1-Benzoyl-3,6-diphenyl-1,4-dihydro-1,2,4,5-tetra­zine

Feng Xu; Zhen-Zhen Yang; Xiao-Fang Chen; Wen-Xiu Zheng

doi:10.1107/S1600536810038067

. 2010 Sep 30;66(Pt 10):o2664. doi: 10.1107/S1600536810038067

1-Benzoyl-3,6-diphenyl-1,4-dihydro-1,2,4,5-tetrazine

Feng Xu ^a,^*, Zhen-Zhen Yang ^a, Xiao-Fang Chen ^a, Wen-Xiu Zheng ^a

PMCID: PMC2983408 PMID: 21587635

Abstract

In the title compound, C₂₁H₁₆N₄O, the central tetrazine ring adopts an unsymmetrical boat conformation with the two N atoms as the bow and stern. The crystal packing is stabilized by intermolecular N—H—O hydrogen bonds.

Related literature

For related structures, see: Xu et al. (2010 ▶); Hu et al. (2004 ▶); Rao et al. (2006 ▶). For applications of 1,2,4,5-tetrazine derivatives, see: Sauer et al. (1996 ▶).

Experimental

Crystal data

C₂₁H₁₆N₄O
M _r = 340.38
Orthorhombic,
a = 7.1100 (19) Å
b = 12.115 (3) Å
c = 19.884 (6) Å
V = 1712.7 (8) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 93 K
0.43 × 0.27 × 0.27 mm

Data collection

Rigaku AFC10/Saturn724+ diffractometer
13708 measured reflections
2254 independent reflections
2128 reflections with I > 2σ(I)
R _int = 0.032

Refinement

R[F ² > 2σ(F ²)] = 0.033
wR(F ²) = 0.085
S = 1.00
2254 reflections
239 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2008 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810038067/bq2236sup1.cif

e-66-o2664-sup1.cif^{(20.1KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810038067/bq2236Isup2.hkl

e-66-o2664-Isup2.hkl^{(110.8KB, 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
N4—H4N⋯O1ⁱ	0.91 (2)	1.97 (2)	2.806 (2)	150.9 (18)

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Symmetry code: (i) Inline graphic .

Acknowledgments

We are very grateful to the Science Foundation for Excellent Youth Scholars of the Department of Education of Zhejiang Province and the Educational Commission of Zhejiang Province of China (Y201018289).

supplementary crystallographic information

Comment

1,2,4,5-Tetrazine derivatives have high potential for biological activity, possessing a wide spectrum of antiviral and antitumor properties. They have been widely used in pesticides and herbicides (Sauer, 1996). Dihydro-1,2,4,5- tetrazine has four isomers, namely 1,2-, 1,4-, 1,6- and 3,6-dihydro-1,2,4,5- tetrazines. The 1,4-dihydro structures (Rao et al., 2006) were found to have potential antitumor properties. In continuation of our work on the structure-activity relationship of dihydro-1,2,4,5-tetrazine derivatives (Hu et al., 2004 & Xu et al., 2010), we report here the crystal structure of the title compound (I) (Fig. 1).

In the tetrazine ring, atoms N2, C3, N5 and C6 are almost coplanar, while atoms N1 and N4 deviate from the plane by 0.447 (2) and 0.330 (2) Å, respectively. The N1/N2/C6 and C3/N4/N5 planes make dihedral angles of 35.76 (2)° and 27.66 (2)°, respectively, with the N2/C3/N5/C6 plane, i.e. the tetrazine ring adopts an unsymmetrical boat conformation. The benzene rings C7—C12, C13—C18 and C20—C25 make dihedral angles of 22.88 (2)°, 17.80 (2)° and 87.09 (2)° with the N2/C3/N5/C6 plane, respectively. Atom N1 is almost sp² hybridized due to the angles around it add up to 358.0 (2)°.

The crystal packing (Fig.2) is stabilized by intermolecular N—H—O interactions between a hydrogen on nitrogen N(4) and the O atom of carbonyl group, with a N—H—O separation of 2.806 (2) Å (Table 2).

Experimental

To a solution of 1,2-dihydro-1,2,4,5-tetrazine (0.47 g, 2 mmol) in chloroform (20 ml) was added dropwise benzoyl chloride (0.28 g, 2 mmol) in chloroform (10 ml) under stirring at room temperature using pyridine (0.17 g, 2.1 mmol) as the catalyst. After stirring for 2 h, the solvent was distilled off under vacuum. The residue was chromatographed on a silica gel column using cyclohexane-dichloromethane (V/V, 1:2) as the eluent to get the yellow solid (0.37 g, 55%). An anhydrous ethanol solution of the title compound was stood at room temperature, and by slowly evaporating ethanol from the solution, yellow crystals suitable for X-ray diffraction analysis were isolated one month later. m.p.: 500–501 K.