2-(2-Chloro­phen­yl)-3-methyl-5,6-diphenyl-2,3-dihydro­pyrazine

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

doi:10.1107/S1600536811036336

. 2011 Sep 14;67(Pt 10):o2598. doi: 10.1107/S1600536811036336

2-(2-Chlorophenyl)-3-methyl-5,6-diphenyl-2,3-dihydropyrazine

N Anuradha ^a, S Chitra ^b, A Thiruvalluvar ^a,^*, K Pandiarajan ^c, R J Butcher ^d, J P Jasinski ^e, J A Golen ^e

PMCID: PMC3201404 PMID: 22065837

Abstract

Related literature

For the biological properties of heterocyclic ring systems having a dihydropyrazine nucleus, see: Sondhi et al. (2005 ▶). For the use of dihydropyrazines, with reference to DNA breakage activity, see: Takechi et al. (2011 ▶). For the inhibition of the growth of Escherichia coli, see: Takeda et al. (2005 ▶). For a closely related crystal structure, see: Anuradha et al. (2009 ▶).

Experimental

Crystal data

C₂₃H₁₉ClN₂
M _r = 358.85
Monoclinic,
a = 10.5675 (8) Å
b = 19.7014 (9) Å
c = 10.4207 (7) Å
β = 118.479 (9)°
V = 1907.0 (3) Å³
Z = 4
Cu Kα radiation
μ = 1.82 mm⁻¹
T = 298 K
0.25 × 0.14 × 0.10 mm

Data collection

Oxford Diffraction Xcalibur Eos Gemini diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2010 ▶) T _min = 0.659, T _max = 1.000
22812 measured reflections
3831 independent reflections
3092 reflections with I > 2σ(I)
R _int = 0.052

Refinement

R[F ² > 2σ(F ²)] = 0.052
wR(F ²) = 0.150
S = 1.04
3831 reflections
240 parameters
2 restraints
H-atom parameters constrained
Δρ_max = 0.32 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2010 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis RED (Oxford Diffraction, 2010 ▶); 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, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811036336/wn2451sup1.cif

e-67-o2598-sup1.cif^{(21.9KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811036336/wn2451Isup2.hkl

e-67-o2598-Isup2.hkl^{(184KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811036336/wn2451Isup3.cml

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

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

Cg2, Cg3 and Cg4 are the centroids of the C21–C26, C51–C56 and C61–C66 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C24—H24⋯Cg4ⁱ	0.93	2.80	3.643 (3)	152
C53—H53⋯Cg2ⁱⁱ	0.93	2.99	3.873 (4)	159
C64—H64⋯Cg3ⁱⁱⁱ	0.93	2.88	3.729 (2)	153

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

Acknowledgments

JPJ acknowledges the NSF–MRI program (grant No. CHE1039027) for funds to purchase the X-ray diffractometer.

supplementary crystallographic information

Comment

Heterocyclic ring systems having the dihydropyrazine nucleus have aroused great interest in the past and recent years due to their wide variety of biological properties (Sondhi et al., 2005). Dihydropyrazines are used to break DNA strands and inhibit bacterial growth (Takechi et al., 2011). In addition, these compounds have inhibited the growth of Escherichia coli (Takeda et al., 2005). Anuradha et al. (2009) have reported the crystal structure of 2-methyl-3,5,6-triphenyl-2,3-dihydropyrazine, in which the heterocyclic ring adopts a screw-boat conformation.

In the title molecule, C₂₃H₁₉ClN₂, the heterocyclic ring adopts a screw-boat conformation, with all substituents equatorial. The benzene ring at position 2 makes dihedral angles of 77.88 (12)° and 76.31 (12)° with the phenyl rings at position 5 and 6, respectively. The dihedral angle between the phenyl rings at positions 5 and 6 is 70.05 (10)° (Fig. 1). A C24—H24···π interaction involving the phenyl (C61—C66) ring, a C53—H53···π interaction involving the benzene (C21—C26) ring and a C64—H64···π interaction involving the phenyl (C51—C56) ring are also found in the crystal structure (Table 1). The Cl atom is disordered over two positions. Its occupancy ratio refined to 0.946 (5):0.054 (5).

Experimental

To a homogeneous solution of benzil (1.05 g, 0.005 mol) and 1-methyl-2-(2'-chlorophenyl)-ethanediamine dihydrochloride (1.29 g, 0.005 mol) in ethanol (20 ml), 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 and purified by column chromatography on silica gel. Elution with benzene-petroleum ether (3:2 v/v) at 333–353 K gave the pure product (1.68 g) in 76% yield. Crystals suitable for X-ray diffraction studies were obtained by recrystallization of the pure product from ethyl acetate.