(E)-3-(3,5-Dimeth­oxy­phen­yl)-1-(2-meth­oxy­phen­yl)prop-2-en-1-one

Yoongho Lim; Dongsoo Koh

doi:10.1107/S1600536813006302

. 2013 Mar 9;69(Pt 4):o514. doi: 10.1107/S1600536813006302

(E)-3-(3,5-Dimethoxyphenyl)-1-(2-methoxyphenyl)prop-2-en-1-one

Yoongho Lim ^a, Dongsoo Koh ^b,^*

PMCID: PMC3629573 PMID: 23634060

Abstract

In the title molecule, C₁₈H₁₈O₄, the dihedral angle between the benzene rings is 52.52 (7)°. The C=C bond of the central enone group adopts a trans conformation. The relative conformation of the two double bonds in the enone group is s-transoid. In the crystal, molecules are linked by pairs of weak C—H⋯O hydrogen bonds, forming inversion dimers.

Related literature

For the synthesis and biological properties of chalcone derivatives, see: Shin et al. (2012 ▶); Hwang et al. (2011 ▶). For related structures, see: Fun et al. (2012 ▶); Lee et al. (2012 ▶); Prasath et al. (2010 ▶).

Experimental

Crystal data

C₁₈H₁₈O₄
M _r = 298.32
Monoclinic,
a = 12.0925 (18) Å
b = 8.4460 (12) Å
c = 15.109 (2) Å
β = 92.340 (3)°
V = 1541.9 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 200 K
0.24 × 0.14 × 0.10 mm

Data collection

Bruker SMART CCD diffractometer
11328 measured reflections
3865 independent reflections
1544 reflections with I > 2σ(I)
R _int = 0.053

Refinement

R[F ² > 2σ(F ²)] = 0.043
wR(F ²) = 0.132
S = 0.81
3865 reflections
202 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.27 e Å⁻³

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT (Bruker, 2000 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Supplementary Material

Click here for additional data file.^{(24.1KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536813006302/lh5589sup1.cif

e-69-0o514-sup1.cif^{(24.1KB, cif)}

Click here for additional data file.^{(189.5KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813006302/lh5589Isup2.hkl

e-69-0o514-Isup2.hkl^{(189.5KB, hkl)}

Click here for additional data file.^{(6.1KB, cml)}

Supplementary material file. DOI: 10.1107/S1600536813006302/lh5589Isup3.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—H2⋯O1ⁱ	0.95	2.51	3.457 (3)	172

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Symmetry code: (i) Inline graphic .

supplementary crystallographic information

Comment

Chalcones have an α,β-unsaturated carbonyl (enone) group which connects two aromatic rings at the 1,3-positions. Typically, the conformation of enone system is s-cisoid, in which the C═C and C═O double bonds are cis with respect to each other. Few examples of s-transoid conformations have been reported in the literature (Fun et al., 2012; Prasath et al., 2010). As a part of our studies on the substituent effects of chalcones on structures and biological activities (Shin et al., 2012; Hwang et al., 2011), the crystal structure of title compound has been determined.

The molecular structure of the title compound is shown in Fig. 1. The relative conformation of two double bonds of the central enone group is s-transoid. The trans configuration at the C1═C2 bond is reflected in the O1-C1-C2-C3 torsion angle of -168.7 (2)° compared to the value of -1.1 (5)° in a structure with an s-cisoid configuration (Lee et al., 2012). The dihedral angle between the benzene rings is 52.52 (7)°. Two methoxy groups at meta positions of the C4-C6/C8/C9/C11 ring are essentially co-planar with the ring [C8—C6—O2—C7 = -2.4 (3)° and C11—C9—O3—C10 = -1.2 (3)°]. However, the methoxy group at the ortho position of the C12-C17 ring is slightly twisted with respect to the benzene ring [C16—C17—O4—C18 = 21.6 (3)°]. In the crystal, molecules are linked by a pair of weak C—H···O hydrogen bonds to form inversion dimers (Table 1, Fig. 2).

Experimental

To a solution of 3,5-dimethoxybenzaldehyde (415 mg, 2.5 mmol) in 30 ml of ethanol was added 2-methoxyacetophenone (300 mg, 2 mmol) and the temperature was adjusted to around 276 K in an ice-bath. To the cooled reaction mixture was added 2 ml of 50% aqueous KOH solution, and the reaction mixture was stirred at room temperature for 5 h. This mixture was poured into iced water (50 ml) was acidified (pH = 3) with 3 N HCl solution to give a precipitate. Filtration and washing with water afforded crude solid of the title compound (560 mg, 94%). Recrystallization of the solid in ethanol gave single crystals (mp: 353–355 K).