Synthesis of 1,3-bis[(3-aryl)-s-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl] benzenes

Article abstract of DOI:10.1080/10426500500265008

1,3-bis[(3-aryl)-s-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]benzenes 2 were synthesized in high yields by the reaction of 3-aryl 4-amino-5-mercapto-1,2,4- triazole 1 with m-phthalic acid. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426500500265008

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Synthesis of 1,3-Bis[(3-
aryl)-S-triazolo[3,4-b]-
[1,3,4]thiadiazole-6-
yl]benzenes
Dejiang Li a , Deqing Long a & Heqing Fu b
a Department of Chemistry , Yunyang Teachers
College, Danjiangkou , Hubei, P. R. China
b Research Institute of Chemical Engineering, South
China University of Technology , Guangzhou, P. R.
China
Published online: 01 Feb 2007.
To cite this article: Dejiang Li , Deqing Long & Heqing Fu (2006) Synthesis of 1,3-
Bis[(3-aryl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]benzenes, Phosphorus, Sulfur, and
Silicon and the Related Elements, 181:3, 519-526, DOI: 10.1080/10426500500265008
To link to this article: http://dx.doi.org/10.1080/10426500500265008
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Phosphorus, Sulfur, and Silicon, 181:519–526, 2006
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500500265008
Synthesis of 1,3-Bis[(3-aryl)-S-triazolo[3,4-b]-
[1,3,4]thiadiazole-6-yl]benzenes
Dejiang Li
Deqing Long
Department of Chemistry, Yunyang Teachers College, Danjiangkou,
Hubei, P. R. China
Heqing Fu
Research Institute of Chemical Engineering, South China University
of Technology, Guangzhou, P. R. China
1,3-bis[(3-aryl)-s-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]benzenes
2 were synthe-
sized in high yields by the reaction of 3-aryl 4-amino-5-mercapto-1,2,4-triazole 1
with m-phthalic acid.
Keywords 1,3-Bis[(3-aryl)-s-triazolo-[3,4-b]-[1,3,4]thiadiazole-6-yl]benzenes; 2,4-tri-
azole; 3-aryl-4-amino-5-mercapto-1; synthesis
S-triazolo[3,4-b]-[1,3,4]thiadiazole derivatives were found to possess
significant biological activities such as antiflammatory, antiviral, anti-
fungal, antineoplastic, and antidepressant effects1−4 and electrochem-
ical properties.5 They are highly important heterocycles and have been
used in the research and development of agrochemicals and in the phar-
maceutical chemistry. Most derivatives that have been reported only
contain one s-triazolo[3,4-b]-[1,3,4]thiadiazole in one moleclule.6−11 As
part of our current studies on the synthesis of the biologically active s-
triazolo[3, 4-b]-[1,3,4]thiadiazole derivatives, we now report an efficient
synthesis of some novel fused heterocyclic compounds combining two
s-triazolo[3,4-b]-[1,3,4]thiadiazole rings in one framework from 3-aryl
4-amino-5-mercapto-1,2,4-triazoles with the hope to obtain compounds
of better biological activities.
Received March 28, 2005; accepted May 1, 2005.
We gratefully acknowledge financial support of this work by the Science Foundation
of Hubei Province Education Committee, China (Project No. 2004D001).
Address correspondence to Dejiang Li, Department of Chemistry, Yunyang Teachers
College Danjiangkou, Hubei 442700, P. R. China. E-mail: lidejiang999@yahoo.com.cn
519

520
D. Li et al.
RESULTS AND DISCUSSION
The aroylhydrazides were prepared by the esterification and hydrazi-
nolysis of corresponding aromatic carboxylic acids (Scheme 1). The reac-
tion of aroylhydrazides with CS2/KOH in absolute ethanol gave potas-
sium aroyldithiocarbazates, and then the hydrazinolysis of potassium
aroyldithiocarbazates with hydrazine hydrate afforded 3-aryl-4-amino-
5-mercapto-1,2,4-triazoles 1 (Scheme 2).12
SCHEME 1
SCHEME 2
The synthesis of 2 was accomplished in one step with good yields
by condensing 3-aryl-4-amino-5-mercapto-1,2,4-triazoles 1 with m-
phthalic acid in the presence of POCl3 and the phase transfer catalyst
tetrabutylammonium iodide (Scheme 3, Table I).
SCHEME 3
The structures of all of compounds 2 was established on the basis of
elemental analysis and spectral data. The IR spectral data of compound
2 showed bands at 1600–1630 cm−1, 1235–1260 cm−1, and 700 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 7.00–8.70 range accounting for
hydrogens of the aryl group. With compound 2g, as an example, multiple
signals appeared in the range of δ 8.59–8.44, δ 8.30–8.24, δ 8.07–8.05,
and δ 7.59–7.56, which accounted for the 12 hydrogens of the aryl group.
A single signal at δ 2.57 accounted for 6 hydrogens of 2 methyl group.
The EI-MS for compounds 2, except for 2b, 2c, and 2d, exhibited strong

1,3-Bis[(3-aryl)-S-triazolo[3, 4-b]-[1,3,4]thiadiazole-6-yl]benzenes
521
TABLE I Preparation of 1,3-Bis[(3-aryl)-s-triazolo[3,4-b]-[1,
3,4]thiadiazole-6-yl]benzenes 2 from 3-aryl-4-amino-5-
mercapto-1,2,4-triazoles 1
Entry
Ar
Condition
Yield (%)a
m.p. (◦)
2a
2b
2c
2d
2e
2f
2g
2h
2i
2j
2k
2l
2m
2n
2o
2p
Ph
115–120◦C/11 h
115–120◦C/12 h
115–120◦C/13 h
115–120◦C/11 h
115–120◦C/14 h
115–120◦C/13 h
115–120◦C/14 h
115–120◦C/12 h
115–120◦C/11 h
115–120◦C/11 h
115–120◦C/11 h
115–120◦C/10 h
115–120◦C/15 h
115–120◦C/12 h
115–120◦C/13 h
115–120◦C/10 h
76
62
60
65
56
61
70
63
68
60
67
70
66
53
51
45
>300
>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
2-Furyl
aPurified yields of 2a–2p based on m-ophthalmic acid.
molecular ion peaks, including some base peaks, for example, 2g and 2o.
Compounds 2b, 2c, and 2d showed molecular ion peaks corresponding
to [M++1] at m/z 548 and [M+−1] m/z 546.
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 4000–400 cm−1
.
1H NMR spectra were recorded on a Varian Mercury-Plus 400 NMR
spectrometer in CF3COOD or pyridine-d5 solution 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.
General Procedure for the Preparation of
3-Aryl-4-amino-5-mercapto-1,2,4-triazole 112
A mixture of potassium aroyldithiocarbazate (30 mmol) and hydrazine
hydrate (80%, 36 mL) was refluxed with stirring for 4–5 h at 120◦C.
The color of the reaction mixture changed to green, and a homogeneous

522
D. Li et al.
solution resulted. The acidification with HCl (3 mol/L) resulted in the
precipitation of a white solid. The product was filtered, washed with
cold water, and recrystallized (ethanol) to give the pure products 1.
3-p-Methylphenyl-4-amino-5-mercapto-1,2,4-triazole (1 g)
1
Needle crystals, yield 55%, m.p. 217–218◦. H NMR (DMSO-d6, 400
MHz) δ 12.7 (s, 1H, S-H), 7.51–8.24 (m, 4H, Ar-H), 5.63 (s, 2H, NH2),
2.54 (s, 3H, CH3); IR (cm−1): 3270, 1621, 1600, 1548, 1251. Elemental
anal. calcd. for C9H10N4S: C, 52.41; H, 4.89; N, 27.16. Found: C, 52.30;
H, 4.97; N, 27.03.
General Procedure for the Preparation of 1,3-bis[(3-aryl)-
S-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]benzenes 2
A mixture of compound 3-aryl-4-amino-5-mercapto-1,2,4-triazole (2.2
mmol), m-phthalic acid (1.0 mmol), the phase transfer catalyst tetra-
butylammonium iodide (0.5 mmol), and POCl3 (7 mL) was stirred for
6 h at 55–60◦C, and then refluxed for 11–15 h at 115–120◦C. Excess
POCl3 was removed under reduced pressure. The concentrated mass
was cooled and poured into crushed ice and neutralized with potas-
sium carbonate. The separated solid was filtered, washed with water
and ethanol, and then dried. The crude material was recrystallized
(ethanol-pyridine), giving the pure products 2.
1,3-Bis[(3-phenyl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-
6-yl]benzene (2a)
Yellow powder, 1H NMR (CF3COOD, 400 MHz) δ 8.52–8.42 (m, 5H, Ar-
H), 8.19–8.11 (m, 4H, Ar-H), 7.83–7.58 (m, 5H, Ar-H); IR (KBr, cm−1):
1614, 1253, 702; MS (m/z): 478 (M+, 2%), 321 (2%), 303 (3%), 146 (86%),
128 (100%). elemental anal. calcd. for C24H14N8S2: C, 60.24; H, 2.95; N,
23.42. Found: C, 60.15; H, 2.88; N, 23.61.
1,3-Bis[(3-o-chlorophenyl)-S-triazolo[3, 4-b]-[1,3,4]
thiadiazole-6-yl]benzene (2b)
1
Yellow powder, H NMR (CF3COOD, 400 MHz) 8.53–8.47 (m, 4H, Ar-
H), 8.31–8.26 (m, 3H, Ar-H), 8.20–8.14 (m, 2H, Ar-H), 7.83–7.51 (m, 3H,
Ar-H); IR (KBr, cm−1): 1623, 1251, 701; MS (m/z): 548 (M++1, 54%), 546
(M+-1, 100%), 356 (1%), 357 (22%), 146 (53%). Elemental anal. calcd.
for C24H12N8S2Cl2: C, 52.66; H, 2.21; N, 20.47. Found: C, 52.81; H, 2.13;
N, 20.56.

1,3-Bis[(3-aryl)-S-triazolo[3, 4-b]-[1,3,4]thiadiazole-6-yl]benzenes
523
1,3-Bis[(3-m-chlorophenyl)-S-triazolo[3,4-b]-[1,3,4]-
thiadiazole-6-yl]benzene(2c)
1
Pale yellow powder, H NMR (CF3COOD, 400 MHz) δ 8.71–8.46 (m,
3H, Ar-H), 8.38–8.24 (m, 2H, Ar-H), 8.17–8.10 (m, 4H, Ar-H), 7.81–7.52
(m, 3H, Ar-H); IR (KBr, cm−1): 1609, 1243, 700; MS (m/z): 548 (M++1,
65%), 546 (M+−1, 78%), 356 (4%), 357 (12%), 146 (100%). Elemental
anal. calcd. for C24H12N8S2Cl2: C, 52.66; H, 2.21; N, 20.47. Found: C,
52.51; H, 2.30; N, 20.67.
1,3-Bis[(3-p-chlorophenyl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-
6-yl] benzene (2d)
Yellow powder, 1H NMR (CF3COOD, 400 MHz) δ 8.64–8.34 (m, 7H, Ar-
H), 8.05–7.71 (m, 5H, Ar-H); IR (KBr, cm−1): 1627, 1254, 701; MS (m/z):
548 (M++1, 71%), 546 (M+−1, 100%), 356(3%), 357 (16%), 146 (45%).
Elemental anal. calcd. for C24H12N8S2Cl2: C, 52.66; H, 2.21; N, 20.47.
Found: C, 52.78; H, 2.30; N, 20.41.
1, 3-Bis[(3-o-methylphenyl)-S-triazolo[3, 4-b]-[1,3,4]-
thiadiazole-6-yl]benzene(2e)
Pale yellow powder, 1H NMR (CF3COOD, 400 MHz) δ 8.46–8.41 (m, 3H,
Ar-H), 8.35–8.29 (m, 2H, Ar-H), 8.12–8.05 (m, 4H, Ar-H), 7.57–7.49 (m,
3H, Ar-H), 2.56 (s, 6H, 2CH3); IR (KBr, cm−1): 1627, 1261, 695; MS (m/z):
506 (M+, 94%), 335 (9%), 317 (32%), 146 (21%), 117 (100%). Elemental
anal. calcd. for C26H18N8S2: C, 61.64; H, 3.58; N, 22.12. Found: C, 61.76;
H, 3.60; N, 22.25.
1,3-Bis[(3-m-methylphenyl)-S-triazolo[3,4-b]-[1,3,4]-
thiadiazole-6-yl]benzene (2f)
1
Pale yellow powder, H NMR (CF3COOD, 400 MHz) δ 8.41–8.35 (m,
5H, Ar-H), 8.29–8.01 (m, 4H, Ar-H), 7.51–7.42 (m, 3H, Ar-H), 2.55 (s,
6H, 2CH3); IR (KBr, cm−1): 1621, 1252, 705; MS (m/z): 506 (M+, 100%),
335 (12%), 317 (52%), 146 (13%), 145 (67%), 117 (41%). Elemental anal.
calcd. for C26H18N8S2: C, 61.64; H, 3.58; N, 22.12. Found: C, 61.52; H,
3.49; N, 22.27.
1,3-Bis[(3-p-methylphenyl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-
6-yl]benzene (2g)
Yellow powder, 1H NMR (CF3COOD, 400 MHz) δ 8.59–8.44 (m, 3H, Ar-
H), 8.30–8.24 (m, 4H, Ar-H), 8.07–8.05 (m, 1H, Ar-H), 7.59–7.56 (m, 4H,

524
D. Li et al.
Ar-H), 2.57 (s, 6H, 2CH3); IR (KBr, cm−1): 1615, 1252, 701; MS (m/z):
506 (M+, 100%), 335 (12%), 317 (28%), 146 (32%), 145 (51%), 117 (32%),
116 (91%). Elemental anal. calcd. for C26H18N8S2: C, 61.64; H, 3.58; N,
22.12. Found: C, 61.52; H, 3.69; N, 22.07.
1,3-Bis[(3-m-bromophenyl)-S-triazolo[3,4-b]-[1,3,4]-
thiadiazole-6-yl]benzene (2h)
1
Yellow powder, H NMR (Pyridine-d5, 400 MHz) δ 8.52–8.46 (m, 3H,
Ar-H), 8.37–8.30 (m, 3H, Ar-H), 8.12–8.07 (m, 2H, Ar-H), 7.57–7.52 (m,
4H, Ar-H); IR (KBr, cm−1): 1621, 1263, 704; MS (m/z): 636 (M+, 46%),
555 (8%), 399 (26), 381 (23%), 146 (100%), 101 (43%). Elemental anal.
calcd. for C24H12N8S2Br2: C, 45.31; H, 1.90; N, 17.61. Found: C, 45.42;
H, 2.11; N, 17.49.
1,3-Bis[(3-p-bromophenyl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-
6-yl]benzene (2i)
Yellow powder, 1H NMR (Pyridine-d5, 400 MHz) δ 8.48–8.41 (m, 4H, Ar-
H), 8.31–8.25 (m, 3H, Ar-H), 8.09–8.04 (m, 2H, Ar-H), 7.54–7.50 (m, 3H,
Ar-H); IR (KBr, cm−1): 1614, 1254, 700; MS (m/z): 636 (M+, 55%), 555
(7%), 399 (15), 381 (37%), 146 (63%), 145 (100%), 101 (61%). Elemental
anal. calcd. for C24H12N8S2Br2: C, 45.31; H, 1.90; N, 17.61. Found: C,
45.42; H, 2.11; N, 17.49.
1,3-Bis[(3-o-Iodophenyl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-6-
yl]benzene (2j)
Yellow powder, 1H NMR (CF3COOD, 400MHz) δ 8.71–8.68 (m, 4H, Ar-
H), 8.42–8.34 (m, 2H, Ar-H), 8.21–8.09 (m, 3H, Ar-H), 7.50–7.42 (m, 3H,
Ar-H); IR (KBr, cm−1): 1615, 1258, 703; MS (m/z): 730 (M+, 52%), 604
(2%), 447 (13), 429 (51%), 276 (100%), 229 (26%), 146 (38%), 145 (63%),
101 (71%). Elemental anal. calcd. for C24H12N8S2I2: C, 39.47; H, 1.66;
N, 15.34. Found: C, 39.59; H, 1.58; N, 15.42.
1,3-Bis[(3-m-Iodophenyl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-
6-yl]benzene (2k)
Pale yellow powder, 1H NMR (CF3COOD, 400 MHz) δ 8.76–8.72 (m, 3H,
Ar-H), 8.35–8.45 (m, 4H, Ar-H), 8.15–8.07 (m, 3H, Ar-H), 7.49–7.45 (m,
2H, Ar-H); IR (KBr, cm−1): 1610, 1239, 710; MS (m/z): 730 (M+, 44%),
604 (4%), 447 (10), 429 (55%), 276 (100%), 229 (41%), 146 (50%), 145

1,3-Bis[(3-aryl)-S-triazolo[3, 4-b]-[1,3,4]thiadiazole-6-yl]benzenes
525
(56%), 101 (84%). Elemental anal. calcd. for C24H12N8S2I2: C, 39.47; H,
1.66; N, 15.34. Found: C, 39.59; H, 1.58; N, 15.42.
1,3-Bis[(3-p-Iodophenyl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-6-
yl]benzene (2l)
1
Pale yellow powder, H NMR (CF3COOD, 400 MHz) δ 8.45–8.42 (m,
2H, Ar-H), 8.13–7.81 (m, 10H, Ar-H); IR (KBr, cm−1): 1620, 1247, 700;
MS (m/z): 730 (M+, 88%), 604 (4%), 447 (19), 429 (85%), 302 (20%), 229
(39%), 146 (41%), 145 (100%), 101 (61%). Elemental anal. calcd. for
C24H12N8S2I2: C, 39.47; H, 1.66; N, 15.34. Found: C, 39.38; H, 1.52; N,
15.27.
1,4-Bis[(3-p-methoxyphenyl)-S-triazolo[3,4-b]-[1,3,4]thiadia-
zole-6-yl]benzene (2m)
Pale yellow powder, 1H NMR (CF3COOD, 400 MHz) 8.56–8.42 (m, 4H,
Ar-H), 8.31–8.25 (m, 3H, Ar-H), 8.11–8.04 (m, 3H, Ar-H), 7.42–7.40 (m,
2H, Ar-H), 3.89 (s, 6H, 2OCH3); IR (KBr, cm−1): 1614, 1254, 700; MS
(m/z): 538 (M+, 99%), 351 (3%), 333 (32), 146 (30%), 145 (32%), 132
(100%), 101 (22%). Elemental anal. calcd. for C26H18N8O2S2: C, 57.98;
H, 3.37; N, 20.80. Found: C, 57.83; H, 3.42; N, 20.73.
1,3-Bis[(3-4ꢀ-pyridyl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]-
benzene (2n)
Pale yellow powder, 1H NMR (Pyridine-d5, 400 MHz) 8.51–8.38 (m, 3H,
Ar-H), 8.33–8.24 (m, 4H, Ar-H), 8.17–8.00 (m, 2H, Ar-H), 7.38-7.26 (m,
3H, Ar-H); IR (KBr, cm−1): 1626, 1242, 707; MS (m/z): 480 (M+, 100%),
322 (26), 304 (10), 146 (23%), 145 (51%), 104 (11%). Elemental anal.
calcd. for C22H12N10S2: C, 54.99; H, 2.52; N, 29.15. Found: C, 54.81; H,
2.42; N, 29.26.
1,3-Bis[(3-3ꢀ-pyridyl)-S-triazolo[3,4-b]-[1,3,4]thiadiazole-6-yl]-
benzene (2o)
1
Yellow powder, H NMR (Pyridine-d5, 400 MHz) 8.57-8.43 (m, 4H, Ar-
H), 8.35–8.22 (m, 3H, Ar-H), 8.14–8.01 (m, 3H, Ar-H), 7.31–7.25 (m,
2H, Ar-H); IR (KBr, cm−1): 1614, 1254, 700; MS (m/z): 480 (M+, 100%),
324 (7%), 322 (42), 304 (12), 146 (27%), 145 (40%), 104 (18%). Elemental
anal. calcd. for C22H12N10S2: C, 54.99; H, 2.52; N, 29.15. Found: C, 54.83;
H, 2.69; N, 29.06.

526
D. Li et al.
1,3-Bis[(3-2ꢀ-furyl)-S-triazolo[3, 4-b]-[1,3,4]thiadiazole-6-yl]-
benzene (2p)
Pale yellow powder, 1H NMR (Pyridine-d5, 400 MHz) 8.45–8.34 (m, 2H,
Ar-H), 8.27–8.16 (m, 2H, Ar-H), 7.12–6.37 (m, 6H, furyl-H ); IR (KBr,
cm−1): 1614, 1254, 700; MS (m/z): 458 (M+, 48%), 311 (9%), 293 (64), 146
(32%), 145 (100%), 93 (27%). Elemental anal. calcd. for C20H10N8O2S2:
C, 52.39; H, 2.20; N, 24.40. Found: C, 52.48; H, 2.11; N, 24.31.
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