8-Chloro-4-oxo-4H-chromene-3-carbaldehyde

Yoshinobu Ishikawa

doi:10.1107/S1600536814012483

. 2014 Jun 4;70(Pt 7):o743. doi: 10.1107/S1600536814012483

8-Chloro-4-oxo-4H-chromene-3-carbaldehyde

Yoshinobu Ishikawa ^a,^*

PMCID: PMC4120543 PMID: 25161540

Abstract

In the title compound, C₁₀H₅ClO₃, a chlorinated 3-formylchromone derivative, all atoms are essentially coplanar (r.m.s. deviation = 0.032 Å for the non-H atoms), with the largest deviation from the least-squares plane [0.0598 (14) Å] being for a pyran-ring C atom. In the crystal, molecules are linked through stacking interactions along the b axis [shortest centroid–centroid distance between the pyran and benzene rings = 3.566 (2) Å].

Related literature

For related structures, see: Ishikawa & Motohashi (2013 ▶); Ishikawa (2014 ▶). For the synthesis of the precursor of the title compound, see: Fumagalli et al. (2012 ▶). For van der Waals radii; see: Bondi (1964 ▶). For halogen bonding, see: Auffinger et al. (2004 ▶); Metrangolo et al. (2005 ▶); Wilcken et al. (2013 ▶); Sirimulla et al. (2013 ▶). graphic file with name e-70-0o743-scheme1.jpg

Experimental

Crystal data

C₁₀H₅ClO₃
M _r = 208.60
Triclinic,
a = 6.9436 (15) Å
b = 7.1539 (17) Å
c = 9.165 (2) Å
α = 102.049 (19)°
β = 103.403 (17)°
γ = 100.650 (19)°
V = 419.89 (18) Å³
Z = 2
Mo Kα radiation
μ = 0.43 mm⁻¹
T = 100 K
0.38 × 0.25 × 0.10 mm

Data collection

Rigaku AFC-7R diffractometer
Absorption correction: ψ scan (North et al., 1968 ▶) T _min = 0.902, T _max = 0.958
2376 measured reflections
1932 independent reflections
1750 reflections with F ² > 2σ(F ²)
R _int = 0.011
3 standard reflections every 150 reflections intensity decay: −0.039%

Refinement

R[F ² > 2σ(F ²)] = 0.028
wR(F ²) = 0.075
S = 1.09
1932 reflections
127 parameters
H-atom parameters constrained
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: WinAFC Diffractometer Control Software (Rigaku, 1999 ▶); cell refinement: WinAFC Diffractometer Control Software; data reduction: WinAFC Diffractometer Control Software; program(s) used to solve structure: SIR2008 (Burla et al., 2007 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CrystalStructure (Rigaku, 2010 ▶); software used to prepare material for publication: CrystalStructure.

Supplementary Material

Crystal structure: contains datablock(s) General, I. DOI: 10.1107/S1600536814012483/zl2591sup1.cif

e-70-0o743-sup1.cif^{(23.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814012483/zl2591Isup2.hkl

e-70-0o743-Isup2.hkl^{(95.1KB, hkl)}

Click here for additional data file.^{(3.3KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814012483/zl2591Isup3.cml

Additional supporting information: crystallographic information; 3D view; checkCIF report

Acknowledgments

The University of Shizuoka is acknowledged for instrumental support.

supplementary crystallographic information

S1. Comment

Halogen bonds have been found to occur in organic, inorganic, and biological systems, and have recently attracted much attention in medicinal chemistry, chemical biology and supramolecular chemistry (Auffinger et al., 2004, Metrangolo et al., 2005, Wilcken et al., 2013, Sirimulla et al., 2013). We have recently reported the crystal structures of chlorinated 3-formylchromone derivatives 6,8-dichloro-4-oxochromene-3-carbaldehyde (Ishikawa & Motohashi, 2013, Fig.2 (top)) and 6-chloro-4-oxo-4H-chromene-3-carbaldehyde (Ishikawa, 2014, Fig.2 (middle)). It was found that a halogen bond is formed for 6,8-dichloro-4-oxochromene-3-carbaldehyde between the formyl oxygen atom and the chlorine atom at the 8-position, but none is formed for 6-chloro-4-oxo-4H-chromene-3-carbaldehyde between the formyl oxygen atom and the chlorine atom at the 6-position. As part of our interest in this type of chemical bonding, we herein report the crystal structure of a monochlorinated 3-formylchromone derivative 8-chloro-4-oxo-4H-chromene-3-carbaldehyde. The objective of this study is to reveal whether halogen bond(s) can be formed in the crystal of the title compound with the chlorine atom at 8-position and without a halogen atom at 6-position.

The mean deviation of the least-square planes for the non-hydrogen atoms is 0.0316 Å, and the largest deviation is 0.0598 (14) Å for C1. These mean that these atoms are essentially coplanar. In the crystal, the molecules are stacked with their inversion-symmetry equivalent along the b-axis direction [centroid–centroid distance between the pyran and benzene rings of the 4H-chromene units = 3.566 (2) Å, symmetry operator i: -x + 1, -y + 1, -z + 2], as shown in Fig.1.

The distance between the chlorine atom and the formyl oxygen atom of the translation-symmetry equivalent [Cl1···O3ⁱⁱ = 3.301 (2) Å, ii: x, y, z + 2] is nearly equal to the sum of their van der Waals radii [3.27 Å] (Bondi, 1964), as shown at the bottom of Fig.2. Thus, it is concluded that there is no halogen bond in the title compound. On the other hand, the angles of C–Cl···O (157.15 (6)°) and Cl···O=C (129.24 (10)°) are close to those of 6,8-dichloro-4-oxochromene-3-carbaldehyde, (C–Cl···O (160.4 (3)°) and Cl···O=C (138.7 (4)°), Fig.2(top)). Thus, the significance of the vicinal electron-withdrawing substituent in forming of a halogen bond (Wilcken et al., 2013) is crystallographically validated from the fact that halogen bonding is observed in the dichlorinated 3-formylchromone, but is not observed in the monochlorinated ones. These results should be invaluable for rational drug design.

S2. Experimental

2-Hydroxy-3-chloroacetophenone was prepared according to a literature method (Fumagalli et al., 2012). To a solution of 2-hydroxy-3-chloroacetophenone (11.1 mmol) in N,N-dimethylformamide (30 ml) was added dropwise POCl₃ (27.7 mmol) for 5 min at 0 °C. After the mixture was stirred for 16 h at room temperature, water (50 ml) was added. The precipitates were collected, washed with water, and dried in vacuo (yield: 72%). ¹H NMR (400 MHz, DMSO-d₆): δ = 7.58 (t, 1H, J = 7.8 Hz), 8.07 (d, 1H, J = 7.8 Hz), 8.10 (d, 1H, J = 7.8 Hz), 9.03 (s, 1H), 10.12 (s, 1H). DART-MS calcd for [C₁₀H₅Cl₁O₃ + H⁺]: 209.001, found 209.014. Single crystals suitable for X-ray diffraction were obtained by slow evaporation of a chloroform solution of the title compound at room temperature.