1-Meth­oxy-3-o-tolyl­bicyclo­[2.2.2]oct-5-ene-2,2-dicarbonitrile

Orhan Büyükgüngör; Serkan Yavuz; Mustafa Odabaşoğlu; Özgür Pamir; Yılmaz Yıldırır

doi:10.1107/S1600536809032474

. 2009 Aug 22;65(Pt 9):o2208. doi: 10.1107/S1600536809032474

1-Methoxy-3-o-tolylbicyclo[2.2.2]oct-5-ene-2,2-dicarbonitrile

Orhan Büyükgüngör ^a,^*, Serkan Yavuz ^b, Mustafa Odabaşoğlu ^c, Özgür Pamir ^b, Yılmaz Yıldırır ^b

PMCID: PMC2970108 PMID: 21577609

Abstract

In the title compound, C₁₈H₁₈N₂O, the cyclohexene and cyclohexane rings of the bicyclo[2.2.2]oct-5-ene unit adopt distorted boat conformations. In the crystal, molecules exist as C—H⋯N hydrogen-bonded centrosymmetric R ₂ ²(14) dimers, which are further linked by C—H⋯π interactions.

Related literature

For general background, see: Çete et al. (2007 ▶); Corey (2002 ▶); Kurt & Anker (1998 ▶); Mamedov et al. (2007 ▶); Özkan et al., (2007 ▶); Potapov (1988 ▶). For the synthesis, see: Zhang et al. (2006 ▶). For graph-set notation, see: Bernstein et al. (1995 ▶); Etter (1990 ▶). For ring conformations, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C₁₈H₁₈N₂O
M _r = 278.34
Triclinic,
a = 7.5922 (6) Å
b = 9.5026 (8) Å
c = 11.5584 (9) Å
α = 91.201 (7)°
β = 107.206 (6)°
γ = 110.856 (6)°
V = 736.89 (10) Å³
Z = 2
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 296 K
0.48 × 0.42 × 0.17 mm

Data collection

Stoe IPDS II diffractometer
Absorption correction: integration (X-RED32; Stoe & Cie, 2002 ▶) T _min = 0.956, T _max = 0.989
8047 measured reflections
3057 independent reflections
2532 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.108
S = 1.05
3057 reflections
192 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Data collection: X-AREA (Stoe & Cie, 2002 ▶); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809032474/ci2877sup1.cif

e-65-o2208-sup1.cif^{(19.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809032474/ci2877Isup2.hkl

e-65-o2208-Isup2.hkl^{(147KB, 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
C12—H12⋯N1ⁱ	0.93	2.70	3.509 (3)	146
C7—H7C⋯Cg1ⁱⁱ	0.96	2.84	3.688 (2)	146

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Symmetry codes: (i) Inline graphic ; (ii) . Cg1 is the centroid of the C1–C6 ring.

Acknowledgments

The authors gratefully acknowledge financial support from the Scientific and Technical Research Council of Turkey (TUBITAK, Project No. 107 T676). We also thank the Turkish Grain Board (TMO) for the supply of thebaine.

supplementary crystallographic information

Comment

The Diels-Alder reactions are among the most useful of all synthetic processes for the construction of complex molecules and, for this reason, they have been studied extensively (Kurt & Anker, 1998). The reaction is easy, rapid and is a key reaction in fundamental organic synthesis. Cycloadducts of asymmetric Diels-Alder reactions have attracted attention owing to their utility in the synthesis of natural compounds (Corey, 2002).

In the conventional Diels-Alder reaction a double bond adds 1,4 to a conjugated diene. The title compound, (I), was prepared by a cycloaddiction reaction from 2-(2-methylbenzylidene) malononitrile and 1-methoxycyclohexa-1,3-diene. Bicyclo[2.2.2]octane and bicycle[2.2.2]octane moieties are essential fragment of many important natural and synthetic biologically active compounds (Potapov, 1988). Both this type bicyclo compounds and many cyano group containing compounds show biological activity (Özkan et al. 2007; Çete et al. 2007). Therefore, synthesis of these compounds in the practically active form is of practical interest (Mamedov et al. 2007).

The overall view and atom-labeling of the molecule of (I) are displayed in Fig. 1. The hydrogen-bonding parameters are given in Table 1 and the packing arrangement of the molecules is illustrated in Fig. 2. In the molecule, cyclohexene rings A(C8/C9/C10/C11/C12/C13) and B(C10/C11/C12/C13/C17/C16), and the cyclohexane ring C(C8/C9/C10/C16/C17/C13) of the bicyclo[2.2.2]oct-5-ene unit all adopt distorted boat conformations. The Cremer and Pople (1975) puckering parameters Q, θ and φ are 0.810 (2) Å, 84.8 (1)° and 111.8 (1)°, respectively for ring A, 0.788 (2) Å, 86.7 (1)° and 186.3 (1)°, respectively for ring B, and 0.906 (2) Å, 88.4 (1)° and 310.3 (1)°, respectively for ring C.

The crystal structure is stabilized by intermolecular C—H···N hydrogen bonds and C—H···π interactions (Table 1). As shown in Fig. 2, the molecules exist as C12—H12···N1 hydrogen-bonded centrosymmetric R₂²(14) dimers (Bernstein et al., 1995; Etter, 1990). The dimers are linked through C7—H7C···π interactions.

Experimental

2-(2-Methylbenzylidene)malononitrile was prepared from 2-methyl benzaldehyde, malononitrile and potassium carbonate according to the literature method (Zhang et al. 2006). For the preparation of the title compound, 1-methoxycyclohexa-1,3-diene (330 mg, 3 mmol) and 2-(2-methylbenzylidene) malononitrile (459 mg, 3 mmol) were dissolved in benzene (20 ml). The reaction mixture was refluxed for 4 h, and monitored by TLC. After evaporation of the solvent, the reaction mixture was separated by column chromatography, using the mixture of hexane-ethyl acetate (1:2) as the eluant. The title compound was recrystallized from methanol in 3 d (m.p. 431–432 K).