2,3,5-Triphenyl­pyrazine

N Anuradha; A Thiruvalluvar; K Pandiarajan; S Chitra; R J Butcher

doi:10.1107/S1600536808041627

. 2008 Dec 13;65(Pt 1):o106. doi: 10.1107/S1600536808041627

2,3,5-Triphenylpyrazine

N Anuradha ^a, A Thiruvalluvar ^a,^*, K Pandiarajan ^b, S Chitra ^b, R J Butcher ^c

PMCID: PMC2968030 PMID: 21581569

Abstract

In the title molecule, C₂₂H₁₆N₂, the pyrazine ring deviates very slightly from planarity [maximum deviation 0.044 (3) Å], tending towards a twist-boat conformation. The phenyl ring at position 3 makes dihedral angles of 64.0 (2) and 45.8 (2)°, respectively, with the phenyl rings at positions 2 and 5. The dihedral angle between the phenyl rings at positions 2 and 5 is 49.7 (2)°. A C—H⋯π interaction is found in the crystal structure, but no classical hydrogen bonds form.

Related literature

For the biological properties of pyrazines, see: Foks et al. (2004 ▶); Premkumar & Govindarajan (2005 ▶); Sondhi et al. (2005 ▶).

Experimental

Crystal data

C₂₂H₁₆N₂
M _r = 308.37
Orthorhombic,
a = 15.563 (2) Å
b = 6.2005 (9) Å
c = 16.845 (3) Å
V = 1625.5 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 296 (2) K
0.44 × 0.35 × 0.21 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.968, T _max = 0.985
17890 measured reflections
1730 independent reflections
1109 reflections with I > 2σ(I)
R _int = 0.091

Refinement

R[F ² > 2σ(F ²)] = 0.050
wR(F ²) = 0.129
S = 1.02
1730 reflections
218 parameters
1 restraint
H-atom parameters constrained
Δρ_max = 0.13 e Å⁻³
Δρ_min = −0.13 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT-NT (Bruker, 2004 ▶); data reduction: SAINT-NT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶); software used to prepare material for publication: PLATON (Spek, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808041627/wn2297sup1.cif

e-65-0o106-sup1.cif^{(21.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808041627/wn2297Isup2.hkl

e-65-0o106-Isup2.hkl^{(83.5KB, 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
C53—H53⋯Cgⁱ	0.93	2.98	3.909 (5)	174

Open in a new tab

Symmetry code: (i) Inline graphic . Cg is the centroid of the C21–C26 phenyl ring.

Acknowledgments

AT thanks the UGC, India, for the award of a Minor Research Project [File No. MRP-2355/06(UGC-SERO), Link No. 2355, 10/01/2007]. RJB acknowledges the NSF–MRI program for funding to purchase the X-ray CCD diffractometer.

supplementary crystallographic information

Comment

Pyrazines are heterocycles which exhibit nutty, roasted or earth flavouring agents. 2-Cyanopyrazine derivatives show anticancer, anti-inflammatory and analgesic activities (Sondhi et al., 2005). Pyrazine derivatives exhibit tuberculostatic activity (Foks et al., 2004) and antimicrobial activity (Premkumar & Govindarajan, 2005).

In the title molecule, C₂₂H₁₆N₂, (Fig. 1), the pyrazine ring deviates very slightly from planarity, tending towards a twist-boat conformation. The phenyl ring at position 3 makes dihedral angles of 64.0 (2)° and 45.8 (2)° with the phenyl rings at positions 2 and 5, respectively. The dihedral angle between the phenyl rings at positions 2 and 5 is 49.7 (2)°. A C53—H53···π interaction involving the phenyl (C21–C26) ring at position 2 is found in the crystal structure, but no classical hydrogen bonds.

Experimental

To a homogeneous solution of benzil (1.05 g, 0.005 mol) and 1-phenylethanediamine dihydrochloride (1.04 g, 0.005 mol) in ethanol, sodium acetate trihydrate (2.04 g, 0.015 mol) was added. The precipitated sodium chloride was filtered off and the filtrate was refluxed for 2 h. On completion of the reaction, as indicated by TLC, the reaction mixture was poured into crushed ice and the resulting solid was filtered off and purified by column chromatography on silica gel. Elution with benzene: petroleum ether (4:1 v/v) at 333–353 K gave the product in pure form. Yield 1.6 g (80%).