organic compounds
(Z)-4,6-Dichloro-N-(4-chlorophenyl)quinoline-3-carbimidoyl chloride
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
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 GABAA 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).
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)°.
Individual molecules are arranged in layers parallel to (10). 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.
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 (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 .
details are summarized in Table 2Structural data
CCDC reference: 1533438
https://doi.org/10.1107/S2414314617002747/bt4044sup1.cif
contains datablocks I, global. DOI: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
Data collection: APEX3 (Bruker, 2015); cell
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).C16H8Cl4N2 | Z = 2 |
Mr = 370.04 | F(000) = 372 |
Triclinic, P1 | Dx = 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 |
Bruker APEXII CCD diffractometer | 3750 reflections with I > 2σ(I) |
ω– and φ–scans | Rint = 0.033 |
Absorption correction: multi-scan (SADABS; Bruker, 2015) | θmax = 30.0°, θmin = 2.3° |
Tmin = 0.689, Tmax = 0.746 | h = −12→13 |
26858 measured reflections | k = −13→13 |
4335 independent reflections | l = −14→14 |
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(Fo2) + (0.0357P)2 + 0.2338P] where P = (Fo2 + 2Fc2)/3 |
S = 1.04 | (Δ/σ)max = 0.001 |
4335 reflections | Δρmax = 0.46 e Å−3 |
199 parameters | Δρmin = −0.20 e Å−3 |
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. |
x | y | z | Uiso*/Ueq | ||
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* |
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) |
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 |
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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