(Z)-4,6-Di­chloro-N-(4-chloro­phen­yl)quinoline-3-carbimidoyl chloride

Weil, M.; Siebert, D.C.B.; Schnürch, M.

doi:10.1107/S2414314617002747

organic compounds

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ISSN: 2414-3146

Volume 2| Part 2| February 2017| x170274

https://doi.org/10.1107/S2414314617002747

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(Z)-4,6-Dichloro-N-(4-chlorophenyl)quinoline-3-carbimidoyl chloride

Matthias Weil,^a ^* David Chan Bodin Siebert ^b and Michael Schnürch ^b

^aInstitute for Chemical Technologies and Analytics, Division of Structural Chemistry, TU Wien, Getreidemarkt 9/164-SC, A-1060 Vienna, Austria, and ^bInstitute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163, A-1060 Vienna, Austria
^*Correspondence e-mail: matthias.weil@tuwien.ac.at

Edited by M. Bolte, Goethe-Universität Frankfurt, Germany (Received 16 February 2017; accepted 17 February 2017; online 21 February 2017)

The title imidoyl chloride, C₁₆H₈Cl₄N₂, has formed accidentally as a side product during the synthesis of a quinolin-3-one derivative. The molecule is not flat [the dihedral angle between the 4,6-dichloroquinoline and the imidoyl chloride planes is 53.43 (5)°], preventing π-conjugation over the complete entity. In the crystal, C—H⋯N hydrogen bonding between a chlorophenyl C—H group and the quinoline N atom, as well as π–π stacking between neighbouring quinoline rings, consolidate the packing.

Keywords: crystal structure; quinoline derivative; imidoyl chloride.

CCDC reference: 1533438

Structure description

Pyrazoloquinolinones are reported as highly active compounds (agonists, antagonists and partial agonists) for the benzodiazepine binding site at the GABA_A receptor (Yokoyama et al., 1982 ). Additionally, they act as allosteric modulators via the α+β-interface (Ramerstorfer et al., 2011 ; Varagic et al., 2013 ). In the context of this research, we obtained the title compound, (III), as a by-product during the synthesis of ethyl 4,6-dichloroquinoline-3-carboxylate, (II) (Fig. 1).

Figure 1
The reaction scheme for the synthesis of the title compound, (III), and the originally intended product (II).

The molecular structure of the title compound is displayed in Fig. 2. The 4,6-dichloroquinoline moiety is essentially planar (r.m.s. deviation = 0.0198 Å), with one of the substituted Cl atoms having the largest deviation from the mean plane [Cl2, 0.0468 (6) Å]. The complete molecule is not flat, with the imidoyl chloride moiety twisted out of the 4,6-dichloroquinoline plane by 53.43 (5)°. The dihedral angles between the imidoyl chloride moiety and the attached 3-chlorophenyl ring and between the 4,6-dichloroquinoline and the 3-chlorophenyl ring are 71.30 (14) and 18.20 (4)°, respectively. The torsion angle of the backbone connecting the three moieties, i.e. C8—C10—N2—C11, is −178.03 (13)°.

Figure 2
The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level and H atoms are given as spheres of arbitrary radius.

Individual molecules are arranged in layers parallel to (10 $[\overline{1}]$ ). Within a layer, π–π stacking between parallel quinoline rings (centroid-to-centroid distance between phenyl and pyridine rings = 3.595 Å; plane-to-plane distance = 3.446 Å) stabilize this arrangement. Mutual intermolecular C—H⋯N hydrogen-bonding interactions between a C—H group of the chlorophenyl ring and the quinoline N atom of two molecules in neighbouring layers leads to the formation of inversion dimers (Fig. 3 and Table 1), with an R₂²(16) ring motif. Further intermolecular halogen–halogen contacts, i.e. Cl3⋯Cl3(−x + 1, −y + 1, −z), with a distance of 3.3453 (7) Å, might also help to consolidate the crystal structure.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C16—H16⋯N1ⁱ	0.95	2.55	3.453 (2)	159
Symmetry code: (i) -x, -y+1, -z+1.

Figure 3
The packing of the molecules in the crystal structure of the title compound in a view along the b* axis. C—H⋯N interactions are shown as magenta dashed lines.

Synthesis and crystallization

Ethyl 6-chloro-4-oxo-1,4-dihydroquinoline-3-carboxylate, (I), was prepared via the Gould–Jacobs reaction (Gould & Jacobs, 1939 ). 2 g of the crude product were dispersed in 10 ml phosphoryl chloride and refluxed for 2 h. The reaction mixture was then poured on ice, neutralized with saturated NaHCO₃ solution and extracted with CH₂Cl₂ (3 × 40 ml). The organic layer was washed with water (1 × 40 ml) and brine (1 × 40 ml), dried over Na₂SO₄, filtered and evaporated. The residue was purified via flash column chromatography (5–20% EtOAc in petroleum ether) to give a colourless solid (yield: 1.74 g, 6.45 mmol, 81%) of (II). The side product (III), representing the title compound, consisted of a light-yellow solid (32 mg). We assume that for formation of (III), the 3-chloroaniline employed in the synthesis of (I) was still present in the crude product and reacted in the following step with (II) to give (III) as a minor by-product.

¹H NMR (400 MHz, CDCl₃) for (III): δ 7.11 (d, J = 8.6 Hz, 2H, H₂′ and H₆′), 7.44 (d, J = 8.5 Hz, 2H, H₃′ and H₅′), 7.80 (dd, J = 8.9, 2.3 Hz, 1H, H₇), 8.13 (d, J = 9.0 Hz, 1H, H₈), 8.37 (d, J = 2.3 Hz, 1H, H₅), 9.06 (s, 1H, H₂).

Refinement

Crystal data, data collection, and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₆H₈Cl₄N₂
M_r	370.04
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	100
a, b, c (Å)	9.2595 (14), 9.9204 (15), 10.1731 (15)
α, β, γ (°)	64.259 (4), 72.322 (5), 64.093 (4)
V (Å³)	749.6 (2)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.78
Crystal size (mm)	0.30 × 0.20 × 0.05

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2015 )
T_min, T_max	0.689, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	26858, 4335, 3750
R_int	0.033
(sin θ/λ)_max (Å⁻¹)	0.703

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.068, 1.04
No. of reflections	4335
No. of parameters	199
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.46, −0.20
Computer programs: APEX3 and SAINT (Bruker, 2015), SHELXT (Sheldrick, 2015a ), SHELXL2014 (Sheldrick, 2015b ), XP (Sheldrick, 2008 ), Mercury (Macrae et al., 2006 ) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 1533438

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S2414314617002747/bt4044sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617002747/bt4044Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314617002747/bt4044Isup3.cml

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2015); cell refinement: SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: XP (Sheldrick, 2008) and Mercury (Macrae et al., 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

(Z)-4,6-Dichloro-N-(4-chlorophenyl)quinoline-3-carbimidoyl chloride top

Crystal data top

C₁₆H₈Cl₄N₂	Z = 2
M_r = 370.04	F(000) = 372
Triclinic, P1	D_x = 1.639 Mg m⁻³
a = 9.2595 (14) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.9204 (15) Å	Cell parameters from 9901 reflections
c = 10.1731 (15) Å	θ = 2.3–29.9°
α = 64.259 (4)°	µ = 0.78 mm⁻¹
β = 72.322 (5)°	T = 100 K
γ = 64.093 (4)°	Plate, light yellow
V = 749.6 (2) Å³	0.30 × 0.20 × 0.05 mm

Data collection top

Bruker APEXII CCD diffractometer	3750 reflections with I > 2σ(I)
ω– and φ–scans	R_int = 0.033
Absorption correction: multi-scan (SADABS; Bruker, 2015)	θ_max = 30.0°, θ_min = 2.3°
T_min = 0.689, T_max = 0.746	h = −12→13
26858 measured reflections	k = −13→13
4335 independent reflections	l = −14→14

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.025	H-atom parameters constrained
wR(F²) = 0.068	w = 1/[σ²(F_o²) + (0.0357P)² + 0.2338P] where P = (F_o² + 2F_c²)/3
S = 1.04	(Δ/σ)_max = 0.001
4335 reflections	Δρ_max = 0.46 e Å⁻³
199 parameters	Δρ_min = −0.20 e Å⁻³

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cl2	0.47318 (3)	0.78291 (3)	0.06212 (3)	0.02002 (7)
Cl3	0.44918 (4)	0.43177 (3)	0.18302 (3)	0.01907 (7)
Cl4	0.82948 (4)	−0.21042 (3)	0.69589 (3)	0.02329 (8)
Cl1	0.10737 (4)	1.41289 (3)	−0.17857 (4)	0.02702 (8)
N2	0.36407 (12)	0.44659 (11)	0.45370 (11)	0.01588 (19)
N1	−0.03955 (12)	0.86631 (12)	0.30708 (11)	0.0181 (2)
C8	0.23627 (14)	0.68779 (13)	0.26551 (12)	0.0139 (2)
C5	0.15842 (13)	0.96888 (12)	0.11060 (12)	0.0136 (2)
C10	0.34979 (13)	0.52050 (13)	0.31946 (12)	0.0140 (2)
C4	0.00070 (14)	0.98888 (13)	0.19243 (13)	0.0154 (2)
C11	0.47579 (14)	0.28773 (13)	0.50743 (12)	0.0144 (2)
C9	0.07433 (14)	0.72394 (14)	0.34052 (13)	0.0172 (2)
H9	0.0469	0.6389	0.4204	0.021*
C12	0.64151 (15)	0.25868 (14)	0.47403 (13)	0.0178 (2)
H12	0.6800	0.3437	0.4112	0.021*
C7	0.27708 (13)	0.81186 (13)	0.15223 (12)	0.0132 (2)
C13	0.75057 (15)	0.10521 (14)	0.53263 (14)	0.0186 (2)
H13	0.8639	0.0846	0.5109	0.022*
C1	0.06808 (15)	1.24874 (13)	−0.03627 (13)	0.0186 (2)
C2	−0.08890 (15)	1.27159 (14)	0.04404 (14)	0.0195 (2)
H2	−0.1711	1.3749	0.0209	0.023*
C14	0.69239 (14)	−0.01764 (13)	0.62317 (13)	0.0166 (2)
C3	−0.12176 (14)	1.14356 (14)	0.15572 (14)	0.0186 (2)
H3	−0.2278	1.1582	0.2094	0.022*
C6	0.19062 (14)	1.10229 (13)	−0.00598 (13)	0.0159 (2)
H6	0.2954	1.0902	−0.0621	0.019*
C15	0.52756 (15)	0.00998 (14)	0.65689 (13)	0.0191 (2)
H15	0.4897	−0.0757	0.7184	0.023*
C16	0.41786 (15)	0.16421 (13)	0.59996 (13)	0.0179 (2)
H16	0.3045	0.1851	0.6240	0.021*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl2	0.01386 (13)	0.01335 (12)	0.02513 (15)	−0.00307 (10)	0.00064 (10)	−0.00410 (10)
Cl3	0.02500 (15)	0.01218 (12)	0.01400 (13)	−0.00016 (10)	−0.00392 (10)	−0.00510 (10)
Cl4	0.02391 (15)	0.01314 (13)	0.02437 (15)	0.00239 (10)	−0.01131 (12)	−0.00309 (11)
Cl1	0.03162 (17)	0.01036 (12)	0.03095 (17)	−0.00513 (11)	−0.01023 (13)	0.00125 (11)
N2	0.0173 (5)	0.0109 (4)	0.0146 (5)	−0.0015 (3)	−0.0033 (4)	−0.0031 (3)
N1	0.0156 (5)	0.0163 (5)	0.0182 (5)	−0.0027 (4)	−0.0028 (4)	−0.0051 (4)
C8	0.0153 (5)	0.0107 (4)	0.0132 (5)	−0.0019 (4)	−0.0037 (4)	−0.0038 (4)
C5	0.0160 (5)	0.0104 (4)	0.0139 (5)	−0.0016 (4)	−0.0061 (4)	−0.0042 (4)
C10	0.0137 (5)	0.0113 (4)	0.0143 (5)	−0.0025 (4)	−0.0013 (4)	−0.0047 (4)
C4	0.0151 (5)	0.0138 (5)	0.0161 (5)	−0.0013 (4)	−0.0059 (4)	−0.0056 (4)
C11	0.0181 (5)	0.0107 (5)	0.0109 (5)	−0.0010 (4)	−0.0043 (4)	−0.0033 (4)
C9	0.0164 (5)	0.0152 (5)	0.0153 (5)	−0.0042 (4)	−0.0016 (4)	−0.0031 (4)
C12	0.0198 (6)	0.0131 (5)	0.0183 (5)	−0.0052 (4)	−0.0042 (4)	−0.0034 (4)
C7	0.0123 (5)	0.0117 (5)	0.0139 (5)	−0.0016 (4)	−0.0033 (4)	−0.0048 (4)
C13	0.0159 (5)	0.0167 (5)	0.0212 (6)	−0.0026 (4)	−0.0059 (4)	−0.0061 (4)
C1	0.0254 (6)	0.0106 (5)	0.0193 (6)	−0.0038 (4)	−0.0105 (5)	−0.0025 (4)
C2	0.0206 (6)	0.0123 (5)	0.0239 (6)	0.0021 (4)	−0.0117 (5)	−0.0072 (4)
C14	0.0207 (6)	0.0113 (5)	0.0143 (5)	0.0002 (4)	−0.0081 (4)	−0.0036 (4)
C3	0.0154 (5)	0.0163 (5)	0.0218 (6)	0.0009 (4)	−0.0065 (4)	−0.0087 (4)
C6	0.0179 (5)	0.0117 (5)	0.0168 (5)	−0.0035 (4)	−0.0050 (4)	−0.0040 (4)
C15	0.0228 (6)	0.0128 (5)	0.0160 (5)	−0.0050 (4)	−0.0033 (4)	−0.0012 (4)
C16	0.0172 (5)	0.0142 (5)	0.0160 (5)	−0.0028 (4)	−0.0024 (4)	−0.0027 (4)

Geometric parameters (Å, º) top

Cl2—C7	1.7268 (12)	C11—C16	1.3933 (16)
Cl3—C10	1.7680 (11)	C9—H9	0.9500
Cl4—C14	1.7424 (11)	C12—C13	1.3881 (15)
Cl1—C1	1.7407 (12)	C12—H12	0.9500
N2—C10	1.2551 (15)	C13—C14	1.3861 (17)
N2—C11	1.4224 (13)	C13—H13	0.9500
N1—C9	1.3121 (14)	C1—C6	1.3698 (15)
N1—C4	1.3704 (15)	C1—C2	1.4083 (18)
C8—C7	1.3768 (15)	C2—C3	1.3678 (17)
C8—C9	1.4255 (16)	C2—H2	0.9500
C8—C10	1.4817 (14)	C14—C15	1.3858 (17)
C5—C6	1.4190 (15)	C3—H3	0.9500
C5—C4	1.4202 (16)	C6—H6	0.9500
C5—C7	1.4237 (14)	C15—C16	1.3920 (15)
C4—C3	1.4209 (15)	C15—H15	0.9500
C11—C12	1.3911 (17)	C16—H16	0.9500

C10—N2—C11	122.47 (10)	C5—C7—Cl2	118.57 (8)
C9—N1—C4	117.52 (10)	C14—C13—C12	119.30 (11)
C7—C8—C9	117.66 (10)	C14—C13—H13	120.4
C7—C8—C10	124.91 (10)	C12—C13—H13	120.4
C9—C8—C10	117.38 (10)	C6—C1—C2	122.32 (11)
C6—C5—C4	119.79 (10)	C6—C1—Cl1	119.01 (10)
C6—C5—C7	123.51 (10)	C2—C1—Cl1	118.67 (9)
C4—C5—C7	116.71 (10)	C3—C2—C1	119.32 (10)
N2—C10—C8	121.50 (10)	C3—C2—H2	120.3
N2—C10—Cl3	123.61 (9)	C1—C2—H2	120.3
C8—C10—Cl3	114.73 (8)	C15—C14—C13	121.29 (10)
N1—C4—C5	123.25 (10)	C15—C14—Cl4	119.47 (9)
N1—C4—C3	117.90 (11)	C13—C14—Cl4	119.25 (9)
C5—C4—C3	118.85 (10)	C2—C3—C4	120.85 (11)
C12—C11—C16	120.60 (10)	C2—C3—H3	119.6
C12—C11—N2	119.73 (10)	C4—C3—H3	119.6
C16—C11—N2	119.57 (10)	C1—C6—C5	118.87 (11)
N1—C9—C8	124.64 (11)	C1—C6—H6	120.6
N1—C9—H9	117.7	C5—C6—H6	120.6
C8—C9—H9	117.7	C14—C15—C16	119.52 (11)
C13—C12—C11	119.87 (11)	C14—C15—H15	120.2
C13—C12—H12	120.1	C16—C15—H15	120.2
C11—C12—H12	120.1	C15—C16—C11	119.41 (11)
C8—C7—C5	120.21 (10)	C15—C16—H16	120.3
C8—C7—Cl2	121.19 (8)	C11—C16—H16	120.3

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C16—H16···N1ⁱ	0.95	2.55	3.453 (2)	159

Symmetry code: (i) −x, −y+1, −z+1.

Acknowledgements

The X-ray centre of TU Wien is acknowledged for financial support and providing access to the single-crystal diffractometer.

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