3-(2-Bromo-4,5-dimethoxy­phen­yl)propiononitrile

Abstract

In the mol­ecule of the title compound, C₁₁H₁₂BrNO₂, a weak intra­molecular C—H⋯Br hydrogen bond results in the formation of a five-membered ring, which adopts an envelope conformation with the H atom displaced by 0.486 Å from the plane of the other ring atoms. In the crystal structure, inter­molecular C—H⋯O hydrogen bonds link the mol­ecules.

Related literature

For related literature, see: Kametani et al. (1973 ▶); Paull & Cheng (1972 ▶); Lerestif et al. (2005 ▶).

Experimental

Crystal data

• C₁₁H₁₂BrNO₂

• M _r = 270.13

• Tetragonal,

• a = 17.552 (3) Å

• c = 7.4870 (15) Å

• V = 2306.5 (7) ų

• Z = 8

• Mo Kα radiation

• μ = 3.54 mm⁻¹

• T = 294 (2) K

• 0.30 × 0.10 × 0.10 mm

Data collection

• Enraf–Nonius CAD-4 diffractometer

• Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.416, T _max = 0.718

• 4281 measured reflections

• 1128 independent reflections

• 657 reflections with I > 2σ(I)

• R _int = 0.047

• 3 standard reflections frequency: 120 min intensity decay: none

Refinement

• R[F ² > 2σ(F ²)] = 0.052

• wR(F ²) = 0.113

• S = 0.99

• 1128 reflections

• 137 parameters

• H-atom parameters constrained

• Δρ_max = 0.36 e Å⁻³

• Δρ_min = −0.40 e Å⁻³

• Absolute structure: Flack (1983 ▶), with no Friedel pairs

• Flack parameter: 0.00 (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: PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

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
C2—H2A⋯O1i	0.97	2.32	3.193 (10)	150
C3—H3B⋯Br	0.97	2.76	3.195 (9)	108

Symmetry code: (i) .

supplementary crystallographic information

Comment

2-Bromo-4,5-dimethoxyhydrocinnamonitrile is the precursor of 1-cyano-4,5-di- methoxybenzocyclobutene, which is a key intermediate of ivabradine (Lerestif et al., 2005), xylopinine (Kametani et al., 1973) and 4-substituted 3a,4,5,9 b-terahydrobenz[e]isoindolinea (Paull & Cheng, 1972). As part of our studies in this area, we report herein the synthesis and crystal structure of the title compound, (I).

In the molecule of (I), (Fig. 1), ring A (C4-C9) is, of course, planar. Br, O1, O2, C3 and C10 atoms lie in the ring plane. A weak intramolecular C-H···Br [C3-H3B = 0.97, H3B···Br = 2.76, C3···Br = 3.195 (9) Å and C3-H3B···Br = 108°] hydrogen bond results in the formation of a five-membered ring B (C3-C5/Br/H3B), which adopts envelope conformation with hydrogen atom displaced by -0.486 (3) Å from the plane of the other ring atoms.

In the crystal structure, intermolecular C-H···O [C2-H2A = 0.97, H2A···O1 = 2.32, C2···O1 = 3.193 (8) Å and C2-H2A···O1 = 150°] hydrogen bonds link the molecules (Fig. 2), in which they may be effective in the stabilization of the structure.

Experimental

For the preparation of the title compound, beta-(2-bromo-4,5-dimethoxypenyl) -alpha-cyanoproponic acid (16 mmol) was dissolved in dimethylacetamide (10 ml), the mixture was heated at 443 K and evolution of the calculated amount of CO₂ ceased after 30 min. The mixture was poured into water and set aside overnight. Crystals were separated, collected and washed with water and hexane. Crystals of (I) suitable for X-ray analysis were obtained by slow evaporation of a methanol solution.

Refinement

H atoms were positioned geometrically, with C-H = 0.93, 0.97 and 0.96 Å for aromatic, methylene and methyl H, respectively, 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 all other H atoms.

Figures

Fig. 1.

The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Hydrogen bond is shown as dashed line.

Fig. 2.

A partial packing diagram of (I). Hydrogen bonds are shown as dashed lines.

Crystal data

C11H12BrNO2	Z = 8
Mr = 270.13	F000 = 1088
Tetragonal, P42bc	Dx = 1.556 Mg m−3
Hall symbol: P 4c -2ab	Mo Kα radiation λ = 0.71073 Å
a = 17.552 (3) Å	Cell parameters from 25 reflections
b = 17.552 (3) Å	θ = 10–13º
c = 7.4870 (15) Å	µ = 3.54 mm−1
α = 90º	T = 294 (2) K
β = 90º	Block, colorless
γ = 90º	0.30 × 0.10 × 0.10 mm
V = 2306.5 (7) Å3

Data collection

Enraf–Nonius CAD-4 diffractometer	Rint = 0.047
Radiation source: fine-focus sealed tube	θmax = 25.2º
Monochromator: graphite	θmin = 1.6º
T = 294(2) K	h = −21→21
ω/2θ scans	k = −21→0
Absorption correction: ψ scan(North et al., 1968)	l = 0→8
Tmin = 0.416, Tmax = 0.718	3 standard reflections
4281 measured reflections	every 120 min
1128 independent reflections	intensity decay: none
657 reflections with I > 2σ(I)

Refinement

Refinement on F2	H-atom parameters constrained
Least-squares matrix: full	w = 1/[σ2(Fo2) + (0.052P)2] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.052	(Δ/σ)max < 0.001
wR(F2) = 0.113	Δρmax = 0.36 e Å−3
S = 0.99	Δρmin = −0.39 e Å−3
1128 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
137 parameters	Extinction coefficient: 0.0026 (5)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), with no Friedel pairs
Secondary atom site location: difference Fourier map	Flack parameter: 0.00 (3)
Hydrogen site location: inferred from neighbouring sites

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 > 2sigma(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	0.95483 (5)	0.91044 (5)	0.9098 (3)	0.0796 (5)
N	0.6404 (5)	0.9114 (5)	0.6468 (17)	0.083 (4)
O1	0.7337 (3)	0.6500 (3)	0.8860 (13)	0.051 (2)
O2	0.8737 (4)	0.6253 (3)	0.8147 (10)	0.055 (2)
C1	0.6900 (6)	0.9379 (5)	0.7195 (18)	0.057 (3)
C2	0.7527 (6)	0.9707 (5)	0.8211 (15)	0.060 (4)
H2A	0.7383	1.0216	0.8585	0.073*
H2B	0.7965	0.9754	0.7429	0.073*
C3	0.7763 (5)	0.9255 (5)	0.9855 (13)	0.050 (3)
H3A	0.7329	0.9212	1.0649	0.060*
H3B	0.8158	0.9535	1.0482	0.060*
C4	0.8058 (4)	0.8459 (4)	0.9433 (19)	0.040 (3)
C5	0.8811 (4)	0.8304 (4)	0.906 (2)	0.043 (2)
C6	0.9068 (5)	0.7583 (5)	0.8663 (14)	0.053 (5)
H6A	0.9585	0.7501	0.8462	0.064*
C7	0.8568 (5)	0.6988 (4)	0.8560 (11)	0.034 (3)
C8	0.7797 (4)	0.7129 (4)	0.899 (2)	0.038 (2)
C9	0.7556 (4)	0.7846 (4)	0.939 (2)	0.040 (3)
H9A	0.7043	0.7929	0.9639	0.047*
C10	0.6556 (4)	0.6598 (4)	0.932 (3)	0.056 (3)
H10A	0.6297	0.6117	0.9225	0.084*
H10B	0.6326	0.6957	0.8516	0.084*
H10C	0.6519	0.6784	1.0520	0.084*
C11	0.9502 (5)	0.6090 (5)	0.758 (2)	0.077 (4)
H11A	0.9549	0.5556	0.7324	0.116*
H11B	0.9852	0.6228	0.8507	0.116*
H11C	0.9615	0.6378	0.6519	0.116*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Br	0.0517 (6)	0.0477 (6)	0.1394 (12)	−0.0149 (4)	−0.0013 (13)	−0.0086 (14)
N	0.084 (7)	0.070 (6)	0.095 (10)	0.022 (5)	−0.025 (8)	−0.018 (7)
O1	0.039 (3)	0.036 (3)	0.078 (7)	−0.003 (2)	0.006 (5)	−0.015 (5)
O2	0.044 (4)	0.031 (4)	0.090 (6)	0.010 (3)	0.009 (4)	0.000 (4)
C1	0.067 (8)	0.041 (6)	0.062 (10)	0.013 (6)	0.002 (7)	−0.009 (6)
C2	0.064 (7)	0.032 (6)	0.085 (10)	0.008 (5)	−0.007 (7)	−0.010 (6)
C3	0.042 (6)	0.055 (6)	0.052 (9)	0.002 (5)	0.009 (5)	−0.012 (6)
C4	0.041 (5)	0.035 (4)	0.045 (8)	−0.001 (3)	−0.002 (7)	−0.006 (7)
C5	0.042 (5)	0.038 (5)	0.047 (7)	−0.011 (4)	−0.006 (9)	−0.007 (9)
C6	0.033 (4)	0.042 (5)	0.085 (14)	0.001 (4)	0.003 (6)	−0.003 (6)
C7	0.041 (5)	0.031 (4)	0.030 (8)	0.005 (4)	−0.008 (4)	−0.002 (4)
C8	0.039 (4)	0.026 (4)	0.048 (7)	−0.007 (3)	0.013 (8)	−0.001 (7)
C9	0.037 (4)	0.038 (4)	0.044 (7)	0.001 (4)	−0.005 (7)	0.002 (7)
C10	0.036 (5)	0.053 (5)	0.079 (8)	−0.013 (4)	0.001 (9)	0.008 (10)
C11	0.054 (6)	0.049 (6)	0.128 (13)	0.009 (5)	0.000 (8)	−0.013 (8)

Geometric parameters (Å, °)

Br—C5	1.911 (7)	C4—C9	1.391 (10)
N—C1	1.128 (13)	C5—C6	1.376 (11)
O1—C8	1.371 (9)	C6—C7	1.367 (11)
O1—C10	1.422 (9)	C6—H6A	0.9300
O2—C7	1.358 (9)	C7—C8	1.414 (10)
O2—C11	1.438 (10)	C8—C9	1.360 (10)
C1—C2	1.456 (14)	C9—H9A	0.9300
C2—C3	1.521 (13)	C10—H10A	0.9600
C2—H2A	0.9700	C10—H10B	0.9600
C2—H2B	0.9700	C10—H10C	0.9600
C3—C4	1.524 (11)	C11—H11A	0.9600
C3—H3A	0.9700	C11—H11B	0.9600
C3—H3B	0.9700	C11—H11C	0.9600
C4—C5	1.376 (11)
C8—O1—C10	116.9 (6)	C5—C6—H6A	119.9
C7—O2—C11	117.4 (7)	O2—C7—C6	126.7 (8)
N—C1—C2	177.3 (14)	O2—C7—C8	115.3 (7)
C1—C2—C3	115.0 (9)	C6—C7—C8	117.9 (8)
C1—C2—H2A	108.5	C9—C8—O1	125.3 (7)
C3—C2—H2A	108.5	C9—C8—C7	120.7 (7)
C1—C2—H2B	108.5	O1—C8—C7	113.9 (7)
C3—C2—H2B	108.5	C8—C9—C4	121.5 (8)
H2A—C2—H2B	107.5	C8—C9—H9A	119.2
C2—C3—C4	113.7 (8)	C4—C9—H9A	119.2
C2—C3—H3A	108.8	O1—C10—H10A	109.5
C4—C3—H3A	108.8	O1—C10—H10B	109.5
C2—C3—H3B	108.8	H10A—C10—H10B	109.5
C4—C3—H3B	108.8	O1—C10—H10C	109.5
H3A—C3—H3B	107.7	H10A—C10—H10C	109.5
C5—C4—C9	116.8 (7)	H10B—C10—H10C	109.5
C5—C4—C3	123.3 (7)	O2—C11—H11A	109.5
C9—C4—C3	119.9 (8)	O2—C11—H11B	109.5
C4—C5—C6	122.7 (7)	H11A—C11—H11B	109.5
C4—C5—Br	120.1 (6)	O2—C11—H11C	109.5
C6—C5—Br	117.1 (6)	H11A—C11—H11C	109.5
C7—C6—C5	120.2 (8)	H11B—C11—H11C	109.5
C7—C6—H6A	119.9
C1—C2—C3—C4	62.4 (12)	C5—C6—C7—C8	−4.2 (18)
C2—C3—C4—C5	88.6 (16)	C10—O1—C8—C9	−6(3)
C2—C3—C4—C9	−90.8 (16)	C10—O1—C8—C7	178.6 (13)
C9—C4—C5—C6	0(2)	O2—C7—C8—C9	−178.5 (13)
C3—C4—C5—C6	−179.2 (13)	C6—C7—C8—C9	4(2)
C9—C4—C5—Br	−179.7 (11)	O2—C7—C8—O1	−2.4 (17)
C3—C4—C5—Br	1(2)	C6—C7—C8—O1	−179.8 (11)
C4—C5—C6—C7	2(2)	O1—C8—C9—C4	−177.5 (13)
Br—C5—C6—C7	−177.9 (9)	C7—C8—C9—C4	−2(3)
C11—O2—C7—C6	−7.0 (15)	C5—C4—C9—C8	0(3)
C11—O2—C7—C8	175.9 (12)	C3—C4—C9—C8	179.1 (13)
C5—C6—C7—O2	178.7 (11)

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2A···O1i	0.97	2.32	3.193 (10)	150
C3—H3B···Br	0.97	2.76	3.195 (9)	108

Symmetry codes: (i) −x+3/2, y+1/2, z.