Dimethyl 2,2′-[(4-oxo-2-phenyl-4H-chromene-5,7-diyl)dioxy]diacetate: a more densely packed polymorph

Angannan Nallasivam; Munirathinam Nethaji; Nagarajan Vembu; Buckle Jaswant; Nagarajan Sulochana

doi:10.1107/S1600536809001020

. 2009 Jan 14;65(Pt 2):o312–o313. doi: 10.1107/S1600536809001020

Dimethyl 2,2′-[(4-oxo-2-phenyl-4H-chromene-5,7-diyl)dioxy]diacetate: a more densely packed polymorph

Angannan Nallasivam ^a, Munirathinam Nethaji ^b, Nagarajan Vembu ^c,^*, Buckle Jaswant ^d, Nagarajan Sulochana ^a

PMCID: PMC2968396 PMID: 21581920

Abstract

The title molecule, C₂₁H₁₈O₈, crystallizes in two crystal polymorphs, see also Nallasivam, Nethaji, Vembu & Jaswant [Acta Cryst. (2009), E65, o314–o315]. The molecules of both polymorphs differ by the conformation of the oxomethylacetate groups. The title molecules are rather planar compared to the molecules of the other polymorph. In the title molecule, one of the oxomethylacetate groups is disordered (occupancies of 0.6058/0.3942). The structures of both polymorphs are stabilized by C—H⋯O and C—H⋯π interactions. Due to the planarity of the title molecules and similar intermolecular interactions, the title molecules are more densely packed than those of the other polymorph.

Related literature

For a more detailed description of the two polymorphs, see: Nallasivam et al. (2009 ▶). For related structures, see: Wang, Fang et al. (2003 ▶); Wang, Zheng et al. (2003 ▶). For hydrogen bonding, see: Desiraju & Steiner (1999 ▶).

Experimental

Crystal data

C₂₁H₁₈O₈
M _r = 398.35
Triclinic,
a = 7.4290 (15) Å
b = 9.2582 (19) Å
c = 13.480 (3) Å
α = 84.232 (3)°
β = 88.775 (4)°
γ = 82.982 (3)°
V = 915.5 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 293 (2) K
0.34 × 0.28 × 0.22 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1998 ▶) T _min = 0.963, T _max = 0.975
9755 measured reflections
3781 independent reflections
2887 reflections with I > 3σ(I)
R _int = 0.016

Refinement

R[F ² > 2σ(F ²)] = 0.059
wR(F ²) = 0.118
S = 2.47
3781 reflections
268 parameters
H-atom parameters constrained
Δρ_max = 0.40 e Å⁻³
Δρ_min = −0.26 e Å⁻³

Data collection: SMART (Bruker, 1999 ▶); cell refinement: SAINT (Bruker, 1999 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: JANA2000 (Petříček et al., 2000 ▶); molecular graphics: PLATON (Spek, 2003 ▶); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008 ▶) and JANA2000.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809001020/fb2129sup1.cif

e-65-0o312-sup1.cif^{(21KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809001020/fb2129Isup2.hkl

e-65-0o312-Isup2.hkl^{(177.6KB, 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
C8—H8⋯O27ⁱ	0.93	2.38	3.304 (2)	169
C12—H12⋯O1	0.93	2.33	2.664 (2)	101
C15—H15⋯O21Bⁱⁱ	0.93	2.46	3.31 (6)	153
C25—H25B⋯O17ⁱⁱⁱ	0.97	2.56	3.447 (3)	153
C29—H29B⋯O17^iv	0.96	2.50	3.403 (3)	156
C29—H29C⋯O21B^iv	0.96	2.55	3.26 (6)	131
C23B—H23BB⋯Cg1^v	0.96	2.76	3.67 (6)	159 (6)

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) . Cg1 is the centroid of the C11–C16 phenyl ring.

Acknowledgments

AN thanks Dr Naresh Kumar and Dr G. Vengatachalam, School of Chemistry, Bharathidasan University, Tiruchirappalli, and Organica Aromatics Pvt Ltd, Bangalore, India, for providing laboratory facilities.

supplementary crystallographic information

Comment

The importance of the benzopyrans and their derivatives is described in Nallasivam et al. (2009).

The chromene ring is almost planar and similar to that found in the related chromene derivatives (Wang, Zheng et al., 2003; Wang, Fang et al., 2003). The total puckering amplitude of the chromene ring is 0.040 (2)Å. The interplanar angle between the chromene ring and the 2-phenyl ring is 2.90 (6)° thereby indicating the almost coplanar arrangement (Fig. 1). The oxomethylacetate substituent at C7 is slightly distorted from coplanarity as discerned from the interplanar angle of 12.7 (1)°. Such a calculation for the oxomethylacetate group at C5 is not done due to disorder.

The crystal structure is stabilized by the interplay of C–H···O, C–H···π interactions (Tab. 1) as well as π···π-electron interactions. The H-bond distances agree with those reported in literature (Desiraju & Steiner, 1999). There is a π···π-electron interaction between the rings C5\C6···\C10 Cg2 and C11\C12···\C16 [1-x, 2-y, 2-z] whose centroids are at the distance 3.714 (1) Å.

Experimental

Into the round bottom flask a suspension of chrysin (3.93 mmol, 1 g) and potassium carbonate (11.81 mmol, 1.64 g) were deposited and to this mixture dimethylformamide (10 ml) was added. The reaction mixture was heated to 383 K and maintained at this temperature for 2–3 hrs. The reaction mixture was cooled to 353 K. Methyl chloroacetate (15.74 mmol, 1.70 g) was slowly added to the reaction mixture with the help of a dropping funnel. The reaction mixture was kept for 8–9 hrs at 353 K while the reaction was monitored by high pressure liquid chromatography. Once the reaction was completed, the reaction mixture was quenched with water and stirred for 30–45 min at 303 K. The obtained solid was filtered and washed with plenty of water followed by methanol. The wet cake was dried under vacuum at 343 K. The crude product of the title compound, i. e. the more densely packed polymorph, was dissolved in dichloromethane (10 ml) and mixed with equal amount of n-hexane. The clear solution was kept aside for a week without stirring. Diffraction quality prism shaped crystals with average size about 0.30 mm along the longest edge were obtained. The crystals were filtered and washed with n-hexane and dried under vacuum at 70°C. Yield: 85%