The synthesis and antibacterial activities of 2,5-bis[(3-aryl)-1,2,4- triazolo[3,4-b]-[1,3,4] thiadiazole-6-yl]thiophenes

Article abstract of DOI:10.1080/10426500701852794

2,5-bis[(3-aryl)-1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]thiophenes 2 were synthesized in high yields by cyclization of 3-aryl 4-amino-5-mercapto-1, 2,4-triazole 1 with thiophene-2,5-dicarboxylic acid in the presence of POCl3 and tetrabutylammonium iodide as catalyst. The preliminary antibacterial tests showed that most of them were effective against S. aureus, E. coli and B. subtilis. Compounds 2b, 2c, 2d, 2m, 2n, and 2o exhibited promising antibacterial activity. Compounds 2 were screened for their fungicidal activities against Gibberella zeae, Cerospora beticola sacc, Physalospora piricola and Pellicularia sasakii. Compounds 2b, 2c, and 2d showed a high degree of inhibition against Cerospora beticola sacc. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426500701852794

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Phosphorus, Sulfur, and Silicon
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The Synthesis and Antibacterial
Activities of 2,5-Bis[(3-
aryl)-1,2,4-triazolo[3,4-
b]-[1,3,4] thiadiazole-6-
yl]thiophenes
Dejiang Li a & Heqing Fu b
a College of Chemistry and Life Science , China
Three Gorges University , Yichang, P. R. China
b Research Institute of Chemical Engineering , South
China University of Technology , Guangzhou, P. R.
China
Published online: 12 Aug 2008.
To cite this article: Dejiang Li & Heqing Fu (2008) The Synthesis and Antibacterial
Activities of 2,5-Bis[(3-aryl)-1,2,4-triazolo[3,4-b]-[1,3,4] thiadiazole-6-yl]thiophenes,
Phosphorus, Sulfur, and Silicon and the Related Elements, 183:9, 2229-2236, DOI:
10.1080/10426500701852794
To link to this article: http://dx.doi.org/10.1080/10426500701852794
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Phosphorus, Sulfur, and Silicon, 183:2229–2236, 2008
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500701852794
The Synthesis and Antibacterial Activities of
2,5-Bis[(3-aryl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophenes
Dejiang Li1 and Heqing Fu2
1College of Chemistry and Life Science, China Three Gorges University,
Yichang, P. R. China
2Research Institute of Chemical Engineering, South China University of
Technology, Guangzhou, P. R. China
2,5-bis[(3-aryl)-1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]thiophenes 2 were syn-
thesized in high yields by cyclization of 3-aryl 4-amino-5-mercapto-1,2,4-triazole 1
with thiophene-2,5-dicarboxylic acid in the presence of POCl3 and tetrabutylam-
monium iodide as catalyst. The preliminary antibacterial tests showed that most
of them were effective against S. aureus, E. coli and B. subtilis. Compounds 2b, 2c,
2d, 2m, 2n, and 2o exhibited promising antibacterial activity. Compounds 2 were
screened for their fungicidal activities against Gibberella zeae, Cerospora beticola
sacc, Physalospora piricola and Pellicularia sasakii. Compounds 2b, 2c, and 2d
showed a high degree of inhibition against Cerospora beticola sacc.
Keywords 2,5-Bis[(3-aryl)-1,2,4-triazolo-[3,4-b]-[1,3,4]thiadiazole-6-yl]thiophenes; an-
tibacterial activities; synthesis
INTRODUCTION
Bis[1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-4-yl]alkanes were reported
to possess antibacterial property1 and bis[1,2,4-triazolo[3,4-b]-
[1,3,4]thiadiazole-3-ylmethoxy] phenylenes possess anticancer activity
against a panel of 60 cell lines derived from seven cancer types
namely, lung, colon, melanoma, renal, ovarian, CNS and leukemia.2
2,6-Bis[(3-aryl)-1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]pyridines
endowed with good fungicidal activities against Cerospora beticola
sacc have been reported from our laboratory.3 Prompted by these
Received October 2, 2007; accepted December 3, 2007.
We gratefully acknowledge financial support of this work by the Natural Science Foun-
dation of Hubei Province Education Committee of China (Project No. D200660001).
Address correspondence to Dejiang Li, College of Chemistry and Life Science,
China Three Gorges University, Yichang 443002, P. R. China. E-mail: lidejiang999@
yahoo.com.cn
2229

2230
D. Li and H. Fu
observations and in continuation of our search for bioactive molecules,
we designed a facile one-pot method to prepare a series of novel
2,5-bis[(3-aryl)-1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]thiophene
by cyclization of 3-aryl-4-amino-5-mercapto-1,2,4-triazoles with
thiophene-2,5-dicarboxylic acid. The synthesis, characterization and
the results of antibacterial activities screening studies of the newly
synthesized compounds are presented in this paper.
RESULTS AND DISCUSSION
The synthesis of 2,5-bis[(3-aryl)-1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-
6-yl]thiophenes 2 were accomplished in one-step with good yields
by condensing 3-aryl-4-amino-5-mercapto-1,2,4-triazoles
1
with
thiophene-2,5-dicarboxylic acid in the presence of POCl3 and tetrabuty-
lammonium iodide as catalyst (Scheme 1) (Table 1). Because of the poor
solubility of 1 and thiophene 2,5-dicarboxylic acid in POCl3, the yield of
2 is very low. For example, the yield of 2a was 41%. However, where the
tetrabutylammonium iodide as phase transfer catalyst were utilized
and the mixture was first stirred for 6 h at 55–60◦C, then refluxed for
10–14 h at 115–120◦C. For example, 2a was obtained in 87% yield.
SCHEME 1
The IR spectral data of compounds 2 showed bands at 1615–
1645 cm−1, 1235–1260 cm−1, and 700–720 cm−1 due to C N, N N C
and C S C, respectively. The 1H NMR spectra of 2 exhibited multiple
signals in the δ 8.40–7.60 range accounting for hydrogen of aryl group.
The 13C NMR spectra displayed the characteristic signals of all carbons.
With compound 2a as an example, it exhibited multiple signals in the δ
8.39–8.37, 8.09–7.78 ranges accounting for the 12 hydrogens of phenyl
and thiophene group. The EI-MS for compounds 2 exhibited molecular
ion peaks. With compound 2a as an example, it showed a strong
molecular ion peak M+ with m/z 484 and 33% relative abundance.
Compounds 2 were screened for their antibacterial activities against
E. coli, S. aureus, and B. subtilis employing the cup-plate method at the
concentration of 100 µg/mL in the nutrient agar. The preliminary re-
sults indicated that most of compounds were effective against S. aureus,
E. coli and B. subtilis (see Table II).

Thiadiazole Thiophenes
2231
TABLE I Preparation of 2,5-Bis[(3-aryl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene 2 from 3-Aryl-4-amino-5-mercapto-1,2,-
4-triazoles 1
Entry
Ar
Condition
Yield (%)a
M.p. (◦C)
2a
2b
2c
2d
2e
2f
2g
2h
2i
2j
2k
2l
2m
2n
2o
Ph
115–120◦C/13 h
115–120◦C/11 h
115–120◦C/12 h
115–120◦C/12 h
115–120◦C/14 h
115–120◦C/14 h
115–120◦C/13 h
115–120◦C/12 h
115–120◦C/13 h
115–120◦C/12 h
115–120◦C/11h
115–120◦C/12 h
115–120◦C/13 h
115–120◦C/10 h
115–120◦C/10 h
87
72
85
76
64
67
70
68
70
65
71
77
80
71
65
>300
>300
>300
>300
>300
>300
>300
>300
>300
>300
>300
>300
>300
>300
>300
2-Cl Ph
3-Cl Ph
4-Cl Ph
2-CH3 Ph
3-CH3 Ph
4-CH3 Ph
3-Br Ph
4-Br Ph
2-I Ph
3-I Ph
4-I Ph
4-OCH3 Ph
4-Pyridyl
3-Pyridyl
aPurified yields of 2a–2o based on thiophene-2,5-dicarboxylic acid.
Compounds 2 were screened for their fungicidal activities against
Gibberella zeae, Cerospora beticola sacc, Physalospora piricola and
Pellicularia sasakii. Among all the compounds tested, 2b, 2c and 2d
showed a high degree of inhibition against Cerospora beticola sacc (see
Table III).
TABLE II The Antibacterial Activities of
Compounds 2 (100 mg/L, Relative Inhibition %)
Compd.
S .aureus
E. coli
B. subtilis
2a
2b
2c
2d
2e
3f
2g
2h
2i
2j
2k
2l
2m
2n
2o
52
94
92
94
34
68
56
54
75
36
35
41
90
95
93
47
75
87
91
42
40
25
43
52
32
46
32
68
97
95
78
95
96
97
46
75
31
70
81
52
57
36
85
94
96

2232
D. Li and H. Fu
TABLE III The Fungicidal Activities of 2 (50 mg/L,
Relative Inhibition %)
Gibberella
zeae
Cerospora
beticola sacc
Physalospora Pellicularia
Entry
piricola
sasakii
2a
2b
2c
2d
2e
2f
2g
2h
2i
2j
2k
2l
2m
2n
2o
30
56
63
74
30
35
39
41
35
31
31
28
38
52
61
75
95
96
97
79
76
71
76
85
87
84
81
76
92
90
62
82
79
81
68
62
56
55
43
50
51
52
32
76
73
40
81
90
82
32
42
25
43
39
43
30
32
40
51
55
CONCLUSION
In conclusion, tetrabutylammonium iodide is an efficient catalyst for
the synthesis of 2,5-bis[(3-aryl)-1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-
6-yl]thiophene by reaction of 3-aryl-4-amino-5-mercapto-1, 2, 4-
triazoles with thiophene-2,5-dicarboxylic acid. Among all the com-
pounds tested, 2b, 2c, 2d, 2n and 2o showed were effective against
S. aureus, E. coli, and B. subtilis. Hence, 2b, 2c, 2d, 2m, 2n, and
2o stand to be a promising antibacterial agent. Among all the com-
pounds tested, 2b, 2c, and 2d showed a high degree of inhibition against
Cerospora beticola sacc.
EXPERIMENTAL
Melting points were determined on an X4 melting point apparatus and
were uncorrected. The IR spectra were recorded on a Nicolet Nexus 470
FT-IR spectrophotometer using KBr discs in the range 4000–4400 cm−1
.
1H NMR spectra were recorded on a Varian Mercury-Plus (400 MHz)
spectrometer in CF3COOD or pyridine-d5 solution using TMS as an
internal reference, and 13C NMR spectra were recorded on a Varian
Mercury-Plus (100 MHz) spectrometer in CF3COOD or pyridine-d5 so-
lution using TMS as an internal reference. MS spectra were recorded
on a Finnigan Trace GC-MS spectrometer. Elemental Analyses were
taken on a Perkin-Elemer-2400-CHN Elemental Analysis Instrument.

Thiadiazole Thiophenes
2233
The General Procedure for the Preparation of 3-Aryl-4-
amino-5-mercapto-1,2,4-triazoles from Aromatic Carboxylic
Acids by Four Steps According to the Literature3-5
The General Procedure for the Preparation of 2,5-Bis[(3-aryl)-
1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]thiophene 2
A
mixture of compound 3-aryl-4-amino-5-mercapto-1,2,4-triazole
(2.2 mmol), thiophene-2,5-dicarboxylic acid (0.182 g, 1.0 mmol), the
phase transfer catalyst tetrabutylammonium iodide (0.185 g, 0.5 mmol),
and POCl3 (7 mL) was stirred for 6 h at 55–60◦C, and then refluxed
for 10–14 h at 115–120◦C. Excess POCl3 was removed under reduced
pressure. The concentrated mass was cooled, poured into crushed ice,
and neutralized with potassium carbonate. The separated solid was fil-
tered, washed with water, ethanol, and then dried. The crude material
was recrystallized (ethanol-pyridine), giving the pure products 2a-o.
2,5-Bis[(3-phenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-6-
yl]thiophene (2a)
Yellow powder, 1H NMR (CF3COOD, 400 MHz): δ 8.39–8.37 (m, 4H,
Ar H), 8.09–7.78 (m, 8H, Ar H); 13C NMR (100 MHz, ppm): 164.1,
159.3, 152.5, 147.4, 145.6, 138.1, 128.6, 127.4, 122.3; IR (KBr, cm−1):
1630, 1244, 712; MS-EI (m/z): 484 (M+, 33%), 327 (30%), 309 (15%), 152
(100%), 103 (29%). Elemental anal. calcd. for C22H12N8S3: C, 54.53; H,
2.50; N, 23.12. Found: C, 54.71; H, 2.52; N, 23.01.
2,5-Bis[(3-o-chlorophenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2b)
Pale yellow powder, 1H NMR (CF3COOD, 400 MHz): δ 8.38–8.34 (m,
4H, Ar H), 8.07–7.66 (m, 6H, Ar H); 13C NMR (100 MHz, ppm): 160.6,
157.8, 147.9, 146.3, 142.7, 138.2, 132.9, 128.7, 128.5, 126.7, 125.1; IR
(KBr, cm−1): 1621, 1234, 708. MS-EI (m/z): 556 (M+4, 3%), 554 (M+2,
14%), 552 (M+, 22%), 361 (15%), 343 (14%), 152 (100%), 102 (16%).
Elemental anal. calcd. for C22H10N8S3Cl2: C, 47.74; H, 1.82; N, 20.24.
Found: C, 47.89; H, 1.76; N, 20.08.
2,5-Bis[(3-m-chlorophenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2c)
Pale yellow powder, 1H NMR (CF3COOD, 400 MHz): δ 8.33–8.27 (m,
4H, Ar H), 8.18–8.12 (m, 3H, Ar H), 7.85–7.78 (m, 3H, Ar H);13C
NMR (100 MHz, ppm): 162.1, 158.3, 156.4, 153.3, 148.7, 139.1, 126.7,
135.1, 129.3, 128.9, 124.5; IR (KBr, cm−1): 1620, 1231, 711. MS-EI (m/z):
556 (M+4, 4%), 554 (M+2, 10%), 552 (M+, 19%), 361 (12%), 343 (21%),
152 (100%), 102 (4%). Elemental anal. calcd. for C22H10N8S3Cl2: C,
47.74; H, 1.82; N, 20.24. Found: C, 47.91; H, 1.85; N, 20.11.

2234
D. Li and H. Fu
2,5-Bis[(3-p-chlorophenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2d)
Yellow powder, 1H NMR (CF3COOD, 400 MHz): δ 8.38–8.35 (m, 4H,
Ar H), 8.10 (s, 2H, Ar H), 7.80–7.77 (m, 4H, Ar H);13C NMR (100
MHz, ppm): 159.2, 157.3, 155.1, 148.7, 145.6, 136.1, 134.5, 129.7, 127.5;
IR (KBr, cm−1): 1631, 1246, 715. MS-EI (m/z): 556 (M+4, 4%), 554 (M+2,
21%), 552 (M+, 25%), 361 (18%), 343 (25%), 152 (100%), 102 (5%). El-
emental anal. calcd. for C22H10N8S3Cl2: C, 47.74; H, 1.82; N, 20.24.
Found: C, 47.60; H, 1.79; N, 20.38.
2,5-Bis[(3-o-methylphenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2e)
Yellow powder, 1H NMR (CF3COOD, 400 MHz): δ 8.37–8.34 (m, 2H,
ArH), 8.19–8.15 (m, 3H, Ar H), 7.62–7.57 (m, 5H, Ar H), 2.58 (s, 6H,
2CH3); 13C NMR (100 MHz, ppm): 156.1, 153.3, 149.1, 142.7, 140.5,
138.7, 135.4, 129.1, 128.2, 126.4, 123.2, 20.79 (CH3); IR (KBr, cm−1):
1642, 1251, 718. MS-EI (m/z): 512 (M+, 25%), 341 (12%), 323 (51%), 152
(100%). Elemental anal. calcd. for C24H16N8S3: C, 56.23; H, 3.14; N,
21.86. Found: C, 56.05; H, 3.18; N, 21.98.
2,5-Bis[(3-m-methylphenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2f)
Pale yellow powder, 1H NMR (CF3COOD, 400 MHz): δ 8.41–8.38 (m,
3H, ArH), 8.21–8.16 (m, 2H, Ar H), 7.79–7.74 (m, 5H, Ar H), 2.57 (s,
6H, 2CH3); 13C NMR (100 MHz, ppm): 153.7, 150.5, 148.7, 145.3, 140.2,
137.6, 128.1, 126.3, 123.2, 21.5(CH3); IR (KBr, cm−1): 1628, 1236, 714.
MS-EI (m/z): 512 (M+, 39%), 341 (28%), 323 (40%), 152 (100%). Elemen-
tal anal. calcd. for C24H16N8S3: C, 56.23; H, 3.14; N, 21.86. Found: C,
56.41; H, 3.20; N, 21.71.
2,5-Bis[(3-p-methylphenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2g)
Yellow powder, 1H NMR (CF3COOD, 400 MHz): δ 8.30–8.27 (m,
4H, ArH), 8.09 (s, 2H, Ar H), 7.65–7.62 (m, 4H, Ar H), 2.60 (s,
6H, 2CH3);13C NMR (100 MHz, ppm): 148.7, 145.4, 142.2, 140.7,
138.2,136.9, 133.1, 129.4, 126.5, 19.8(CH3); IR (KBr, cm−1): 1640, 1243,
717. MS-EI (m/z): 512 (M+, 48%), 341 (41%), 323 (50%), 152 (100%).
Elemental anal. calcd. for C24H16N8S3: C, 56.23; H, 3.14; N, 21.86.
Found: C, 56.36; H, 3.01; N, 21.69.
2,5-Bis[(3-m-bromophenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2h)
Brown powder, 1H NMR (CF3COOD, 400 MHz): δ 8.32–8.28 (m, 3H,
Ar H), 8.09–8.05 (m, 3H, Ar H), 7.71–7.68 (m, 4H, Ar H); 13C NMR

Thiadiazole Thiophenes
2235
(100 MHz, ppm): 160.2, 157.3, 153.1, 147.6, 145.1, 140.2, 131.2, 130.8,
128.7, 125.5. 123.3; IR (KBr, cm−1): 1619, 1252, 704. MS-EI (m/z): 644
(M+4, 5%), 642 (M+2, 5%), 640 (M+, 6%), 405 (19%), 387 (42%), 181
(63), 152 (100%). Elemental anal. calcd. for C22H10N8S3Br2: C, 41.13;
H, 1.57; N, 17.44. Found: C, 41.02; H, 1.63; N, 17.59.
2,5-Bis[(3-p-bromophenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2i)
Brown powder, 1H NMR (CF3COOD, 400 MHz): δ 8.30–8.27 (m, 4H,
Ar H), 8.09 (s, 2H, Ar H), 7.65–7.62 (m, 4H, Ar H);13C NMR (100
MHz, ppm): 159.4, 156.5, 153.1, 147.2, 142.5, 137.1, 132.2, 128.9, 122.1;
IR (KBr, cm−1): 1621, 1230, 708. MS-EI (m/z): 644 (M+4, 7%), 642 (M+2,
6%), 640 (M+, 7%), 405 (16%), 387 (53%), 181 (72), 152 (100%). Elemen-
tal anal. calcd. for C22H10N8S3Br2: C, 41.13; H, 1.57; N, 17.44. Found:
C, 41.29; H, 1.49; N, 17.30.
2,5-Bis[(3-o-iodophenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2j)
Yellow powder, 1H NMR (Pyridine-d5, 400 MHz): δ 8.31–8.28 (m, 3H,
Ar H), 8.24–8.21 (m, 2H, Ar H), 7.53–7.49 (m, 5H, Ar H); 13C NMR
(100 MHz, ppm):161.3, 157.2, 154.1, 150.2, 147.8, 142.6, 139.9, 130.9,
127.7, 98.6; IR (KBr, cm−1): 1638, 1241, 716. MS-EI (m/z): 736 (M+,
29%), 453 (3%), 435 (11%), 152 (60%), 102 (100%). Elemental anal.
calcd. for C22H10N8S3I2: C, 35.88; H, 1.37; N, 15.22. Found: C, 36.05;
H, 1.30; N, 15.03.
2,5-Bis[(3-m-iodophenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2k)
Yellow powder, 1H NMR (Pyridine-d5, 400 MHz): δ 8.29–8.26 (m, 2H,
Ar H), 8.16–8.12 (m, 5H, Ar H), 7.67–7.62 (m, 3H, Ar H);13C NMR
(100 MHz, ppm):159.4, 155.1, 150.2, 147.6, 145.3, 143.2, 140.9, 138.7,
136.7, 127.4, 96.8; IR (KBr, cm−1): 1627, 1239, 713. MS-EI (m/z): 736
(M+, 31%), 453 (7%), 435 (10%), 152 (48%), 102 (100%). Elemental anal.
calcd. for C22H10N8S3I2: C, 35.88; H, 1.37; N, 15.22. Found: C, 36.03; H,
1.42; N, 15.10.
2,5-Bis[(3-p-iodophenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2l)
Yellow powder, 1H NMR (Pyridine-d5, 400 MHz): δ 8.35–8.31 (m,
4H, Ar H), 8.07 (s, 2H, Ar H), 7.61–7.58 (m, 4H, Ar H);13C NMR
(100 MHz, ppm):157.6, 155.3, 153.1, 149.2, 147.5, 139.1, 129.4, 97.2; IR
(KBr, cm−1): 1641, 1254, 717. MS-EI (m/z): 736 (M+, 36%), 453 (4%), 435
(12%), 152 (59%), 102 (100%). Elemental anal. calcd. for C22H10N8S3I2:
C, 35.88; H, 1.37; N, 15.22. Found: C, 35.71; H, 1.33; N, 15.38.

2236
D. Li and H. Fu
2,5-Bis[(3-p-methoxyhenyl)-1,2,4-triazolo[3,4-b]-[1,3,4]
thiadiazole-6-yl]thiophene (2m)
Pale yellow powder, 1H NMR (CF3COOD, 400 MHz): δ 8.32–8.29 (m,
4H, Ar H), 8.07 (s, 2H, Ar H), 7.51–7.49 (m, 4H, Ar H), 3.97 (s, 6H,
2OCH3);13C NMR (100 MHz, ppm):162.1, 160.7, 157.7, 148.9, 145.1,
129.1, 126.5, 113.2, 58.7(OCH3); IR (KBr, cm−1): 1630, 1241, 706. MS-
EI (m/z): 544 (M+, 42%), 357 (6%), 339 (8%), 152 (100%). Elemental
anal. calcd. for C24H16N8O3S2: C, 52.93; H, 2.96; N, 20.57. Found: C,
51.80; H, 2.89; N, 20.71.
2,5-Bis[(3-(3–4/-pyridyl)-1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-
6-yl]thiophene (2n)
Yellow powder, 1H NMR (CF3COOD, 400 MHz): δ 8.27–8.24 (m, 4H,
Ar H), 7.78–7.72 (m, 6H, Ar H); 13C NMR (100 MHz, ppm): 164.3,
160.2, 159.1, 148.0, 143.2, 135.7, 123.9; IR (KBr, cm−1): 1621, 1236, 703.
MS-EI (m/z): 486 (M+, 21%), 328 (8%), 310 (25%), 152 (100%). Elemental
anal. calcd. for C20H10N10S3: C, 49.37; H, 2.07; N, 28.79. Found: C, 49.50;
H, 2.01; N, 28.62.
2,5-Bis[(3-(3–3/-pyridyl)-1,2,4-triazolo[3,4-b]-[1,3,4]thiadiazole-
6-yl]thiophene (2n)
Yellow powder, 1H NMR (CF3COOD, 400 MHz): δ 8.22–8.19 (m, 3H,
Ar H), 8.15–8.12 (m, 3H, Ar H), 7.68–7.64 (m, 4H, Ar H); 13C NMR
(100 MHz, ppm): 161.2, 158.1, 156.9, 153.2, 150.1, 149.3, 146.7, 143.2,
124.8; IR (KBr, cm−1): 1630, 1229, 707. MS-EI (m/z): 486 (M+, 16%), 328
(5%), 310 (30%), 152 (100%). Elemental anal. calcd. for C20H10N10S3:
C, 49.37; H, 2.07; N, 28.79. Found: C, 49.21; H, 2.12; N, 28.92.
REFERENCES
[1] B. S. Holla, R. Gonsalves, and S. Shenoy, I l Farmco, 53, 574 (1998).
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[4] D. J. Li, D. Q. Long, and H. Q. Fu, Phosphorus, Sulfur, Silicon, Relat. Elem., 181, 519
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[5] D. J. Li, D. Q. Long, and H. Q. Fu, Synth. Commun., 35, 2495 (2005).