1-Dibromo­methyl-4-meth­oxy-2-nitro­benzene

Hoong-Kun Fun; Jia Hao Goh; B Chandrakantha; Arun M Isloor

doi:10.1107/S1600536809031833

. 2009 Aug 19;65(Pt 9):o2193–o2194. doi: 10.1107/S1600536809031833

1-Dibromomethyl-4-methoxy-2-nitrobenzene

Hoong-Kun Fun ^a,^*,^‡, Jia Hao Goh ^a, B Chandrakantha ^b, Arun M Isloor ^c

PMCID: PMC2970072 PMID: 21577597

Abstract

The asymmetric unit of the title compound, C₈H₇Br₂NO₃, comprises two crystallographically independent molecules (A and B). The nitro groups are twisted from the attached benzene rings, making dihedral angles of 39.26 (9) and 35.90 (9)° in molecules A and B, respectively. In each molecule, the dibromomethyl group is orientated in such a way that the two Br atoms are tilted away from the benzene ring. An interesting features of the crystal structure is the two short Br⋯Br interactions which, together with intermolecular C—H⋯O hydrogen bonds, link the molecules into an extended three-dimensional network. The crystal structure is further stabilized by weak C—H⋯π interactions.

Related literature

For general background to and applications of brominated organic compounds, see Augustine et al. (2007 ▶); Derdau et al. (2003 ▶); Khatuya (2001 ▶); Tyeklar et al. (1993 ▶). For related structures, see: Fun, Chantrapromma, Maity et al. (2009 ▶); Fun, Chantrapromma, Sujith et al. (2009 ▶); Yeap et al. (2008 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₈H₇Br₂NO₃
M _r = 324.97
Triclinic,
a = 7.9591 (1) Å
b = 11.1949 (2) Å
c = 12.2509 (2) Å
α = 106.285 (1)°
β = 99.691 (1)°
γ = 102.401 (1)°
V = 992.45 (3) Å³
Z = 4
Mo Kα radiation
μ = 8.15 mm⁻¹
T = 100 K
0.28 × 0.25 × 0.19 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.210, T _max = 0.311 (expected range = 0.147–0.218)
32659 measured reflections
8800 independent reflections
7332 reflections with I > 2σ(I)
R _int = 0.027

Refinement

R[F ² > 2σ(F ²)] = 0.026
wR(F ²) = 0.066
S = 1.01
8800 reflections
261 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.78 e Å⁻³
Δρ_min = −0.47 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809031833/wn2343sup1.cif

e-65-o2193-sup1.cif^{(21KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809031833/wn2343Isup2.hkl

e-65-o2193-Isup2.hkl^{(430.4KB, hkl)}

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

Table 1. Selected interatomic distances (Å).

Br1A⋯Br2Bⁱ	3.5915 (3)
Br2A⋯Br1Bⁱⁱ	3.6279 (2)

Open in a new tab

Symmetry codes: (i) Inline graphic ; (ii) .

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C7A—H7A⋯O2B	0.95 (2)	2.47 (2)	3.134 (2)	126.8 (17)
C8B—H8BA⋯O1Aⁱⁱⁱ	0.96	2.52	3.370 (2)	148
C8A—H8AA⋯Cg2^iv	0.96	2.95	3.839 (2)	155

Open in a new tab

Symmetry codes: (iii) Inline graphic ; (iv) . Cg2 is the centroid of the C1B–C6B benzene ring.

Acknowledgments

HKF and JHG thank Universiti Sains Malaysia (USM) for the Research Universiti Golden Goose Grant (No. 1001/PFIZIK/811012). JHG thanks USM for the award of a USM Fellowship. AMI is grateful to the Director, NITK, Surathkal, India, for providing research facilities.

supplementary crystallographic information

Comment

Brominated organic compounds are important synthetic intermediates and products in organic chemistry (Augustine et al., 2007). They are found in C-C coupling reactions, as precursors to organometallic species and in nucleophilic substitutions (Tyeklar et al., 1993). They are also used for the synthesis of useful pharmaceutical materials and agrochemicals (Derdau et al., 2003). However the use of molecular bromine as an electrophilic brominating reagent has several drawbacks arising from its toxic and corrosive nature and its high reactivity (Tyeklar et al., 1993). Alternative brominating reagents such as N-bromosuccinimide make for easier handling and result in improved selectivity (Khatuya, 2001).

In the asymmetric unit of the title compound, there are two crystallographically independent molecules, designated A and B (Fig. 1). In each molecule, the nitro group is twisted from the mean plane of the C1-C6 benzene ring, as shown by the dihedral angle formed between the mean plane through C5/N1/O2/O3 and the C1-C6 benzene ring of 39.26 (9)° in molecule A; the comparable angle is 35.90 (9)° for molecule B. Meanwhile, the dibromomethyl group is orientated in such a way that the two Br atoms are tilted away from the benzene ring. The bond lengths and angles are comparable to those found in related structures (Fun, Chantrapromma, Maity et al., 2009; Fun, Chantrapromma, Sujith et al., 2009; Yeap et al., 2008).

In the crystal structure (Fig. 2), the interesting features are the Br1A···Br2B and Br2A···Br1B short interactions (Table 1). Together with intermolecular C7A—H7A···O2B and C8B—H8BA···O1A hydrogen bonds (Table 2), they link the molecules into a three-dimensional extended network. The crystal structure is further stabilized by weak C8A—H8AA···Cg2 interactions (Table 2).

Experimental

Benzoyl peroxide (0.20 g, 10 %) and N-bromosuccinimide (6.38 g, 0.0358 mol) were added in portions to a solution of 4-methyl-2-nitroanisole (2.00 g, 0.0119 mol) in CCl₄ (20 ml). The reaction mixture was heated at 85 °C under a nitrogen atmosphere for 12 h. The reaction mass was cooled and filtered. The filtrate was concentrated to produce a crude product. The latter was recrystallized with hexane to afford the title compound as a colourless crystalline solid. The yield was 3.50 g, 92 %. M.p. 370–373 K.