3-(3,4-Dichloro­benzyl­idene)chroman-4-one

Kaalin Gopaul; Neil Anthony Koorbanally; Mahidansha M Shaikh; Hong Su; Deresh Ramjugernath

doi:10.1107/S1600536812040561

. 2012 Oct 3;68(Pt 11):o3062. doi: 10.1107/S1600536812040561

3-(3,4-Dichlorobenzylidene)chroman-4-one

Kaalin Gopaul ^a, Neil Anthony Koorbanally ^a,^*, Mahidansha M Shaikh ^a, Hong Su ^b, Deresh Ramjugernath ^c

PMCID: PMC3515170 PMID: 23284397

Abstract

The distinctive feature of the structure of the title compound, C₁₆H₁₀Cl₂O₂, is the formation of a zigzag chain along [100] via Cl⋯Cl interactions [3.591 (1) and 3.631 (1) Å]. The chromanone moiety is fused with the benzene ring and adopts a half-chair conformation. The dihedral angle between the benzene ring of the chromanone moiety and the dichlorobenzene plane is 56.14 (8)°.

Related literature

For background to homoisoflavonoids, see: Kirkiacharian et al. (1984 ▶). For a related structure, see: Gopaul et al. (2012 ▶).

Experimental

Crystal data

C₁₆H₁₀Cl₂O₂
M _r = 305.14
Monoclinic,
a = 3.9224 (3) Å
b = 11.5175 (10) Å
c = 28.957 (3) Å
β = 92.270 (2)°
V = 1307.12 (19) Å³
Z = 4
Mo Kα radiation
μ = 0.49 mm⁻¹
T = 173 K
0.16 × 0.12 × 0.11 mm

Data collection

Bruker Kappa Duo APEXII Diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1997 ▶) T _min = 0.925, T _max = 0.948
15291 measured reflections
3258 independent reflections
2611 reflections with I > 2σ(I)
R _int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.089
S = 1.03
3258 reflections
181 parameters
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 2012 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Click here for additional data file.^{(17.3KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812040561/hg5252sup1.cif

e-68-o3062-sup1.cif^{(17.3KB, cif)}

Click here for additional data file.^{(159.8KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812040561/hg5252Isup2.hkl

e-68-o3062-Isup2.hkl^{(159.8KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

We thank the University of KwaZulu-Natal and the South Africa Research Chairs initiative of the Department of Science and Technology for financial support and the National Research Foundation of South Africa for a bursary for KG.

supplementary crystallographic information

Comment

The title compound, 3-(3,4-dichlorobenzylidene)chroman-4-one (C₁₆H₁₀Cl₂O₂), belongs to a class of compounds called homoisoflavonoids, which are C-16, α,β unsaturated carbonyl compounds containing two aromatic rings. They are a group of naturally occurring molecules that are structurally related to isoflavonoids but differ by containing one more carbon atom (Kirkiacharian et al., 1984; Gopaul et al., 2012).

A view of the the title compound is shown in Fig. 1. The chromanone moiety is fused with the benzene ring and adopts a half chair conformation. The dihedral angle between the benzene ring of the chromanone moiety and the dichlorobenzene plane is 56.14 (8)°. The inversion-related molecules are linked into zigzag chains via Cl···Cl interactions between Cl2 at (x, y, z) and Cl2 at (1 - x, 1 - y, 1 - z) and Cl2 at (-x, 1 - y, 1 - z) with distances of 3.591 (1) Å and 3.631 (1) Å respectively. Molecules related by translation along the a axis stack via double π···π interactions of the aromatic rings, with a centroid distance equal to the length of a axis. This feature is illustrated in Fig. 2.

Experimental

A mixture of chroman-4-one (1 g, 6.749 mmol), 3,4-dichlorobenzaldehyde (1.417 g, 8.099 mmol) and 10–15 drops of piperidine was heated at 80°C for 18 hrs. The reaction mixture was monitored for completion by thin layer chromatography. Upon completion, the reaction mixture was cooled, diluted with water and neutralized using 10% HCl. The reaction mixture was extracted with ethyl acetate (3 × 30 ml). The ethyl acetate layers were combined, washed with brine (20 ml), water (2 × 10 ml) and dried over anhydrous magnesium sulfate. The solvent was reduced and the compound purified by column chromatography using silica gel (Merck 9385, 40–63 µm particle size) with a mobile phase of 2% ethyl acetate in hexane to yield the title compound with a m.p. of 165–167 °C.

¹H NMR: δ (p.p.m.): 5.27 (2H, d, J = 1.88 Hz, H-2), 6.96 (1H, d, J = 8.28 Hz, H-8), 7.07 (1H, td, J = 7.52, 0.68 Hz, H-6), 7.12 (1H, dd, J = 8.28, 1.96 Hz, H-6'), 7.38 (1H, d, J = 1.92 Hz, H-2'), 7.49 (1H, ddd, J = 8.72, 7.48, 1.72 Hz, H-7), 7.50 (1H, d, J = 8.40 Hz, H-5'), 7.72 (1H, s, H-9), 8.00 (1H, dd, J = 7.88, 1.64 Hz, H-5)

¹³C NMR: δ (p.p.m.): 67.27 (C-2), 118.00 (C-8), 121.79 (C-4a), 122.16 (C-6), 128.00 (C-5), 128.94 (C-6'), 130.79 (C-5'), 131.41 (C-2'), 132.44 (C-3), 133.15 (C-1'), 133.69 (C-3'), 134.28 (C-4'), 134.55 (C-9), 136.19 (C-7), 161.13 (C-8a), 181.71(C-4)