5-(2,6-Difluoro­phen­yl)-1,3,4-thia­diazol-2-amine

Wang, Y.; Wan, R.; Han, F.; Wang, P.

doi:10.1107/S1600536809047990

organic compounds

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ISSN: 2056-9890

Volume 65| Part 12| December 2009| Page o3108

doi:10.1107/S1600536809047990

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5-(2,6-Difluorophenyl)-1,3,4-thiadiazol-2-amine

Yao Wang,^a Rong Wan,^a ^* Feng Han ^a and Peng Wang ^a

^aDepartment of Applied Chemistry, College of Science, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing, Nanjing 210009, People's Republic of China
^*Correspondence e-mail: rwan@njut.edu.cn

(Received 6 May 2009; accepted 12 November 2009; online 18 November 2009)

The title compound, C₈H₅F₂N₃S, was synthesized by the reaction of 2,6-difluorobenzoic acid and thiosemicarbazide. The dihedral angle between the thiadiazole and phenyl ring is 35.19 (14)°. In the crystal structure, intermolecular N—H⋯N hydrogen bonds form chains along the b and c axes.

Related literature

For the biological activity of 1,3,4-thiadiazole derivatives, see: Nakagawa et al. (1996 ); Wang et al. (1999 ). For bond-length data see: Allen et al. (1987 ).

Experimental

Crystal data

C₈H₅F₂N₃S
M_r = 213.21
Monoclinic, P 2₁ /c
a = 9.0920 (18) Å
b = 8.7400 (17) Å
c = 10.936 (2) Å
β = 95.85 (3)°
V = 864.5 (3) Å³
Z = 4
Mo Kα radiation
μ = 0.37 mm⁻¹
T = 293 K
0.20 × 0.10 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (North et al., 1968 ) T_min = 0.931, T_max = 0.964
1670 measured reflections
1568 independent reflections
1189 reflections with I > 2σ(I)
R_int = 0.018
3 standard reflections every 200 reflections intensity decay: 1%

Refinement

R[F² > 2σ(F²)] = 0.042
wR(F²) = 0.109
S = 1.01
1568 reflections
127 parameters
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3A⋯N2ⁱ	0.86	2.17	3.017 (4)	166
N3—H3B⋯N1ⁱⁱ	0.86	2.30	3.088 (3)	152
Symmetry codes: (i) -x+1, -y+1, -z; (ii) $[x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ .

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1989 ); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995 ); 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: SHELXL97.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809047990/rn2058sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809047990/rn2058Isup2.hkl

checkCIF report

Comment top

1,3,4-Thiadiazole derivatives represent a class of biologically important compounds, which often exhibit insecticidal, fungicidal and other biological activities (Nakagawa et al., 1996; Wang et al., 1999). We report here the crystal structure of the title compound, (I).

The molecular structure of (I) is shown in Fig.1, in which the bond lengths and angles are generally within normal ranges (Allen et al., 1987). The dihedral angle between the thiadiazole and phenyl ring is 35.19 (14)°. In the crystal structure, intermolecular N—H···N hydrogen bonds (Fig. 2) form chains along the b and c axes. There are also intermolecular N-H···S contacts between the molecules, which may further stabilize the structure.

Related literature top

For the biological activity of 1,3,4-thiadiazole derivatives, see: Nakagawa et al. (1996); Wang et al. (1999). For bond-length data see: Allen et al. (1987).

Experimental top

2,6-difluorobenzoic acid (2 mmol) and thiosemicarbazide (5 mmol) were mixed in a 25 ml flask, and kept in the oil bath at 90°C for 6 h. After cooling, the crude product (I) precipitated and was filtrated. Pure compound (I) was obtained by crystallization from ethanol (20 ml). Crystals of (I) suitable for X-ray diffraction were obtained by slow evaporation of an acetone solution.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1989); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1989); data reduction: XCAD4 (Harms & Wocadlo, 1995); 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: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. A view of the molecular structure of (I). Displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Partial packing view showing the hydrogen-bonded network. Dashed lines indicate intermolecular N—H···N hydrogen bonds and intermolecular N-H···S contacts between the molecules.

5-(2,6-Difluorophenyl)-1,3,4-thiadiazol-2-amine top

Crystal data top

C₈H₅F₂N₃S	D_x = 1.638 Mg m⁻³
M_r = 213.21	Melting point: 533 K
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 9.0920 (18) Å	Cell parameters from 25 reflections
b = 8.7400 (17) Å	θ = 10–13°
c = 10.936 (2) Å	µ = 0.37 mm⁻¹
β = 95.85 (3)°	T = 293 K
V = 864.5 (3) Å³	Block, colorless
Z = 4	0.20 × 0.10 × 0.10 mm
F(000) = 432

Data collection top

Enraf–Nonius CAD-4 diffractometer	1189 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.018
Graphite monochromator	θ_max = 25.3°, θ_min = 2.3°
ω/2θ scans	h = 0→10
Absorption correction: ψ scan (North et al., 1968)	k = 0→10
T_min = 0.931, T_max = 0.964	l = −13→13
1670 measured reflections	3 standard reflections every 200 reflections
1568 independent reflections	intensity decay: 1%

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) = 0.109	H-atom parameters constrained
S = 1.01	w = 1/[σ²(F_o²) + (0.060P)² + 0.150P] where P = (F_o² + 2F_c²)/3
1568 reflections	(Δ/σ)_max < 0.001
127 parameters	Δρ_max = 0.26 e Å⁻³
0 restraints	Δρ_min = −0.28 e Å⁻³

Crystal data top

C₈H₅F₂N₃S	V = 864.5 (3) Å³
M_r = 213.21	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 9.0920 (18) Å	µ = 0.37 mm⁻¹
b = 8.7400 (17) Å	T = 293 K
c = 10.936 (2) Å	0.20 × 0.10 × 0.10 mm
β = 95.85 (3)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	1189 reflections with I > 2σ(I)
Absorption correction: ψ scan (North et al., 1968)	R_int = 0.018
T_min = 0.931, T_max = 0.964	3 standard reflections every 200 reflections
1670 measured reflections	intensity decay: 1%
1568 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.042	0 restraints
wR(F²) = 0.109	H-atom parameters constrained
S = 1.01	Δρ_max = 0.26 e Å⁻³
1568 reflections	Δρ_min = −0.28 e Å⁻³
127 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
S	0.68075 (8)	0.14488 (8)	0.16016 (6)	0.0423 (2)
F1	0.8904 (2)	0.0561 (2)	−0.18276 (16)	0.0637 (5)
N1	0.6608 (3)	0.1922 (3)	−0.07123 (19)	0.0475 (6)
C1	0.8942 (4)	−0.3350 (4)	−0.0851 (3)	0.0606 (9)
H1B	0.9319	−0.4285	−0.1078	0.073*
F2	0.6767 (2)	−0.1812 (2)	0.14183 (15)	0.0616 (5)
N2	0.6037 (3)	0.3224 (3)	−0.02139 (19)	0.0495 (6)
C2	0.9208 (3)	−0.2061 (4)	−0.1510 (3)	0.0531 (8)
H2B	0.9784	−0.2110	−0.2165	0.064*
N3	0.5574 (3)	0.4251 (3)	0.1678 (2)	0.0521 (7)
H3A	0.5209	0.5074	0.1338	0.062*
H3B	0.5620	0.4143	0.2462	0.062*
C3	0.8608 (3)	−0.0705 (3)	−0.1185 (2)	0.0442 (7)
C4	0.7736 (3)	−0.0549 (3)	−0.0209 (2)	0.0362 (6)
C5	0.7556 (3)	−0.1889 (3)	0.0433 (3)	0.0446 (7)
C6	0.8123 (4)	−0.3281 (3)	0.0144 (3)	0.0571 (8)
H6A	0.7961	−0.4149	0.0603	0.069*
C7	0.7062 (3)	0.0912 (3)	0.0101 (2)	0.0357 (6)
C8	0.6070 (3)	0.3142 (3)	0.0986 (2)	0.0376 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
S	0.0628 (5)	0.0382 (4)	0.0272 (3)	0.0092 (3)	0.0101 (3)	0.0052 (3)
F1	0.0799 (13)	0.0567 (11)	0.0601 (11)	0.0030 (10)	0.0351 (10)	0.0104 (9)
N1	0.0737 (17)	0.0411 (12)	0.0278 (11)	0.0138 (12)	0.0064 (11)	−0.0010 (9)
C1	0.069 (2)	0.0476 (18)	0.065 (2)	0.0180 (16)	0.0049 (17)	−0.0093 (16)
F2	0.0825 (13)	0.0493 (10)	0.0580 (11)	0.0069 (9)	0.0309 (10)	0.0111 (8)
N2	0.0803 (18)	0.0405 (13)	0.0280 (11)	0.0176 (12)	0.0069 (11)	0.0017 (10)
C2	0.0503 (18)	0.063 (2)	0.0471 (17)	0.0128 (16)	0.0116 (14)	−0.0065 (15)
N3	0.0824 (19)	0.0448 (13)	0.0304 (12)	0.0185 (13)	0.0128 (12)	0.0008 (10)
C3	0.0479 (16)	0.0468 (16)	0.0384 (14)	0.0020 (13)	0.0071 (13)	0.0000 (12)
C4	0.0389 (15)	0.0363 (14)	0.0333 (13)	0.0015 (11)	0.0035 (11)	−0.0016 (11)
C5	0.0468 (16)	0.0446 (15)	0.0430 (15)	0.0022 (13)	0.0077 (13)	0.0015 (13)
C6	0.069 (2)	0.0377 (16)	0.065 (2)	0.0041 (15)	0.0080 (17)	0.0039 (14)
C7	0.0432 (15)	0.0362 (13)	0.0279 (12)	0.0014 (12)	0.0051 (11)	0.0011 (11)
C8	0.0481 (16)	0.0348 (14)	0.0298 (13)	0.0042 (12)	0.0042 (11)	0.0032 (10)

Geometric parameters (Å, º) top

S—C8	1.733 (3)	C2—C3	1.367 (4)
S—C7	1.745 (2)	C2—H2B	0.9300
F1—C3	1.352 (3)	N3—C8	1.336 (3)
N1—C7	1.291 (3)	N3—H3A	0.8600
N1—N2	1.385 (3)	N3—H3B	0.8600
C1—C2	1.372 (4)	C3—C4	1.400 (4)
C1—C6	1.382 (4)	C4—C5	1.384 (4)
C1—H1B	0.9300	C4—C7	1.471 (3)
F2—C5	1.356 (3)	C5—C6	1.370 (4)
N2—C8	1.311 (3)	C6—H6A	0.9300

C8—S—C7	86.98 (12)	C5—C4—C3	114.2 (2)
C7—N1—N2	113.4 (2)	C5—C4—C7	123.0 (2)
C2—C1—C6	121.1 (3)	C3—C4—C7	122.8 (2)
C2—C1—H1B	119.5	F2—C5—C6	118.0 (2)
C6—C1—H1B	119.5	F2—C5—C4	117.4 (2)
C8—N2—N1	112.2 (2)	C6—C5—C4	124.6 (3)
C3—C2—C1	118.6 (3)	C5—C6—C1	117.8 (3)
C3—C2—H2B	120.7	C5—C6—H6A	121.1
C1—C2—H2B	120.7	C1—C6—H6A	121.1
C8—N3—H3A	120.0	N1—C7—C4	123.1 (2)
C8—N3—H3B	120.0	N1—C7—S	113.60 (19)
H3A—N3—H3B	120.0	C4—C7—S	123.26 (18)
F1—C3—C2	117.9 (2)	N2—C8—N3	123.6 (2)
F1—C3—C4	118.4 (2)	N2—C8—S	113.82 (19)
C2—C3—C4	123.7 (3)	N3—C8—S	122.63 (19)

C7—N1—N2—C8	−0.5 (4)	C2—C1—C6—C5	1.5 (5)
C6—C1—C2—C3	−1.9 (5)	N2—N1—C7—C4	−178.8 (2)
C1—C2—C3—F1	178.7 (3)	N2—N1—C7—S	0.9 (3)
C1—C2—C3—C4	0.2 (5)	C5—C4—C7—N1	−146.4 (3)
F1—C3—C4—C5	−176.8 (2)	C3—C4—C7—N1	33.2 (4)
C2—C3—C4—C5	1.6 (4)	C5—C4—C7—S	33.9 (4)
F1—C3—C4—C7	3.6 (4)	C3—C4—C7—S	−146.5 (2)
C2—C3—C4—C7	−178.0 (3)	C8—S—C7—N1	−0.7 (2)
C3—C4—C5—F2	177.7 (2)	C8—S—C7—C4	178.9 (2)
C7—C4—C5—F2	−2.7 (4)	N1—N2—C8—N3	−179.6 (3)
C3—C4—C5—C6	−2.1 (4)	N1—N2—C8—S	−0.1 (3)
C7—C4—C5—C6	177.5 (3)	C7—S—C8—N2	0.4 (2)
F2—C5—C6—C1	−179.2 (3)	C7—S—C8—N3	−180.0 (3)
C4—C5—C6—C1	0.6 (5)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3A···N2ⁱ	0.86	2.17	3.017 (4)	166
N3—H3B···N1ⁱⁱ	0.86	2.30	3.088 (3)	152

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

Experimental details

Crystal data
Chemical formula	C₈H₅F₂N₃S
M_r	213.21
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	9.0920 (18), 8.7400 (17), 10.936 (2)
β (°)	95.85 (3)
V (Å³)	864.5 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.37
Crystal size (mm)	0.20 × 0.10 × 0.10

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	ψ scan (North et al., 1968)
T_min, T_max	0.931, 0.964
No. of measured, independent and observed [I > 2σ(I)] reflections	1670, 1568, 1189
R_int	0.018
(sin θ/λ)_max (Å⁻¹)	0.600

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.042, 0.109, 1.01
No. of reflections	1568
No. of parameters	127
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.26, −0.28

Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1989), XCAD4 (Harms & Wocadlo, 1995), 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
N3—H3A···N2ⁱ	0.8600	2.1700	3.017 (4)	166.00
N3—H3B···N1ⁱⁱ	0.8600	2.3000	3.088 (3)	152.00

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

Acknowledgements

The authors gratefully acknowledge Professor Hua-Qin Wang of the Analysis Center, Nanjing University, for providing the Enraf–Nonius CAD-4 diffractometer for this research project.

References

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