4-Amino-3,5-bis­(1-hydroxy­ethyl)-4H-1,2,4-triazole

In the title compound, C₄H₈N₄O₂, which was synthesized by the reaction of lactic acid with hydrazine hydrate under solvent-free conditions, all bond lengths and angles are normal. In the crystal structure, inter­molecular O—H...N and N—H...O hydrogen bonds link the mol­ecules into two-dimensional corrugated sheets parallel to the bc plane.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.039
• wR factor = 0.106
• Data-to-parameter ratio = 12.0

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S1. Comment

In this paper, we present the title compound, 4-amino-3,5-bis(1-hydroxyethyl)-l,2,4-triazole, (I), synthesized through the condensation of lactic acid and hydrazine hydrate under solvent-free conditions.

In (I) (Fig. 1), all bond lengths and angles are normal and comparable to those observed in the complex [Cu(L)₂] (HL=4-salicylideneamino-3,5-dimethanol-1,2,4-triazole) (Yi et al., 2004)

In the crystal, there exist typical intermolecular N—H···O and O—H···N hydrogen bonds (Table 1), which assemble the molecules into infinite two-dimensional sheets (Fig. 2).

Related literature

In the complex [Cu(L)₂] (HL=4-salicylideneamino-3,5-dimethanol-1,2,4-triazole) (Yi et al., 2004), all bond lengths and angles in L are comparable with those found in the title compound.

S2. Experimental

A mixture of lactic acid (1 mmol) and hydrazine hydrate (1.05 mmol) was well stirred at room temperature for 10 minutes. The crude compound was purified by silica gel column chromatography. Elemental analysis: calculated for C₄H₈N₄O₂: C 33.33, H 5.59, N 38.87%; found: C 33.38, H 5.52, N 38.75%.

S3. Refinement

The methylene H atoms were placed in idealized positions and constrained to ride on their parent atoms with methylene C—H distances of 0.97 Å. The U_iso(H) values were set at 1.2U_eq(C). The hydroxy H atoms were placed in idealized positions and constrained to ride on their parent atoms with O—H distances of 0.82 Å. The U_iso(H) values were set at 1.5 U_eq(O). The amino H atoms were placed in idealized positions and constrained to ride on their parent atoms with N—H distances of 0.90 Å. The U_iso(H) values were set at 1.2 U_eq(N).

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SMART; data reduction: SAINT (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. ORTEP drawing of the title complex with atomic numbering scheme and thermal ellipsoids at 30% probability level.
	Fig. 2. A perspective view of the crystal packing of (I). Dashed lines denote intermolecular hydrogen bonds.

4-Amino-3,5-bis(1-hydroxyethyl)-4H-1,2,4-triazole

Crystal data

C4H8N4O2	Dx = 1.530 Mg m^−3
Mr = 144.14	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbca	Cell parameters from 2134 reflections
a = 8.7936 (17) Å	θ = 2.5–27.6°
b = 8.8609 (18) Å	µ = 0.12 mm^−1
c = 16.058 (2) Å	T = 298 K
V = 1251.3 (4) Å^3	Block, colourless
Z = 8	0.54 × 0.47 × 0.40 mm
F(000) = 608

Data collection

Bruker SMART CCD area-detector diffractometer	1107 independent reflections
Radiation source: fine-focus sealed tube	853 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.048
φ and ω scans	θmax = 25.0°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −5→10
Tmin = 0.936, Tmax = 0.952	k = −10→9
4961 measured reflections	l = −19→17

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.039	H-atom parameters constrained
wR(F^2) = 0.106	w = 1/[σ^2(Fo^2) + (0.045P)^2 + 0.8519P] where P = (Fo^2 + 2Fc^2)/3
S = 1.00	(Δ/σ)max < 0.001
1107 reflections	Δρmax = 0.21 e Å^−3
92 parameters	Δρmin = −0.20 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997a), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.061 (4)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
N1	−0.06178 (18)	0.76742 (18)	0.23561 (10)	0.0344 (4)
N2	0.05790 (18)	0.66499 (18)	0.23983 (10)	0.0349 (4)
N3	0.01255 (17)	0.71644 (17)	0.10961 (9)	0.0307 (4)
N4	0.0336 (2)	0.7147 (2)	0.02318 (10)	0.0443 (5)
H4A	0.0599	0.8063	0.0037	0.053*
H4B	−0.0503	0.6824	−0.0034	0.053*
O1	0.16445 (16)	0.38730 (15)	0.11444 (8)	0.0402 (4)
H1	0.1196	0.3501	0.1542	0.060*
O2	−0.13453 (18)	1.04642 (15)	0.10268 (8)	0.0444 (5)
H2	−0.0956	1.0836	0.1443	0.067*
C1	0.1008 (2)	0.6365 (2)	0.16332 (11)	0.0307 (5)
C2	−0.0871 (2)	0.7968 (2)	0.15687 (11)	0.0304 (5)
C3	0.2228 (2)	0.5305 (2)	0.13717 (13)	0.0385 (5)
H3A	0.2771	0.5733	0.0902	0.046*
H3B	0.2945	0.5182	0.1825	0.046*
C4	−0.2009 (2)	0.9057 (2)	0.12349 (12)	0.0378 (5)
H4C	−0.2482	0.8629	0.0743	0.045*
H4D	−0.2798	0.9215	0.1648	0.045*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0390 (9)	0.0334 (9)	0.0310 (9)	0.0043 (7)	0.0023 (7)	0.0010 (7)
N2	0.0402 (10)	0.0332 (9)	0.0313 (9)	0.0032 (8)	0.0007 (7)	0.0027 (7)
N3	0.0347 (9)	0.0327 (9)	0.0246 (8)	−0.0026 (7)	0.0005 (6)	−0.0009 (7)
N4	0.0573 (12)	0.0504 (11)	0.0253 (9)	0.0000 (9)	0.0020 (8)	0.0000 (8)
O1	0.0542 (9)	0.0333 (8)	0.0331 (8)	0.0002 (7)	0.0046 (6)	−0.0030 (6)
O2	0.0614 (10)	0.0369 (9)	0.0350 (8)	−0.0017 (7)	−0.0072 (7)	0.0048 (6)
C1	0.0315 (10)	0.0287 (10)	0.0320 (10)	−0.0039 (8)	0.0007 (8)	0.0008 (8)
C2	0.0321 (10)	0.0280 (10)	0.0312 (10)	−0.0036 (8)	−0.0008 (8)	−0.0010 (8)
C3	0.0365 (11)	0.0379 (11)	0.0411 (11)	0.0003 (9)	0.0044 (9)	0.0007 (9)
C4	0.0378 (11)	0.0387 (11)	0.0369 (11)	0.0020 (9)	−0.0051 (9)	0.0007 (9)

Geometric parameters (Å, º)

N1—C2	1.310 (2)	O1—H1	0.8200
N1—N2	1.391 (2)	O2—C4	1.417 (2)
N2—C1	1.310 (2)	O2—H2	0.8200
N3—C1	1.359 (2)	C1—C3	1.486 (3)
N3—C2	1.361 (2)	C2—C4	1.489 (3)
N3—N4	1.400 (2)	C3—H3A	0.9700
N4—H4A	0.9000	C3—H3B	0.9700
N4—H4B	0.9000	C4—H4C	0.9700
O1—C3	1.417 (2)	C4—H4D	0.9700
C2—N1—N2	107.79 (14)	N1—C2—C4	126.18 (17)
C1—N2—N1	107.30 (15)	N3—C2—C4	124.81 (17)
C1—N3—C2	106.64 (15)	O1—C3—C1	112.19 (16)
C1—N3—N4	123.21 (16)	O1—C3—H3A	109.2
C2—N3—N4	130.08 (16)	C1—C3—H3A	109.2
N3—N4—H4A	111.6	O1—C3—H3B	109.2
N3—N4—H4B	111.4	C1—C3—H3B	109.2
H4A—N4—H4B	109.5	H3A—C3—H3B	107.9
C3—O1—H1	109.5	O2—C4—C2	112.22 (16)
C4—O2—H2	109.5	O2—C4—H4C	109.2
N2—C1—N3	109.32 (16)	C2—C4—H4C	109.2
N2—C1—C3	126.46 (17)	O2—C4—H4D	109.2
N3—C1—C3	124.19 (17)	C2—C4—H4D	109.2
N1—C2—N3	108.94 (16)	H4C—C4—H4D	107.9

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2···N2^i	0.82	2.02	2.820 (2)	164
N4—H4B···O1^ii	0.90	2.14	2.955 (2)	151
N4—H4A···O2^iii	0.90	2.25	3.058 (2)	150
O1—H1···N1^iv	0.82	1.98	2.782 (2)	165

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