4-Amino-2-(p-chloro­phenyl)-5-methyl-3,4-di­hydro-2H-1,2,4-triazol-3-one

In the title compound, C₉H₉ClN₄O, the dihedral angle between the substituted phenyl and triazole rings is 4.86 (5)°. In the crystalline state, the mol­ecules exist as centrosymmetrically related N—H...O hydrogen-bonded dimers.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.042
• wR factor = 0.117
• Data-to-parameter ratio = 14.2

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level B:



CELLV_02  Alert B The supplied cell volume s.u. differs from that
          calculated from the cell parameter s.u.'s by > 4
          Calculated cell volume su =      20.63
          Cell volume su given      =      16.00

REFLT_03
         From the CIF: _diffrn_reflns_theta_max           27.82
         From the CIF: _reflns_number_total               2060
         TEST2: Reflns within _diffrn_reflns_theta_max
         Count of symmetry unique reflns         2372
         Completeness (_total/calc)             86.85%
          Alert B: < 90% complete (theta max?)


 Alert Level C:



CRYSC_01  Alert C There is an ordering error in _exptl_crystal_colour.
          It should be (QUALIFIER) (INTENSITY) (BASE_COLOUR).


 0 Alert Level A = Potentially serious problem

 2 Alert Level B = Potential problem

 1 Alert Level C = Please check

---

S1. Comment

The amino functionalized triazole derivatives serve as starting compounds for heterocyclic synthesis. The triazole moiety possesses many pharmacological properties, e.g. antimicrobial (Habib et al., 1997), antiviral (Ergen et al., 1996), anti-HIV-1 (Invidiata et al., 1996), antifungal, antimycobacterial and anticonvulsant (Gu¨lerman et al., 1997). It is also a highly potent eosinophilia inhibitor (Naito et al., 1996) and used as fungicide (Crofton, 1996) and herbicide (Tada et al., 1995). Some triazole derivatives have been evaluated for their antibacterial activity against both Gram-positive and Gram-negative bacteria (Bs et al., 1996). In view of these findings, the structure determination of the title compound, (I), was undertaken.

A perspective view of (I), including the atomic numbering scheme, is shown in Fig. 1. The bond lengths and angles in (I) are unexceptional (Table 1) and comparable with those reported for related structures (Chen et al., 1998; Wang et al., 1998; Thamotharan, Parthasarathi, Sunagar et al., 2003; Thamotharan, Parthasarathi, Hunnur et al., 2003). The sum of bond angles around N41 is 320° which indicates pyramidal geometry at N41. The dihedral angle between phenyl and triazole rings is 4.86 (5)°, while the same angles in chloro (Thamotharan, Parthasarathi, Sunagar et al., 2003) and bromo (Thamotharan, Parthasarathi, Hunnur et al., 2003) derivatives of triazole are 30.63 (9) and 8.93 (14)°, respectively. In the crystal structure, centrosymmetrically related molecules form dimeric pairs through N—H···O intermolecular hydrogen bonds (Fig. 2) and have a graph-set motif of R²₂(10) (Table 2) (Bernstein et al., 1995).

S2. Experimental

The title compound prepared by heating 3-(4-chlorophenyl)-5-methyl-1,3,4-oxadiazolin-2-one with hydrazine hydrate in ethanol. The solid obtained, (I), was crystallized from absolute ethanol (m.p. 458–459 K).

S3. Refinement

The structure was solved with DIRDIF99 (Beurskens et al., 1999) using the TRACOR option, with the input Cl atom at the origin. The positions of the amino H atoms were located from difference Fourier map and refined freely along with its isotropic displacement parameter. The methyl H atoms were constrained to an ideal geometry (C—H = 0.96 Å), with U_iso(H) = 1.5U_eq(C), but were allowed to rotate freely about the parent C—C bond. All remaining H atoms were placed in geometrically idealized position (C—H = 0.93 Å) and constrained to ride on their parent atoms with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: IPDS Software Package (Stoe & Cie, 1997); cell refinement: IPDS Software Package; data reduction: IPDS Software Package; program(s) used to solve structure: DIRDIF99 (Beurskens et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

Figures

	Fig. 1. A view of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented by circles of arbitrary radii.
	Fig. 2. Connection of molecules into dimers [symmetry codes: (*) 1 − x, 2 − y, 1 − z; (#) −x, 2 − y, 1 − z]. H atoms bonded to C atoms have been omitted for clarity.

4-Amino-2-(p-chlorophenyl)-5-methyl-3,4-dihydro-2H-1,2,4-triazol-3-one

Crystal data

C9H9ClN4O	Z = 2
Mr = 224.65	F(000) = 232
Triclinic, P1	Dx = 1.492 Mg m^−3
Hall symbol: -P 1	Melting point: 458 K
a = 4.0135 (8) Å	Mo Kα radiation, λ = 0.71073 Å
b = 11.691 (2) Å	Cell parameters from 4074 reflections
c = 11.986 (2) Å	θ = 12.2–27.9°
α = 117.09 (3)°	µ = 0.36 mm^−1
β = 90.79 (3)°	T = 293 K
γ = 91.89 (3)°	Platelet, translucent colourless
V = 500.17 (16) Å^3	0.61 × 0.30 × 0.15 mm

Data collection

Stoe IPDS diffractometer	1807 reflections with I > 2σ(I)
Radiation source: sealed LFF X-ray tube, 12 x 0.4 mm	Rint = 0.024
Plane graphite monochromator	θmax = 27.8°, θmin = 3.9°
Detector resolution: 9 pixels mm^-1	h = −4→4
rotation method scans	k = −15→15
4391 measured reflections	l = −15→15
2060 independent reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.042	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.117	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0674P)^2 + 0.0798P] where P = (Fo^2 + 2Fc^2)/3
2060 reflections	(Δ/σ)max < 0.001
145 parameters	Δρmax = 0.17 e Å^−3
0 restraints	Δρmin = −0.17 e Å^−3

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
Cl1	1.01725 (13)	0.25508 (4)	0.25344 (5)	0.0687 (2)
O3	0.2956 (3)	0.84827 (10)	0.44989 (9)	0.0522 (3)
N1	0.5942 (4)	0.74844 (12)	0.14814 (11)	0.0459 (3)
N2	0.5474 (3)	0.73160 (11)	0.25536 (10)	0.0411 (3)
N4	0.3286 (3)	0.90980 (11)	0.28987 (10)	0.0414 (3)
N41	0.1680 (5)	1.02716 (13)	0.34326 (14)	0.0534 (4)
H411	0.311 (6)	1.084 (2)	0.406 (2)	0.072 (6)*
H412	0.000 (8)	1.018 (3)	0.380 (3)	0.086 (8)*
C3	0.3821 (4)	0.83051 (12)	0.34512 (12)	0.0396 (3)
C5	0.4575 (4)	0.85647 (13)	0.17266 (13)	0.0427 (3)
C6	0.6598 (4)	0.61839 (12)	0.25724 (12)	0.0393 (3)
C7	0.7941 (5)	0.52468 (15)	0.14989 (14)	0.0513 (4)
H7	0.8086	0.5368	0.0786	0.062*
C8	0.9069 (5)	0.41330 (16)	0.14796 (16)	0.0554 (4)
H8	0.9994	0.3510	0.0761	0.066*
C9	0.8809 (4)	0.39557 (14)	0.25356 (16)	0.0488 (4)
C10	0.7467 (5)	0.48814 (16)	0.36130 (15)	0.0538 (4)
H10	0.7311	0.4750	0.4320	0.065*
C11	0.6354 (5)	0.60032 (15)	0.36411 (14)	0.0506 (4)
H11	0.5454	0.6628	0.4364	0.061*
C51	0.4467 (5)	0.91773 (17)	0.08833 (16)	0.0577 (4)
H511	0.5387	0.8618	0.0094	0.086*
H512	0.5747	0.9978	0.1259	0.086*
H513	0.2196	0.9333	0.0751	0.086*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0770 (4)	0.0466 (3)	0.0876 (4)	0.0169 (2)	0.0015 (2)	0.0343 (2)
O3	0.0677 (8)	0.0487 (6)	0.0415 (5)	0.0181 (5)	0.0189 (5)	0.0204 (4)
N1	0.0588 (8)	0.0433 (6)	0.0374 (6)	0.0113 (5)	0.0101 (5)	0.0190 (5)
N2	0.0517 (8)	0.0361 (5)	0.0352 (5)	0.0101 (5)	0.0086 (4)	0.0154 (4)
N4	0.0472 (7)	0.0358 (5)	0.0397 (6)	0.0095 (4)	0.0050 (4)	0.0153 (4)
N41	0.0638 (10)	0.0426 (7)	0.0515 (7)	0.0214 (6)	0.0091 (6)	0.0180 (6)
C3	0.0428 (8)	0.0353 (6)	0.0374 (6)	0.0060 (5)	0.0047 (5)	0.0133 (5)
C5	0.0481 (8)	0.0401 (6)	0.0389 (6)	0.0055 (5)	0.0033 (5)	0.0169 (5)
C6	0.0411 (8)	0.0351 (6)	0.0398 (6)	0.0059 (5)	0.0042 (5)	0.0151 (5)
C7	0.0654 (11)	0.0462 (8)	0.0424 (7)	0.0165 (6)	0.0140 (6)	0.0189 (6)
C8	0.0666 (11)	0.0430 (7)	0.0506 (8)	0.0185 (7)	0.0130 (7)	0.0150 (6)
C9	0.0486 (9)	0.0381 (7)	0.0596 (9)	0.0067 (6)	0.0010 (6)	0.0217 (6)
C10	0.0665 (11)	0.0503 (8)	0.0511 (8)	0.0111 (7)	0.0076 (7)	0.0281 (7)
C11	0.0667 (11)	0.0440 (7)	0.0415 (7)	0.0141 (6)	0.0116 (6)	0.0188 (6)
C51	0.0747 (12)	0.0554 (9)	0.0517 (8)	0.0145 (8)	0.0088 (7)	0.0312 (7)

Geometric parameters (Å, º)

Cl1—C9	1.7477 (16)	C6—C11	1.394 (2)
O3—C3	1.2329 (17)	C7—C8	1.383 (2)
N1—C5	1.3017 (19)	C7—H7	0.9300
N1—N2	1.4001 (16)	C8—C9	1.377 (2)
N2—C3	1.3682 (18)	C8—H8	0.9300
N2—C6	1.4220 (18)	C9—C10	1.383 (2)
N4—C5	1.3687 (18)	C10—C11	1.386 (2)
N4—C3	1.3828 (18)	C10—H10	0.9300
N4—N41	1.4063 (17)	C11—H11	0.9300
N41—H411	0.92 (2)	C51—H511	0.9600
N41—H412	0.84 (3)	C51—H512	0.9600
C5—C51	1.482 (2)	C51—H513	0.9600
C6—C7	1.386 (2)
C5—N1—N2	104.81 (12)	C8—C7—H7	119.7
C3—N2—N1	111.97 (11)	C6—C7—H7	119.7
C3—N2—C6	128.90 (12)	C9—C8—C7	119.31 (15)
N1—N2—C6	119.10 (11)	C9—C8—H8	120.3
C5—N4—C3	109.34 (12)	C7—C8—H8	120.3
C5—N4—N41	124.21 (13)	C8—C9—C10	120.81 (14)
C3—N4—N41	126.46 (12)	C8—C9—Cl1	120.36 (13)
N4—N41—H411	105.8 (16)	C10—C9—Cl1	118.84 (13)
N4—N41—H412	108 (2)	C9—C10—C11	120.16 (15)
H411—N41—H412	106 (2)	C9—C10—H10	119.9
O3—C3—N2	130.39 (13)	C11—C10—H10	119.9
O3—C3—N4	126.73 (13)	C10—C11—C6	119.22 (14)
N2—C3—N4	102.89 (11)	C10—C11—H11	120.4
N1—C5—N4	110.99 (13)	C6—C11—H11	120.4
N1—C5—C51	125.64 (13)	C5—C51—H511	109.5
N4—C5—C51	123.36 (14)	C5—C51—H512	109.5
C7—C6—C11	119.98 (13)	H511—C51—H512	109.5
C7—C6—N2	118.75 (13)	C5—C51—H513	109.5
C11—C6—N2	121.28 (13)	H511—C51—H513	109.5
C8—C7—C6	120.53 (15)	H512—C51—H513	109.5
C5—N1—N2—C3	−0.16 (17)	N41—N4—C5—C51	0.9 (2)
C5—N1—N2—C6	177.82 (13)	C3—N2—C6—C7	173.75 (15)
N1—N2—C3—O3	179.45 (15)	N1—N2—C6—C7	−3.8 (2)
C6—N2—C3—O3	1.7 (3)	C3—N2—C6—C11	−5.9 (2)
N1—N2—C3—N4	−0.19 (15)	N1—N2—C6—C11	176.50 (14)
C6—N2—C3—N4	−177.92 (13)	C11—C6—C7—C8	−0.5 (3)
C5—N4—C3—O3	−179.20 (15)	N2—C6—C7—C8	179.87 (15)
N41—N4—C3—O3	0.8 (3)	C6—C7—C8—C9	0.8 (3)
C5—N4—C3—N2	0.46 (16)	C7—C8—C9—C10	−0.6 (3)
N41—N4—C3—N2	−179.57 (15)	C7—C8—C9—Cl1	179.34 (14)
N2—N1—C5—N4	0.46 (17)	C8—C9—C10—C11	0.2 (3)
N2—N1—C5—C51	178.96 (15)	Cl1—C9—C10—C11	−179.78 (14)
C3—N4—C5—N1	−0.61 (18)	C9—C10—C11—C6	0.1 (3)
N41—N4—C5—N1	179.42 (14)	C7—C6—C11—C10	0.0 (3)
C3—N4—C5—C51	−179.15 (14)	N2—C6—C11—C10	179.67 (15)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N41—H411···O3^i	0.92 (2)	2.17 (2)	3.043 (3)	159 (2)
N41—H412···O3^ii	0.84 (3)	2.30 (3)	2.958 (2)	135 (2)

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