2-(4-Methyl­phen­yl)-7-(2-methyl­prop­oxy)-4H-chromen-4-one–6-chloro-2-(4-methyl­phen­yl)-7-(2-methyl­prop­oxy)-4H-chromen-4-one (19/1)

Vijay M Barot; Mukesh M Jotani; Jeshal G Maheta

doi:10.1107/S1600536812033430

. 2012 Jul 28;68(Pt 8):o2582–o2583. doi: 10.1107/S1600536812033430

2-(4-Methylphenyl)-7-(2-methylpropoxy)-4H-chromen-4-one–6-chloro-2-(4-methylphenyl)-7-(2-methylpropoxy)-4H-chromen-4-one (19/1)

Vijay M Barot ^a, Mukesh M Jotani ^b,^*, Jeshal G Maheta ^a

PMCID: PMC3415021 PMID: 22905008

Abstract

The title co-crystal, 0.95C₂₀H₂₀O₃·0.05C₂₀H₁₉ClO₃, arises as the chloride carried over during the synthesis shares a position with an aromatic H atom; the partial occupancies are 0.947 (2) and 0.053 (2) for H and Cl, respectively. The molecular structure is stabilized by intramolecular C—H⋯O contacts, forming pseudo five- and six-membered rings with S(5) and S(6) graph-set motifs, respectively. The crystal structure features π–π stacking interactions between the centroids of the central fused ring systems [centroid–centroid distance = 3.501 (2) Å].

Related literature

For background to flavones, see: Hollman et al. (1997 ▶); Yao et al. (2004 ▶). For the biological activity of flavones, see: Harborne & Williams (2000 ▶); Khan & Hasan (2003 ▶); Qin et al. (2008 ▶); Mota et al. (2009 ▶); Prakash et al. (2009 ▶). For hydrogen-bond motifs, see: Bernstein et al. (1995 ▶).

Experimental

Crystal data

0.95C₂₀H₂₀O₃·0.05C₂₀H₁₉ClO₃
M _r = 310.19
Triclinic,
a = 9.0371 (2) Å
b = 9.6216 (2) Å
c = 11.0308 (3) Å
α = 75.171 (2)°
β = 65.865 (2)°
γ = 69.833 (1)°
V = 814.20 (4) Å³
Z = 2
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.30 × 0.20 × 0.20 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.973, T _max = 0.982
18174 measured reflections
3847 independent reflections
2737 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.048
wR(F ²) = 0.136
S = 1.06
3847 reflections
219 parameters
H-atom parameters constrained
Δρ_max = 0.34 e Å⁻³
Δρ_min = −0.17 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: APEX2 and SAINT (Bruker, 2004 ▶); data reduction: SAINT and XPREP (Bruker, 2004 ▶); program(s) used to solve structure: SIR92 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: PLATON (Spek, 2009 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812033430/tk5116sup1.cif

e-68-o2582-sup1.cif^{(26.5KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812033430/tk5116Isup2.hkl

e-68-o2582-Isup2.hkl^{(184.7KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812033430/tk5116Isup3.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
C19—H19⋯O3	0.93	2.38	2.702 (2)	100
C1—H1A⋯O1	0.96	2.58	2.900 (2)	100

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Acknowledgments

The authors thank the Department of Science and Technology (DST) and SAIF, IIT Madras, Chennai, India, for the intensity data collection.

supplementary crystallographic information

Comment

Flavones can be considered as the derivatives of a parent compound 2-phenylchromen containing varying degrees of hydroxylation and methoxylation (Yao et al., 2004). Also, flavones and their derivatives at different oxidation level are well known naturally occurring oxygen-containing potent anti-oxidant heterocyclic compounds as they chelate ions, scavenge oxygen free radicals and prevent the oxidation of low density lipoprotein (Hollman et al., 1997). Both natural and synthetic flavones possess a wide spectrum of biological activities such as anti-bacterial, anti-fungal, anti-inflammatory, anti-cancer, etc. (Prakash et al., 2009; Mota et al., 2009; Qin et al., 2008; Khan & Hasan, 2003). The continuous search for the synthesis of new derivatives in this group due to their medicinal importance (Harborne & Williams, 2000) is the main motivation for the study of title flavone molecule. In view of their importance, the title compound, 2-(4-methylphenyl)-7-(2-methylpropoxy)-4H-chromen-4-one (I) was synthesized and its crystal structure studied.

The molecular structure of (I), Fig. 1, consists of a central chromen ring extended by a toluene ring on one side and a propoxy moiety on other side. The bicyclic chromen ring is almost coplanar with C8, C12 and C13 atoms have maximum respective deviations of -0.205 (16), 0.0185 (16) and 0.158 (15) Å with respect to least square plane through it. The fractional chlorine atom remains in the molecule of (I) during the synthesis and its presence is confirmed during the structural refinement as it shares a position with the aromatic hydrogen H19 atom; the partial occupancies are 0.947 (2) and 0.053 (2) for H19 and Cl1 atoms, respectively. In the absence of hydrogen bonds, the crystal structure of (I) is stabilized by intramolecular short C—H···O contacts forming pseudo five- and six-membered rings of S(5) and S(6) graph-set motif (Bernstein et al., 1995), Table 1, and by π—π stacking interactions between symmetry related fused chromen rings (Cg1—Cg2 (2 - x, -y, 1 - z) = 3.501 (2) Å; Cg1 = C5—C10 and Cg2 = O3/C9/C8/C11—C13), Fig. 2.

Experimental

(2E)-1-[2-Hydroxy-4-(2-methylpropoxy)phenyl]-3-(4-methylphenyl)prop-2-ene-1-one (0.01 mol) was dissolved in DMSO (30 ml) and iodine, in crystalline powder form, was added. The mixture was then heated at about 140–145 °C for 1 h and the reaction was monitored by continuous TLC. The resulting solution was cooled and diluted with water after the completion of reaction. Excess iodine was removed by filtering and washing the product with 20% aqueous sodium bisulphite. The crude product was then purified by column chromatography using toluene-ethyl acetate (10:1) as the mobile phase and a silica gel as the stationary phase. The melting point was measured on an Electro thermal 9200 apparatus and is uncorrected (Yield: 68%, M.pt: 442 K). The colourless block-shaped crystals of the title compound were obtained by re-crystallization from its ethanol solution.