8-Bromo-2-methyl­quinoline

Abstract

In the crystal structure of the title compound, C₁₀H₈BrN, the dihedral angle between the two six-membered rings of the quinoline system is 0.49 (16)°. The mol­ecules are packed in a face-to-face arrangement fashion, with a centroid–centroid distance of 3.76 Å between the benzene and pyridine rings of adjacent mol­ecules. No hydrogen bonding is found in the crystal structure.

Related literature

The title compound is an important inter­mediate in the pharmaceutical industry, see: Shen & Hartwig (2006 ▶); Ranu et al. (2000 ▶); Lee & Hartwig (2005 ▶). For related structures, see: Amini et al. (2008 ▶); Faza­eli et al. (2008 ▶); Sattarzadeh et al. (2009 ▶).

Experimental

Crystal data

• C₁₀H₈BrN

• M _r = 222.08

• Monoclinic,

• a = 5.0440 (17) Å

• b = 13.467 (4) Å

• c = 13.391 (4) Å

• β = 97.678 (4)°

• V = 901.4 (5) ų

• Z = 4

• Mo Kα radiation

• μ = 4.50 mm⁻¹

• T = 291 K

• 0.36 × 0.31 × 0.28 mm

Data collection

• Bruker SMART APEX CCD diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T _min = 0.235, T _max = 0.286

• 4668 measured reflections

• 1765 independent reflections

• 1039 reflections with I > 2σ(I)

• R _int = 0.156

Refinement

• R[F ² > 2σ(F ²)] = 0.071

• wR(F ²) = 0.195

• S = 1.01

• 1765 reflections

• 110 parameters

• H-atom parameters constrained

• Δρ_max = 0.88 e Å⁻³

• Δρ_min = −0.91 e Å⁻³

Data collection: SMART (Bruker, 2003 ▶); cell refinement: SAINT-Plus (Bruker, 2001 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

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

supplementary crystallographic information

Comment

The title compound, 8-bromo-2-methylquinoline, is an important intermediate of medcine industry (Shen & Hartwig, 2006; Ranu et al., 2000; Lee & Hartwig, 2005). The unit-cell of the title compound contains four molecules, and the corresponding bond lengths and angles of these molecules are agree with each other. The molecules are stablizated by π-π stacking (centroids distance is 3.76 Å). Herein we report the synthesis and crystal structure of 8-bromo-2-methylquinoline. For more related structures, see: Amini et al.(2008), Fazaeli et al. (2008), Sattarzadeh et al. (2009).

Experimental

A solution of 2-bromoaniline (0.05 mol), boric acid (3.10 g) and 18% HCl (50 ml) was heated to reflux. Then a mixture of crotonaldehyde (0.06 mol) and 2-bromonitrobenzene (0.01 mol) was slowly added with stirring in 1 h. The reaction mixture was subsequently stirred at 373 K for another 2.5 h, and then an equimolar amount of anhydrous ZnCl₂ was added with vigorous stirring for 0.5 h. After the reaction was completed, the reaction solution was cooled in an ice bath and the crude brown solid was filtered, washed with 2-propanol, dissolved in the water, and neutralized with concentrated NH_3.H₂O solution to pH of 8. After cool immersed, filtrated and air dried, the product was obtained as a grey solid. Yield: 52.0%. m.p. 342–343 K. Crystals suitable for X-ray structure determination were obtained by slow evaporation of an ethanol solution at room temperature.

Refinement

The H-atoms were positioned geometrically, with C—H = 0.93 Å for aromatic, 0.96 Å for methyl, and refined as riding with U_iso(H) = 1.2 or 1.5 U_eq(C).

Figures

Fig. 1.

Molecular structure showing 30% probability displacement ellipsoids.

Crystal data

C10H8BrN	F(000) = 440
Mr = 222.08	Dx = 1.636 Mg m−3
Monoclinic, P21/c	Melting point: 343 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 5.0440 (17) Å	Cell parameters from 1765 reflections
b = 13.467 (4) Å	θ = 2.2–26.0°
c = 13.391 (4) Å	µ = 4.50 mm−1
β = 97.678 (4)°	T = 291 K
V = 901.4 (5) Å3	Block, colourless
Z = 4	0.36 × 0.31 × 0.28 mm

Data collection

Bruker SMART APEX CCD diffractometer	1765 independent reflections
Radiation source: fine-focus sealed tube	1039 reflections with I > 2σ(I)
graphite	Rint = 0.156
φ and ω scans	θmax = 26.0°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −6→6
Tmin = 0.235, Tmax = 0.286	k = −13→16
4668 measured reflections	l = −15→16

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)] = 0.071	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.195	H-atom parameters constrained
S = 1.01	w = 1/[σ2(Fo2) + (0.0989P)2] where P = (Fo2 + 2Fc2)/3
1765 reflections	(Δ/σ)max < 0.001
110 parameters	Δρmax = 0.88 e Å−3
0 restraints	Δρmin = −0.91 e Å−3

Special details

Experimental. 1H NMR (CDCl3, 400 MHz) δ: 2.82 (s, 3H, CH3), 7.33(m, 2H, quinoline 3,6-H), 7.73 (dd, J=8.0 Hz, J=1.2 Hz, 1H, quinoline 7-H), 8.02 (m, 2H, quinoline 4,5-H).

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
Br1	1.04425 (17)	0.41478 (5)	0.40291 (5)	0.0783 (4)
N1	0.6713 (11)	0.2556 (3)	0.2991 (3)	0.0507 (12)
C1	0.9974 (14)	0.3782 (4)	0.2655 (4)	0.0536 (16)
C8	0.8122 (12)	0.3021 (4)	0.2325 (4)	0.0429 (13)
C9	0.7845 (13)	0.2775 (4)	0.1287 (4)	0.0517 (15)
C7	0.5039 (14)	0.1846 (4)	0.2646 (5)	0.0568 (16)
C2	1.1397 (14)	0.4256 (4)	0.2022 (6)	0.0586 (16)
H2	1.2578	0.4757	0.2266	0.070*
C5	0.6014 (14)	0.2003 (5)	0.0957 (5)	0.0643 (18)
H5	0.5778	0.1807	0.0285	0.077*
C3	1.1122 (15)	0.4004 (5)	0.0989 (5)	0.0621 (18)
H3	1.2156	0.4321	0.0561	0.074*
C6	0.4624 (16)	0.1559 (5)	0.1622 (5)	0.070 (2)
H6	0.3394	0.1064	0.1408	0.084*
C4	0.9318 (15)	0.3287 (5)	0.0624 (5)	0.068 (2)
H4	0.9066	0.3138	−0.0061	0.082*
C10	0.3468 (14)	0.1364 (5)	0.3370 (6)	0.0694 (19)
H10A	0.3969	0.0677	0.3444	0.104*
H10B	0.1596	0.1412	0.3123	0.104*
H10C	0.3821	0.1690	0.4011	0.104*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br1	0.1139 (9)	0.0735 (6)	0.0436 (4)	−0.0082 (4)	−0.0042 (4)	−0.0114 (3)
N1	0.059 (3)	0.050 (3)	0.042 (3)	0.011 (3)	0.004 (2)	0.005 (2)
C1	0.074 (5)	0.044 (3)	0.040 (3)	0.005 (3)	−0.001 (3)	−0.001 (2)
C8	0.037 (3)	0.050 (3)	0.040 (3)	0.012 (3)	0.001 (2)	−0.001 (2)
C9	0.054 (4)	0.063 (3)	0.037 (3)	0.009 (3)	0.002 (3)	−0.001 (3)
C7	0.059 (4)	0.053 (3)	0.059 (4)	0.011 (3)	0.009 (3)	0.007 (3)
C2	0.051 (4)	0.055 (3)	0.070 (4)	0.002 (3)	0.010 (3)	0.004 (3)
C5	0.057 (5)	0.083 (4)	0.050 (4)	0.003 (4)	−0.006 (3)	−0.015 (3)
C3	0.054 (5)	0.073 (4)	0.063 (4)	0.004 (4)	0.021 (3)	0.013 (3)
C6	0.080 (6)	0.063 (4)	0.062 (4)	−0.002 (4)	−0.008 (4)	−0.007 (3)
C4	0.081 (6)	0.085 (5)	0.039 (3)	0.013 (4)	0.012 (3)	0.004 (3)
C10	0.054 (4)	0.068 (4)	0.088 (5)	0.002 (4)	0.015 (4)	0.007 (4)

Geometric parameters (Å, °)

Br1—C1	1.889 (6)	C2—H2	0.9300
N1—C7	1.318 (8)	C5—C6	1.344 (10)
N1—C8	1.365 (7)	C5—H5	0.9300
C1—C2	1.344 (9)	C3—C4	1.371 (10)
C1—C8	1.416 (8)	C3—H3	0.9300
C8—C9	1.418 (7)	C6—H6	0.9300
C9—C4	1.411 (9)	C4—H4	0.9300
C9—C5	1.422 (9)	C10—H10A	0.9600
C7—C6	1.414 (8)	C10—H10B	0.9600
C7—C10	1.481 (9)	C10—H10C	0.9600
C2—C3	1.412 (10)
C7—N1—C8	118.0 (5)	C6—C5—H5	120.2
C2—C1—C8	122.1 (6)	C9—C5—H5	120.2
C2—C1—Br1	118.9 (5)	C4—C3—C2	119.5 (6)
C8—C1—Br1	119.0 (4)	C4—C3—H3	120.2
N1—C8—C1	120.5 (5)	C2—C3—H3	120.2
N1—C8—C9	122.8 (5)	C5—C6—C7	119.9 (7)
C1—C8—C9	116.7 (5)	C5—C6—H6	120.1
C4—C9—C8	120.8 (6)	C7—C6—H6	120.1
C4—C9—C5	122.4 (6)	C3—C4—C9	119.9 (6)
C8—C9—C5	116.8 (5)	C3—C4—H4	120.1
N1—C7—C6	122.9 (6)	C9—C4—H4	120.1
N1—C7—C10	117.6 (6)	C7—C10—H10A	109.5
C6—C7—C10	119.5 (7)	C7—C10—H10B	109.5
C1—C2—C3	120.9 (6)	H10A—C10—H10B	109.5
C1—C2—H2	119.6	C7—C10—H10C	109.5
C3—C2—H2	119.6	H10A—C10—H10C	109.5
C6—C5—C9	119.6 (6)	H10B—C10—H10C	109.5