(E)-3-[4-(Pent­yloxy)phen­yl]-1-phenyl­prop-2-en-1-one

Asghar Abbas; M Khawar Rauf; Michael Bolte; Aurangzeb Hasan

doi:10.1107/S1600536809016754

. 2009 May 14;65(Pt 6):o1280. doi: 10.1107/S1600536809016754

(E)-3-[4-(Pentyloxy)phenyl]-1-phenylprop-2-en-1-one

Asghar Abbas ^a, M Khawar Rauf ^a, Michael Bolte ^b, Aurangzeb Hasan ^a,^*

PMCID: PMC2969684 PMID: 21583142

Abstract

The title compound, C₂₀H₂₂O₂, crystallizes with two independent molecules in the asymmetric unit. In each molecule, all the non-H atoms lie in a common plane (r.m.s. deviations of 0.098 and 0.079 Å). There is a π–π stacking interaction in the crystal structure. The central aromatic rings of the two molecules, which are stacked head-to-tail one above the other, are separated by centroid-to-centroid distances of 3.872 (13) and 3.999 (10) Å.

Related literature

For background information on chalcones and their properties, see: Achanta et al. (2006 ▶); Zhang et al. (2009 ▶); Tran et al. (2009 ▶); Yagura et al. (2008 ▶); Sarissky et al. (2008 ▶); Tang et al. (2008 ▶); Srivastava et al. (2008 ▶); For bond-length data, see: Allen et al. (1987 ▶). For related structures, see: Rosli et al. (2006 ▶); Harrison et al. (2006 ▶). For the synthesis, see: Wattanasin & Murphy (1980 ▶).

Experimental

Crystal data

C₂₀H₂₂O₂
M _r = 294.38
Monoclinic,
a = 7.4881 (4) Å
b = 21.3067 (11) Å
c = 20.8328 (11) Å
β = 93.974 (4)°
V = 3315.8 (3) Å³
Z = 8
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 173 K
0.38 × 0.22 × 0.22 mm

Data collection

Stoe IPDS II two-circle-diffractometer
Absorption correction: none
25934 measured reflections
5819 independent reflections
3319 reflections with I > 2σ(I)
R _int = 0.086

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.101
S = 0.82
5819 reflections
398 parameters
H-atom parameters constrained
Δρ_max = 0.15 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2001 ▶); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809016754/su2111sup1.cif

e-65-o1280-sup1.cif^{(27.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809016754/su2111Isup2.hkl

e-65-o1280-Isup2.hkl^{(284.9KB, hkl)}

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

Table 1. Selected torsion angles (°).

C11—C1—C2—C3	−177.21 (17)
C2—C1—C11—C12	−13.4 (3)
C2—C1—C11—C16	167.85 (17)
C11A—C1A—C2A—C3A	−170.05 (18)
C2A—C1A—C11A—C12A	−9.5 (3)
C2A—C1A—C11A—C16A	171.52 (17)

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Acknowledgments

AA is grateful to the Higher Education Commission of Pakistan for financial support for his PhD program under scholarship No. IIC–0317109.

supplementary crystallographic information

Comment

Benzylideneacetophenones (α, β-Unsaturated ketones) comprise a class of synthetic and naturally occurring compounds belonging to the flavonoid family of compounds, commonly known as "chalcones". Chalcones and their derivatives are used as precursors for the synthesis of a variety of bioactive organic compounds including heterocyclic compounds. Chalcone analogues have been reported to exhibits potent anticancer activity through inhibition of the proteasome (Achanta et al., 2006), tyrosinase (Zhang et al., 2009) and prostaglandin E-2 (Tranet al., 2009). Naringenin chalcone, the aglycone of isosalipurposide (Yagura et al., 2008) have strong anti-proliferative activity. Some synthetic (Sarissky et al., 2008) and naturally occurring chalcones (Tang et al., 2008) have shown good anticancer activity against Ben-Men-1 human benign meningioma cell line and bladder cancer. Oxygenated chalcones and bischalcones (Srivastava et al.,2008) are a new class of inhibitors of DNA topoisomerase-II of malarial parasites. Here, we report on the crystal structure of the title compound, which was prepared and used as a precursor for the synthesis of heterocyclic compounds.

The molecular structue of the title compound is shown in Fig. 1. The geometrical parameters are normal (Allen et al., 1987) and consistent with those of recently reported chalcone derivatives (Rosli et al., 2006). The asymmetric unit consists of two independent conformers distinctly twisted about the C11—C1 / C11A—C1A and the C1—C2 / C1A—C2A bonds (Table 1), as was also observed for 2-bromo-1-chlorophenyl-3-(4-methoxyphenyl)-2-propen-1-one (Harrison et al., 2006). The dihedral angle between the benzene ring mean planes (C11–C16) and (C21–C26), and (C11A–C16A) and (C21A–C26A) are 12.33 (4) and 7.63 (2)°, respectively. Atoms C1 and O1 deviate from the mean plane (C11–C16) by 0.035 (3) and 0.291 (3) Å, respectively. While atoms C1A and O1A deviated from the mean plane (C11A–C16A) by 0.033 (3) and 0.209 (3) Å, respectively.

In the crystal structure of the title compound the two independent molecules stack head-to-tail (Fig. 2). The central aromatic rings of the two molecules are separated by centroid-to-centroid distances of ca. 3.872 and 3.999 Å.

Experimental

The title compound was synthesized by base catalyzed Claisen–Schmidt condensation reaction (Wattanasin et al., 1980). A mixture of acetophenone (1.20 g, 0.01 mol) and 4-(pentyloxy)benzaldehyde (1.92 g, 0.01 mol) was dissolved in ethanol (50 ml) and then 20 ml of an aqueous solution of potassium hydroxide (5%) was added. The mixture was stirred for 3–4 hr, neutralized with dilute HCl and left to stand for 12 hr. The resulting crude solid mass was collected by filtration and recrystallized from ethanol, yielding crystals of the title compound. Full spectroscopic and physical characterization will be reported elsewhere.