(4Z,6Z)-4,6-Bis(4-meth­oxy­benzyl­idene)-2,2-dimethyl-1,3-dioxan-5-one

Mohammad M Mojtahedi; Werner Massa; M Saeed Abaee; A Wahid Mesbah

doi:10.1107/S1600536812000372

. 2012 Jan 11;68(Pt 2):o356. doi: 10.1107/S1600536812000372

(4Z,6Z)-4,6-Bis(4-methoxybenzylidene)-2,2-dimethyl-1,3-dioxan-5-one

Mohammad M Mojtahedi ^a, Werner Massa ^b,^*, M Saeed Abaee ^a,^*, A Wahid Mesbah ^a

PMCID: PMC3275038 PMID: 22346983

Abstract

The title compound, C₂₂H₂₂O₅, crystallizes with two independent molecules in the asymmetric unit, both of which possess pseudo-C _s symmetry. The central 1,3-dioxanone rings have envelope conformations, with the C atom bearing the two methyl groups at the flap. The benzene rings of the methoxybenzylidene units, attached in the 4- and 6-positions on the central 1,3-dioxanone rings, are tilted in the same direction with dihedral angles varying between 8.2 (1) and 18.1 (1)°. The crystal packing is influenced by π-stacking interactions of the parallel displaced type [centroid–centroid distance of 3.723 (1) Å for molecule 1 and 3.884 (1) Å for molecule 2, with ring slippages of 1.432 and 1.613 Å, respectively] and the T-shaped type, with the long molecular axes all aligned along [010].

Related literature

For the synthesis of bisarylidenes of hetero- and homocyclic ketones, see: Abaee et al. (2008a ▶,b ▶). For the crystal structures of similar compounds, see: Abaee et al. (2012 ▶); Nesterov et al. (2011 ▶); Shahani et al. (2010 ▶). For details concerning π-stacking interactions, see: Hunter & Sanders (1990 ▶).

Experimental

Crystal data

C₂₂H₂₂O₅
M _r = 366.39
Monoclinic,
a = 9.2400 (7) Å
b = 40.384 (4) Å
c = 10.1643 (8) Å
β = 91.988 (9)°
V = 3790.5 (6) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 193 K
0.45 × 0.24 × 0.03 mm

Data collection

Stoe IPDS diffractometer
Absorption correction: multi-scan (Blessing, 1995 ▶) T _min = 0.972, T _max = 1.000
28928 measured reflections
6486 independent reflections
3306 reflections with I > 2σ(I)
R _int = 0.068

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.058
S = 0.87
6486 reflections
495 parameters
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.15 e Å⁻³

Data collection: EXPOSE (Stoe & Cie, 1999 ▶); cell refinement: CELL (Stoe & Cie, 1999 ▶); data reduction: INTEGRATE (Stoe & Cie, 1999 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 2011 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812000372/su2363sup1.cif

e-68-0o356-sup1.cif^{(33.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812000372/su2363Isup2.hkl

e-68-0o356-Isup2.hkl^{(311.1KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812000372/su2363Isup3.cml

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

Table 1. Hydrogen-bond geometry (Å, °).

Cg(II_2) is the centroid of ring II (C8–C13) of molecule 2.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C13—H13⋯Cg(II_2)ⁱ	0.95	2.68	3.604 (2)	164

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Symmetry code: (i) Inline graphic .

Acknowledgments

The authors thank the Ministry of Science, Research and Technology of Iran for partial financial support of this work.

supplementary crystallographic information

Comment

In the course of our investigations on the synthesis of bisarylidenes of hetero- and homo-cyclic ketones (Abaee et al., 2008a,b), we herein report on the synthesis and crystal structure of the title compound.

The asymmetric unit of the title compound contains two crystallographically independent molecules (1 and 2, Fig. 1), both having pseudo-C_s symmetry. The bond distances and angles are close to those observed in similar compounds (Abaee et al., 2012; Nesterov et al., 2011; Shahani et al., 2010).

The two independent molecules differ mainly in the degree of bending of the benzene substituents with respect to the almost planar part of the central 1,3-dioxanone ring [plane I: (O1,C1-C3,O2); max. deviation 0.0584 (18) Å in molecule 1, and 0.0166 (18) Å in molecule 2], as shown in Fig. 1. The dihedral angles between this mean plane and the benzene rings, II [C8–C13] and III [C16–C21], are respectively, 17.4 (1) and 18.1 (1)° for molecule 1, and 15.7 (1) and 8.2 (1)° for molecule 2. The benzene rings are inclined to one another by 24.8 (1) in molecule 1, and 13.7 (1)° in molecule 2. Thus, molecule 2 is closer to planarity than molecule 1.

The crystal packing is influenced by π-stacking interactions (Hunter & Sanders, 1990) in a parallel displaced way concerning benzene ring II (C8–C13) and its symmetry equivalent in both independent molecules [symmetry center: -x, -y, -z+1 for molecule 1, and -x+1, -y+2, -z+2 for molecule 2]. The centroid-centroid distances are 3.723 (1) Å for molecule 1, and 3.884 (1) Å for molecule 2, with ring slippages of 1.432 and 1.613 Å, respectively. In addition, a T-shaped π-stacking contact is observed, involving the same benzene ring, II of molecule 1, via a C–H···π interaction with an equivalent benzene ring II of molecule 2 (Table 1). These interactions result in a mutually perpendicular orientation of molecules 1 and 2, and a parallel orientation of the benzene rings II of all molecules of type 1 to each other and all molecules of type 2 to each other. All the long axes of both molecules are oriented parallel to the [010] direction (Fig. 2).

Experimental

A mixture of 2,2-dimethyl-1,3-dioxan-5-one (2 mmol), 4-methoxybenzaldehyde (4 mmol), diethylamine (8 mmol), and MgBr₂.OEt₂ (0.2 mmol, 10 mol%) was stirred at room temperature under an atmosphere of argon for 2 h. The progress of the reaction was checked by TLC using a 1:4 mixture of EtOAc/hexane. At the end of the reaction, the mixture was diluted by CH₂Cl₂ and washed with brine. The organic layer was dried using Na₂SO₄ and concentrated under reduced pressure. The product was isolated (83%) by column chromatography over silicagel using a 1:4 mixture of EtOAc/hexane. The solid product was recrystallized from EtOAc, giving yellow plate-like crystals of the title compound.