1138
YAROVENKO et al.
N-(4-Chlorophenyl)-5-(trichloromethyl)-1,3,4-
Synthesis of 5-aryl-1,3,4-thiadiazole-2-carb-
oxamides VIa c. A mixture of 1 mmol of thiohydr-
azide IVa, c and 1.1 mmol of aldehyde in 6 ml of
ethanol was boiled for 15 min. To the reaction mix-
ture obtained a solution was added of 2 mmol of
iron(III) chloride hexahydrate in 5 ml of ethanol, and
the mixture was heated for 1.5 h more. Then the reac-
tion mixture was cooled to room temperature, the
separated precipitate was filtered off, twice washed
with 3 ml of ethanol, with 5 ml of water, and dried in
air.
thiadiazole-2-carboxamide (Vf). Yield 62%, mp
165 167 C. 1H NMR spectrum, , ppm (J, Hz):
7.4 d (2H, Harom, J 8.73); 7.9 d (2H, Harom,
J 8.72); 11.40 s (1H, NH). Mass spectrum, m/z: 357
[M]+ . Found, %: C 33.72; H 1.53; Cl 39.64;
N 11.85; S 9.05. C10H5Cl4N3OS. Calculated, %:
C 33.64; H 1.41; Cl 39.72; N 11.77; S 8.98.
N-(4-Methoxyphenyl)-5-(trichloromethyl)-1,3,4-
thiadiazole-2-carboxamide (Vg). Yield 75%, mp
1
157 158 C. H NMR spectrum, , ppm (J, Hz): 4.7 s
(3H, CH3); 6.9 d (2H, Harom, J 8.83); 7.80 d (2H,
Harom, J 8.84); 11.20 s (1H, NH). Mass spectrum,
m/z: 352 [M]+ . Found, %: C 37.34; H 2.20;
Cl 30.29; N 12.04; S 9.15. C11H8Cl3N3O2S. Cal-
culated, %: C 37.47; H 2.29; Cl 30.16; N 11.92;
S 9.09.
N-Phenyl-5-phenyl-1,3,4-thiadiazole-2-carb-
oxamide (VIa). Yield 70%, mp 228 230 C.
1H NMR spectrum, , ppm (J, Hz): 7.1 t (1H,
Harom, J 7.37); 7.25 t (1H, Harom, J 7.38); 7.6 m
(4 H, Harom); 7.8 d (2 H, Harom, J 7.92); 8.1 d
(2H, Harom, J 7.92); 11.0 s (1H, NH). Mass spec-
trum, m/z: 281 [M]+ . Found, %: C 63.92; H 4.01;
N 15.09; S 11.32. C15H11N3OS. Calculated, %: C
64.04; H 3.94; N 14.94; S 11.40.
N-(2,3-Dimethylphenyl)-5-(trichloromethyl)-
1,3,4-thiadiazole-2-carboxamide (Vh). Yield 52%,
1
mp 138 140 C. H NMR spectrum, , ppm (J, Hz):
2.1 s (3H, CH3); 2.2 s (3H, CH3); 7.10 7.20 m (3H,
Harom); 10.85 s (1H, NH). Mass spectrum, m/z: 349
[M]+ . Found, %: C 41.21; H 2.95; Cl 30.36;
N 11.86; S 9.03. C12H10Cl3N3OS. Calculated, %:
C 41.10; H 2.87; Cl 30.33; N 11.98; S 9.14.
N-Phenyl-5-(4-nitrophenyl)-1,3,4-thiadiazole-2-
carboxamide (VIb). Yield 72%, mp 248 250 C.
1H NMR spectrum, , ppm (J, Hz): 7.1 t (1H,
Harom, J 7.92); 7.35 t (2H, Harom, J 7.38); 7.65 m
(4H, Harom); 8.4 d (2H, Harom, J 7.92); 11.0 s
(1H, NH). Mass spectrum, m/z: 326 [M]+ . Found,
%: C 55.11; H 3.03; N 17.12; S 9.95. C15H10N4O3S.
Calculated, %: C 55.21; H 3.09; N 17.17; S 9.83.
5-(Dichloromethyl)-1,3,4-thiadiazole-2-carbox-
amide Vi. To 10 mmol of oxamic acid thiohydraside
IVi in 5 ml of DMF was added 20 ml of dichloro-
acetyl chloride. After 4 h the reaction mixture was
poured into water, the separated precipitate was
filtered off and recrystallized from ethanol. Yield
N-(4-Methoxyphenyl)-5-phenyl-1,3,4-thiadiazole-
2-carboxamide (VIc). Yield 67%, mp 225 226 C.
1H NMR spectrum, , ppm (J, Hz): 3.8 s (3H, CH3);
7.0 d (2H, Harom, J 8.83); 7.6 m (3H, Harom);
7.8 m (2H, Harom); 8.1 d (2H, Harom, J 7.92);
11.0 s (1H, NH). Mass spectrum, m/z: 311 [M]+ .
Found, %: C 61.64; H 4.33; N 13.39; S 10.43.
C16H13N3O2S. Calculated, %: C 61.72; H 4.21;
N 13.50; S 10.30.
1
78%, mp 133 135 C. H NMR spectrum, , ppm (J,
Hz): 4.7 s (3H, CH3); 6.4 s (1H, CH3); 6.9 d (2H,
Harom, J 8.83); 7.80 d (2H, Harom, J 8.84); 11.20 s
(1H, NH). Mass spectrum, m/z: 318 [M]+ . Found,
%: C 41.65; H 2.73; Cl 22.32; N 13.19; S 10.01.
C11H9Cl2N3O2S. Calculated, %: C 41.52; H 2.85;
Cl 22.28; N 13.21; S 10.08.
Ethyl 5-{[(4-methoxyphenyl)amino]carbonyl}-
1,3,4-thiadiazole-2-carboxylate (VIIa). To 10 mmol
of oxamic acid thiohydrazide IVc in 5 ml of DMF
was added 20 mmol of methyl oxalyl chloride. In 4 h
the separated precipitate was filtered off and recrystal-
lyzed from methanol. Yield 72%, mp 135 138 C.
1H NMR spectrum, , ppm (J, Hz): 2.5 t (3H, CH3);
4.5 d (2H, CH2); 3.8 s (3H, CH3); 6.9 d (2H, Harom,
J 8.83); 7.80 d (2H, Harom, J 8.84); 11.20 s (1H,
NH). Mass spectrum, m/z: 307 [M]+ . Found, %:
C 50.92; H 4.14; N 13.73; S 10.55. C13H13N3O4S.
Calculated, %: C 50.81; H 4.26; N 13.67; S 10.43.
5-(Chloromethyl)-1,3,4-thiadiazole-2-carbox-
amide Vj. To 10 mmol of oxamic acid thiohydraside
IVc in 5 ml of DMF was added 20 ml of monochloro-
acetyl chloride. After 4 h the reaction mixture was
poured into water, the separated precipitate was
filtered off and recrystallized from ethanol. Yield
1
51%, mp 146 148 C. H NMR spectrum, , ppm (J,
Hz): 4.7 s (3H, CH3); 6.9 d (2H, Harom, J 8.83);
7.80 d (2H, Harom, J 8.84); 11.20 s (1H, NH). Mass
spectrum, m/z: 283 [M]+ . Found, %: C 46.44;
H 3.46; Cl 12.61; N 14.74; S 11.45. C11H10ClN3O2S.
Calculated, %: C 46.56; H 3.55; Cl 12.49; N 14.81;
S 11.30.
tert-Butyl
5-{[(4-methoxyphenyl)amino]carb-
onyl}-1,3,4-thiadiazole-2-carboxylate (VIIb). To
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 39 No. 8 2003