(4aR,8aR)-2,3-Diphenyl-4a,5,6,7,8,8a-hexa­hydro­quinoxaline

Guo-Xi Wang; Heng-Yun Ye

doi:10.1107/S1600536807067505

. 2008 Jan 4;64(Pt 2):o359. doi: 10.1107/S1600536807067505

(4aR,8aR)-2,3-Diphenyl-4a,5,6,7,8,8a-hexahydroquinoxaline

Guo-Xi Wang ^a, Heng-Yun Ye ^a,^*

PMCID: PMC2960268 PMID: 21201391

Abstract

The title molecule, C₂₀H₂₀N₂, is chiral; the absolute configuration follows from the known chirality of the input reagents. In addition to van der Waals forces, C—H⋯π ring interactions are also present. The angle between the planes of the phenyl rings is 65.6 (1)°. The heterocyclic ring of the quinoxaline system has a twist-boat configuration, while the cyclohexane ring has a chair configuration.

Related literature

For examples of the synthesis of non-centrosymmetric solid materials by reactions of chiral organic ligands and inorganic salts, see: Qu et al. (2004 ▶). For the geometric parameters of C=N bonds, see: Figuet et al. (2001 ▶); Kennedy & Reglinski (2001 ▶).

Experimental

Crystal data

C₂₀H₂₀N₂
M _r = 288.38
Orthorhombic,
a = 5.6253 (11) Å
b = 15.402 (3) Å
c = 18.315 (4) Å
V = 1586.8 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 293 (2) K
0.12 × 0.08 × 0.05 mm

Data collection

Rigaku SCXmini diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005 ▶) T _min = 0.901, T _max = 1.000 (expected range = 0.898–0.996)
15676 measured reflections
2134 independent reflections
1880 reflections with I > 2σ(I)
R _int = 0.053

Refinement

R[F ² > 2σ(F ²)] = 0.056
wR(F ²) = 0.132
S = 1.19
2134 reflections
200 parameters
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.13 e Å⁻³

Data collection: CrystalClear (Rigaku, 2005 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997 ▶); molecular graphics: SHELXTL (Sheldrick, 1999 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536807067505/fb2074sup1.cif

e-64-0o359-sup1.cif^{(17KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807067505/fb2074Isup2.hkl

e-64-0o359-Isup2.hkl^{(105KB, hkl)}

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

Table 1. D—H⋯π-ring interactions calculated by PLATON (Spek, 2003 ▶).

Cg1 and Cg2 are the centroids of the phenyl rings C15–C20 and C8–C13, respectively.

D–H⋯Cg	D—H	H⋯Cg	D⋯Cg	D—H⋯Cg
C3—H3A⋯Cg1ⁱ	0.97	2.82	3.761 (4)	164
C4—H4A⋯Cg2ⁱⁱ	0.97	2.94	3.840 (3)	154
C11—H11A⋯Cg1ⁱⁱⁱ	0.93	2.87	3.769 (3)	164

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

This work was supported by a Start-up Grant from Southeast University to HYY.

supplementary crystallographic information

Comment

Presence of chiral centres in organic ligands is important for synthesis of chiral coordination polymers (Qu et al., 2004). We report here the crystal structure of (4aR,8aR)-4a,5,6,7,8,8a-hexahydro-2,3-diphenylquinoxaline (Fig. 1).

The lengths of the C?N double bonds (1.276 (3) and 1.278 (3) Å) are similar as in the following compounds containing the C?N double bonds: tris[(5-bromosalicylidene)aminoethyl]amine (Figuet et al. (2001) and N,N'-bis(salicylidene)-1,4,butanediamine (Kennedy et al.(2001).

Experimental

Benzil (2.10 g, 10.0 mmol) and (1R,2R)-(-)-diaminocyclohexane (1.20 g, 10.5 mmol) were dissolved in methanol (20 ml) containing sulfuric acid (0.08 g) as a catalytic agent. The solution was stirred at room temperature. After 4 h, a yellow precipitate appeared. It was filtered off and washed with chilled methanol (10 ml). The crude product was recrystallized by slow evaporation of the saturated ethanol solution. Yellow block-like crystals with dimensions of tenths of mm were isolated.