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Acta Crystallogr Sect E Struct Rep Online. 2008 August 1; 64(Pt 8): o1432.
Published online 2008 July 9. doi:  10.1107/S1600536808020199
PMCID: PMC2962064

6-Methyl-N-(2-methyl­phen­yl)-3-phenyl-1,6-dihydro-1,2,4,5-tetra­zine-1-carbox­amide

Abstract

In the title compound, C17H16N5O, the central tetra­zine ring adopts an unsymmetrical boat conformation with the two C atoms as flagpoles. This compound can be considered as having homoaromaticity. The crystal structure is stabilized by inter­molecular C—H(...)O inter­actions between a benzene H atom and the carbonyl O atom.

Related literature

For related literature, see: Hu et al. (2004 [triangle], 2005 [triangle]); Jennison et al. (1986 [triangle]); Sauer (1996 [triangle]); Stam et al. (1982 [triangle]); Xu et al. (2006 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-o1432-scheme1.jpg

Experimental

Crystal data

  • C17H16N5O
  • M r = 306.35
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-o1432-efi5.jpg
  • a = 13.941 (6) Å
  • b = 5.675 (2) Å
  • c = 20.614 (8) Å
  • β = 102.055 (6)°
  • V = 1594.9 (11) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.08 mm−1
  • T = 291 (2) K
  • 0.12 × 0.10 × 0.06 mm

Data collection

  • Bruker SMART APEX CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 1996 [triangle]) T min = 0.980, T max = 0.995
  • 6815 measured reflections
  • 3116 independent reflections
  • 1882 reflections with I > 2σ(I)
  • R int = 0.084

Refinement

  • R[F 2 > 2σ(F 2)] = 0.072
  • wR(F 2) = 0.193
  • S = 0.94
  • 3116 reflections
  • 226 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.54 e Å−3
  • Δρmin = −0.31 e Å−3

Data collection: SMART (Bruker, 2005 [triangle]); cell refinement: SAINT (Bruker, 2005 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808020199/lx2060sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808020199/lx2060Isup2.hkl

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

Acknowledgments

The authors are very grateful to the National Natural and Scientific Foundation (grant No. 20272053) for financial support.

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 1,6-dihydro structures (Stam et al., 1982; Jennison et al., 1986) were found, by X-ray diffraction, to be homoaromatic. In continuation of our work on the structure–activity relationship of 1,6-dihydro-1,2,4,5-tetrazine derivatives (Hu et al., 2004, 2005), we report the crystal structure of the title compound (I) (Fig. 1).

In the tetrazine ring, atoms N1, N2, N3 and N4 are coplanar, while atoms C1 and C2 deviate from the plane by 0.597 (3) and 0.225 (3)°, respectively. The N1/C1/N4 and N2/C3/N3 planes make dihedral angles of 42.3 (2)° and 19.7 (2)°, respectively, with the N1–N4 plane, i.e. the tetrazine ring adopts an unsymmetrical boat conformation. The C3–C8 benzene ring make dihedral angles of 13.2 (1)°, with the N1–N4 plane. N1 is almost sp2 hybridized due to the angles around it add up to 359.6 (2)°. In keeping with similar situations in 3-phenyl-6-ethyl-1,6-dihydro-1,2,4,5-tetrazine (Stam et al., 1982), 3-(p-chlorophenyl)-6-methyl-1,6-dihydro-1,2,4,5-tetrazine (Xu et al., 2006) and 1-acetyl-3,6-dimethyl-1,2,4,5-tetrazine (Jennison et al., 1986), it can be considered that the molecule is homoaromatic.

The Fig. 2 shows that intramolecular C—H···O hydrogen bonds form a pseudo-five-membered ring. The crystal packing (Fig. 2) is stabilized by intermolecular C—H···O interactions between a benzene H atom and the O atom of carbonyl group, with a C6—H6···Oi separation of 3.385 (3) Å (Table 1; symmetry code as in Fig. 2).

Experimental

6-methyl-3-phenyl-1,6-dihydro-1,2,4,5-tetrazine (3.0 mmol), chloroform (10 ml) and pyridine (0.25 ml, 3.1 mmol) were mixed. 1-isocyanato-2-methylbenzene (3.0 mmol) in chloroform (10 ml) was added dropwise with stirring at room temperature. After the starting 1,6-dihydro-1,2,4,5-tetrazine was completely consumed (the reaction courses was monitored by TLC, dichloromethane system), evaporation of the chloroform, crude N-(o-methylphenyl) 3-phenyl-6-methyl-1,6-dihydro-1,2,4,5-tetrazine-1-carboxamide was obtained and purified by preparative thin-layer chromatography over silica gel PF254 (2 mm) (dichloromethane:petroleum ether = 1:1). The solution of the compound in anhydrous ethanol was concentrated gradually at room temperature to afford single crystals, which was suitable for X-ray diffraction. m.p. 378–380 K. Spectroscopic analysis: 1H NMR (CDCl3) δ p.p.m.: 8.64 (s, 1H), 8.14–8.16 (m, 2H, ArH), 7.92 (d, 1H, J = 8.0 Hz), 7.52–7.55 (m, 3H, ArH), 7.22 (m, 2H, ArH), 7.08 (t, 1H, J = 7.2 Hz), 6.91 (q, 1H, J=6.4 Hz), 2.34 (s, 3H), 1.09 (d, 3H, J = 6.8 Hz).

Refinement

The positions of H atoms bound to C17 and N5 were obtained from difference Fourier map and refined isotropically. Other H atoms were placed in calculated positions with C—H = 0.93 (aromatic) and 0.96 Å (methyl), and refined in riding model, with Uiso(H) = 1.5Ueq(C)for methyl and 1.2Ueq for aromatic H atoms.

Figures

Fig. 1.
The structure of (I), shown with 30% probability displacement ellipsoids.
Fig. 2.
C—H···O interaction (dotted line) in the title compound. [Symmetry codes: (i) x, -y+3/2, z-1/2; (ii) x, -y+3/2, z+1/2.]

Crystal data

C17H16N5OF000 = 644
Mr = 306.35Dx = 1.276 Mg m3
Monoclinic, P21/cMelting point = 378–380 K
Hall symbol: -P 2ybcMo Kα radiation λ = 0.71073 Å
a = 13.941 (6) ÅCell parameters from 742 reflections
b = 5.675 (2) Åθ = 3.2–24.8º
c = 20.614 (8) ŵ = 0.08 mm1
β = 102.055 (6)ºT = 291 (2) K
V = 1594.9 (11) Å3Prism, red
Z = 40.12 × 0.10 × 0.06 mm

Data collection

Bruker SMART APEX CCD area-detector diffractometer3116 independent reflections
Radiation source: fine-focus sealed tube1882 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.084
Detector resolution: 10.0 pixels mm-1θmax = 26.0º
T = 293(2) Kθmin = 1.5º
[var phi] and ω scansh = −17→8
Absorption correction: multi-scan(SADABS; Sheldrick, 1996)k = −6→7
Tmin = 0.980, Tmax = 0.995l = −25→25
6815 measured reflections

Refinement

Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.072  w = 1/[σ2(Fo2) + (0.1133P)2] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.193(Δ/σ)max < 0.001
S = 0.94Δρmax = 0.54 e Å3
3116 reflectionsΔρmin = −0.31 e Å3
226 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.031 (5)
Secondary atom site location: difference Fourier map

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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)

xyzUiso*/Ueq
O0.79549 (13)0.2358 (3)0.73526 (8)0.0685 (5)
N10.82379 (14)0.4541 (3)0.64939 (9)0.0552 (5)
N20.79315 (13)0.5181 (3)0.58485 (9)0.0522 (5)
N30.88534 (17)0.8632 (4)0.61618 (12)0.0685 (6)
N40.91853 (17)0.7948 (4)0.67409 (12)0.0724 (6)
N50.68918 (15)0.2115 (4)0.63448 (10)0.0598 (6)
H5N0.6759 (17)0.282 (4)0.5967 (12)0.054 (6)*
C10.91906 (18)0.5354 (4)0.68427 (11)0.0587 (6)
C20.83633 (17)0.7032 (4)0.56768 (11)0.0526 (6)
C30.82173 (17)0.7755 (4)0.49788 (12)0.0542 (6)
C40.77371 (19)0.6256 (5)0.44798 (12)0.0644 (7)
H40.74900.48240.45920.077*
C50.7624 (2)0.6873 (6)0.38197 (14)0.0813 (9)
H50.73070.58530.34910.098*
C60.7975 (2)0.8971 (6)0.36496 (16)0.0825 (9)
H60.78890.93920.32050.099*
C70.8452 (3)1.0452 (6)0.41287 (18)0.0876 (10)
H70.87011.18700.40090.105*
C80.8571 (2)0.9862 (5)0.47985 (15)0.0788 (8)
H80.88891.08970.51230.095*
C90.76906 (18)0.2904 (4)0.67787 (11)0.0535 (6)
C100.61865 (18)0.0506 (4)0.64801 (11)0.0559 (6)
C110.6437 (2)−0.1223 (5)0.69669 (13)0.0724 (8)
H110.7077−0.13290.72100.087*
C120.5740 (3)−0.2762 (6)0.70856 (15)0.0883 (10)
H120.5905−0.39100.74120.106*
C130.4807 (3)−0.2619 (6)0.67292 (18)0.0928 (11)
H130.4330−0.36460.68170.111*
C140.4564 (2)−0.0944 (6)0.62345 (16)0.0817 (9)
H140.3926−0.08910.59870.098*
C150.52429 (19)0.0652 (4)0.60974 (12)0.0601 (7)
C161.00241 (18)0.4238 (5)0.65920 (13)0.0658 (7)
H16A1.00130.25640.66560.099*
H16B1.06360.48650.68320.099*
H16C0.99550.45750.61280.099*
C170.4969 (3)0.2482 (6)0.55605 (17)0.0790 (8)
H17A0.431 (3)0.232 (5)0.5290 (16)0.102 (10)*
H17B0.543 (2)0.223 (5)0.5212 (15)0.092 (9)*
H17C0.511 (3)0.408 (7)0.5726 (16)0.107 (11)*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O0.0755 (12)0.0808 (13)0.0475 (10)−0.0050 (9)0.0090 (8)0.0014 (7)
N10.0491 (11)0.0653 (12)0.0486 (10)−0.0056 (10)0.0039 (8)0.0001 (8)
N20.0469 (11)0.0556 (11)0.0529 (11)−0.0018 (9)0.0077 (8)0.0026 (8)
N30.0682 (14)0.0511 (12)0.0823 (15)−0.0009 (10)0.0067 (12)−0.0101 (10)
N40.0740 (15)0.0636 (14)0.0742 (15)−0.0012 (11)0.0030 (12)−0.0181 (11)
N50.0537 (12)0.0737 (14)0.0501 (12)−0.0109 (10)0.0064 (10)0.0102 (9)
C10.0521 (15)0.0578 (14)0.0616 (14)−0.0068 (12)0.0015 (11)−0.0095 (10)
C20.0488 (13)0.0424 (12)0.0658 (14)0.0002 (11)0.0098 (11)−0.0017 (9)
C30.0427 (13)0.0485 (13)0.0722 (15)0.0022 (10)0.0137 (11)0.0085 (10)
C40.0610 (16)0.0681 (16)0.0637 (15)−0.0068 (13)0.0123 (12)0.0116 (11)
C50.0763 (19)0.101 (2)0.0649 (16)−0.0060 (17)0.0117 (14)0.0133 (14)
C60.0736 (19)0.095 (2)0.0832 (19)0.0109 (18)0.0271 (16)0.0321 (17)
C70.094 (2)0.0653 (19)0.115 (3)−0.0012 (17)0.047 (2)0.0308 (17)
C80.084 (2)0.0583 (17)0.098 (2)−0.0070 (15)0.0271 (16)0.0097 (14)
C90.0520 (14)0.0604 (14)0.0484 (13)0.0014 (11)0.0111 (11)−0.0033 (10)
C100.0597 (15)0.0570 (14)0.0548 (13)−0.0092 (12)0.0210 (11)−0.0027 (10)
C110.0846 (19)0.0703 (17)0.0646 (15)−0.0100 (15)0.0209 (14)0.0082 (12)
C120.119 (3)0.080 (2)0.0732 (18)−0.028 (2)0.035 (2)0.0027 (14)
C130.106 (3)0.089 (2)0.097 (2)−0.042 (2)0.053 (2)−0.0174 (18)
C140.0644 (18)0.090 (2)0.096 (2)−0.0193 (16)0.0277 (16)−0.0261 (17)
C150.0571 (16)0.0621 (15)0.0645 (14)−0.0049 (12)0.0205 (12)−0.0115 (11)
C160.0513 (15)0.0635 (16)0.0779 (16)−0.0031 (12)0.0029 (12)0.0007 (11)
C170.064 (2)0.078 (2)0.087 (2)0.0031 (17)−0.0032 (17)−0.0037 (16)

Geometric parameters (Å, °)

O—C91.204 (3)C7—C81.397 (4)
N1—N21.359 (3)C7—H70.9300
N1—C91.406 (3)C8—H80.9300
N1—C11.447 (3)C10—C151.388 (4)
N2—C21.296 (3)C10—C111.395 (4)
N3—N41.249 (3)C11—C121.366 (4)
N3—C21.416 (3)C11—H110.9300
N4—C11.487 (3)C12—C131.356 (5)
N5—C91.351 (3)C12—H120.9300
N5—C101.412 (3)C13—C141.383 (5)
N5—H5N0.86 (2)C13—H130.9300
C1—C161.506 (3)C14—C151.381 (4)
C2—C31.469 (3)C14—H140.9300
C3—C81.374 (4)C15—C171.508 (4)
C3—C41.394 (4)C16—H16A0.9600
C4—C51.382 (4)C16—H16B0.9600
C4—H40.9300C16—H16C0.9600
C5—C61.361 (4)C17—H17A0.98 (4)
C5—H50.9300C17—H17B1.07 (3)
C6—C71.360 (5)C17—H17C0.97 (4)
C6—H60.9300
N2—N1—C9119.9 (2)O—C9—N5127.3 (2)
N2—N1—C1118.0 (2)O—C9—N1119.9 (2)
C9—N1—C1121.7 (2)N5—C9—N1112.8 (2)
C2—N2—N1114.5 (2)C15—C10—C11121.1 (2)
N4—N3—C2120.2 (2)C15—C10—N5117.7 (2)
N3—N4—C1115.6 (2)C11—C10—N5121.1 (2)
C9—N5—C10126.5 (2)C12—C11—C10119.9 (3)
C9—N5—H5N115.8 (16)C12—C11—H11120.1
C10—N5—H5N117.0 (16)C10—C11—H11120.1
N1—C1—N4105.6 (2)C13—C12—C11120.2 (3)
N1—C1—C16112.9 (2)C13—C12—H12119.9
N4—C1—C16110.4 (2)C11—C12—H12119.9
N2—C2—N3120.7 (2)C12—C13—C14120.0 (3)
N2—C2—C3121.1 (2)C12—C13—H13120.0
N3—C2—C3117.4 (2)C14—C13—H13120.0
C8—C3—C4118.4 (2)C15—C14—C13122.0 (3)
C8—C3—C2121.6 (2)C15—C14—H14119.0
C4—C3—C2120.0 (2)C13—C14—H14119.0
C5—C4—C3120.7 (2)C14—C15—C10116.9 (2)
C5—C4—H4119.7C14—C15—C17121.5 (3)
C3—C4—H4119.7C10—C15—C17121.5 (2)
C6—C5—C4120.2 (3)C1—C16—H16A109.5
C6—C5—H5119.9C1—C16—H16B109.5
C4—C5—H5119.9H16A—C16—H16B109.5
C7—C6—C5120.1 (3)C1—C16—H16C109.5
C7—C6—H6120.0H16A—C16—H16C109.5
C5—C6—H6120.0H16B—C16—H16C109.5
C6—C7—C8120.6 (3)C15—C17—H17A114.5 (19)
C6—C7—H7119.7C15—C17—H17B107.6 (16)
C8—C7—H7119.7H17A—C17—H17B104 (2)
C3—C8—C7120.1 (3)C15—C17—H17C112.6 (19)
C3—C8—H8120.0H17A—C17—H17C113 (3)
C7—C8—H8120.0H17B—C17—H17C105 (3)
C9—N1—N2—C2166.3 (2)C4—C3—C8—C7−0.5 (4)
C1—N1—N2—C2−21.5 (3)C2—C3—C8—C7177.5 (3)
C2—N3—N4—C110.6 (3)C6—C7—C8—C31.0 (5)
N2—N1—C1—N452.3 (3)C10—N5—C9—O1.3 (4)
C9—N1—C1—N4−135.5 (2)C10—N5—C9—N1−178.6 (2)
N2—N1—C1—C16−68.4 (3)N2—N1—C9—O−179.1 (2)
C9—N1—C1—C16103.7 (2)C1—N1—C9—O8.9 (3)
N3—N4—C1—N1−45.4 (3)N2—N1—C9—N50.8 (3)
N3—N4—C1—C1677.0 (3)C1—N1—C9—N5−171.2 (2)
N1—N2—C2—N3−19.4 (3)C9—N5—C10—C15152.7 (2)
N1—N2—C2—C3171.32 (19)C9—N5—C10—C11−29.4 (4)
N4—N3—C2—N225.8 (3)C15—C10—C11—C12−2.0 (4)
N4—N3—C2—C3−164.6 (2)N5—C10—C11—C12−179.8 (2)
N2—C2—C3—C8171.8 (2)C10—C11—C12—C130.3 (4)
N3—C2—C3—C82.2 (3)C11—C12—C13—C141.4 (5)
N2—C2—C3—C4−10.2 (4)C12—C13—C14—C15−1.6 (5)
N3—C2—C3—C4−179.8 (2)C13—C14—C15—C100.0 (4)
C8—C3—C4—C50.3 (4)C13—C14—C15—C17−179.5 (3)
C2—C3—C4—C5−177.7 (2)C11—C10—C15—C141.8 (3)
C3—C4—C5—C6−0.5 (4)N5—C10—C15—C14179.7 (2)
C4—C5—C6—C71.0 (5)C11—C10—C15—C17−178.7 (3)
C5—C6—C7—C8−1.2 (5)N5—C10—C15—C17−0.8 (3)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C6—H6···Oi0.932.563.385 (3)148

Symmetry codes: (i) x, −y+3/2, z−1/2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LX2060).

References

  • Bruker (2005). SMART and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
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  • Hu, W. X., Shi, H. B., Yuan, Q. & &Sun, Y. Q. (2005). J. Chem. Res. pp. 291–293.
  • Jennison, C. P. R., Mackay, D., Watson, K. N. & Taylor, N. J. (1986). J. Org. Chem.51, 3043–3051.
  • Sauer, J. (1996). Comprehensive Heterocyclic Chemistry, 2nd ed., edited by A. J. Boulton, Vol. 6, pp. 901–955. Oxford: Elsevier.
  • Sheldrick, G. M. (1996). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Stam, C. H., Counotte-Potman, A. D. & Van der Plas, H. C. (1982). J. Org. Chem.47, 2856–2858.
  • Xu, F., Hu, W.-X., Zhou, W. & Xia, C.-N. (2006). Acta Cryst. E62, o2875–o2876.

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