(E)-Methyl 2,6-dichloro-N-cyano­benzimidate

Wu, X.-A.; Yin, P.; He, L.; Li, Z.-C.; Huang, W.-C.

doi:10.1107/S1600536809026452

organic compounds

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ISSN: 2056-9890

Volume 65| Part 8| August 2009| Page o1837

doi:10.1107/S1600536809026452

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(E)-Methyl 2,6-dichloro-N-cyanobenzimidate

Xiao-Ai Wu,^a Ping Yin,^a Ling He,^a Zi-Cheng Li ^b and Wen-Cai Huang ^b ^*

^aKey Laboratory of Drug Targeting and Drug-Delivery Systems of the Ministry of Education, Department of Medicinal Chemistry, West China School of Pharmacy, Sichuan University, Chengdu, 610041, People's Republic of China, and ^bDepartment of Pharmaceutical and Bioengineering, School of Chemical Engineering, Sichuan University, Chengdu 610065, People's Republic of China
^*Correspondence e-mail: hwc@scu.edu.cn

(Received 26 June 2009; accepted 7 July 2009; online 11 July 2009)

The molecule of the title compound, C₉H₆Cl₂N₂O, displays an E conformation about the C=N double bond. The N-cyanoimidate fragment is substantially planar [maximum deviation 0.010 (4) Å] and perpendicular to the benzene ring [dihedral angle = 88.50 (14)°]. In the crystal packing, intermolecular Cl⋯Cl interactions [3.490 (2) Å] are observed.

Related literature

For the synthesis of substituted cyanoimidates, see: Huffman & Schaefer (1963 ). For the crystal structures of compounds containing the N-cyanoimidate fragment, see: Zöllinger et al. (2006 ); Ponomareva et al. (1995 ); Jäger et al. (1996 ). For details of halogen⋯halogen interactions, see: Desiraju & Parthasarathy (1989 ).

Experimental

Crystal data

C₉H₆Cl₂N₂O
M_r = 229.06
Monoclinic, C 2/c
a = 21.199 (4) Å
b = 8.548 (3) Å
c = 15.005 (4) Å
β = 128.49 (4)°
V = 2128.2 (16) Å³
Z = 8
Mo Kα radiation
μ = 0.58 mm⁻¹
T = 291 K
0.52 × 0.46 × 0.28 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: spherical (WinGX; Farrugia, 1999 ) T_min = 0.754, T_max = 0.855
2116 measured reflections
1948 independent reflections
1167 reflections with I > 2σ(I)
R_int = 0.016
3 standard reflections every 120 reflections intensity decay: 3.8%

Refinement

R[F² > 2σ(F²)] = 0.054
wR(F²) = 0.170
S = 1.04
1948 reflections
129 parameters
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.32 e Å⁻³

Data collection: DIFRAC (Gabe & White, 1993 ); cell refinement: DIFRAC; data reduction: NRCVAX (Gabe et al., 1989 ); 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: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809026452/rz2343sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809026452/rz2343Isup2.hkl

checkCIF report

Comment top

In the course of our studies aimed to prepare substituted cyanoimidates (Huffman & Schaefer, 1963) from the corresponding aromatic aldehyde by oxidation using 1-bromopyrrolidine-2,5-dione, the title compound was obtained in 84% yield, and its crystal structure is reported herein.

The molecule of the title compound (Fig. 1) displays an E conformation about the C═N double bond. The O—C═N—C≡N N-cyanoimidate fragment is substantially planar [maximum deviation 0.010 (4) Å for atom N2] and forms a dihedral angle of 88.50 (14)° with the plane of the benzene ring. As far as the authors are aware, crystal structures reporting the presence of the N-cyanoimidate fragment are very rare, the only examples found in the literature being 1-(2,3-dibromo-10-oxo-7,8-dihydro-6H,10H-dipyrrolo[1,2-a:1',2'-d]pyrazin-5-yl)-2-(2,6-dimethylphenyl)-3-cyanoisourea monohydrate (Zöllinger et al., 2006), catena-poly-[(µ⁶-benzoylcyanamido)-thallium(I)] (Ponomareva et al., 1995) and tris(ethylenediamine)-nickel(II) bis[2-methyl-4-chlorophenoxy(cyanamido)acetate] (Jäger et al., 1996). In the crystal structure, molecules are connected by intermolecular Cl···Cl interactions of 3.490 (2) Å (Desiraju & Parthasarathy, 1989) into one-dimensional chains running parallel to [101].

Related literature top

For the synthesis of substituted cyanoimidates, see: Huffman & Schaefer (1963). For the crystal structures of compounds containing the N-cyanoimidate fragment, see: Zöllinger et al. (2006); Ponomareva et al. (1995); Jäger et al. (1996). For details of halogen···halogen interactions, see: Desiraju & Parthasarathy (1989).

Experimental top

A mixture of 2,6-dichlorobenzaldehyde (1 mmol), H₂NCN (3 equiv) and t-BuONa (3 equiv) in MeOH (8 ml) was stirred for 30 min at room temperature, then N-bromosuccinimide (NBS; 3 equiv) was added. After stirring for 12 h at 323 K, the mixture was purified by flash chromatography on silica gel with petroleum ether/ethyl acetate (100:1–25:1 v/v) as eluent to give the title compound in 84% yield. Colourless crystals suitable for X-ray analysis were obtained by slow evaporation of a petroleum ether/acetyl acetate solution (25:1 v/v) at room temperature.

Computing details top

Data collection: DIFRAC (Gabe & White, 1993); cell refinement: DIFRAC (Gabe & White, 1993); data reduction: NRCVAX (Gabe et al., 1989); 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: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title compound, with displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. Crystal packing of the title compound approximately viewed along the b axis. Cl···Cl interactions are shown as dotted lines.

(E)-Methyl 2,6-dichloro-N-cyanobenzimidate top

Crystal data top

C₉H₆Cl₂N₂O	F(000) = 928
M_r = 229.06	D_x = 1.430 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 28 reflections
a = 21.199 (4) Å	θ = 4.8–9.2°
b = 8.548 (3) Å	µ = 0.58 mm⁻¹
c = 15.005 (4) Å	T = 291 K
β = 128.49 (4)°	Block, colourless
V = 2128.2 (16) Å³	0.52 × 0.46 × 0.28 mm
Z = 8

Data collection top

Enraf–Nonius CAD-4 diffractometer	1167 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.016
Graphite monochromator	θ_max = 25.5°, θ_min = 2.5°
ω/2θ scans	h = −25→17
Absorption correction: for a sphere (WinGX; Farrugia, 1999)	k = 0→10
T_min = 0.754, T_max = 0.855	l = −18→18
2116 measured reflections	3 standard reflections every 120 reflections
1948 independent reflections	intensity decay: 3.8%

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.054	H-atom parameters constrained
wR(F²) = 0.170	w = 1/[σ²(F_o²) + (0.1053P)²] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max < 0.001
1948 reflections	Δρ_max = 0.30 e Å⁻³
129 parameters	Δρ_min = −0.32 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0069 (15)

Crystal data top

C₉H₆Cl₂N₂O	V = 2128.2 (16) Å³
M_r = 229.06	Z = 8
Monoclinic, C2/c	Mo Kα radiation
a = 21.199 (4) Å	µ = 0.58 mm⁻¹
b = 8.548 (3) Å	T = 291 K
c = 15.005 (4) Å	0.52 × 0.46 × 0.28 mm
β = 128.49 (4)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	1167 reflections with I > 2σ(I)
Absorption correction: for a sphere (WinGX; Farrugia, 1999)	R_int = 0.016
T_min = 0.754, T_max = 0.855	3 standard reflections every 120 reflections
2116 measured reflections	intensity decay: 3.8%
1948 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.054	0 restraints
wR(F²) = 0.170	H-atom parameters constrained
S = 1.04	Δρ_max = 0.30 e Å⁻³
1948 reflections	Δρ_min = −0.32 e Å⁻³
129 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
Cl1	0.54862 (5)	0.67130 (14)	0.65350 (8)	0.0881 (5)
Cl2	0.24528 (6)	0.72469 (18)	0.26898 (9)	0.1121 (6)
O1	0.36902 (14)	0.4760 (2)	0.5066 (2)	0.0672 (7)
N1	0.35148 (15)	0.7020 (3)	0.5663 (2)	0.0563 (7)
N2	0.3600 (2)	0.9913 (4)	0.5784 (3)	0.0866 (10)
C1	0.40050 (16)	0.7037 (3)	0.4547 (2)	0.0472 (7)
C2	0.48117 (18)	0.7300 (3)	0.5135 (3)	0.0545 (8)
C3	0.5094 (2)	0.8077 (4)	0.4632 (3)	0.0675 (9)
H3	0.5642	0.8259	0.5039	0.081*
C4	0.4550 (3)	0.8571 (4)	0.3523 (3)	0.0745 (10)
H4	0.4735	0.9086	0.3179	0.089*
C5	0.3742 (2)	0.8318 (4)	0.2917 (3)	0.0750 (10)
H5	0.3379	0.8664	0.2169	0.090*
C6	0.3471 (2)	0.7542 (4)	0.3432 (3)	0.0613 (9)
C7	0.37157 (16)	0.6295 (3)	0.5129 (2)	0.0486 (7)
C8	0.3474 (3)	0.3932 (4)	0.5685 (4)	0.0930 (13)
H8A	0.3881	0.4102	0.6487	0.139*
H8B	0.3433	0.2833	0.5525	0.139*
H8C	0.2966	0.4312	0.5453	0.139*
C9	0.3568 (2)	0.8581 (4)	0.5699 (3)	0.0619 (8)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0583 (5)	0.1217 (9)	0.0646 (6)	0.0019 (5)	0.0285 (5)	0.0127 (5)
Cl2	0.0589 (6)	0.1721 (13)	0.0731 (7)	−0.0024 (6)	0.0252 (5)	0.0231 (7)
O1	0.0903 (16)	0.0367 (12)	0.0958 (17)	0.0011 (10)	0.0684 (15)	0.0009 (10)
N1	0.0733 (17)	0.0436 (14)	0.0707 (16)	−0.0010 (11)	0.0540 (15)	0.0000 (11)
N2	0.129 (3)	0.0544 (18)	0.122 (3)	−0.0121 (17)	0.100 (3)	−0.0177 (17)
C1	0.0566 (16)	0.0401 (14)	0.0550 (16)	0.0025 (12)	0.0397 (14)	−0.0008 (12)
C2	0.0587 (17)	0.0537 (17)	0.0574 (17)	0.0016 (13)	0.0393 (15)	−0.0039 (13)
C3	0.0639 (19)	0.070 (2)	0.087 (2)	−0.0075 (16)	0.056 (2)	−0.0115 (18)
C4	0.103 (3)	0.069 (2)	0.090 (3)	0.000 (2)	0.079 (2)	0.0017 (19)
C5	0.096 (3)	0.078 (2)	0.066 (2)	0.013 (2)	0.058 (2)	0.0132 (18)
C6	0.0620 (18)	0.068 (2)	0.0564 (18)	0.0022 (15)	0.0382 (16)	0.0003 (15)
C7	0.0502 (15)	0.0413 (15)	0.0535 (16)	0.0004 (12)	0.0319 (13)	−0.0001 (12)
C8	0.123 (3)	0.050 (2)	0.144 (4)	−0.004 (2)	0.101 (3)	0.014 (2)
C9	0.080 (2)	0.055 (2)	0.076 (2)	−0.0076 (16)	0.0612 (19)	−0.0101 (16)

Geometric parameters (Å, º) top

Cl1—C2	1.724 (3)	C2—C3	1.389 (4)
Cl2—C6	1.724 (4)	C3—C4	1.374 (5)
O1—C7	1.314 (3)	C3—H3	0.9300
O1—C8	1.451 (4)	C4—C5	1.367 (5)
N1—C7	1.278 (4)	C4—H4	0.9300
N1—C9	1.338 (4)	C5—C6	1.385 (5)
N2—C9	1.143 (4)	C5—H5	0.9300
C1—C2	1.370 (4)	C8—H8A	0.9600
C1—C6	1.382 (4)	C8—H8B	0.9600
C1—C7	1.486 (4)	C8—H8C	0.9600

C7—O1—C8	117.2 (3)	C4—C5—H5	120.4
C7—N1—C9	117.1 (3)	C6—C5—H5	120.4
C2—C1—C6	118.8 (3)	C1—C6—C5	120.9 (3)
C2—C1—C7	119.9 (3)	C1—C6—Cl2	119.2 (3)
C6—C1—C7	121.3 (3)	C5—C6—Cl2	119.8 (3)
C1—C2—C3	121.1 (3)	N1—C7—O1	121.0 (3)
C1—C2—Cl1	119.5 (2)	N1—C7—C1	125.6 (2)
C3—C2—Cl1	119.4 (2)	O1—C7—C1	113.4 (2)
C4—C3—C2	119.0 (3)	O1—C8—H8A	109.5
C4—C3—H3	120.5	O1—C8—H8B	109.5
C2—C3—H3	120.5	H8A—C8—H8B	109.5
C5—C4—C3	121.1 (3)	O1—C8—H8C	109.5
C5—C4—H4	119.5	H8A—C8—H8C	109.5
C3—C4—H4	119.5	H8B—C8—H8C	109.5
C4—C5—C6	119.2 (3)	N2—C9—N1	174.8 (4)

C6—C1—C2—C3	0.8 (4)	C7—C1—C6—Cl2	−2.1 (4)
C7—C1—C2—C3	−176.1 (3)	C4—C5—C6—C1	0.6 (5)
C6—C1—C2—Cl1	178.8 (2)	C4—C5—C6—Cl2	178.7 (3)
C7—C1—C2—Cl1	1.9 (4)	C9—N1—C7—O1	179.2 (3)
C1—C2—C3—C4	−0.6 (5)	C9—N1—C7—C1	0.2 (4)
Cl1—C2—C3—C4	−178.6 (3)	C8—O1—C7—N1	−3.7 (4)
C2—C3—C4—C5	0.4 (5)	C8—O1—C7—C1	175.4 (3)
C3—C4—C5—C6	−0.4 (5)	C2—C1—C7—N1	89.7 (4)
C2—C1—C6—C5	−0.8 (5)	C6—C1—C7—N1	−87.1 (4)
C7—C1—C6—C5	176.0 (3)	C2—C1—C7—O1	−89.4 (3)
C2—C1—C6—Cl2	−178.9 (2)	C6—C1—C7—O1	93.8 (3)

Experimental details

Crystal data
Chemical formula	C₉H₆Cl₂N₂O
M_r	229.06
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	291
a, b, c (Å)	21.199 (4), 8.548 (3), 15.005 (4)
β (°)	128.49 (4)
V (Å³)	2128.2 (16)
Z	8
Radiation type	Mo Kα
µ (mm⁻¹)	0.58
Crystal size (mm)	0.52 × 0.46 × 0.28

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	For a sphere (WinGX; Farrugia, 1999)
T_min, T_max	0.754, 0.855
No. of measured, independent and observed [I > 2σ(I)] reflections	2116, 1948, 1167
R_int	0.016
(sin θ/λ)_max (Å⁻¹)	0.606

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.054, 0.170, 1.04
No. of reflections	1948
No. of parameters	129
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.30, −0.32

Computer programs: DIFRAC (Gabe & White, 1993), NRCVAX (Gabe et al., 1989), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997).

References

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