3-Pyridin-2-yl-1H-1,2,4-triazol-5-amine

Dolzhenko, A.V.; Tan, G.K.; Koh, L.L.; Dolzhenko, A.V.; Chui, W.K.

doi:10.1107/S1600536808042177

organic compounds

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ISSN: 2056-9890

Volume 65| Part 1| January 2009| Page o125

doi:10.1107/S1600536808042177

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3-Pyridin-2-yl-1H-1,2,4-triazol-5-amine

Anton V. Dolzhenko,^a ^* Geok Kheng Tan,^b Lip Lin Koh,^b Anna V. Dolzhenko ^a and Wai Keung Chui ^a

^aDepartment of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore, and ^bDepartment of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
^*Correspondence e-mail: phada@nus.edu.sg

(Received 13 November 2008; accepted 11 December 2008; online 17 December 2008)

In the title compound, C₇H₇N₅, the non-H atoms are almost coplanar (r.m.s. deviation = 0.050 Å), with the N atom of pyridine ring oriented to the N—N(H) side of the 1,2,4-triazole ring. The mean planes of the pyridine and 1,2,4-triazole rings form a dihedral angle of 5.58 (7)°. The N atom of the amino group adopts a pyramidal configuration. The molecules are linked into a two-dimensional network parallel to (10 $[\overline{1}]$ ) by N—H⋯N hydrogen bonds.

Related literature

For 1,2,4-triazol-5-amines as building blocks in the synthesis of fused heterocyclic systems, see: Dolzhenko et al. (2006 , 2007a ,b ); Fischer, (2007 ). For a summary of structural data for 1,2,4-triazoles, see: Buzykin et al. (2006 ). For crystal structures of Cu^II complexes with 3-pyridin-2-yl-1,2,4-triazol-5-amine, see: Ferrer et al. (2004 ).

Experimental

Crystal data

C₇H₇N₅
M_r = 161.18
Monoclinic, P 2₁ /n
a = 7.3863 (6) Å
b = 7.9096 (6) Å
c = 13.2157 (11) Å
β = 91.832 (2)°
V = 771.70 (11) Å³
Z = 4
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 223 (2) K
0.36 × 0.16 × 0.12 mm

Data collection

Bruker SMART APEX CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2001 ) T_min = 0.967, T_max = 0.989
5336 measured reflections
1772 independent reflections
1519 reflections with I > 2σ(I)
R_int = 0.026

Refinement

R[F² > 2σ(F²)] = 0.042
wR(F²) = 0.110
S = 1.05
1772 reflections
121 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2N⋯N5ⁱ	0.90 (2)	2.01 (2)	2.9010 (16)	171 (1)
N4—H4A⋯N3ⁱⁱ	0.90 (2)	2.11 (2)	2.9971 (16)	172 (1)
N4—H4B⋯N1ⁱ	0.93 (2)	2.19 (2)	3.0264 (16)	151 (1)
Symmetry codes: (i) $[-x+{\script{3\over 2}}, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (ii) -x+1, -y, -z+1.

Data collection: SMART (Bruker, 2001 ); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; 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.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808042177/ci2719sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808042177/ci2719Isup2.hkl

checkCIF report

Comment top

1,2,4-Triazol-5-amines have been recognized as valuable synthons for the construction of fused heterocyclic systems, e.g. 1,2,4-triazolo[1,5-a]pyrimidines (Fischer, 2007) and 1,2,4-triazolo[1,5-a][1,3,5]triazines (Dolzhenko et al., 2006). It also should be mentioned that 1,2,4-triazol-5-amines are widely used as ligands and crystallographic data on three different mononuclear complexes of 3-pyridin-2-yl-1,2,4-triazol-5-amine with Cu^II have been reported by Ferrer et al. (2004). However, no crystallographic study has been performed on the ligand.

In continuation of our investigations on using 1,2,4-triazol-5-amines in the synthesis of fused heterocyclic systems (Dolzhenko et al., 2007a,b), we report herein the crystal structure of a synthetically important building block viz. 3-pyridin-2-yl-1,2,4-triazol-5-amine.

Due to annular tautomerism, 3-pyridin-2-yl-1,2,4-triazol-5-amine may theoretically exist in three tautomeric forms (A, B and C) and for each of them, rotameric structures A', B' and C' are possible (Fig.1). As observed in reported Cu^II complexes (Ferrer et al., 2004), 3-pyridin-2-yl-1,2,4-triazol-5-amine was the only tautomeric form found in the crystal (Fig. 2). However, the molecule exists in the crystal as rotamer A in contrast to rotamer A' found in Cu^II complexes.

Bond lengths and angles in the molecule of 3-pyridin-2-yl-1,2,4-triazol-5-amine are within normal ranges, and comparable with values summarized for 1,2,4-triazoles by Buzykin et al. (2006). 3-Pyridin-2-yl-1,2,4-triazol-5-amine has practically planar geometry with slight deviation of the pyridyl moiety, which makes a dihedral angle of 5.58 (7)° with mean plane of the 1,2,4-triazole ring. The nitrogen atom (N4) of the amino group adopts a pyramidal configuration with 0.26 (2) Å deviation of the nitrogen atom from the C2/H4A/H4B plane.

The molecules are linked into a two-dimensional network parallel to the (101) by N—H···N hydrogen bonds (Table 1 and Fig.3).

Related literature top

For 1,2,4-triazol-5-amines as building blocks in the synthesis of fused heterocyclic systems, see: Dolzhenko et al. (2006, 2007a,b); Fischer, (2007). For a summary of structural data for 1,2,4-triazoles in crystals, see: Buzykin et al. (2006). For crystal structures of Cu^II complexes with 3-pyridin-2-yl-1,2,4-triazol-5-amine, see: Ferrer et al. (2004).

Experimental top

3-Pyridin-2-yl-1,2,4-triazol-5-amine was prepared according to general method reported by Dolzhenko et al. (2007a,b). Single crystals suitable for crystallographic analysis were grown by recrystallization from ethanol.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); 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

	Fig. 1. Possible tautomers and rotamers of 3-pyridin-2-yl-1,2,4-triazol-5-amine.
	Fig. 2. The molecular structure of the title compound, with the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 3. Molecular packing of the title compound, viewed along the c axis.

3-Pyridin-2-yl-1H-1,2,4-triazol-5-amine top

Crystal data top

C₇H₇N₅	F(000) = 336
M_r = 161.18	D_x = 1.387 Mg m⁻³
Monoclinic, P2₁/n	Melting point: 493 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 7.3863 (6) Å	Cell parameters from 1841 reflections
b = 7.9096 (6) Å	θ = 3.0–26.6°
c = 13.2157 (11) Å	µ = 0.10 mm⁻¹
β = 91.832 (2)°	T = 223 K
V = 771.70 (11) Å³	Block, colourless
Z = 4	0.36 × 0.16 × 0.12 mm

Data collection top

Bruker SMART APEX CCD diffractometer	1772 independent reflections
Radiation source: fine-focus sealed tube	1519 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.026
ϕ and ω scans	θ_max = 27.5°, θ_min = 3.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)	h = −9→9
T_min = 0.967, T_max = 0.989	k = −8→10
5336 measured reflections	l = −14→17

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.110	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ²(F_o²) + (0.0539P)² + 0.1487P] where P = (F_o² + 2F_c²)/3
1772 reflections	(Δ/σ)_max = 0.001
121 parameters	Δρ_max = 0.21 e Å⁻³
0 restraints	Δρ_min = −0.20 e Å⁻³

Crystal data top

C₇H₇N₅	V = 771.70 (11) Å³
M_r = 161.18	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 7.3863 (6) Å	µ = 0.10 mm⁻¹
b = 7.9096 (6) Å	T = 223 K
c = 13.2157 (11) Å	0.36 × 0.16 × 0.12 mm
β = 91.832 (2)°

Data collection top

Bruker SMART APEX CCD diffractometer	1772 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2001)	1519 reflections with I > 2σ(I)
T_min = 0.967, T_max = 0.989	R_int = 0.026
5336 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.042	0 restraints
wR(F²) = 0.110	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	Δρ_max = 0.21 e Å⁻³
1772 reflections	Δρ_min = −0.20 e Å⁻³
121 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

	x	y	z	U_iso*/U_eq
N1	0.72741 (16)	0.34999 (14)	0.68693 (8)	0.0383 (3)
N2	0.66107 (16)	0.19639 (15)	0.71630 (8)	0.0393 (3)
H2N	0.669 (2)	0.164 (2)	0.7817 (14)	0.052 (5)*
N3	0.61324 (14)	0.20352 (14)	0.55193 (8)	0.0345 (3)
N4	0.51489 (16)	−0.04181 (15)	0.64256 (9)	0.0398 (3)
H4A	0.488 (2)	−0.095 (2)	0.5842 (13)	0.049 (4)*
H4B	0.564 (2)	−0.106 (2)	0.6948 (13)	0.050 (4)*
N5	0.80901 (15)	0.62905 (15)	0.56803 (8)	0.0388 (3)
C1	0.69411 (16)	0.34759 (16)	0.58805 (9)	0.0331 (3)
C2	0.59494 (16)	0.11150 (17)	0.63532 (9)	0.0343 (3)
C3	0.74353 (16)	0.48955 (17)	0.52229 (9)	0.0343 (3)
C4	0.72299 (19)	0.47748 (19)	0.41755 (10)	0.0425 (3)
H4	0.6758	0.3786	0.3873	0.051*
C5	0.77288 (19)	0.6128 (2)	0.35870 (11)	0.0491 (4)
H5	0.7598	0.6076	0.2878	0.059*
C6	0.8419 (2)	0.7554 (2)	0.40516 (12)	0.0486 (4)
H6	0.8781	0.8489	0.3668	0.058*
C7	0.85663 (19)	0.75796 (19)	0.50930 (12)	0.0455 (4)
H7	0.9029	0.8561	0.5408	0.055*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0476 (6)	0.0387 (6)	0.0282 (5)	−0.0007 (5)	−0.0076 (4)	0.0006 (4)
N2	0.0518 (7)	0.0392 (6)	0.0261 (6)	−0.0013 (5)	−0.0092 (5)	0.0000 (5)
N3	0.0362 (5)	0.0396 (6)	0.0273 (5)	0.0042 (4)	−0.0059 (4)	−0.0028 (4)
N4	0.0498 (7)	0.0397 (6)	0.0291 (6)	−0.0021 (5)	−0.0110 (5)	−0.0001 (5)
N5	0.0420 (6)	0.0409 (6)	0.0332 (6)	0.0030 (5)	−0.0043 (5)	0.0012 (5)
C1	0.0330 (6)	0.0385 (7)	0.0273 (6)	0.0057 (5)	−0.0056 (5)	−0.0035 (5)
C2	0.0357 (6)	0.0391 (7)	0.0274 (6)	0.0053 (5)	−0.0068 (5)	−0.0030 (5)
C3	0.0305 (6)	0.0419 (7)	0.0301 (6)	0.0076 (5)	−0.0028 (5)	−0.0010 (5)
C4	0.0442 (7)	0.0522 (8)	0.0310 (7)	0.0046 (6)	−0.0016 (5)	−0.0025 (6)
C5	0.0488 (8)	0.0683 (10)	0.0304 (7)	0.0080 (7)	0.0032 (6)	0.0071 (7)
C6	0.0444 (8)	0.0558 (9)	0.0457 (8)	0.0057 (7)	0.0046 (6)	0.0150 (7)
C7	0.0454 (8)	0.0447 (8)	0.0460 (8)	0.0013 (6)	−0.0035 (6)	0.0050 (6)

Geometric parameters (Å, º) top

N1—C1	1.3221 (16)	N5—C3	1.3410 (17)
N1—N2	1.3708 (16)	C1—C3	1.4729 (18)
N2—C2	1.3422 (16)	C3—C4	1.3909 (18)
N2—H2N	0.902 (19)	C4—C5	1.380 (2)
N3—C2	1.3312 (17)	C4—H4	0.94
N3—C1	1.3656 (16)	C5—C6	1.374 (2)
N4—C2	1.3538 (18)	C5—H5	0.94
N4—H4A	0.896 (18)	C6—C7	1.377 (2)
N4—H4B	0.925 (17)	C6—H6	0.94
N5—C7	1.3354 (18)	C7—H7	0.94

C1—N1—N2	102.14 (10)	N5—C3—C4	122.10 (13)
C2—N2—N1	109.99 (11)	N5—C3—C1	116.99 (11)
C2—N2—H2N	129.2 (11)	C4—C3—C1	120.91 (12)
N1—N2—H2N	120.8 (11)	C5—C4—C3	119.01 (14)
C2—N3—C1	102.81 (10)	C5—C4—H4	120.5
C2—N4—H4A	116.4 (10)	C3—C4—H4	120.5
C2—N4—H4B	112.7 (10)	C6—C5—C4	119.12 (14)
H4A—N4—H4B	117.2 (14)	C6—C5—H5	120.4
C7—N5—C3	117.65 (12)	C4—C5—H5	120.4
N1—C1—N3	115.02 (12)	C5—C6—C7	118.36 (14)
N1—C1—C3	122.04 (12)	C5—C6—H6	120.8
N3—C1—C3	122.94 (11)	C7—C6—H6	120.8
N3—C2—N2	110.03 (12)	N5—C7—C6	123.76 (15)
N3—C2—N4	127.19 (11)	N5—C7—H7	118.1
N2—C2—N4	122.71 (12)	C6—C7—H7	118.1

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N···N5ⁱ	0.90 (2)	2.01 (2)	2.9010 (16)	171 (1)
N4—H4A···N3ⁱⁱ	0.90 (2)	2.11 (2)	2.9971 (16)	172 (1)
N4—H4B···N1ⁱ	0.93 (2)	2.19 (2)	3.0264 (16)	151 (1)

Symmetry codes: (i) −x+3/2, y−1/2, −z+3/2; (ii) −x+1, −y, −z+1.

Experimental details

Crystal data
Chemical formula	C₇H₇N₅
M_r	161.18
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	223
a, b, c (Å)	7.3863 (6), 7.9096 (6), 13.2157 (11)
β (°)	91.832 (2)
V (Å³)	771.70 (11)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.10
Crystal size (mm)	0.36 × 0.16 × 0.12

Data collection
Diffractometer	Bruker SMART APEX CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2001)
T_min, T_max	0.967, 0.989
No. of measured, independent and observed [I > 2σ(I)] reflections	5336, 1772, 1519
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.110, 1.05
No. of reflections	1772
No. of parameters	121
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.21, −0.20

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2N···N5ⁱ	0.90 (2)	2.01 (2)	2.9010 (16)	171 (1)
N4—H4A···N3ⁱⁱ	0.90 (2)	2.11 (2)	2.9971 (16)	172 (1)
N4—H4B···N1ⁱ	0.93 (2)	2.19 (2)	3.0264 (16)	151 (1)

Symmetry codes: (i) −x+3/2, y−1/2, −z+3/2; (ii) −x+1, −y, −z+1.

Acknowledgements

This work was supported by the National Medical Research Council, Singapore (grant Nos. NMRC/NIG/0019/2008 and NMRC/NIG/0020/2008).

References

Bruker (2001). SMART and SAINT. Bruker AXS GmbH, Karlsruhe, Germany. Google Scholar
Buzykin, B. I., Mironova, E. V., Nabiullin, V. N., Gubaidullin, A. T. & Litvinov, I. A. (2006). Russ. J. Gen. Chem. 76, 1471–1486. Web of Science CrossRef CAS Google Scholar
Dolzhenko, A. V., Dolzhenko, A. V. & Chui, W. K. (2006). Heterocycles, 68, 1723–1759. CAS Google Scholar
Dolzhenko, A. V., Dolzhenko, A. V. & Chui, W. K. (2007a). Heterocycles, 71, 429–436. CAS Google Scholar
Dolzhenko, A. V., Dolzhenko, A. V. & Chui, W. K. (2007b). Tetrahedron, 63, 12888–12895. Web of Science CrossRef CAS Google Scholar
Ferrer, S., Ballesteros, R., Sambartolome, A., Gonzalez, M., Alzuet, G., Borras, J. & Liu, M. (2004). J. Inorg. Biochem. 98, 1436–1446. Web of Science CSD CrossRef PubMed CAS Google Scholar
Fischer, G. (2007). Adv. Heterocycl. Chem. 95, 143–219. Web of Science CrossRef Google Scholar
Sheldrick, G. M. (2001). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar