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

Yoshinobu Ishikawa

doi:10.1107/S1600536814007788

. 2014 Apr 12;70(Pt 5):o547. doi: 10.1107/S1600536814007788

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

Yoshinobu Ishikawa ^a,^*

PMCID: PMC4011269 PMID: 24860355

Abstract

In the title compound, C₁₀H₄ClNO₅, the non-H atoms of the 6-chlorochromone unit are coplanar (r.m.s. deviation = 0.017 Å) with the largest deviation from the mean plane [0.031 (2) Å] being found for the C=O C atom. The nitro group (NO₂) is inclined to the chromone unit mean plane by 13.3 (2) °. The formyl group is also twisted with respect to the attached ring [C—C—C—O torsion angles = 10.8 (4) and −171.8 (2)°]. In the crystal, molecules are linked via C-H⋯O hydrogen bonds forming slab-like networks lying parallel to (-301). The slabs are linked by π–π interactions involving the benzene rings of the chromone units [centroid–centroid distance = 3.770 (3) Å].

Related literature

For related structures, see: Ishikawa & Motohashi (2013 ▶); Ishikawa (2014 ▶). For halogen bonding, see: Auffinger et al. (2004 ▶); Metrangolo et al. (2005 ▶); Wilcken et al. (2013 ▶); Sirimulla et al. (2013 ▶).

Experimental

Crystal data

C₁₀H₄ClNO₅
M _r = 253.60
Monoclinic,
a = 18.585 (9) Å
b = 10.4918 (17) Å
c = 11.094 (3) Å
β = 119.23 (3)°
V = 1887.7 (12) Å³
Z = 8
Mo Kα radiation
μ = 0.41 mm⁻¹
T = 100 K
0.38 × 0.22 × 0.18 mm

Data collection

Rigaku AFC-7R diffractometer
2588 measured reflections
2173 independent reflections
1903 reflections with F ² > 2σ(F ²)
R _int = 0.019
3 standard reflections every 150 reflections intensity decay: −0.7%

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.098
S = 1.05
2173 reflections
154 parameters
H-atom parameters constrained
Δρ_max = 0.29 e Å⁻³
Δρ_min = −0.38 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., 1989 ▶); 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/S1600536814007788/tk5305sup1.cif

e-70-0o547-sup1.cif^{(25.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536814007788/tk5305Isup2.hkl

e-70-0o547-Isup2.hkl^{(107KB, hkl)}

Click here for additional data file.^{(3.8KB, cml)}

Supporting information file. DOI: 10.1107/S1600536814007788/tk5305Isup3.cml

CCDC reference: 996005

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1⋯O4ⁱ	0.95	2.53	3.463 (3)	169
C4—H2⋯O2ⁱⁱ	0.95	2.35	3.250 (3)	158
C6—H3⋯O5ⁱⁱⁱ	0.95	2.27	3.191 (3)	164

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

We acknowledge the University of Shizuoka for instrumental support.

supplementary crystallographic information

1. Structural commentary

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 a dichlorinated 3-formylchromone derivative 6,8-dichloro-4-oxochromene-3-carbaldehyde (Ishikawa & Motohashi, 2013) and a monochlorinated 3-formylchromone derivative 6-chloro-4-oxo-4H-chromene-3-carbaldehyde (Ishikawa, 2014). It was found that halogen bonding is observed between the formyl oxygen atom and the chlorine atom at 8-position (Fig. 1, left), and is not observed between any oxygen atom and the chlorine atom at 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 with a nitro group, 6-chloro-8-nitro-4-oxo-4H-chromene-3-carbaldehyde. The objective of this study is to reveal whether halogen bond(s) can be formed in the crystal structure of this compound with an electron-withdrawing group near the chlorine atom at 6-position. It was postulated that the size of a σ hole of the chlorine atom might be large enough to form halogen bond(s) by electron-withdrawing inductive effect of the nitro group (Wilcken et al., 2013).

The mean deviation of the least-square planes for the non-hydrogen atoms of the 6-chlorochromone unit is 0.0228 Å, and the largest deviations is 0.054 (2) Å for C2 (Fig. 2). The nitro group is twisted from this plane as seen in the dihedral angle between the least-squares planes of 14.116 (10) Å. The formyl group is also twisted [C1–C2–C10–O5 = 10.8 (4)° and C3–C2–C10–O5 = -171.8 (2)°], as shown in Fig. 2.

In the crystal, the molecules are linked through stacking interaction along the a axis [centroid–centroid distance between the benzene rings of the chromone units = 3.770 (3) Å], as shown in Fig. 3. The distances between the chlorine atom and the oxygen atoms of the nitro group [3.874 (2) Å], the formyl group [3.535 (3) and 3.666 (2) Å], and the α,β-unsaturated carbonyl group [3.595 (2) Å] are far from halogen bonding. A structure with halogen bonds can be envisaged for the title compound (Fig. 1, right), but it is not observed in the present crystal structure.

2. Synthesis and crystallization

To a solution of 5'-chloro-2'-hydroxy-3'-nitroacetophenone (3.5 mmol) in N,N-dimethylformamide (10 ml) was added dropwise POCl₃ (8.7 mmol) for 5 min at 0 °C. After the mixture was stirred for 14 h at room temperature, water (40 ml) was added. The precipitates were collected, washed with water and dried in vacuo. Recrystallization from ethyl acetate gave yellow crystals (yield: 25%). ¹H NMR (400 MHz, DMSO-d₆): δ = 8.40 (d, 1H, J = 2.4 Hz), 8.71 (d, 1H, J = 2.4 Hz), 9.06 (s, 1H), 10.08 (s, 1H). DART-MS calcd for [C₁₀H₄Cl₁N₁O₅ + H⁺]: 253.978, found 254.005.

3. Refinement

The C(sp²)-bound hydrogen atoms were placed in geometrical positions [C–H 0.95 Å, U_iso(H) = 1.2U_eq(C)], and refined using a riding model.