(E)-1-(Thio­phen-2-yl)-3-(2,4,6-tri­meth­oxy­phen­yl)prop-2-en-1-one

Hoong-Kun Fun; Thitipone Suwunwong; Teerasak Anantapong; Chatchanok Karalai; Suchada Chantrapromma

doi:10.1107/S1600536811042930

. 2011 Oct 29;67(Pt 11):o3074–o3075. doi: 10.1107/S1600536811042930

(E)-1-(Thiophen-2-yl)-3-(2,4,6-trimethoxyphenyl)prop-2-en-1-one

Hoong-Kun Fun ^a,^*,^‡, Thitipone Suwunwong ^b, Teerasak Anantapong ^c, Chatchanok Karalai ^b, Suchada Chantrapromma ^b,^§

PMCID: PMC3247464 PMID: 22220082

Abstract

There are two crystallograpically independent molecules in the asymmetric unit of the title heteroaryl chalcone derivative, C₁₆H₁₆O₄S, with slightly different conformations. The thienyl ring of one molecule is disordered over two positions, with a refined site-occupancy ratio of 0.713 (5):0.287 (5). The molecules are twisted: the dihedral angle between the thienyl and benzene rings is 9.72 (19)° in the ordered molecule, and 3.8 (4) and 2.1 (8)° for the major and minor components, respectively, in the disordered molecule. In both molecules, all three substituted methoxy groups are coplanar with the benzene ring to which they are attached. In each molecule, a weak intramolecular C—H⋯O interaction generates an S(6) ring motif. In the crystal structure, adjacent molecules are linked into a three-dimensional network by weak C—H⋯O interactions.

Related literature

For bond-length data, see: Allen et al. (1987 ▶). For related literature on hydrogen-bond motifs, see: Bernstein et al. (1995 ▶). For related structures, see: Chantrapromma et al. (2009 ▶); Fun et al. (2010 ▶, 2011 ▶); Suwunwong et al. (2009 ▶). For background to and applications of chalcones, see: Go et al. (2005 ▶); Liu et al. (2008 ▶); Ng et al. (2009 ▶); Ni et al. (2004 ▶); Suwunwong et al. (2011 ▶); Tewtrakul et al. (2003 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₁₆H₁₆O₄S
M _r = 304.36
Orthorhombic,
a = 22.8482 (10) Å
b = 31.2117 (13) Å
c = 3.9876 (2) Å
V = 2843.7 (2) Å³
Z = 8
Mo Kα radiation
μ = 0.24 mm⁻¹
T = 100 K
0.60 × 0.06 × 0.05 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.869, T _max = 0.988
20029 measured reflections
8085 independent reflections
5348 reflections with I > 2σ(I)
R _int = 0.065

Refinement

R[F ² > 2σ(F ²)] = 0.066
wR(F ²) = 0.178
S = 1.01
8085 reflections
402 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 1.08 e Å⁻³
Δρ_min = −0.56 e Å⁻³
Absolute structure: Flack (1983 ▶), with 3389 Friedel pairs
Flack parameter: 0.09 (11)

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: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811042930/rz2650sup1.cif

e-67-o3074-sup1.cif^{(29.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811042930/rz2650Isup2.hkl

e-67-o3074-Isup2.hkl^{(395.5KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811042930/rz2650Isup3.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
C2B—H2B⋯O3A	0.93	2.56	3.482 (10)	171
C6A—H6A⋯O4A	0.93	2.22	2.815 (4)	121
C6B—H6B⋯O4B	0.93	2.24	2.824 (4)	120
C15A—H15C⋯O1Bⁱ	0.96	2.51	3.451 (5)	166
C15B—H15F⋯O1Aⁱⁱ	0.96	2.55	3.355 (5)	141
C16B—H16E⋯O3Bⁱⁱⁱ	0.96	2.59	3.401 (4)	142

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

Acknowledgments

The authors thank the Thailand Research Fund (TRF) for a research grant (No. RSA 5280033) and Prince of Songkla University for financial support. The authors also thank Universiti Sains Malaysia for a Research University grant (No. 1001/PFIZIK/811160).

supplementary crystallographic information

Comment

Chalcones have been reported to be responsible for a variety of biological activities such as analgesic, anti-inflammatory, antibacterial and antimycotic (Go et al., 2005; Liu et al., 2008; Ni et al., 2004) as well as HIV-1 protease inhibitory (Tewtrakul et al., 2003) and tyrosinase inhibitory (Ng et al., 2009) properties. Our research on the fluorescent and biological studies of chalcones and heteroaryl chalcone derivatives (Chantrapromma et al., 2009; Suwunwong et al., 2009, 2011) led us to synthesize the title heteroaryl chalcone (I). (I) exhibits fluorescent property (Suwunwong et al., 2011) and possess moderate analgesic property. It was also tested for antibacterial activities but found to be inactive. Herein we report the crystal structure of (I).

There are two crystallographic independent molecules A and B in the asymmetric unit of (I) with different conformations of the methoxy group at para position or at atom C11 and also in bond angles (Fig. 1). The thienyl ring of molecule B is disordered over two orientations with the refined site-occupancy ratio of 0.713 (5):0.287 (5). The thienyl rings in the major and minor components are related by 180° rotation. The molecule of (I) is slightly twisted. The dihedral angle between the thienyl and benzene rings is 9.72 (19)° in molecule A whereas these values are 3.8 (4) and 2.1 (8)° for the major and minor components in the disordered molecule B. The central prop-2-en-1-one bridge (C5–C7/O1) in both molecules is slightly twisted as indicated by the torsion angle O1—C5—C6—C7 = 5.8 (6) and 6.6 (6)° in molecules A and B, respectively. The mean plane through this bridge makes dihedral angles of 8.9 (3) and 2.3 (2)° with the thienyl and benzene rings, respectively, in molecule A whereas the corresponding values are 4.2 (4) and 8.0 (3)° in molecule B for the major component, and 8.2 (8) and 8.0 (3)° for the minor component. In both molecules, all the three substituted methoxy groups are co-planar with the attached benzene with torsion angles C14—O2—C9—C10 = -5.3 (5)°; C15—O3—C11—C12 = 3.7 (5)° and C16—O4—C13—C12 = 0.3 (5)° in molecule A. The corresponding values are 0.6 (5), 178.0 (3) and 0.6 (5)° in molecule B. This also indicates that the methoxy group at the para position (or at atom C11) has different conformations as it points toward the methoxy group at the ortho position at atom C13 (in molecule A) whereas it points toward the ortho methoxy at atom C9 (in molecule B). In each molecule, intramolecular C—H···O weak interaction (Table 1) generates S(6) ring motif (Bernstein et al., 1995). The bond distances agree with the literature values (Allen et al., 1987) and are comparable with those observed in related structures (Chantrapromma et al., 2009; Fun et al., 2010, 2011; Suwunwong et al., 2009).

In the crystal packing (Fig. 2), adjacent molecules are linked into a three-dimensional network by weak C—H···O interactions (Table 1).

Experimental

The title compound was synthesized by the condensation of 2,4,6-trimethoxybenzaldehyde (0.40 g, 2 mmol) with 2-acethylthiophene (0.35 ml, 2 mmol) in ethanol (30 ml) in the presence of 30% NaOH (aq) (5 ml). After stirring for 3 h in ice bath at 278 K, the resulting pale-yellow solid was collected by filtration, washed with distilled water, dried in air and purified by recrystallization from acetone. Pale-yellow needle-shaped single crystals of the title compound suitable for X-ray structure determination were recrystallized from acetone–ethanol (1:1 v/v) by slow evaporation of the solvent at room temperature after several days; m.p. 381–382 K.