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

Gowda, R.; Alawandi, G.N.; Kulkarni, M.V.; Gowda, K.V.A.

doi:10.1107/S160053680903596X

organic compounds

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ISSN: 2056-9890

Volume 65| Part 10| October 2009| Page o2446

doi:10.1107/S160053680903596X

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

Ramakrishna Gowda,^a ^* Ganesh N. Alawandi,^b Manohar V. Kulkarni ^b and K. V. Arjuna Gowda ^c

^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 ); 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

Crystal data

C₁₁H₇BrN₂O₆
M_r = 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 ) 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[F² > 2σ(F²)] = 0.060
wR(F²) = 0.171
S = 1.05
2196 reflections
182 parameters
H-atom parameters constrained
Δρ_max = 0.63 e Å⁻³
Δρ_min = −0.82 e Å⁻³

Data collection: CAD-4 Software (Enraf–Nonius, 1989 ); cell refinement: CAD-4 Software; 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.

Supporting information

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

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

checkCIF report

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.

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

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

C₁₁H₇BrN₂O₆	F(000) = 1360
M_r = 343.09	D_x = 1.825 Mg m⁻³
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 25 reflections
a = 8.122 (2) Å	θ = 10–15°
b = 11.091 (4) Å	µ = 3.32 mm⁻¹
c = 27.723 (6) Å	T = 294 K
V = 2497.3 (12) Å³	Plate, colourless
Z = 8	0.2 × 0.2 × 0.1 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	1148 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.000
Graphite monochromator	θ_max = 25.0°, θ_min = 2.9°
ω–2θ scans	h = 0→9
Absorption correction: ψ scan (North et al., 1968)	k = 0→13
T_min = 0.520, T_max = 0.72	l = 0→32
2196 measured reflections	2 standard reflections every 60 min
2196 independent reflections	intensity decay: none

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.060	w = 1/[σ²(F_o²) + (0.0687P)² + 11.8667P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.171	(Δ/σ)_max = 0.001
S = 1.05	Δρ_max = 0.63 e Å⁻³
2196 reflections	Δρ_min = −0.82 e Å⁻³
182 parameters

Crystal data top

C₁₁H₇BrN₂O₆	V = 2497.3 (12) Å³
M_r = 343.09	Z = 8
Orthorhombic, Pbca	Mo Kα radiation
a = 8.122 (2) Å	µ = 3.32 mm⁻¹
b = 11.091 (4) Å	T = 294 K
c = 27.723 (6) Å	0.2 × 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)	R_int = 0.000
T_min = 0.520, T_max = 0.72	2 standard reflections every 60 min
2196 measured reflections	intensity decay: none
2196 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.060	0 restraints
wR(F²) = 0.171	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.0687P)² + 11.8667P] where P = (F_o² + 2F_c²)/3
2196 reflections	Δρ_max = 0.63 e Å⁻³
182 parameters	Δρ_min = −0.82 e Å⁻³

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

	x	y	z	U_iso*/U_eq
C1	0.7703 (11)	0.2886 (7)	0.6819 (3)	0.047 (2)
C2	0.9438 (10)	0.2873 (7)	0.6922 (3)	0.045 (2)
H3	0.9856	0.3447	0.7134	0.054*
C3	1.0484 (9)	0.2073 (6)	0.6727 (3)	0.0380 (18)
C4	1.0779 (9)	0.0341 (6)	0.6146 (3)	0.0364 (18)
H5	1.1898	0.0281	0.6213	0.044*
C5	1.0085 (9)	−0.0431 (6)	0.5812 (2)	0.0348 (17)
C6	0.8400 (9)	−0.0445 (6)	0.5709 (3)	0.0395 (19)
C7	0.7498 (9)	0.0406 (6)	0.5954 (2)	0.0358 (16)
C8	0.9860 (8)	0.1194 (6)	0.6381 (3)	0.0326 (17)
C9	0.8194 (9)	0.1222 (6)	0.6280 (3)	0.0339 (17)
C10	1.2259 (10)	0.2058 (7)	0.6867 (3)	0.049 (2)
H11A	1.2542	0.2804	0.7030	0.059*
H11B	1.2942	0.1987	0.6581	0.059*
C11	0.7574 (12)	−0.1318 (7)	0.5373 (3)	0.057 (2)
H12A	0.8385	−0.1842	0.5234	0.085*
H12B	0.7020	−0.0882	0.5122	0.085*
H12C	0.6787	−0.1790	0.5550	0.085*
N1	1.1229 (9)	−0.1278 (6)	0.5564 (3)	0.0483 (17)
N2	0.5699 (8)	0.0459 (6)	0.5897 (3)	0.0477 (17)
O1	0.7146 (6)	0.2044 (4)	0.64815 (18)	0.0406 (13)
O2	0.6689 (8)	0.3553 (6)	0.6980 (2)	0.0649 (18)
O3	1.2252 (9)	−0.1757 (6)	0.5791 (3)	0.085 (2)
O4	1.1032 (9)	−0.1384 (6)	0.5134 (3)	0.079 (2)
O5	0.5137 (9)	0.0940 (7)	0.5564 (3)	0.099 (3)
O6	0.4882 (8)	0.0020 (9)	0.6212 (3)	0.113 (3)
Br	1.26518 (11)	0.06847 (7)	0.72976 (3)	0.0597 (4)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.061 (6)	0.043 (4)	0.037 (4)	0.004 (5)	−0.002 (5)	−0.002 (4)
C2	0.060 (6)	0.036 (4)	0.040 (4)	−0.001 (4)	−0.002 (4)	−0.006 (4)
C3	0.040 (4)	0.039 (4)	0.034 (4)	−0.008 (4)	−0.002 (3)	0.004 (3)
C4	0.034 (4)	0.038 (4)	0.038 (4)	0.000 (3)	−0.004 (3)	−0.001 (3)
C5	0.039 (4)	0.036 (4)	0.029 (4)	0.007 (3)	0.003 (3)	−0.002 (3)
C6	0.045 (5)	0.040 (4)	0.034 (4)	−0.003 (4)	−0.009 (4)	0.001 (3)
C7	0.030 (4)	0.039 (4)	0.039 (4)	−0.002 (4)	−0.002 (4)	0.006 (3)
C8	0.028 (4)	0.034 (4)	0.036 (4)	−0.004 (3)	0.000 (3)	−0.003 (3)
C9	0.033 (4)	0.037 (4)	0.032 (4)	0.007 (3)	0.004 (3)	0.005 (3)
C10	0.056 (6)	0.048 (4)	0.044 (4)	−0.013 (4)	−0.004 (4)	−0.001 (4)
C11	0.072 (6)	0.040 (4)	0.058 (5)	−0.001 (5)	−0.024 (5)	−0.011 (4)
N1	0.049 (5)	0.049 (4)	0.045 (5)	0.001 (4)	0.001 (4)	−0.001 (4)
N2	0.037 (4)	0.046 (4)	0.058 (5)	0.001 (3)	−0.012 (4)	0.001 (4)
O1	0.031 (3)	0.049 (3)	0.042 (3)	0.010 (2)	−0.003 (2)	−0.002 (3)
O2	0.071 (4)	0.063 (4)	0.061 (4)	0.026 (4)	0.003 (3)	−0.013 (3)
O3	0.074 (5)	0.092 (5)	0.088 (5)	0.039 (4)	−0.010 (4)	−0.023 (4)
O4	0.102 (6)	0.076 (4)	0.059 (5)	0.023 (4)	0.012 (4)	−0.014 (4)
O5	0.060 (5)	0.130 (7)	0.108 (6)	0.004 (4)	−0.033 (5)	0.048 (5)
O6	0.038 (4)	0.160 (8)	0.141 (8)	−0.011 (5)	−0.002 (5)	0.073 (7)
Br	0.0621 (6)	0.0560 (5)	0.0611 (6)	0.0056 (5)	−0.0181 (5)	−0.0042 (4)

Geometric parameters (Å, º) top

C1—O2	1.194 (9)	C7—C9	1.397 (10)
C1—O1	1.398 (9)	C7—N2	1.471 (10)
C1—C2	1.438 (11)	C8—C9	1.382 (9)
C2—C3	1.342 (10)	C9—O1	1.368 (8)
C2—H3	0.9300	C10—H11A	0.9700
C3—C8	1.458 (10)	C10—H11B	0.9700
C3—C10	1.494 (11)	C11—H12A	0.9600
C4—C8	1.370 (10)	C11—H12B	0.9600
C4—C5	1.383 (9)	C11—H12C	0.9600
C4—H5	0.9300	N1—O3	1.169 (9)
C5—C6	1.398 (10)	N1—O4	1.210 (9)
C5—N1	1.488 (10)	N2—O5	1.160 (8)
C6—C7	1.375 (10)	N2—O6	1.201 (9)
C6—C11	1.501 (10)

O2—C1—O1	116.2 (8)	C9—C8—C3	117.3 (7)
O2—C1—C2	127.4 (8)	O1—C9—C8	122.8 (7)
O1—C1—C2	116.3 (7)	O1—C9—C7	116.4 (6)
C3—C2—C1	123.1 (7)	C8—C9—C7	120.9 (7)
C3—C2—H3	118.4	C3—C10—Br	108.9 (5)
C1—C2—H3	118.4	C3—C10—H11A	109.9
C2—C3—C8	119.2 (7)	Br—C10—H11A	109.9
C2—C3—C10	120.9 (7)	C3—C10—H11B	109.9
C8—C3—C10	120.0 (7)	Br—C10—H11B	109.9
C8—C4—C5	121.6 (7)	H11A—C10—H11B	108.3
C8—C4—H5	119.2	C6—C11—H12A	109.5
C5—C4—H5	119.2	C6—C11—H12B	109.5
C4—C5—C6	122.9 (7)	H12A—C11—H12B	109.5
C4—C5—N1	116.5 (7)	C6—C11—H12C	109.5
C6—C5—N1	120.7 (7)	H12A—C11—H12C	109.5
C7—C6—C5	114.4 (7)	H12B—C11—H12C	109.5
C7—C6—C11	120.8 (7)	O3—N1—O4	125.5 (8)
C5—C6—C11	124.8 (7)	O3—N1—C5	118.9 (7)
C6—C7—C9	123.3 (7)	O4—N1—C5	115.6 (7)
C6—C7—N2	120.2 (7)	O5—N2—O6	123.2 (8)
C9—C7—N2	116.5 (6)	O5—N2—C7	119.7 (8)
C4—C8—C9	116.9 (7)	O6—N2—C7	117.0 (7)
C4—C8—C3	125.8 (7)	C9—O1—C1	121.2 (6)

O2—C1—C2—C3	179.1 (8)	C3—C8—C9—O1	1.3 (10)
O1—C1—C2—C3	−2.9 (11)	C4—C8—C9—C7	0.4 (11)
C1—C2—C3—C8	2.1 (11)	C3—C8—C9—C7	−179.7 (6)
C1—C2—C3—C10	−176.6 (7)	C6—C7—C9—O1	177.6 (6)
C8—C4—C5—C6	−3.6 (11)	N2—C7—C9—O1	−4.9 (9)
C8—C4—C5—N1	177.2 (7)	C6—C7—C9—C8	−1.5 (11)
C4—C5—C6—C7	2.5 (11)	N2—C7—C9—C8	176.0 (7)
N1—C5—C6—C7	−178.4 (6)	C2—C3—C10—Br	104.6 (7)
C4—C5—C6—C11	−175.8 (7)	C8—C3—C10—Br	−74.1 (7)
N1—C5—C6—C11	3.3 (11)	C4—C5—N1—O3	41.9 (11)
C5—C6—C7—C9	0.0 (10)	C6—C5—N1—O3	−137.3 (8)
C11—C6—C7—C9	178.4 (7)	C4—C5—N1—O4	−136.2 (8)
C5—C6—C7—N2	−177.3 (6)	C6—C5—N1—O4	44.6 (10)
C11—C6—C7—N2	1.0 (11)	C6—C7—N2—O5	−81.1 (10)
C5—C4—C8—C9	2.0 (11)	C9—C7—N2—O5	101.4 (9)
C5—C4—C8—C3	−177.9 (7)	C6—C7—N2—O6	101.1 (10)
C2—C3—C8—C4	178.7 (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—C1	178.7 (6)
C10—C3—C8—C9	177.5 (7)	O2—C1—O1—C9	−178.9 (7)
C4—C8—C9—O1	−178.6 (6)	C2—C1—O1—C9	2.9 (10)

Experimental details

Crystal data
Chemical formula	C₁₁H₇BrN₂O₆
M_r	343.09
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	294
a, b, c (Å)	8.122 (2), 11.091 (4), 27.723 (6)
V (Å³)	2497.3 (12)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	3.32
Crystal size (mm)	0.2 × 0.2 × 0.1

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.520, 0.72
No. of measured, independent and observed [I > 2σ(I)] reflections	2196, 2196, 1148
R_int	0.000
(sin θ/λ)_max (Å⁻¹)	0.594

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.060, 0.171, 1.05
No. of reflections	2196
No. of parameters	182
H-atom treatment	H-atom parameters constrained
	w = 1/[σ²(F_o²) + (0.0687P)² + 11.8667P] where P = (F_o² + 2F_c²)/3
Δρ_max, Δρ_min (e Å⁻³)	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

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