3,5,7-Trimeth­oxy-2-(4-methoxy­phen­yl)-4H-1-benzopyran-4-one

Thammarat Aree; Pattara Sawasdee

doi:10.1107/S1600536809040938

. 2009 Oct 10;65(Pt 11):o2706. doi: 10.1107/S1600536809040938

3,5,7-Trimethoxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one

Thammarat Aree ^a,^*, Pattara Sawasdee ^a

PMCID: PMC2971014 PMID: 21578306

Abstract

In the title compound, C₁₉H₁₈O₆, also known as 3,4′,5,7-tetramethoxyflavone, the dihedral angle between the benzopyran-4-one group and the attached benzene ring is 11.23 (8)°. An intramolecular C—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, molecules are linked into a two-dimensional network parallel to (0 Inline graphic 1) by intermolecular C—H⋯O hydrogen bonds, which generate R ₄ ⁴(20), R ₄ ⁴(12) and R ₂ ²(14) ring motifs. Adjacent networks interact by π–π interactions between the pyran ring and its methoxyphenyl substituent [centroid–centroid distance = 3.5267 (8) Å].

Related literature

For related structures, see: Aree et al. (2009 ▶) and the Cambridge Structural Database [Allen (2002 ▶); Bruno et al. (2002 ▶)]. For the graph-set description of hydrogen-bond patterns, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

C₁₉H₁₈O₆
M _r = 342.33
Triclinic,
a = 8.7854 (3) Å
b = 9.2743 (4) Å
c = 10.6950 (4) Å
α = 70.749 (1)°
β = 81.448 (1)°
γ = 83.078 (1)°
V = 811.15 (5) Å³
Z = 2
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 298 K
0.40 × 0.22 × 0.18 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.839, T _max = 0.946
5901 measured reflections
3930 independent reflections
2827 reflections with I > 2σ(I)
R _int = 0.023

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.131
S = 1.06
3930 reflections
230 parameters
H-atom parameters constrained
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and Mercury (Macrae et al. 2006 ▶).; software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809040938/ci2932sup1.cif

e-65-o2706-sup1.cif^{(20.4KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809040938/ci2932Isup2.hkl

e-65-o2706-Isup2.hkl^{(192.6KB, hkl)}

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
C15—H15⋯O5	0.93	2.23	2.8690 (18)	126
C17—H17B⋯O2ⁱ	0.96	2.48	3.2674 (19)	139
C17—H17B⋯O3ⁱ	0.96	2.61	3.458 (2)	148
C18—H18B⋯O6ⁱⁱ	0.96	2.57	3.530 (2)	173
C19—H19C⋯O5ⁱⁱⁱ	0.96	2.51	3.457 (2)	170

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

Acknowledgments

This work was supported by the Department of Chemistry and Research Funds from the Faculty of Science, Chulalongkorn University to TA and by the Thailand Research Fund and the Commission on Higher Education (grant No. MRG4980018) to PS.

supplementary crystallographic information

Comment

The title compound, (I), (3,5,7-trimethoxy-2-(4-methoxyphenyl)-4H- 1-benzopyran-4-one or 3,4',5,7-tetramethoxyflavone), (Fig.1), is a secondary metabolite that was isolated from a Thai medicinal plant, Kaempferia parviflora. Several flavones have also been isolated from this plant and their crystal structures have been reported, for example see Aree et al. (2009) and references cited therein. Here, we report the crystal structure of another flavone in an anhydrous form having no strong hydrogen bond donor. Weak C—H···O hydrogen bonds play a key role in stabilizing the crystal lattice.

The molecular structure of (I) deviates from a planar geometry; the interplanar angle between the benzopyran-4-one group and the attached phenyl group is 11.23 (8)° (Fig. 1). A search in the Cambridge Structural Database [Version 1.11 (Allen, 2002); CONQUEST (Bruno et al., 2002)] indicate that this feature is frequently observed . The three methoxy C16, C17 and C19 atoms slightly deviate from the mean planes of the attached benzopyran or phenyl rings by 0.288 (3), -0.119 (3) and 0.355 (3) Å whereas atom C18 deviates from the benzopyran plane by -0.933 (3) Å. The corresponding values of torsion angles are C16—O4—C3—C2 = 3.0 (2)°, C17—O3—C5—C4 = 0.4 (2)°, C19—O6—C13—C12 = -15.9 (2)° and C18—O5—C8—C9 = 111.09 (17)°. The flavone molecule is stabilized by an intramolecular C15—H···O5 hydrogen bond that generates an S(6) ring motif (Bernstein et al., 1995).

In the crystal, molecules are linked to form a ribbon-like structure by intermolecular C18—H18B···O6ⁱⁱ and C19—H19C···.O5ⁱⁱⁱ hydrogen bonds, generating R₂²(20) and R₄⁴(12) ring motifs (Bernstein et al., 1995) (Fig. 2). The adjacent inversion-related ribbons are cross-linked into a two-dimensional network parallel to the (011) by intermolecular C17—H17B···O2ⁱ and C17—H17B···O3ⁱ hydrogen bonds, generating R₂²(14) ring motifs (Bernstein et al., 1995) (Fig. 3). The crystal structure is further stabilized by π–π interactions (Fig. 4) between O1/C1/C6-C9 and C10-C15 rings of the molecules in adjacent networks, with a centroid-to-centroid distance of 3.5267 (8) Å.

Experimental

The title compound, (I), was extracted from Kaempferia parviflora, a medicinal plant from the north-east of Thailand. Single crystals of (I) were obtained by slow evaporation of a methanol–water (1:1, v/v) solution at room temperature.