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Ethyl 6-methyl-8-phenyl-1,2,4-triazolo[1,5-a]pyridine-7-carboxyl­ate

aSchool of Chemical Engineering, Taishan Medical University, Taian 271016, People's Republic of China
*Correspondence e-mail: chemyangli@gmail.com

(Received 29 October 2013; accepted 13 November 2013; online 23 November 2013)

In title compound, C16H15N3O2, the 1,2,4-triazolo[1,5-a]pyridine ring system is almost planar (r.m.s. deviation = 0.0068 Å) and forms a dihedral angle of 61.4 (3)° with the phenyl ring. In the structure, centrosymmetrically related mol­ecules are linked into dimers by pairs of C—H⋯N hydrogen bonds.

Related literature

For application of [1,2,4]triazolo[1,5-a]pyridine derivatives, see: Luo & Hu (2006[Luo, Y. & Hu, Y. (2006). Arch. Pharm. Chem. Life Sci. 339, 262-266.]); Liu & Hu (2002[Liu, T. & Hu, Y. (2002). Bioorg. Med. Chem. Lett. 12, 2411-2413.]). For the synthesis of [1,2,4]triazolo[1,5-a]pyridine derivatives, see: Jones & Sliskovic (1983[Jones, G. & Sliskovic, D. R. (1983). Adv. Heterocycl. Chem. 34, 79-143.]); Wang et al. (2003[Wang, J. W., Jia, J., Hou, D. J., li, H. M. & Yin, J. (2003). Chin. J. Org. Chem. 23, 173-175.]); Ge et al. (2009[Ge, Y. Q., Jia, J., Yang, H., Zhao, G. L., Zhan, F. X. & Wang, J. W. (2009). Heterocycles, 78, 725-736.]); Jia et al. (2010[Jia, J., Ge, Y. Q., Tao, X. T. & Wang, J. W. (2010). Heterocycles, 81, 185-194.]). For standard bond lengths, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]).

[Scheme 1]

Experimental

Crystal data
  • C16H15N3O2

  • Mr = 281.31

  • Monoclinic, P 21 /n

  • a = 13.401 (3) Å

  • b = 7.4825 (19) Å

  • c = 15.068 (4) Å

  • β = 98.986 (4)°

  • V = 1492.4 (7) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 298 K

  • 0.23 × 0.19 × 0.15 mm

Data collection
  • Brucker SMART APEXII CCD area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 1999[Bruker (1999). SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.981, Tmax = 0.987

  • 7312 measured reflections

  • 2611 independent reflections

  • 1920 reflections with I > 2σ(I)

  • Rint = 0.086

Refinement
  • R[F2 > 2σ(F2)] = 0.049

  • wR(F2) = 0.152

  • S = 1.05

  • 2611 reflections

  • 192 parameters

  • H-atom parameters constrained

  • Δρmax = 0.22 e Å−3

  • Δρmin = −0.23 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C6—H6⋯N2i 0.93 2.49 3.332 (3) 151
Symmetry code: (i) -x, -y+2, -z+1.

Data collection: SMART (Bruker, 1998[Bruker (1998). SMART. Bruker AXS Inc., Madison, Wisconsin, USA. ]); cell refinement: SAINT (Bruker, 1999[Bruker (1999). SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT (Bruker, 1999[Bruker (1999). SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]).

Supporting information


Comment top

[1,2,4]Triazolo[1,5-a]pyridine derivatives are important heterocyclic compounds which exhibit antifungal, anticancer and anti-inflammatory activities (Luo & Hu, 2006; Liu & Hu, 2002). Despite possessing outstanding biological activities, only a few [1,2,4]triazolo[1,5-a]pyridines are known. Some commonly used synthetic methods are the annulation of the 1,2,4-triazole ring starting with amino substituted pyridines by a multistep procedure (Jones & Sliskovic, 1983). Previously, imidazo[1,5-a]pyridines, pyrazolo[1,5-a]pyridines, imidazo[1,2-a]pyridines and indolizines had been synthesized by a novel tandem reaction in our group (Wang et al., 2003; Ge et al., 2009; Jia et al., 2010). As an extension of this work, the synthesis of [1,2,4]triazolo[1,5-a]pyridine heterocycles through this procedure has been undertaken. We present here the crystal structure of one of such compounds, ethyl 8-phenyl-6-methyl-[1,2,4]triazolo[1,5-a]pyridine-7-carboxylate.

In title compound (Fig. 1) the the [1,2,4]triazolo[1,5-a]pyridine ring system is almost planar, as indicated by its r.m.s. deviation of 0.0068 Å and by the dihedral angle of 0.9 (3)° between the pyridine and triazole rings. The C10–C15 phenyl ring is tilted by 61.4 (3)° with respect to the mean plane through the fused-ring system. All bond lengths (Allen et al., 1987) and angles in the molecule are normal. In the crystal structure, centrosymmetrically related molecules form dimeric units by a pair of C—H···N intermolecular hydrogen bonds (Table 1).

Related literature top

For application of [1,2,4]triazolo[1,5-a]pyridine derivatives, see: Luo & Hu (2006); Liu & Hu (2002). For the synthesis of [1,2,4]triazolo[1,5-a]pyridine derivatives, see: Jones & Sliskovic (1983); Wang et al. (2003); Ge et al. (2009); Jia et al. (2010). For standard bond lengths, see: Allen et al. (1987).

Experimental top

Phenyl(1H-1,2,4-triazol-5-yl)methanone (6 mmol), ethyl 4-bromo-3-methylbut-2-enoate (12 mmol), potassium carbonate (1.8 g, 13.2 mmol) and DMF (30 ml) were added to a 100 ml round-bottomed flask and stirred for 8 h. The mixture was then poured into water (200 ml) and extracted with dichloromethane (3 × 50 ml). The organic layers were combined and dried over anhydrous Na2SO4, then filtered, and the mixture concentrated by rotary evaporation. The crude products were depurated by using column chromatography in 72% isolated yield. Crystals suitable for X-ray diffraction analysis were obtained by slow evaporation of a solution of the title compound in a hexane/ethyl acetate mixture (3:1 v/v) at room temperature over a period of one week.

Refinement top

All H atoms were found on a difference Fourier map, with C—H = 0.93–0.97 Å and included in the final cycles of refinement using a riding model, with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C) for methyl H atoms.

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT (Bruker, 1999); 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: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compouns, with displacement ellipsoids drawn at the 30% probability level.
Ethyl 6-methyl-8-phenyl-1,2,4-triazolo[1,5-a]pyridine-7-carboxylate top
Crystal data top
C16H15N3O2F(000) = 592
Mr = 281.31Dx = 1.252 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 3034 reflections
a = 13.401 (3) Åθ = 2.7–25.1°
b = 7.4825 (19) ŵ = 0.09 mm1
c = 15.068 (4) ÅT = 298 K
β = 98.986 (4)°Block, colourless
V = 1492.4 (7) Å30.23 × 0.19 × 0.15 mm
Z = 4
Data collection top
Brucker SMART APEXII CCD area-detector
diffractometer
2611 independent reflections
Radiation source: fine-focus sealed tube1920 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.086
phi and ω scansθmax = 25.0°, θmin = 1.9°
Absorption correction: multi-scan
(SADABS; Bruker, 1999)
h = 1015
Tmin = 0.981, Tmax = 0.987k = 87
7312 measured reflectionsl = 1717
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.049Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.152H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.073P)2 + 0.2662P]
where P = (Fo2 + 2Fc2)/3
2611 reflections(Δ/σ)max < 0.001
192 parametersΔρmax = 0.22 e Å3
0 restraintsΔρmin = 0.23 e Å3
Crystal data top
C16H15N3O2V = 1492.4 (7) Å3
Mr = 281.31Z = 4
Monoclinic, P21/nMo Kα radiation
a = 13.401 (3) ŵ = 0.09 mm1
b = 7.4825 (19) ÅT = 298 K
c = 15.068 (4) Å0.23 × 0.19 × 0.15 mm
β = 98.986 (4)°
Data collection top
Brucker SMART APEXII CCD area-detector
diffractometer
2611 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 1999)
1920 reflections with I > 2σ(I)
Tmin = 0.981, Tmax = 0.987Rint = 0.086
7312 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0490 restraints
wR(F2) = 0.152H-atom parameters constrained
S = 1.05Δρmax = 0.22 e Å3
2611 reflectionsΔρmin = 0.23 e Å3
192 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
xyzUiso*/Ueq
N10.10885 (12)0.7854 (2)0.55820 (10)0.0547 (4)
N20.09507 (14)0.9165 (2)0.61803 (11)0.0672 (5)
N30.23653 (13)0.7566 (2)0.66890 (10)0.0628 (5)
O10.25306 (14)0.4080 (2)0.34386 (12)0.0912 (6)
O20.14672 (10)0.22579 (18)0.39941 (9)0.0636 (4)
C10.2563 (2)0.0255 (4)0.3838 (2)0.0930 (8)
H1A0.31660.04530.38740.140*
H1B0.26290.13060.34860.140*
H1C0.24630.05980.44320.140*
C20.16849 (19)0.0806 (3)0.34085 (16)0.0752 (6)
H2A0.18270.12950.28450.090*
H2B0.10980.00350.32780.090*
C30.19373 (14)0.3795 (3)0.39345 (12)0.0555 (5)
C40.16236 (13)0.5171 (2)0.45608 (12)0.0499 (5)
C50.07336 (14)0.6198 (3)0.42544 (13)0.0556 (5)
C60.04891 (14)0.7524 (3)0.47858 (13)0.0589 (5)
H60.00870.82080.46090.071*
C70.17325 (18)0.8910 (3)0.68132 (14)0.0687 (6)
H70.18430.96260.73240.082*
C80.19436 (14)0.6907 (2)0.58965 (12)0.0509 (5)
C90.22271 (13)0.5487 (2)0.53631 (12)0.0488 (5)
C100.31516 (14)0.4442 (3)0.57064 (12)0.0541 (5)
C110.40784 (15)0.5273 (4)0.58803 (16)0.0791 (7)
H110.41320.64960.57890.095*
C140.3930 (2)0.1653 (4)0.62015 (18)0.0902 (8)
H140.38760.04380.63150.108*
C150.30836 (17)0.2630 (3)0.58754 (14)0.0698 (6)
H150.24570.20680.57670.084*
C160.01047 (17)0.5868 (3)0.33544 (15)0.0759 (7)
H16A0.04660.66590.32760.114*
H16B0.01270.46520.33220.114*
H16C0.05050.60810.28890.114*
C120.49383 (18)0.4263 (5)0.61947 (19)0.1016 (10)
H120.55710.48020.62940.122*
C130.4843 (2)0.2469 (5)0.6356 (2)0.1015 (10)
H130.54140.18040.65750.122*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0617 (9)0.0450 (9)0.0561 (9)0.0084 (7)0.0047 (7)0.0023 (7)
N20.0850 (12)0.0518 (10)0.0632 (10)0.0147 (9)0.0069 (9)0.0068 (8)
N30.0732 (11)0.0605 (10)0.0531 (9)0.0066 (9)0.0045 (8)0.0003 (8)
O10.1124 (13)0.0857 (12)0.0881 (11)0.0218 (10)0.0553 (10)0.0121 (9)
O20.0725 (9)0.0494 (8)0.0730 (9)0.0023 (7)0.0240 (7)0.0091 (6)
C10.1027 (18)0.0772 (17)0.1035 (19)0.0237 (15)0.0294 (16)0.0102 (15)
C20.0908 (16)0.0612 (13)0.0759 (14)0.0012 (12)0.0202 (12)0.0175 (11)
C30.0584 (11)0.0556 (12)0.0530 (10)0.0017 (9)0.0102 (9)0.0014 (9)
C40.0528 (10)0.0442 (10)0.0535 (10)0.0008 (8)0.0106 (8)0.0044 (8)
C50.0560 (11)0.0505 (11)0.0581 (11)0.0009 (9)0.0023 (9)0.0046 (9)
C60.0580 (11)0.0506 (11)0.0649 (12)0.0104 (9)0.0006 (9)0.0054 (10)
C70.0871 (15)0.0588 (13)0.0587 (12)0.0090 (12)0.0066 (11)0.0063 (10)
C80.0558 (10)0.0467 (10)0.0494 (10)0.0031 (8)0.0059 (8)0.0071 (8)
C90.0520 (10)0.0450 (10)0.0505 (10)0.0019 (8)0.0112 (8)0.0073 (8)
C100.0541 (10)0.0622 (12)0.0462 (10)0.0089 (9)0.0087 (8)0.0030 (8)
C110.0578 (13)0.0981 (18)0.0817 (15)0.0013 (12)0.0118 (11)0.0211 (14)
C140.0914 (19)0.0786 (17)0.0925 (17)0.0314 (15)0.0107 (14)0.0037 (14)
C150.0719 (13)0.0598 (13)0.0730 (14)0.0130 (11)0.0034 (11)0.0006 (11)
C160.0772 (14)0.0723 (15)0.0710 (13)0.0060 (12)0.0106 (11)0.0051 (11)
C120.0531 (13)0.161 (3)0.0913 (18)0.0025 (17)0.0116 (12)0.0282 (19)
C130.0799 (19)0.127 (3)0.0966 (19)0.0475 (19)0.0126 (15)0.0175 (19)
Geometric parameters (Å, º) top
N1—C61.358 (2)C5—C161.501 (3)
N1—N21.364 (2)C6—H60.9300
N1—C81.368 (2)C7—H70.9300
N2—C71.316 (3)C8—C91.420 (3)
N3—C81.333 (2)C9—C101.488 (2)
N3—C71.347 (3)C10—C111.377 (3)
O1—C31.192 (2)C10—C151.385 (3)
O2—C31.322 (2)C11—C121.397 (4)
O2—C21.458 (2)C11—H110.9300
C1—C21.482 (3)C14—C131.355 (4)
C1—H1A0.9600C14—C151.374 (3)
C1—H1B0.9600C14—H140.9300
C1—H1C0.9600C15—H150.9300
C2—H2A0.9700C16—H16A0.9600
C2—H2B0.9700C16—H16B0.9600
C3—C41.500 (3)C16—H16C0.9600
C4—C91.366 (3)C12—C131.374 (5)
C4—C51.433 (3)C12—H120.9300
C5—C61.347 (3)C13—H130.9300
C6—N1—N2126.33 (15)N3—C7—H7121.5
C6—N1—C8124.03 (16)N3—C8—N1109.50 (17)
N2—N1—C8109.64 (15)N3—C8—C9132.10 (17)
C7—N2—N1101.54 (16)N1—C8—C9118.40 (15)
C8—N3—C7102.27 (16)C4—C9—C8117.18 (16)
C3—O2—C2117.72 (16)C4—C9—C10124.22 (16)
C2—C1—H1A109.5C8—C9—C10118.60 (15)
C2—C1—H1B109.5C11—C10—C15119.36 (19)
H1A—C1—H1B109.5C11—C10—C9120.41 (19)
C2—C1—H1C109.5C15—C10—C9120.21 (18)
H1A—C1—H1C109.5C10—C11—C12119.5 (3)
H1B—C1—H1C109.5C10—C11—H11120.3
O2—C2—C1110.81 (19)C12—C11—H11120.3
O2—C2—H2A109.5C13—C14—C15119.6 (3)
C1—C2—H2A109.5C13—C14—H14120.2
O2—C2—H2B109.5C15—C14—H14120.2
C1—C2—H2B109.5C14—C15—C10120.8 (2)
H2A—C2—H2B108.1C14—C15—H15119.6
O1—C3—O2124.74 (19)C10—C15—H15119.6
O1—C3—C4123.47 (19)C5—C16—H16A109.5
O2—C3—C4111.78 (15)C5—C16—H16B109.5
C9—C4—C5122.70 (17)H16A—C16—H16B109.5
C9—C4—C3119.35 (16)C5—C16—H16C109.5
C5—C4—C3117.77 (16)H16A—C16—H16C109.5
C6—C5—C4118.08 (17)H16B—C16—H16C109.5
C6—C5—C16120.25 (18)C13—C12—C11119.6 (3)
C4—C5—C16121.63 (18)C13—C12—H12120.2
C5—C6—N1119.61 (17)C11—C12—H12120.2
C5—C6—H6120.2C14—C13—C12121.1 (2)
N1—C6—H6120.2C14—C13—H13119.4
N2—C7—N3117.05 (19)C12—C13—H13119.4
N2—C7—H7121.5
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6···N2i0.932.493.332 (3)151
Symmetry code: (i) x, y+2, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C6—H6···N2i0.932.493.332 (3)151.2
Symmetry code: (i) x, y+2, z+1.
 

References

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First citationWang, J. W., Jia, J., Hou, D. J., li, H. M. & Yin, J. (2003). Chin. J. Org. Chem. 23, 173–175.  CAS

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