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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

1,5-Di­bromo-2,4-dimeth­­oxy­benzene

aGITAM University, Department of Engineering Chemistry, GIT, Rushikonda, Visakhapatnam, A.P. 530 045, India, bNational Institute of Technology-Karnataka, Department of Chemistry, Medicinal Chemistry Laboratory, Surathkal, Mangalore 575 025, India, and cNelson Mandela Metropolitan University, Summerstrand Campus, Department of Chemistry, University Way, Summerstrand, PO Box 77000, Port Elizabeth, 6031, South Africa
*Correspondence e-mail: richard.betz@webmail.co.za

(Received 2 November 2012; accepted 21 November 2012; online 30 November 2012)

In the title compound, C8H8Br2O2, all non-H atoms lie essentially in a common plane (r.m.s deviation of all fitted non-H atoms = 0.0330 Å). In the crystal, weak C—H⋯O hydrogen bonds connect the mol­ecules, forming chains which extend along the b-axis direction.

Related literature

For background to the pharmacological importance of the title compound, see: Pahari & Rohr (2009[Pahari, P. & Rohr, J. (2009). J. Org. Chem. 74, 2750-2754.]). For the synthesis of the title compound, see: Yang et al. (2009[Yang, L., Lu, Z. & Stahl, S. S. (2009). Chem. Commun. pp. 6460-6462.]). For a report listing the crystal structure of 1-bromo-5-chloro-2,4-dimeth­oxy­benzene but entered incorrectly as the title compound in the CSD (TASBAR), see: Yang et al. (2005[Yang, Y., Escobedo, J. O., Wong, A., Schowalter, C. M., Touchy, M. C., Jiao, L., Crowe, W. E., Fronczek, F. R. & Strongin, R. M. (2005). J. Org. Chem. 70, 6907-6912.]). For graph-set analysis of hydrogen bonds, see: Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]).

[Scheme 1]

Experimental

Crystal data
  • C8H8Br2O2

  • Mr = 295.96

  • Monoclinic, P 21 /c

  • a = 7.7944 (2) Å

  • b = 8.5884 (4) Å

  • c = 14.7877 (4) Å

  • β = 107.838 (1)°

  • V = 942.32 (6) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 8.56 mm−1

  • T = 200 K

  • 0.47 × 0.46 × 0.34 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2008[Bruker (2008). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.674, Tmax = 1.000

  • 15097 measured reflections

  • 2350 independent reflections

  • 2094 reflections with I > 2σ(I)

  • Rint = 0.032

Refinement
  • R[F2 > 2σ(F2)] = 0.021

  • wR(F2) = 0.049

  • S = 1.08

  • 2350 reflections

  • 111 parameters

  • H-atom parameters constrained

  • Δρmax = 0.55 e Å−3

  • Δρmin = −0.52 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C7—H7C⋯O1i 0.98 2.70 3.632 (3) 160
Symmetry code: (i) [-x, y-{\script{1\over 2}}, -z+{\script{1\over 2}}].

Data collection: APEX2 (Bruker, 2010[Bruker (2010). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2010[Bruker (2010). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]) and Mercury (Macrae et al., 2008[Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466-470.]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]).

Supporting information


Comment top

The title compound 1,5-dibromo-2,4-dimethoxybenzene is an important intermediate for the synthesis of the anti-HIV drug Elvitegravir and the anticancer drug Psoralidin (Pahari et al., 2009). The crystal structure of 1-bromo-5-chloro-2,4-dimethoxybenzene has been determined (Yang et al., 2005), but the compound was in fact reported erroneously as 1,5-dibromo-2,4-dimethoxybenzene in the CSD (CCDC 271922, ref-code: TASBAR). The error is the result of 50% rotational disorder between the two halogen atoms in the molecule and this fact is also mentioned among the deposited experimental details in the CSD entry. Furthermore, the cell constants reported in this entry [a = 7.722 (4) Å, b = 7.949 (3) Å, c = 7.405 (3) Å, β = 91.78 (1) °, V = 454.315 Å3, Z = 2, space group P 2/c] differed significantly from those of the title compound. In view of the importance of the title compound in synthetic as well as medicinal chemistry, and to rectify the anomaly in the deposited crystallographic data, it was resynthesized and the crystal structure is reported herein.

The title compound is essentially planar (r.m.s. of all fitted non-hydrogen atoms = 0.0330 Å), with one of the methyl carbon atoms deviating most from this common plane by -0.073 (2) Å (Fig. 1). Intracyclic C–C–C angles cover a range from 118.96 (16) ° to 120.73 (17)° with the smallest angle found at one of the carbon atoms bearing a methoxy substituent (C4) and the largest angle at the bromo-substituted carbon atom (C1) in the para position to C4.

In the crystal, a weak intermolecular methyl C—H···O contact (Table 1) whose value falls slightly below the sum of van-der-Waals radii of the atoms participating, is observed, connecting the molecules into chains which extend along b (Fig. 2). A C1–Br1···Cgii contact is also present. According to a graph-set analysis (Bernstein et al., 1995), the descriptor for the C–H···O contacts is C(7). The shortest intercentroid distance between two aromatic ring systems is 4.0267 (10) Å (Fig. 3).

Related literature top

For background to the pharmacological importance of the title compound, see: Pahari & Rohr (2009). For the synthesis of the title compound, see: Yang et al. (2009). For a report listing the crystal structure of 1-bromo-5-chloro-2,4-dimethoxybenzene but entered incorrectly as the title compound in the CSD (CCDC 271922), see: Yang et al. (2005). For graph-set analysis of hydrogen bonds, see: Bernstein et al. (1995).

Experimental top

1,5-Dibromo-2,4-dimethoxybenzene was synthesized according to a published procedure (Yang et al., 2009). The crude product was recrystallized from hot ethanol.

Refinement top

Carbon-bound H atoms were placed in calculated positions [C—H(aromatic) = 0.95 Å and C—H(methyl) = 0.98 Å] and with Uiso(H) = 1.2Ueq(C) (aromatic) and allowed to ride in the refinement. The H atoms of the methyl groups were allowed to rotate with a fixed angle around the C—C bond to best fit the experimental electron density, with Uiso(H) = 1.5Ueq(C).

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound showing atom labels, with anisotropic displacement ellipsoids drawn at the 50% probability level.
[Figure 2] Fig. 2. Intermolecular contacts, viewed along [-1 0 0], with hydrogen bonds shown as dashed lines. For symmetry codes, see Table 1.
[Figure 3] Fig. 3. Molecular packing of the title compound, viewed down [0 1 0] (anisotropic displacement ellipsoids drawn at 50% probability level).
1,5-Dibromo-2,4-dimethoxybenzene top
Crystal data top
C8H8Br2O2F(000) = 568
Mr = 295.96Dx = 2.086 Mg m3
Monoclinic, P21/cMelting point = 414–413 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 7.7944 (2) ÅCell parameters from 9980 reflections
b = 8.5884 (4) Åθ = 2.7–28.3°
c = 14.7877 (4) ŵ = 8.56 mm1
β = 107.838 (1)°T = 200 K
V = 942.32 (6) Å3Block, white
Z = 40.47 × 0.46 × 0.34 mm
Data collection top
Bruker APEXII CCD
diffractometer
2350 independent reflections
Radiation source: fine-focus sealed tube2094 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.032
ϕ and ω scansθmax = 28.4°, θmin = 2.8°
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
h = 1010
Tmin = 0.674, Tmax = 1.000k = 1111
15097 measured reflectionsl = 1819
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)] = 0.021Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.049H-atom parameters constrained
S = 1.08 w = 1/[σ2(Fo2) + (0.0199P)2 + 0.5315P]
where P = (Fo2 + 2Fc2)/3
2350 reflections(Δ/σ)max = 0.001
111 parametersΔρmax = 0.55 e Å3
0 restraintsΔρmin = 0.52 e Å3
Crystal data top
C8H8Br2O2V = 942.32 (6) Å3
Mr = 295.96Z = 4
Monoclinic, P21/cMo Kα radiation
a = 7.7944 (2) ŵ = 8.56 mm1
b = 8.5884 (4) ÅT = 200 K
c = 14.7877 (4) Å0.47 × 0.46 × 0.34 mm
β = 107.838 (1)°
Data collection top
Bruker APEXII CCD
diffractometer
2350 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
2094 reflections with I > 2σ(I)
Tmin = 0.674, Tmax = 1.000Rint = 0.032
15097 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0210 restraints
wR(F2) = 0.049H-atom parameters constrained
S = 1.08Δρmax = 0.55 e Å3
2350 reflectionsΔρmin = 0.52 e Å3
111 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br10.43964 (3)0.63810 (3)0.268745 (16)0.04029 (7)
Br20.29505 (3)0.26527 (3)0.060701 (15)0.03453 (7)
O10.07656 (18)0.52208 (17)0.26640 (10)0.0321 (3)
O20.04398 (17)0.19995 (17)0.01445 (10)0.0323 (3)
C10.2839 (2)0.5013 (2)0.18080 (13)0.0256 (4)
C20.3359 (2)0.4436 (2)0.10619 (13)0.0265 (4)
H20.44870.47290.09920.032*
C30.2236 (2)0.3432 (2)0.04159 (13)0.0243 (4)
C40.0576 (2)0.2998 (2)0.05093 (13)0.0235 (4)
C50.0069 (2)0.3587 (2)0.12664 (13)0.0250 (4)
H50.10560.32920.13390.030*
C60.1190 (2)0.4601 (2)0.19174 (13)0.0244 (4)
C70.2196 (3)0.1625 (3)0.00979 (15)0.0338 (4)
H7A0.28150.09570.06360.051*
H7B0.28880.25850.01230.051*
H7C0.20890.10750.04980.051*
C80.0860 (3)0.4691 (3)0.28213 (15)0.0340 (4)
H8A0.09830.51790.33970.051*
H8B0.08160.35570.28980.051*
H8C0.18940.49760.22770.051*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.02623 (10)0.04018 (13)0.05077 (14)0.00833 (8)0.00632 (9)0.01578 (9)
Br20.02932 (11)0.04093 (12)0.03863 (12)0.00448 (8)0.01823 (9)0.00465 (8)
O10.0301 (7)0.0358 (8)0.0333 (7)0.0062 (6)0.0138 (6)0.0083 (6)
O20.0238 (7)0.0400 (8)0.0353 (7)0.0105 (6)0.0123 (6)0.0101 (6)
C10.0209 (8)0.0209 (8)0.0314 (9)0.0031 (6)0.0026 (7)0.0002 (7)
C20.0195 (8)0.0241 (9)0.0356 (10)0.0015 (7)0.0082 (7)0.0049 (7)
C30.0215 (8)0.0235 (9)0.0288 (9)0.0008 (6)0.0093 (7)0.0039 (7)
C40.0197 (8)0.0222 (8)0.0272 (9)0.0012 (7)0.0053 (7)0.0030 (7)
C50.0195 (8)0.0257 (9)0.0309 (9)0.0025 (7)0.0094 (7)0.0026 (7)
C60.0248 (8)0.0218 (8)0.0263 (9)0.0015 (7)0.0071 (7)0.0034 (7)
C70.0227 (9)0.0418 (11)0.0371 (11)0.0098 (8)0.0093 (8)0.0034 (9)
C80.0336 (10)0.0397 (11)0.0328 (10)0.0050 (8)0.0165 (8)0.0030 (9)
Geometric parameters (Å, º) top
Br1—C11.8918 (18)C3—C41.393 (2)
Br2—C31.8873 (19)C4—C51.392 (3)
O1—C61.355 (2)C5—C61.391 (3)
O1—C81.431 (2)C5—H50.9500
O2—C41.352 (2)C7—H7A0.9800
O2—C71.428 (2)C7—H7B0.9800
C1—C21.379 (3)C7—H7C0.9800
C1—C61.389 (2)C8—H8A0.9800
C2—C31.382 (3)C8—H8B0.9800
C2—H20.9500C8—H8C0.9800
C6—O1—C8117.21 (15)C4—C5—H5119.6
C4—O2—C7117.93 (15)O1—C6—C1117.41 (16)
C2—C1—C6120.73 (17)O1—C6—C5123.47 (16)
C2—C1—Br1119.28 (13)C1—C6—C5119.12 (17)
C6—C1—Br1119.99 (14)O2—C7—H7A109.5
C1—C2—C3119.87 (17)O2—C7—H7B109.5
C1—C2—H2120.1H7A—C7—H7B109.5
C3—C2—H2120.1O2—C7—H7C109.5
C2—C3—C4120.59 (17)H7A—C7—H7C109.5
C2—C3—Br2119.71 (13)H7B—C7—H7C109.5
C4—C3—Br2119.70 (14)O1—C8—H8A109.5
O2—C4—C5123.84 (16)O1—C8—H8B109.5
O2—C4—C3117.20 (16)H8A—C8—H8B109.5
C5—C4—C3118.96 (16)O1—C8—H8C109.5
C6—C5—C4120.72 (16)H8A—C8—H8C109.5
C6—C5—H5119.6H8B—C8—H8C109.5
C6—C1—C2—C30.3 (3)O2—C4—C5—C6179.44 (17)
Br1—C1—C2—C3179.81 (14)C3—C4—C5—C60.5 (3)
C1—C2—C3—C40.2 (3)C8—O1—C6—C1174.78 (17)
C1—C2—C3—Br2179.77 (14)C8—O1—C6—C55.2 (3)
C7—O2—C4—C55.2 (3)C2—C1—C6—O1179.57 (17)
C7—O2—C4—C3175.84 (17)Br1—C1—C6—O10.3 (2)
C2—C3—C4—O2179.34 (16)C2—C1—C6—C50.5 (3)
Br2—C3—C4—O21.1 (2)Br1—C1—C6—C5179.65 (13)
C2—C3—C4—C50.3 (3)C4—C5—C6—O1179.48 (17)
Br2—C3—C4—C5179.86 (13)C4—C5—C6—C10.5 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7—H7C···O1i0.982.703.632 (3)160
C1—Br1···Cgii1.89 (1)3.75 (1)5.5701 (19)161 (1)
Symmetry codes: (i) x, y1/2, z+1/2; (ii) x+1, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC8H8Br2O2
Mr295.96
Crystal system, space groupMonoclinic, P21/c
Temperature (K)200
a, b, c (Å)7.7944 (2), 8.5884 (4), 14.7877 (4)
β (°) 107.838 (1)
V3)942.32 (6)
Z4
Radiation typeMo Kα
µ (mm1)8.56
Crystal size (mm)0.47 × 0.46 × 0.34
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2008)
Tmin, Tmax0.674, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
15097, 2350, 2094
Rint0.032
(sin θ/λ)max1)0.668
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.021, 0.049, 1.08
No. of reflections2350
No. of parameters111
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.55, 0.52

Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2010), SHELXS97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 2012) and Mercury (Macrae et al., 2008), SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7—H7C···O1i0.982.703.632 (3)159.7
Symmetry code: (i) x, y1/2, z+1/2.
 

Acknowledgements

AMI is thankful to the Department of Atomic Energy, Board for Research in Nuclear Sciences, Government of India, for a Young Scientist award.

References

First citationBernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573.  CrossRef CAS Web of Science
First citationBruker (2008). SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationBruker (2010). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals
First citationMacrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470.  Web of Science CrossRef CAS IUCr Journals
First citationPahari, P. & Rohr, J. (2009). J. Org. Chem. 74, 2750–2754.  Web of Science CrossRef PubMed CAS
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals
First citationYang, Y., Escobedo, J. O., Wong, A., Schowalter, C. M., Touchy, M. C., Jiao, L., Crowe, W. E., Fronczek, F. R. & Strongin, R. M. (2005). J. Org. Chem. 70, 6907–6912.  Web of Science CSD CrossRef PubMed CAS
First citationYang, L., Lu, Z. & Stahl, S. S. (2009). Chem. Commun. pp. 6460–6462.  Web of Science CrossRef

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds