2-Bromo-1-(4-methoxy­phen­yl)ethanone

Abstract

The title compound, C₉H₉BrO₂, prepared by the reaction of 4-methoxy­acetophenone and cupric bromide, , is approximately planar (r.m.s. deviation 0.0008 Å). In the crystal, weak inter­molecular aromatic C—H⋯O_carbon­yl hydrogen-bonding inter­actions result in a one-dimensional chain structure.

Related literature

For background to hydrazone compounds, see: Domiano et al. (1984 ▶); Li et al. (1988 ▶); Sadik et al. (2004 ▶). For background to thia­zole compounds, see: Shinagawa et al. (1997 ▶); Shivarama et al.(2003 ▶); Dinçer et al. (2005 ▶); Zhang et al. (2009 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

• C₉H₉BrO₂

• M _r = 229.06

• Monoclinic,

• a = 7.7360 (15) Å

• b = 12.441 (3) Å

• c = 10.048 (2) Å

• β = 111.42 (3)°

• V = 900.3 (4) ų

• Z = 4

• Mo Kα radiation

• μ = 4.52 mm⁻¹

• T = 305 K

• 0.20 × 0.10 × 0.10 mm

Data collection

• Enraf–Nonius CAD-4 diffractometer

• Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.465, T _max = 0.661

• 1634 measured reflections

• 1634 independent reflections

• 924 reflections with I > 2σ(I)

• 3 standard reflections every 200 reflections intensity decay: 9%

Refinement

• R[F ² > 2σ(F ²)] = 0.054

• wR(F ²) = 0.116

• S = 1.01

• 1634 reflections

• 109 parameters

• H-atom parameters constrained

• Δρ_max = 0.35 e Å⁻³

• Δρ_min = −0.53 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: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C7—H7A⋯O1i	0.93	2.58	3.505 (7)	171

Symmetry code: (i) .

supplementary crystallographic information

Comment

The chemistry of hydrazones, owing to their coordinating capability, pharmacological activity, antibacterial and antifungal properties, and their use in analytical chemistry as highly selective extractants, has been intensively investigated (Domiano et al., 1984; Li et al., 1988; Sadık et al., 2004). In addition, many thiazole compounds are of considerable importance because of their antibacterial and anti-inflammatory activity (Shinagawa et al., 1997; Shivarama et al., 2003; Dinçer et al., 2005). We have focused our synthetic and structural studies on new derivatives of thiazole-substituted hydrazones (Zhang et al., 2009). We report here the crystal structure of a bromo-substituted methoxyacetophenone, the title compound C₉H₉BrO₂ (I), which is a very important intermediate for the synthesis of thiazole-substituted hydrazones.

In (I), all bond lengths are within normal ranges (Allen et al., 1987). The presence of a strong intramolecular aromatic C8–H···O1_carbonyl hydrogen bond (Table 1) forms a pseudo five-membered ring [O1/C2/C3/C8/H8A with an r.m.s. deviation 0.0069 Å], maintaining essential coplanarity of the ketone side chain with the benzene ring (Fig. 1) [torsion angle: C1–C2–C3–C8, -178.0 (5)°]. The methoxy group is similarly essentially coplanar [torsion angle: C5–C6–O2–C9, 172.0 (6)°].

The molecules of (I) associate through weak intermolecular aromatic C—H···O_carbonyl hydrogen bonds forming one-dimensional chains which extend along the b axial direction in the unit cell (Fig.2).

Experimental

4-Methoxyacetophenone (1.50 g, 0.01 mol) was dissolved in 50 ml ethyl acetate, cupric bromide (3.36 g, 0.015 mol) was added and the mixture was refluxed for ca. 3 h. On cooling, the solid which separated was filtered and recrystallized from ethyl acetate. Crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of ethyl acetate. ¹H NMR (CDCl₃, δ, p.p.m.) 8.17 (d, 2 H), 7.49 (d, 2 H), 4.5 (s, 2 H), 3.81 (s,3 H).

Refinement

All H atoms were positioned geometrically, with C—H = 0.93 Å, and constrained to ride on their parent atoms, with U_iso(H) = xU_eq(C), where x= 1.5 for methyl H and x = 1.2 for methylene and aromatic H atoms.

Figures

Fig. 1.

A view of the molecular structure of (I) showing the atom-numbering scheme with non-H atoms drawn as 30% displacement ellipsoids. The intramolecular hydrogen bond is shown as a dashed line.

Fig. 2.

The crystal packing of (I) showing hydrogen bonds as dashed lines.

Crystal data

C9H9BrO2	F(000) = 456
Mr = 229.06	Dx = 1.690 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 27 reflections
a = 7.7360 (15) Å	θ = 1–25°
b = 12.441 (3) Å	µ = 4.52 mm−1
c = 10.048 (2) Å	T = 305 K
β = 111.42 (3)°	Block, colorless
V = 900.3 (4) Å3	0.20 × 0.10 × 0.10 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	924 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.0000
graphite	θmax = 25.3°, θmin = 2.7°
ω/2θ scans	h = −9→8
Absorption correction: ψ scan (North et al., 1968)	k = 0→14
Tmin = 0.465, Tmax = 0.661	l = 0→12
1634 measured reflections	3 standard reflections every 200 reflections
1634 independent reflections	intensity decay: 9%

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.054	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.116	H-atom parameters constrained
S = 1.00	w = 1/[σ2(Fo2) + (0.048P)2] where P = (Fo2 + 2Fc2)/3
1634 reflections	(Δ/σ)max = 0.001
109 parameters	Δρmax = 0.35 e Å−3
0 restraints	Δρmin = −0.53 e Å−3

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 (Ų)

	x	y	z	Uiso*/Ueq
Br	0.20597 (10)	0.66539 (6)	0.07859 (7)	0.0717 (3)
O1	0.3621 (7)	0.8754 (4)	0.2083 (5)	0.0848 (15)
C1	0.1809 (8)	0.8016 (5)	−0.0164 (6)	0.0576 (17)
H1A	0.2308	0.7957	−0.0918	0.069*
H1B	0.0500	0.8190	−0.0608	0.069*
O2	0.2187 (6)	1.3075 (4)	−0.1487 (5)	0.0689 (13)
C2	0.2781 (8)	0.8917 (5)	0.0820 (6)	0.0534 (16)
C3	0.2657 (7)	0.9994 (5)	0.0181 (6)	0.0478 (14)
C4	0.1597 (8)	1.0221 (5)	−0.1242 (6)	0.0593 (17)
H4A	0.0957	0.9671	−0.1849	0.071*
C5	0.1493 (9)	1.1250 (5)	−0.1751 (7)	0.0633 (18)
H5A	0.0780	1.1390	−0.2703	0.076*
C6	0.2432 (8)	1.2086 (5)	−0.0870 (7)	0.0538 (16)
C7	0.3497 (8)	1.1859 (5)	0.0560 (7)	0.0600 (17)
H7A	0.4138	1.2406	0.1172	0.072*
C8	0.3586 (8)	1.0831 (5)	0.1051 (6)	0.0564 (16)
H8A	0.4297	1.0688	0.2003	0.068*
C9	0.2906 (10)	1.3980 (6)	−0.0610 (8)	0.083 (2)
H9A	0.2625	1.4618	−0.1186	0.124*
H9B	0.4227	1.3908	−0.0151	0.124*
H9C	0.2353	1.4028	0.0102	0.124*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br	0.0721 (5)	0.0588 (5)	0.0722 (5)	0.0064 (4)	0.0121 (3)	0.0076 (4)
O1	0.104 (4)	0.067 (3)	0.050 (3)	0.002 (3)	−0.011 (3)	0.003 (2)
C1	0.054 (4)	0.060 (4)	0.050 (3)	0.002 (3)	0.008 (3)	−0.003 (3)
O2	0.079 (3)	0.054 (3)	0.070 (3)	−0.007 (2)	0.021 (2)	−0.002 (2)
C2	0.042 (3)	0.060 (4)	0.049 (4)	0.007 (3)	0.006 (3)	−0.005 (3)
C3	0.036 (3)	0.050 (4)	0.053 (4)	−0.001 (3)	0.011 (3)	−0.003 (3)
C4	0.060 (4)	0.056 (4)	0.049 (3)	−0.002 (3)	0.005 (3)	−0.012 (3)
C5	0.067 (4)	0.059 (4)	0.052 (4)	0.005 (4)	0.007 (3)	0.000 (3)
C6	0.047 (4)	0.056 (4)	0.058 (4)	−0.004 (3)	0.018 (3)	−0.007 (3)
C7	0.054 (4)	0.062 (5)	0.058 (4)	−0.011 (3)	0.013 (3)	−0.010 (3)
C8	0.044 (4)	0.064 (4)	0.049 (3)	−0.004 (3)	0.001 (3)	−0.005 (3)
C9	0.087 (5)	0.063 (5)	0.096 (5)	−0.012 (4)	0.031 (4)	−0.004 (4)

Geometric parameters (Å, °)

Br—C1	1.920 (6)	C4—H4A	0.9300
O1—C2	1.213 (6)	C5—C6	1.387 (8)
C1—C2	1.502 (8)	C5—H5A	0.9300
C1—H1A	0.9700	C6—C7	1.400 (8)
C1—H1B	0.9700	C7—C8	1.363 (8)
O2—C6	1.359 (7)	C7—H7A	0.9300
O2—C9	1.412 (8)	C8—H8A	0.9300
C2—C3	1.474 (8)	C9—H9A	0.9600
C3—C8	1.380 (7)	C9—H9B	0.9600
C3—C4	1.393 (8)	C9—H9C	0.9600
C4—C5	1.370 (8)
C2—C1—Br	113.3 (4)	C4—C5—H5A	119.4
C2—C1—H1A	108.9	C6—C5—H5A	119.4
Br—C1—H1A	108.9	O2—C6—C5	115.8 (5)
C2—C1—H1B	108.9	O2—C6—C7	125.6 (6)
Br—C1—H1B	108.9	C5—C6—C7	118.6 (6)
H1A—C1—H1B	107.7	C8—C7—C6	119.6 (6)
C6—O2—C9	118.7 (5)	C8—C7—H7A	120.2
O1—C2—C3	122.1 (6)	C6—C7—H7A	120.2
O1—C2—C1	120.8 (6)	C7—C8—C3	122.2 (6)
C3—C2—C1	117.0 (5)	C7—C8—H8A	118.9
C8—C3—C4	118.2 (6)	C3—C8—H8A	118.9
C8—C3—C2	118.3 (5)	O2—C9—H9A	109.5
C4—C3—C2	123.4 (6)	O2—C9—H9B	109.5
C5—C4—C3	120.3 (6)	H9A—C9—H9B	109.5
C5—C4—H4A	119.9	O2—C9—H9C	109.5
C3—C4—H4A	119.9	H9A—C9—H9C	109.5
C4—C5—C6	121.2 (6)	H9B—C9—H9C	109.5
Br—C1—C2—O1	0.0 (8)	C9—O2—C6—C5	172.0 (6)
Br—C1—C2—C3	−179.8 (4)	C9—O2—C6—C7	−6.3 (9)
O1—C2—C3—C8	2.2 (9)	C4—C5—C6—O2	−178.5 (6)
C1—C2—C3—C8	−178.0 (5)	C4—C5—C6—C7	0.0 (9)
O1—C2—C3—C4	−175.3 (6)	O2—C6—C7—C8	178.3 (6)
C1—C2—C3—C4	4.5 (9)	C5—C6—C7—C8	0.0 (9)
C8—C3—C4—C5	0.1 (9)	C6—C7—C8—C3	0.0 (9)
C2—C3—C4—C5	177.6 (6)	C4—C3—C8—C7	−0.1 (9)
C3—C4—C5—C6	0.0 (10)	C2—C3—C8—C7	−177.8 (6)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C8—H8A···O1	0.93	2.47	2.780 (8)	100
C7—H7A···O1i	0.93	2.58	3.505 (7)	171

Symmetry codes: (i) −x+1, y+1/2, −z+1/2.