1
310
M. A. Kukaniev and C. P a´ rk a´ nyi
Vol 48
Table 2
5 h and then refluxed for 10 min. After cooling the reaction
mixture was poured into ice-water (100 mL). The precipitated
compounds 5a–e were filtered off and washed with water.
2-Amino-6-fluoro-7-methyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-
The new derivatives 5.
0
ꢀ
5
R
R
Yield (%)
Mp ( C)
ꢀ
1
5
-one (5a). Yield 1.85 g (93%), mp 276 C. H NMR (DMSO-
): 2.14 ppm (c, 3H from CH ), 7.20 ppm (s, 2H from NH ), ESI
FN OS: C,
6.00; H, 2.52; N, 27.99. Found; C, 36.10; H, 2.49; N, 27.91.
-Fluoro-7-methyl-2-methylamino-1,3,4-thiadiazolo[3,2-a]pyri-
a
b
c
d
e
f
H
H
H
H
CH
93
84
84
84
67
74
73
276
288
275
126
237
182
194
d
6
3
2
3
MS: m/z (%) 201.07 (100). Anal. Calcd. for C
3
6
H
5
4
C
C
2
2
H
5
C
2
H
5
H
5
6
A(CH
2
)
2
AOA(CH
A(CH
ANHA(CH
2
)
2
A
ꢀ
1
midin-5-one (5b). Yield 1.80 g (84%), mp 288 C. H NMR
DMSO-d ): 2.21 ppm (d, 3H from CH ), 2.88 ppm (d, 3H
from CH ), 8.19 ppm (q, 1H from NH), ESI MS: m/z (%)
15.13 (100). Anal. Calcd. for C H FN OS: C, 39.25; H, 3.29;
2 5
) A
(
6
3
g
A(CH
2
)
2
2
)
2
A
3
2
7
7
4
2.26 ppm (d, 3H from CH ), ESI MS: m/z (%) 220.13 (100).
Anal. Calcd. for C H ClFN OS: C, 32.81; H, 1.38; N, 19.13.
N, 26.15. Found; C, 39.33 H, 3.24; N, 26.13.
6-Fluoro-7-methyl-2-ethylamino-1,3,4-thiadiazolo[3,2-a]pyri-
3
6
3
3
ꢀ
1
Found: C, 32.89; H, 1.33; N,19.09.
-Fluoro-7-methyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-5-one
midin-5-one (5c). Yield 1.93 g (84%), mp 275 C. H NMR
(DMSO-d ): 1.18 ppm (t, 3H from CH ), 2.23 ppm (d, 3H
6
3c). Yield 0.55 g (30%), mp 164 C. H NMR (CDCl ): 2.37
6
3
ꢀ
1
(
ppm (d, 3H from CH ), 8.78 ppm (s, 1H from CH), ESI MS:
from CH ), 3.32 ppm (q, 2H from CH ), 8.24 ppm (t, 1H from
3 2
3
3
NH), ESI MS: m/z (%) 229.13 (100). Anal. Calcd. for
C H FN OS: C, 42.10; H, 3.97; N, 24.55. Found; C, 42.16; H,
m/z (%) 186.13 (100). Anal. Calcd. for C
H, 2.18; N, 22.69. Found: C, 38.54; H, 2.16; N, 22.54.
-Ethyl-6-fluoro-7-methyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-
6
H
6
FN
3
OS: C, 38.92;
8
9
4
3.75; N, 24.43.
2-Diethylamino-6-fluoro-7-methyl-1,3,4-thiadiazolo[3,2-a]pyr-
2
ꢀ
1
ꢀ
1
imidin-5-one (5d). Yield 1.93 g, (84%), mp 126 C. H NMR
5
-one (3d). Yield 1.00g (46%), mp 148 C. H NMR (CDCl ):
3
1
ppm (q, 2H from CH
.45 ppm (t, 3H from CH ), 2.39 ppm (d, 3H from CH ), 3.15
3
(CDCl ): 1.22 ppm (t, 6H from 2 CH ), 2.27 ppm (d, 3H from
3
3
3
1
3
2
), ESI MS: m/z (%) 214.13 (100). Anal.
3 2 3
CH ), 3.45 ppm (q, 4H from 2 CH ), C NMR (CDCl ): 12.8
Calcd. for C
C, 45.17; H, 3.66; N, 19.56.
-Tert-butyl-6-fluoro-7-methyl-1,3,4-thiadiazolo[3,2-a]pyrimi-
8
H
8
FN
3
OS: C, 45.05; H, 3.78; N, 19.71. Found:
3 3 2
(CH ), 17.6 (CH ), 45.9 (CH ), 135.8 (C-7), 143.6, (C-6),
147.6 (C-2), 155.4, (C-8), 159.1 (C-5), ESI MS: m/z (%)
257.13 (100). Anal. Calcd. for C H FN OS: C, 46.86; H,
2
10
13
4
ꢀ
1
din-5-one (3e). Yield l.40 g, mp 117 C. H NMR (CDCl3):
.49 ppm (c, 9H from 3 CH ), 2.39 ppm (d, 3H from CH ),
ESI MS: m/z (%): 242.20 (100). Anal. Calcd. for
OS: C, 49.78; H, 5.01; N, 17.41; S, 13.29. Found:
C, 49.84; H, 5.55; N, 17.14; S, 13.16.
-Fluoro-7-methyl-2-phenyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-
5.11; N, 21.86; S, 12.51. Found: C, 46.97; H, 5.75; N, 21.69;
S, 12.61.
6-Fluoro-7-methyl-2-morpholin-4-yl-1,3,4-thiadiazolo[3,2-a]pyr-
1
3
3
ꢀ
1
C
10
H
12FN
3
imidin-5-one (5e). Yield 1.82 g, (67%), mp 237 C. H NMR
(CDCl ): 2.29 ppm (d, 3H from CH ), 3.50 ppm (d, 4H from 2
3
3
13
6
CH ), 3.76 ppm (d, 4H from 2 CH ), C NMR (CDCl ): 17.4
2 2 3
ꢀ
1
5
d
7
-one (3f). Yield 2.43 g (70%), mp 200 C. H NMR (DMSO-
): 2.37 ppm (d, 3H from CH ), 7.64 ppm (m, 2H from Ph-H),
.71 ppm (m, 1H from Ph-H), 8.00 ppm (m, 2H from Ph-H), ESI
3 2 2
(CH ), 48.5 (CH ), 66.0 (CH ), 144.0 (C-7), 145.9, (C-6), 151.0
6
3
(C-2), 152.8, (C-8), 160.5 (C-5), ESI MS: m/z (%) 271,20 (100).
Anal. Calcd. for C H FN O S: C, 44.44; H, 4.10; F, 7.03; N,
10
11
4 2
MS: m/z (%) 262.07 (100). Anal. Calcd. for C H FN OS: C,
8
20.88. Found; C, 44.54; H, 4.03; F, 7.10; N, 20.48.
6-Fluoro-7-methyl-2-piperidin-1-yl-1,3,4-thiadiazolo[3,2-a]pyri-
12
3
5
5.16; H, 3.09; N, 16.08. Found: C, 55.21; H, 3.02; N, 15.98.
6-Fluoro-7-methyl-2-p-tolyl-1,3,4-thiadiazolo[3,2-a]pyrimidin-
-one (3g). Yield 2.63 g (73%), mp 255 C. H NMR (DMSO-
ꢀ
1
midin-5-one (5f). Yield 2.00 g (74%), mp 182 C. H NMR
ꢀ
1
5
(CDCl ): 1.64 ppm (m, 6H from 3 CH ), 2.23 ppm (d, 3H
3
2
13
d ): 2.25 ppm (d, 3H from CH ), 2.38 ppm (c, 3H from CH ),
from CH ), 3.46 ppm (m, 4H from 2 CH ), C NMR
3 2
6
3
3
7
.41 ppm (d, 2H from Ph-H), 7.69 ppm (d, 2H from Ph-H), ESI
MS: m/z (%), 276.07 (100). Anal. Calcd. for C13 OS: C,
6.72; H, 3.66; N, 15.26. Found: C, 56.41; H, 3.59; N, 15.12.
General procedure for the preparation of 2-amino-6-flu-
oro-7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidines
5a–e). Compound 1a (2.64 g, 0.01 mol) was dissolved in
(CDCl ): 17.3 (CH3 ), 23.8 (CH ), 25.2 (CH ), 49.9 (CH ),
3 2 2 2
H10FN
3
144.0 (C-7), 145.4 (C-6), 151.0 (C-2), 154.5, (C-8), 160.1 (C-
5), ESI MS: m/z (%) 269.20 (100). Anal. Calcd. for
C H FN OS: C, 49.24; H, 4.88; N, 20.88. Found: C, 49.29;
5
11
13
4
H, 4.83 N, 20.81.
6-Fluoro-7-methyl-2-piperazin-1-yl-1,3,4-thiadiazolo[3,2-a]pyr-
(
ꢀ
1
imidin-5-one (5g). Yield 1.96 g (73%), mp 194 C. H NMR
methanol and then an amine (0.02 mol) was added with stir-
ring. The reaction mixture was stirred at room temperature for
(CDCl ): 2.55 ppm (d, 3H from CH ), 2.79 ppm (m, 4H from
3
3
Scheme 3
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet