3-(3-Meth­oxy­benzyl­idene)chroman-4-one

Kaalin Gopaul; Mahidansha Shaikh; Deresh Ramjugernath; Neil A Koorbanally; Bernard Omondi

doi:10.1107/S160053681200949X

. 2012 Mar 10;68(Pt 4):o1006. doi: 10.1107/S160053681200949X

3-(3-Methoxybenzylidene)chroman-4-one

Kaalin Gopaul ^a, Mahidansha Shaikh ^a, Deresh Ramjugernath ^b, Neil A Koorbanally ^a, Bernard Omondi ^a,^*

PMCID: PMC3343972 PMID: 22589881

Abstract

In the title compound, C₁₇H₁₄O₃, the dihedral angle between the methoxybenzene unit and the benzene ring of the chromanone system is 64.12 (3)°. The crystal structure is stabilized by weak C—H⋯O interactions.

Related literature

For the preparation, see: Shaikh et al. (2011 ▶). For related structures, see: Kirkiacharian et al. (1984 ▶); Marx et al. (2008 ▶); Suresh et al. (2007 ▶); Chantrapromma et al. (2006 ▶); Augustine et al. (2008 ▶). For the biological activity of this class of compound, see: du Toit et al. (2010 ▶).

Experimental

Crystal data

C₁₇H₁₄O₃
M _r = 266.28
Monoclinic,
a = 12.4143 (9) Å
b = 6.7141 (5) Å
c = 16.0031 (10) Å
β = 98.658 (4)°
V = 1318.67 (16) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 446 K
0.28 × 0.21 × 0.05 mm

Data collection

Nonius KappaCCD diffractometer
4414 measured reflections
2315 independent reflections
1662 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.112
S = 1.00
2315 reflections
182 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: COLLECT (Nonius, 1998 ▶); cell refinement: DENZO-SMN (Otwinowski & Minor, 1997 ▶); data reduction: DENZO-SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S160053681200949X/fj2528sup1.cif

e-68-o1006-sup1.cif^{(23.2KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681200949X/fj2528Isup2.hkl

e-68-o1006-Isup2.hkl^{(111.5KB, hkl)}

Supplementary material file. DOI: 10.1107/S160053681200949X/fj2528Isup3.cml

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

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2B⋯O1ⁱ	0.97	2.54	3.3808 (19)	145
C18—H18B⋯O3ⁱⁱ	0.96	2.50	3.4227 (19)	161

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

Acknowledgments

We thank the University of KwaZulu-Natal, the National Research Foundation (NRF) and the South African Research Chairs initiative of the Department of Science and Technology for financial support and Ms Hong Su for the data collection.

supplementary crystallographic information

Comment

The title compound, 3-(3-Methoxybenzylidene)-chroman-4-one, 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). Homoisoflavonoids may be categorized into four groups depending on the type of structural backbone present. The four groups are 3-benzylidene-4-chromanones, of which the title compound belongs to as well as the 3-benzyl-4-chromanones, 3-benzyl-3-hydroxy-4-chromanones and scillascillins (du Toit et al., 2010).

This compound may undergo chemical conversion into the (E)- and (Z)-isomers (Kirkiacharian et al., 1984). The 3-benzylidene-4-chromanones have been shown to display a wide range of biological activities (du Toit et al., 2010). The most commonly used procedure for the synthesis of homoisoflavoinoids involves the condensation of chroman-4-one with an aromatic aldehyde in the presence of an acidic or basic catalyst (Shaikh et al., 2011).

In the molecular structure, the dihedral angle between the methoxybenzene moeity and the benzene ring of the chromanone moiety is 64.12 (3) °.The Chromanone moiety is fused with a phenyl ring and adopts a half chair conformation (Fig 1). The molecule of (I) is stablized by two weak C—H···O intramolecular interactions (Table 1).

Experimental

A mixture of chroman-4-one (1 g, 6.749 mmol), 3-methoxybenzaldehyde (1.103 g, 8.099 mmol) and 10–15 drops of piperidine was heated at 80°C for 20 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 85–86°C.

¹H NMR: δ (ppm): 3.83 (3H, s, OCH₃), 5.36 (2H, d, J = 1.72 Hz, 2H-2), 6.82 (1H, s, H-2'), 6.87 (1H, d, J = 7.60 Hz, H-6'), 6.93 (2H, m, H-8, H-4'), 7.05 (1H, t, J = 7.52 Hz, H-6), 7.34 (1H, t, J = 7.92 Hz, H-5'), 7.47 (1H, t, J = 8.52 Hz, H-7), 7.82 (1H, s, H-9), 8.00 (1H, dd, J = 7.82, 1.46 Hz, H-5). ¹³C NMR: δ (ppm): 55.36 (OCH₃), 67.66 (C-2), 115.06 (C-4'), 115.42 (C-2'), 117.93 (C-8), 121.92 (C-6), 122.02 (C-4a), 122.28 (C-6'), 127.96 (C-5), 129.76 (C-5'), 131.15 (C-3), 135.69 (C-1'), 135.90 (C-7), 137.40 (C-9), 159.69 (C-3'), 161.18 (C-8a), 182.23(C-4).