Crystalline and molecular structure of 2-amino-5-phenyl-1,3,4-thiadiazole

Article abstract of DOI:10.1023/A:1012464204563

The crystalline and molecular structure of 2-amino-5-phenyl-1,3,4-thiadiazole was studied by the X-ray diffraction method. C₈H₇N₃S. Monoclinic crystals: a = 11.085 (3), b = 7.544 (3), c = 11. 180 (3) A; β = 115.22 (2)°; V

Full text of DOI:10.1023/A:1012464204563

Russian Journal of Organic Chemistry, Vol. 37, No. 5, 2001, pp. 721 723. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 5, 2001,
pp. 759 761.
Original Russian Text Copyright
2001 by Ishankhodzhaeva, Kadyrova, Surazhskaya, Parpiev, Koz’min.
Crystalline and Molecular Structure
of 2-Amino-5-phenyl-1,3,4-thiadiazole
1
1
2
M. M. Ishankhodzhaeva , Sh. A. Kadyrova , M. D. Surazhskaya ,
1
2
N. A. Parpiev , and P. A. Koz’min
1
Ulugbek Tashkent State University, Vuzgorodok, Tashkent, 700174 Uzbekistan
2
Kurnakov Institute of General and Inorganic Chemistry, Moscow, Russia
Received February 28, 2000
Abstract The crystalline and molecular structure of 2-amino-5-phenyl-1,3,4-thiadiazole was studied by
the X-ray diffraction method. C H N S. Monoclinic crystals: a = 11.085(3), b = 7.544(3), c = 11.180(3)
;
8
7 3
3
; dcalc = 1.404 g/cm3; (MoK ) = 0.325 mm ; Z = 4; space group P2 /c.
1
=
115.22(2) ; V = 845.8(5)
1
Molecules of 2-amino-5-phenyl-1,3,4-thiadiazole in crystal form dimers through intermolecular hydrogen
bonds, which are arranged in infinite layers parallel to the xy plane.
Interest in 1,3,4-thiadiazole derivatives is explained
by wide spectrum of their biological, pharmacological,
and antileukemic activity [1 3]. Some compounds
of this series were synthesized and were examined
1H NMR spectrum of II a triplet and two doublet
signals from protons of the phenyl ring were present
at
7.38, 7.66, and 7.73 ppm. The NH signal was
2
partially overlapped by the aromatic triplet. Figure
shows the structure of molecule II and projection
of the crystal lattice on the xz plane. Table 1 contains
coordinates of non-hydrogen atoms and their equiv-
alent isotropic temperature factors; the bond lengths
and angles are collected in Table 2; Table 3 gives
deviations of atoms from the mean-square planes, and
Table 4 contains parameters of hydrogen bonds.
1
mainly by H NMR and IR spectroscopy [4]. The
present communication reports on the results of X-ray
analysis of a single crystal of 2-amino-5-phenyl-1,3,4-
thiadiazole (II), which was synthesized by reaction of
thiosemicarbazide with benzonitrile [5]. Initially,
hydrolysis of benzonitrile in trifluoroactic acid occurs,
and the hydrolysis product reacts with thiosemicarba-
zide to give intermediate I which undergoes intra-
molecular cyclization to 2-amino-5-phenyl-1,3,4-thia-
diazole (II).
(
a)
(
b)
The IR spectrum of compound II contains bands
typical of C N bond vibrations at 1630 ( ) and
s
1
508 cm 1 ( as); stretching vibrations of the N N ,
N C N, and C S fragments give rise to absorption
at 1060, 1556, and 912 cm , respectively [6]. In the
(a) Molecular and (b) crystalline structure of 2-amino-
5-phenyl-1,3,4-thiadiazole (II).
1
1
070-4280/01/3705-0721$25.00 2001 MAIK Nauka/Interperiodica

7
22
ISHANKHODZHAEVA et al.
4
1
Table 1. Coordinates of non-hydrogen atoms ( 10 ) and
Unshared electron pairs on the N and S atoms in
3
2
their equivalent isotropic temperature factors ( 10 ,
)
molecule II are conjugated with the C N double
bonds. This follows from the lengths of the N C ,
2
8
in the molecule of 2-amino-5-phenyl-1,3,4-thiadiazole (II)
3
7
2
3
N
C , N N bonds: 1.306 (3), 1.296 (3), and
Atom
S1
x
y
z
Ua
1.383(3) , respectively (Table 2). The endocyclic
N C bond lengths are similar; they occupy an inter-
mediate place between standard values for double and
single carbon nitrogen bonds. The N atom deviates
from the mean-square plane of the heteroring by only
6819(1)
7709(3)
8424(4)
9164(5)
9202(4)
8495(5)
7742(4)
6963(3)
5919(3)
5409(4)
5762(3)
6381(3)
978(1)
1182(4)
1130(5)
2568(7)
4067(6)
4161(5)
2714(5)
386(4)
2802(4)
3989(4)
2886(3)
1488(3)
532(1)
1739(3)
3102(4)
3768(5)
3093(5)
1757(5)
1068(4)
1028(3)
427(3)
49(1)
46(1)
64(1)
82(1)
82(1)
81(1)
64(1)
42(1)
44(1)
70(1)
51(1)
49(1)
1
1
C
2
C
3
C
0
.0024
(Table 3), indicating the existence of con-
4
C
jugation between the unshared electron pair on the
amino nitrogen atom and the heterocycle; this means
that the exocyclic amino group is coplanar to the thia-
diazole ring. The dihedral angle between the latter
and the benzene ring is 34.6 . The C C bonds in
the benzene ring have approximately equal lengths in
the range 1.363 1.391 . The C1 C bond which
links the benzene and thiadiazole rings is appreciably
extended [to 1.467(4) ]. This may be due to specific
features of the crystal packing where cyclic fragments
of molecule II are arranged at a certain angle to each
other. As a result, only a weak interaction between
their -electron systems is possible.
5
C
6
C
7
C
8
C
1
N
N
1405(3)
664(2)
1502(2)
2
7
3
N
a
*
*
U = (
U a a a a )/3.
ij i j i j
Table 2. Bond lengths and bond angles in the molecule
of 2-amino-5-phenyl-1,3,4-thiadiazole (II)
Bond
d,
Bond
d,
The crystalline structure of thiadiazole II is charac-
terized by the presence of two independent molecules
A and B in a unit cell; they form a pseudocentrosym-
metric dimer through symmetric hydrogen bonds like
S1 C8
1.732(3)
1.741(3)
1.386(4)
1.389(5)
1.467(4)
1.373(5)
0.94(4)
1.369(6)
0.89(5)
1.363(6)
C
C
C
C
C
4
5
5
6
7
3
H
4
0.91(4)
1.391(5)
0.89(4)
1
7
6
S
C
C
H
H
N
1
1
1
2
2
3
3
4
6
2
7
3
2
5
6
3
2
C
C
C
C
C
C
C
C
C
C
C
C
1a
2b
1b
2a
N
H N and N H N . The dimers in crystal
0.96(4)
are linked through intermolecular N H N hydrogen
bonds involving proton of the amino group and that
nitrogen atom of the thiadiazole ring which does not
participate in the dimer formation (Table 4). Mole-
cules of type A (or B) suffer symmetry transforma-
tions with respect to the sliding reflection plane and
are linked through intermolecular hydrogen bonds,
forming infinite bilayers which are parallel to the xy
plane. Each monolayer of a given bilayer consists of
molecules of a single type (A or B).
1.296(3)
1.383(3)
1.306(3)
1.338(4)
0.899(17)
0.886(19)
N
N
N
2
8
H
C
N
4
8
1
1
1
C
H
C
3
N
N
H
H
5
1
2
C
Angle
, deg
Angle
, deg
8
1
7
6 5 5
C S C
86.88(13)
118.9(3)
121.0(3)
120.0(3)
120.4(4)
127(2)
112(2)
120.2(4)
122(3)
118(3)
120.6(4)
121(2)
118(2)
119.9(4)
123(3)
C C H
117(3)
120.0(4)
122(2)
6
1
2
7
7
1
2
1
6
5
6
C C C
C C C
EXPERIMENTAL
6
1
1 6
C C C
C C H
2
1
5
6
6
1
C C C
C C H
117(2)
1
3
2
3
7
The IR spectra (400 4000 cm ) were recorded in
C C C
N C C
124.0(3)
113.3(2)
122.6(2)
113.7(2)
111.8(2)
123.6(3)
114.3(2)
122.1(2)
119.5(17)
122(3)
1
3
2
3
7 1
KBr on a Specord 75IR spectrometer. The H NMR
C C H
N C S
1
2
2
1
7 1
spectra were obtained on XL-100 and XL-200 instru-
C C H
C C S
4
3
2
3
7
3
2
ments using CD OD as solvent and HMDS as internal
C C C
C N N
3
4
3
8
2
3
1
reference.
C C H
C N N
2
3
3
2 8
C C H
N C N
2-Amino-5-phenyl-1,3,4-thiadiazole (II) [5]. Tri-
fluoroacetic acid, 150 ml, was added to a mixture
of 50 g (0.55 mol) of thiosemicarbazide and 51.5 g
(0.5 mol) of benzonitrile. The mixture was refluxed
for 6 h under stirring and cooled to room temperature,
and dilute aqueous amonia was added. A light yellow
solid precipitated immediately. The mixture was
5
4
3
4
2 8 1
C C C
N C S
5
4
1 8 1
C C H
N C S
3
4
4
8
1
1
2
2
C C H
C N H
4
5
6
5
8 1
C C C
C N H
4
5
1 1
C C H
H N H
118(3)
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 5 2001

CRYSTALLINE AND MOLECULAR STRUCTURE OF 2-AMINO-5-PHENYL-.. .
723
Table 3. Deviations of atoms from the mean-square
ring planes in the molecule of 2-amino-5-phenyl-1,3,4-
thiadiazole (II)
X-Ray analysis of single crystals of thiadiazole II
was performed on an Enraf Nonius CAD-4 automatic
diffractometer ( MoK , graphite monochromator,
/
2 -scanning to 2
56 ). The structure was
max
Atom
S1
Deviation,
Atom
Deviation,
solved by the Peterson method and was refined by the
least-squares procedure in full-matrix approximation
using SHELXL-93 program [7]; the final divergence
factor was R 0.031 [from 1536 reflections with F >
2 (I)]. C H N S. Monoclinic crystals with the follow-
1
0.0024
0.0018
0.0036
0.0045
0.0039
0.0311
0.0024
0.7440
C
0.0043
0.0008
0.0060
0.0060
0.0008
0.0043
0.0557
0.7939
0.9415
2
2
2
N
N
C
3
3
C
8
7
3
7
4
C
C
ing unit cell parameters: a = 11.085(3), b = 7.544(3),
8
5
3
C
C
c = 11.180(3)
dcalc = 1.404 g/cm ; (MoK ) = 0.325 mm ; Z = 4;
space group P2 /c.
;
= 115.22(2) ; V = 845.8(5)
;
1
1
a
a
a
6
C
N
C
3
1
7 a
C
6
1 a
1
C
N
1
a
S
REFERENCES
Sandstrom, J., Adv. Heterocycl. Chem., 1969, vol. 9,
a
These atoms were not included in the calculation of the corre-
sponding plane.
1
2
.
.
pp. 165 177, 199 209.
Ovsesyan, T.R., Gushoglyan, L.A., and Mirzo-
yan, V.S., Arm. Khim. Zh., 1988, vol. 41, no. 3,
pp. 136 142.
Table 4. Hydrogen bond parameters in the structure of
-amino-5-phenyl-1,3,4-thiadiazole (II)
2
3
.
Adam, F.A., J. Chin. Chem. Soc., 1987, vol. 34,
pp. 111 115.
Distance,
Bond
D H
Position
of atom A
AHD,
deg
A
4. Eremin, K.I., Golovanov, A.V., Krutikov, V.I., and
Lavrent’ev, A.N., Russ. J. Gen. Chem., 1997, vol. 67,
no. 1, pp. 138 140.
D
A
D
H
H A
N1
N1
H
H
N2 1 x; 1 y; 2.974 0.914 2.068
170.7
172.6
5
.
Suzuki, N., Miwa, T., Aibara, S., Kanno, H., Taka-
mori, H., Tsubokawa, M., Ryokawa, Y., Tsukada, W.,
and Isoda, S., Chem. Pharm. Bull., 1992, vol. 40,
no. 2, pp. 357 363.
z;
N3 x; 0.5 y; 2.983 0.996 1.992
0
.5+ z;
6
.
Nakamoto, K., Infra-Red Spectra of Inorganic and
Coordination Compounds, New York: Wiley, 1963.
Translated under the title IK spektry neorganicheskikh
i koordinatsionnykh soedinenii, Moscow: Mir, 1966,
pp. 204 206.
cooled, and the precipitate was filtered off, washed
several times with hot ethanol, and dried in air. Yield
7
6%, mp 230 232 C. Crystals of II suitable for
X-ray diffraction study were obtained by recrystalliza-
tion from hot ethanol. Colorless crystals were thus
obtained.
7. Sheldrick, G.M., SHELXL93. Program for the Refine-
ment of Crystal Structures, University of Gottingen,
Germany, 1993.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 5 2001