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

Wang, G.-X.; Ye, H.-Y.

doi:10.1107/S1600536807067505

organic compounds

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ISSN: 2056-9890

Volume 64| Part 2| February 2008| Page o359

doi:10.1107/S1600536807067505

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

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

^aOrdered Matter Science Research Center, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 210096, People's Republic of China
^*Correspondence e-mail: hyye@seu.edu.cn

(Received 16 November 2007; accepted 18 December 2007; online 4 January 2008)

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, P 2₁ 2₁ 2₁
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[F² > 2σ(F²)] = 0.056
wR(F²) = 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

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
Symmetry codes: (i) $[-{\script{1\over 2}}+x,{\script{3\over 2}}-y,-z]$ ; (ii) $[2-x,{\script{1\over 2}}+y,{\script{1\over 2}}-z]$ ; (iii) $[{\script{1\over 2}}+x,{\script{1\over 2}}-y,-z]$ .

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.

Supporting information

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

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

checkCIF report

Comment top

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).

Related literature top

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 top

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.

Computing details top

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); 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 (Sheldrick, 1999).

Figures top

	Fig. 1. A view of the title compound with the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. The crystal packing of the title compound viewed along the a axis.

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

Crystal data top

C₂₀H₂₀N₂	F(000) = 616
M_r = 288.38	D_x = 1.207 Mg m⁻³
Orthorhombic, P2₁2₁2₁	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 3447 reflections
a = 5.6253 (11) Å	θ = 3.4–27.5°
b = 15.402 (3) Å	µ = 0.07 mm⁻¹
c = 18.315 (4) Å	T = 293 K
V = 1586.8 (5) Å³	Block, yellow
Z = 4	0.12 × 0.08 × 0.05 mm

Data collection top

Rigaku SCXmini diffractometer	2134 independent reflections
Radiation source: fine-focus sealed tube	1880 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.053
Detector resolution: 13.6612 pixels mm^-1	θ_max = 27.6°, θ_min = 3.5°
ω scans	h = −7→7
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −19→20
T_min = 0.901, T_max = 1.000	l = −23→23
15676 measured reflections

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F² > 2σ(F²)] = 0.056	H-atom parameters constrained
wR(F²) = 0.132	w = 1/[σ²(F_o²) + (0.0548P)² + 0.1683P] where P = (F_o² + 2F_c²)/3
S = 1.19	(Δ/σ)_max < 0.001
2134 reflections	Δρ_max = 0.13 e Å⁻³
200 parameters	Δρ_min = −0.13 e Å⁻³
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
80 constraints	Extinction coefficient: 0.010 (2)
Primary atom site location: structure-invariant direct methods

Crystal data top

C₂₀H₂₀N₂	V = 1586.8 (5) Å³
M_r = 288.38	Z = 4
Orthorhombic, P2₁2₁2₁	Mo Kα radiation
a = 5.6253 (11) Å	µ = 0.07 mm⁻¹
b = 15.402 (3) Å	T = 293 K
c = 18.315 (4) Å	0.12 × 0.08 × 0.05 mm

Data collection top

Rigaku SCXmini diffractometer	2134 independent reflections
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	1880 reflections with I > 2σ(I)
T_min = 0.901, T_max = 1.000	R_int = 0.053
15676 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.056	0 restraints
wR(F²) = 0.132	H-atom parameters constrained
S = 1.19	Δρ_max = 0.13 e Å⁻³
2134 reflections	Δρ_min = −0.13 e Å⁻³
200 parameters

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
C1	0.7959 (6)	0.65882 (17)	0.09928 (14)	0.0512 (7)
H1A	0.6841	0.6288	0.1316	0.061*
C2	0.7195 (7)	0.75311 (18)	0.09215 (16)	0.0645 (8)
H2A	0.5568	0.7557	0.0748	0.077*
H2B	0.8198	0.7822	0.0567	0.077*
C3	0.7381 (7)	0.7995 (2)	0.16551 (17)	0.0699 (9)
H3A	0.7004	0.8605	0.1589	0.084*
H3B	0.6221	0.7752	0.1989	0.084*
C4	0.9823 (7)	0.79159 (18)	0.19858 (17)	0.0659 (9)
H4A	0.9824	0.8180	0.2467	0.079*
H4B	1.0958	0.8227	0.1685	0.079*
C5	1.0578 (7)	0.69734 (16)	0.20496 (15)	0.0592 (8)
H5A	1.2196	0.6944	0.2231	0.071*
H5B	0.9556	0.6678	0.2396	0.071*
C6	1.0429 (5)	0.65242 (16)	0.13156 (14)	0.0511 (7)
H6A	1.1540	0.6811	0.0982	0.061*
C7	1.0503 (5)	0.51148 (15)	0.08549 (13)	0.0476 (6)
C8	1.1020 (5)	0.41698 (17)	0.09128 (14)	0.0503 (7)
C9	1.3120 (6)	0.39001 (19)	0.12512 (15)	0.0583 (7)
H9A	1.4192	0.4307	0.1430	0.070*
C10	1.3595 (7)	0.3016 (2)	0.13178 (17)	0.0673 (9)
H10A	1.4989	0.2834	0.1544	0.081*
C11	1.2019 (7)	0.24103 (19)	0.10512 (18)	0.0684 (9)
H11A	1.2349	0.1821	0.1094	0.082*
C12	0.9971 (7)	0.26799 (18)	0.07241 (16)	0.0656 (9)
H12A	0.8894	0.2270	0.0552	0.079*
C13	0.9474 (6)	0.35524 (17)	0.06444 (15)	0.0565 (7)
H13A	0.8089	0.3725	0.0408	0.068*
C14	0.9184 (5)	0.54805 (16)	0.02031 (14)	0.0464 (6)
C15	0.9435 (5)	0.50996 (15)	−0.05353 (13)	0.0450 (6)
C16	1.1486 (5)	0.46658 (17)	−0.07485 (15)	0.0541 (7)
H16A	1.2679	0.4558	−0.0409	0.065*
C17	1.1760 (6)	0.43947 (19)	−0.14618 (15)	0.0601 (7)
H17A	1.3142	0.4108	−0.1601	0.072*
C18	1.0006 (6)	0.45455 (18)	−0.19673 (15)	0.0600 (8)
H18A	1.0213	0.4365	−0.2448	0.072*
C19	0.7950 (6)	0.49611 (19)	−0.17673 (15)	0.0578 (7)
H19A	0.6759	0.5059	−0.2110	0.069*
C20	0.7659 (6)	0.52341 (16)	−0.10515 (14)	0.0511 (6)
H20A	0.6258	0.5511	−0.0915	0.061*
N1	1.1133 (5)	0.56069 (14)	0.13814 (12)	0.0557 (6)
N2	0.7915 (5)	0.61639 (14)	0.02727 (12)	0.0526 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0596 (17)	0.0478 (14)	0.0463 (13)	0.0055 (13)	0.0037 (13)	−0.0004 (11)
C2	0.084 (2)	0.0535 (16)	0.0564 (16)	0.0211 (17)	−0.0011 (17)	−0.0020 (12)
C3	0.094 (3)	0.0526 (16)	0.0631 (18)	0.0175 (18)	0.0079 (19)	−0.0023 (13)
C4	0.091 (3)	0.0436 (14)	0.0631 (17)	−0.0021 (17)	0.0042 (18)	−0.0010 (13)
C5	0.077 (2)	0.0467 (14)	0.0543 (15)	−0.0056 (16)	−0.0053 (15)	0.0005 (12)
C6	0.0606 (17)	0.0410 (13)	0.0517 (14)	0.0015 (13)	0.0003 (14)	0.0025 (11)
C7	0.0542 (15)	0.0415 (12)	0.0471 (13)	0.0037 (12)	−0.0003 (12)	0.0030 (10)
C8	0.0596 (17)	0.0469 (13)	0.0445 (13)	0.0065 (13)	0.0057 (13)	0.0069 (11)
C9	0.0608 (18)	0.0550 (15)	0.0590 (16)	0.0095 (15)	−0.0028 (14)	0.0039 (13)
C10	0.078 (2)	0.0612 (18)	0.0628 (18)	0.0265 (18)	0.0031 (18)	0.0132 (14)
C11	0.095 (3)	0.0447 (14)	0.0657 (18)	0.0139 (18)	0.0167 (19)	0.0102 (14)
C12	0.085 (2)	0.0454 (14)	0.0665 (18)	−0.0041 (16)	0.0073 (18)	0.0080 (13)
C13	0.0631 (18)	0.0472 (13)	0.0592 (16)	0.0006 (14)	−0.0009 (15)	0.0066 (12)
C14	0.0490 (14)	0.0417 (12)	0.0486 (13)	−0.0007 (12)	−0.0001 (11)	0.0031 (10)
C15	0.0494 (14)	0.0380 (11)	0.0477 (13)	−0.0027 (12)	0.0028 (11)	0.0051 (10)
C16	0.0528 (16)	0.0557 (15)	0.0537 (14)	0.0044 (13)	0.0025 (13)	0.0015 (12)
C17	0.0623 (18)	0.0584 (16)	0.0596 (16)	0.0021 (15)	0.0103 (15)	−0.0048 (14)
C18	0.079 (2)	0.0521 (15)	0.0490 (14)	−0.0030 (16)	0.0042 (15)	−0.0046 (12)
C19	0.0713 (19)	0.0506 (14)	0.0513 (14)	−0.0014 (15)	−0.0106 (15)	0.0051 (12)
C20	0.0562 (16)	0.0431 (13)	0.0539 (14)	0.0002 (13)	−0.0018 (13)	0.0043 (11)
N1	0.0655 (15)	0.0453 (11)	0.0563 (13)	0.0060 (12)	−0.0078 (12)	0.0012 (10)
N2	0.0574 (14)	0.0507 (12)	0.0499 (12)	0.0069 (12)	−0.0034 (11)	0.0012 (10)

Geometric parameters (Å, º) top

C1—N2	1.472 (3)	C9—C10	1.393 (4)
C1—C6	1.513 (4)	C9—H9A	0.9300
C1—C2	1.520 (4)	C10—C11	1.377 (5)
C1—H1A	0.9800	C10—H10A	0.9300
C2—C3	1.525 (4)	C11—C12	1.363 (5)
C2—H2A	0.9700	C11—H11A	0.9300
C2—H2B	0.9700	C12—C13	1.380 (4)
C3—C4	1.506 (6)	C12—H12A	0.9300
C3—H3A	0.9700	C13—H13A	0.9300
C3—H3B	0.9700	C14—N2	1.278 (3)
C4—C5	1.517 (4)	C14—C15	1.481 (3)
C4—H4A	0.9700	C15—C16	1.389 (4)
C4—H4B	0.9700	C15—C20	1.391 (4)
C5—C6	1.514 (4)	C16—C17	1.380 (4)
C5—H5A	0.9700	C16—H16A	0.9300
C5—H5B	0.9700	C17—C18	1.373 (5)
C6—N1	1.472 (3)	C17—H17A	0.9300
C6—H6A	0.9800	C18—C19	1.372 (5)
C7—N1	1.276 (3)	C18—H18A	0.9300
C7—C8	1.488 (3)	C19—C20	1.387 (4)
C7—C14	1.514 (3)	C19—H19A	0.9300
C8—C13	1.379 (4)	C20—H20A	0.9300
C8—C9	1.397 (4)

N2—C1—C6	109.6 (2)	C13—C8—C7	121.7 (3)
N2—C1—C2	110.0 (2)	C9—C8—C7	119.2 (3)
C6—C1—C2	110.8 (3)	C10—C9—C8	119.5 (3)
N2—C1—H1A	108.8	C10—C9—H9A	120.3
C6—C1—H1A	108.8	C8—C9—H9A	120.3
C2—C1—H1A	108.8	C11—C10—C9	120.5 (3)
C1—C2—C3	110.7 (2)	C11—C10—H10A	119.7
C1—C2—H2A	109.5	C9—C10—H10A	119.7
C3—C2—H2A	109.5	C12—C11—C10	119.6 (3)
C1—C2—H2B	109.5	C12—C11—H11A	120.2
C3—C2—H2B	109.5	C10—C11—H11A	120.2
H2A—C2—H2B	108.1	C11—C12—C13	120.9 (3)
C4—C3—C2	112.2 (3)	C11—C12—H12A	119.5
C4—C3—H3A	109.2	C13—C12—H12A	119.5
C2—C3—H3A	109.2	C8—C13—C12	120.4 (3)
C4—C3—H3B	109.2	C8—C13—H13A	119.8
C2—C3—H3B	109.2	C12—C13—H13A	119.8
H3A—C3—H3B	107.9	N2—C14—C15	118.1 (2)
C3—C4—C5	111.3 (3)	N2—C14—C7	120.1 (2)
C3—C4—H4A	109.4	C15—C14—C7	121.7 (2)
C5—C4—H4A	109.4	C16—C15—C20	118.5 (2)
C3—C4—H4B	109.4	C16—C15—C14	121.8 (2)
C5—C4—H4B	109.4	C20—C15—C14	119.6 (2)
H4A—C4—H4B	108.0	C17—C16—C15	120.3 (3)
C6—C5—C4	110.7 (2)	C17—C16—H16A	119.9
C6—C5—H5A	109.5	C15—C16—H16A	119.9
C4—C5—H5A	109.5	C18—C17—C16	120.5 (3)
C6—C5—H5B	109.5	C18—C17—H17A	119.8
C4—C5—H5B	109.5	C16—C17—H17A	119.8
H5A—C5—H5B	108.1	C19—C18—C17	120.3 (3)
N1—C6—C1	110.0 (2)	C19—C18—H18A	119.8
N1—C6—C5	110.5 (2)	C17—C18—H18A	119.8
C1—C6—C5	111.6 (2)	C18—C19—C20	119.6 (3)
N1—C6—H6A	108.2	C18—C19—H19A	120.2
C1—C6—H6A	108.2	C20—C19—H19A	120.2
C5—C6—H6A	108.2	C19—C20—C15	120.9 (3)
N1—C7—C8	118.2 (2)	C19—C20—H20A	119.6
N1—C7—C14	120.7 (2)	C15—C20—H20A	119.6
C8—C7—C14	121.1 (2)	C7—N1—C6	115.7 (2)
C13—C8—C9	119.1 (3)	C14—N2—C1	116.5 (2)

Experimental details

Crystal data
Chemical formula	C₂₀H₂₀N₂
M_r	288.38
Crystal system, space group	Orthorhombic, P2₁2₁2₁
Temperature (K)	293
a, b, c (Å)	5.6253 (11), 15.402 (3), 18.315 (4)
V (Å³)	1586.8 (5)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.07
Crystal size (mm)	0.12 × 0.08 × 0.05

Data collection
Diffractometer	Rigaku SCXmini diffractometer
Absorption correction	Multi-scan (CrystalClear; Rigaku, 2005)
T_min, T_max	0.901, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	15676, 2134, 1880
R_int	0.053
(sin θ/λ)_max (Å⁻¹)	0.652

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.056, 0.132, 1.19
No. of reflections	2134
No. of parameters	200
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.13, −0.13

Computer programs: CrystalClear (Rigaku, 2005), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXTL (Sheldrick, 1999).

D—H···π-ring interactions calculated by PLATON (Spek, 2003) top

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

Symmetry codes:(i) -1/2+x,3/2-y,-z; (ii) 2-x,1/2+y,1/2-z; (iii) 1/2+x,1/2-y,-z. Cg1 and Cg2 are the centroids of the phenyl rings C15–C20 C8–C13, respectively.

Acknowledgements

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

References

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