Synthesis of thiadiazoles, triazoles and oxadiazoles from sulfonyl acetic acids via a common route

Article abstract of DOI:10.1002/jhet.5570420116

A new class of five membered heterocycles, thiadiazoles, triazoles and oxadiazoles were prepared from sulfonyl acetic acids via acid hydrazides.

Full text of DOI:10.1002/jhet.5570420116

Jan-Feb 2005
113
Synthesis of Thiadiazoles, Triazoles and Oxadiazoles from Sulfonyl
Acetic Acids via a Common Route
Venkatapuram Padmavathi*, Pinnu Thriveni, Boggu Jagan Mohan Reddy
and Adivireddy Padmaja
Department of Chemistry, Sri Venkateswara University, Tirupati - 517 502, India
Received March 31, 2004
A new class of five membered heterocycles, thiadiazoles, triazoles and oxadiazoles were prepared from
sulfonyl acetic acids via acid hydrazides.
J. Heterocyclic Chem., 42, 113 (2005).
Introduction.
isoxazolines [5]. In view of our successful results on this
front and our continued interest in the field of heterocycles
herein we report a new class of five membered hetero-
cycles having three heteroatoms nitrogen, oxygen and sul-
phur viz., triazoles, oxadiazoles and thiadiazoles.
The chemistry of five membered heterocycles containing
nitrogen and sulfur has gained importance mainly due to
their varied physiological action and diverse physico-
chemical properties. The triazole nucleus has a broad spec-
trum of antimicrobial activity [1]. In fact molecules having
both triazole and thiadiazine units possess antiparasite
activity [2]. Apart from this triazolo-thiadiazines/ thiadia-
zoles possess antimicrobial properties [3]. Besides, 2-mer-
capto-5-methyl-1,3,4-thiadiazole is an intermediate for
therapeutically useful antibiotic cefazolin [4]. In fact for the
last one and half decades we have been actively involved in
the synthesis of new and novel five membered heterocycles
containing two heteroatoms particularly pyrazolines and
The synthetic method involves the articulation of triazole,
oxadiazole and thiadiazole rings from an intermediate
phenylsulfonylacetic acid (1)/benzylsulfonylacetic acid (2).
The methyl ester of latter (3/4) was prepared by treating 1/2
with methanol in conc. H SO . The IR spectra of 3 and 4
2
4
showed absorption bands in the region 1320-1345 and 1125-
-1
-1
1135 cm (SO ) and 1740-1755 cm (CO CH ). A sharp
2
2
3
singlet was observed at δ 3.90-3.95 for the methylene pro-
tons flanked between ester and sulfonyl groups in their

114
V. Padmavathi, P. Thriveni, B. Jagan M. Reddy and A. Padmaja
Vol. 42
1
H NMR spectra. Apart from this, 4 displayed another sin-
hydrazide (7/8) was prepared from 5/6 on treatment with
carbon disulfide in the presence of potassium hydroxide
under ultrasonic conditions. This on refluxion in acetic acid
cyclized to 5-arylsulfonylmethyl[1,3,4]thiadiazole-2-thiol
(9)/5-arylmethanesulfonylmethyl[1,3,4]thiadiazole-2-thiol
(10). On the other hand treatment of 7/8 with hydrazine
hydrate produced 4-amino-5-arylsulfonylmethyl-4H-
[1,2,4]triazole-3-thiol (11)/4-amino-5-arylmethanesul-
fonylmethyl-4H-[1,2,4]triazole-3-thiol (12). Similarly, base
catalyzed hydrolysis of 7/8 resulted 5-arylsulfonylmethyl-
[1,3,4]oxadiazole-2-thiol (13)/5-arylmethanesulfonyl-
methyl-[1,3,4]oxadiazole-2-thiol (14) (Scheme and
glet at δ 4.12-4.18 for benzylic protons. Both the com-
pounds showed a singlet at δ 3.75-3.83 for methoxy protons
of the carbomethoxy group (Scheme and Table 1). The
compounds 3/4 on reaction with hydrazine hydrate gave the
corresponding acid hydrazide (5/6) [6] which displayed
absorption bands at 1676 cm for amidic carbonyl and at
3275 and 3334 cm for NH and NH respectively. The H
NMR spectra of 5 and 6 displayed a broad signal in the
region δ 7.84-7.95 and 4.49-4.60 for NH and NH , which
-1
-1
1
2
2
disappeared on deuteration apart from signals due to meth-
ylene protons. The potassium dithiocarbazate of the acid
Table 1
Physical and Spectral Data of Compounds 3-6
1
Compd.
mp
(°C)
Yield
(%)
H NMR (δ, ppm)
3a
3b
3c
4a
4b
108-110
127-128
143-145
49-50
82
87
86
79
85
3.79 (s, 3H, OCH ), 3.94 (s, 2H, SO -CH -CO CH ), 7.01-7.25 (m, 5H, Ar-H)
3 2 2 2 3
2.24 (s, 3H, Ar-CH ), 3.76 (s, 3H, OCH ), 3.92 (s, 2H, SO -CH -CO CH ), 6.95-7.26 (m, 4H, Ar-H)
3
3
2
2
2
3
3.82 (s, 3H, OCH ), 3.95 (s, 2H, SO -CH -CO CH ), 7.09- 7.25 (m, 4H, Ar-H)
3
2
2
2
3
3.78 (s, 3H, OCH ), 3.91 (s, 2H, SO -CH - CO CH ), 4.15 (s, 2H, Ar-CH -SO -), 6.98-7.34 (m, 5H, Ar-H)
3
2
2
2
3
2
2
57-58
2.21 (s, 3H, Ar-CH ), 3.75 (s, 3H, OCH ), 3.95 (s, 2H, SO -CH -CO CH ), 4.12 (s, 2H, Ar-CH -SO -),
3
3
2
2
2
3
2
2
6.89-7.35 (m, 4H, Ar-H)
4c
5a
5b
5c
6a
6b
65-66
88
77
73
75
76
78
3.83 (s, 3H, OCH ), 3.94 (s, 2H, SO -CH -CO CH ), 4.18 (s, 2H, Ar-CH -SO ), 7.02-7.28 (m, 4H, Ar-H)
3.95 (s, 2H, -SO -CH -CO), 4.60 (s, 2H, NH ), 6.81-7.55 (m, 5H, Ar-H), 7.95 (s, 1H, NH)
2 2 2
3 2 2 2 3 2 2
132-134
146-147
154-155
144-145
140-142
2.21 (s, 3H, Ar-CH ), 3.97 (s, 2H, -SO -CH -CO), 4.55 (s, 2H, NH ), 6.62-7.49 (m, 4H, Ar-H), 7.84 (s, 1H, NH)
3
2
2
2
3.98 (s, 2H, -SO -CH -CO), 4.62 (s, 2H, NH ), 6.98 – 7.54 (m, 4H, Ar-H), 7.89 (s, 1H, NH)
2
2
2
3.79 (s, 2H, SO -CH -CO), 4.53 (s, 2H, NH ), 4.59 (s, 2H, Ar-CH -SO ), 7.32-7.58 (m, 5H, Ar-H), 7.93 (s, 1H, NH)
2
2
2
2
2
2.19 (s, 3H, Ar-CH ), 3.76 (s, 2H, SO -CH -CO), 4.54 (s, 2H, NH ), 4.57 (s, 2H, Ar-CH -SO ), 6.95 –7.52 (m, 4H,
3
2
2
2
2
2
Ar-H), 7.88 (s, 1H, NH)
6c
164-166
82
3.75 (s, 2H, CH -CO-), 4.49 (s, 2H, NH ), 4.52 (s, 2H, Ar- CH -SO ), 7.27-7.50 (m, 4H, Ar-H), 7.85 (s, 1H, NH)
2
2
2
2
Table 2
Physical Properties for Compounds 9-14
Compd.
mp
( C)
Yield
(%)
Mol. Formula (Mol. Wt.)
C
Calcd. (Found) %
H
o
N
9a
9b
215-217
200-202
244-246
210-213
204-206
238-240
123-124
145-146
159-161
259-261
235-237
214-216
68
71
69
72
74
73
64
69
70
66
65
69
C H N O S
8 2 2 3
39.69
(39.58)
41.94
(41.89)
35.23
(35.20)
41.94
(41.87)
43.98
(44.05)
37.44
(37.40)
39.99
(39.88)
42.24
(42.19)
35.47
(35.54)
42.24
(42.28)
44.28
(44.35)
37.67
(37.59)
2.96
(2.94)
3.52
(3.58)
2.30
(2.28)
3.52
(3.55)
4.02
(4.07)
2.83
(2.78)
3.73
(3.79)
4.25
(4.20)
2.98
(2.94)
4.25
(4.31)
4.73
(4.67)
3.48
(3.45)
10.28
(10.35)
9.78
(9.84)
9.13
(9.20)
9.78
(9.85)
9.32
9
(272.37)
N O S
2 2 3
C
H
10 10
(286.4)
C H ClN O S
9c
9
7
2
2
3
3
3
(306.82)
C H N O S
10 10
10a
10b
10c
11a
11b
11c
12a
12b
12c
2 2
(286.4)
H N O S
C
11 12
2 2
(300.42)
H ClN O S
2 2 3
(9.27)
8.73
C
10
9
(320.84)
C H N O S
10 4 2 2
(8.84)
20.73
(20.85)
19.70
(19.82)
18.38
(18.24)
19.70
(19.82)
18.78
(18.64)
17.57
(17.63)
9
(270.34)
H N O S
C
10 12
4 2 2
(284.36)
C H ClN O S
4 2 2
9
9
(304.78)
N O S
C
H
10 12
4
2
2
2
(284.36)
N O S
C
H
11 14
4 2
(298.39)
H ClN O S
C
10 11
4 2 2
(318.81)

Jan-Feb 2005
Synthesis of Thiadiazoles, Triazoles and Oxadiazoles from Sulfonyl Acetic Acids
115
Table 2 (Continued)
Compd.
mp
( C)
Yield
(%)
Mol. Formula (Mol. Wt.)
Calcd. (Found) %
H
o
C
N
13a
13b
13c
14a
14b
14c
86-88
97-99
71
69
63
66
64
67
C H N O S
8 2 3 2
42.18
(42.12)
44.43
(44.50)
37.18
(37.15)
44.43
(44.39)
46.46
3.14
(3.18)
3.73
(3.79)
2.43
(2.38)
3.73
(3.81)
4.25
10.93
(11.01)
10.36
(10.45)
9.63
(9.69)
10.36
(10.42)
9.85
9
(256.3)
H N O S
C
10 10
2 3 2
(270.33)
C H ClN O S
105-106
159-160
167-169
188-190
9
7
2
3
2
2
2
(290.75)
N O S
C
H
10 10
2 3
(270.33)
N O S
C
H
11 12
2 3
(284.35)
H ClN O S
2 3 2
(46.54)
39.41
(4.18)
2.98
(9.79)
9.19
C
10
9
(304.77)
(39.45)
(2.92)
(9.24)
Table 2). The IR spectra of the compounds 9-14 displayed
an absorption band at 1634 cm for C=N apart from bands
around 10.20-10.45 for SH apart from signals due to meth-
-1
ylene protons. Besides 11 and 12 exhibited signals at 9.94-
-1
due to the SO group. Apart from this, the compounds 11
10.32 cm for NH which disappeared on deuteration
2
2
-1
1
and 12 showed a broad band at 3280 cm for NH . The H
(Table 3). The structures of the compounds 9–14 were fur-
2
13
NMR spectra of compounds 9-14 displayed a singlet
ther confirmed by C NMR spectra (Table 3).
Table 3
Spectral Data of Compounds 9-14
1
13
Product
IR
H NMR (δ, ppm)
C NMR (δ, ppm)
9a
1144,1320 (SO ), 1632 (CN),
10.21 (s, 1H, SH), 4.25 (s, 2H, CH ), 7.04-
168.3 (C ), 163.2 (C ), 138.7, 134.6, 129.3,
2
2
5
2
2554 (SH)
7.22 (m, 5H, Ar-H)
125.4 (Ar-C), 54.6 (CH SO )
2 2
9b
9c
1136,1320 (SO ), 1635 (CN),
2552 (SH)
2.20 (s, 3H, Ar-CH ), 10.28 (s, 1H, SH),
167.5 (C ), 166.8 (C ), 143.2, 137.4, 131.5,
5 2
2
3
4.23 (s, 2H, CH ), 7.01-7.23 (m, 4H, Ar-H)
126.3 (Ar-C), 54.4 (CH SO ), 20.3 (ArCH )
2
2 2 3
1124,1322 (SO ), 1630 (CN),
10.43 (s, 1H, SH), 4.26 (s, 2H, CH ), 7.12-
169.4 (C ), 166.3 (C ), 137.6, 135.8, 130.3,
5 2
2
2
128.5 (Ar-C), 55.4 (CH SO )
2
2
2558 (SH)
7.28 (m, 4H, Ar-H)
10a
10b
1128,1334 (SO ), 1627 (CN),
2562 (SH)
10.24 (s, 1H, SH), 4.21 (s, 2H, CH ), 4.38
167.9 (C ), 164.5 (C ), 131.7, 130.5, 128.7
5 2
2
2
(s, 2H, Ar-CH ), 7.03-7.28 (m, 5H, Ar-H)
(Ar-C), 58.5 (PhCH ), 52.8 (CH SO )
2
2 2 2
1126,1330 (SO ), 1625 (CN),
2.22 (s, 3H, Ar-CH ), 10.26 (s, 1H, SH),
165.7 (C ), 163.8 (C ), 137.5, 131.6, 128.7,
5 2
2
3
2560 (SH)
4.24 (s, 2H, CH ), 4.41 (s, 2H, Ar-CH ),
124.9 (Ar-C), 59.4 (ArCH ), 53.2
2
2
2
6.95-7.25 (m, 4H, Ar-H)
(CH SO ), 20.6 (ArCH )
2 2 3
10c
11a
11b
1122,1335 (SO ), 1628 (CN),
2564 (SH)
10.22 (s, 1H, SH), 4.22 (s, 2H, CH ), 4.45
168.8 (C ), 160.5 (C ), 131.3, 128.9, 128.7,
127.3 (Ar-C), 59.3 (ArCH ), 55.9 (CH SO )
2 2 2
2
2
5 2
(s, 2H, Ar-CH ), 7.08-7.32 (m, 4H, Ar-H)
2
1135,1332 (SO ), 1632 (CN), 2580
10.45 (s, 1H, SH), 4.21 (s, 2H, CH ), 7.02-
162.5 (C ), 149.4 (C ), 137.7, 132.5, 128.6,
2
2
5 3
(SH), 3262 (NH )
7.29 (m, 5H, Ar-H), 10.32 (bs, 2H, NH )
125.7 (Ar-C), 43.8 (CH SO )
2 2
2
2
1132,1330 (SO ), 1630 (CN), 2575
2.21 (s, 3H, Ar-CH ), 10.36 (s, 1H, SH),
163.4(C ), 148.5 (C ), 141.7, 134.5, 131.6,
2
3
5 3
(SH), 3260 (NH )
4.23 (s, 2H, CH ), 6.95-7.26 (m, 4H,
125.8 (Ar-C), 44.6 (CH SO ), 21.2 (ArCH )
2 2 3
2
2
Ar-H), 10.24 (bs, 2H, NH )
2
11c
12a
1130,1336 (SO ), 1625 (CN), 2572
10.31 (s, 1H, SH), 4.22 (s, 2H, CH ), 7.08-
163.8 (C ), 150.1 (C ), 137.8, 135.7, 130.2,
5 3
2
2
(SH), 3264 (NH )
7.34 (m, 4H, Ar-H), 10.21(bs, 2H, NH )
128.5 (Ar-C), 43.6 (CH SO )
2
2
2 2
1142,1338 (SO ), 1634 (CN), 2620
10.32 (s, 1H, SH), 4.19 (s, 2H, CH ), 4.47
161.7 (C ), 148.6 (C ), 138.5, 132.7, 130.2,
5 3
2
2
(SH), 3270 (NH )
(s, 2H, Ar-CH ), 6.98-7.32 (m, 5H, Ar-H),
127.5 (Ar-C), 56.5 (PhCH ), 42.9 (CH SO )
2
2
2 2 2
9.94 (bs, 2H, NH )
2
12b
12c
1141,1325 (SO ), 1632 (CN), 2630
2.22 (s, 3H, Ar-CH ), 10.34 (s, 1H, SH),
162.5 (C ), 148.1 (C ), 139.5, 131.6, 129.7,
5 3
2
3
(SH), 3280 (NH )
4.17 (s, 2H, CH ), 4.46 (s, 2H, Ar-CH ),
124.6 (Ar-C), 57.2 (ArCH ), 43.3
2
2
2
2
6.78-7.24 (m, 4H, Ar-H), 10.02 (bs, 2H,
NH )
(CH SO ), 21.2 (ArCH )
2 2 3
2
1132,1320 (SO ), 1630 (CN),
10.30 (s, 1H, SH), 4.22 (s, 2H, CH ), 4.51
162.3 (C ), 147.8 (C ), 135.2, 133.3, 130.6,
5 3
2
2
2645 (SH), 3275 (NH )
(s, 2H, Ar-CH ), 7.04-7.38 (m, 4H, Ar-H),
125.8 (Ar-C), 57.2 (ArCH ), 43.1 (CH SO )
2
2
2 2 2
10.21 (bs, 2H, NH )
2
13a
13b
13c
1138,1335 (SO ), 1626 (CN),
2640 (SH)
10.28 (s, 1H, SH), 4.14 (s, 2H, CH ), 6.94-
7.31 (m, 5H, Ar-H).
167.4 (C ), 159.5 (C ), 139.7, 135.2, 130.5,
5 2
2
2
124.8 (Ar-C), 54.4 (CH SO )
2 2
1125,1332 (SO ), 1625 (CN),
2.20 (s, 3H, Ar-CH ), 10.27 (s, 1H, SH),
167.7 (C ), 158.7 (C ), 141.5, 134.7, 131.2,
5 2
2
3
2620 (SH)
4.17 (s, 2H, CH ), 6.82-7.29 (m, 4H, Ar-H)
125.9 (Ar-C), 54.9 (CH SO ), 20.4 (ArCH )
2
2 2 3
1130,1340 (SO ), 1628 (CN),
10.23 (s, 1H, SH), 4.18 (s, 2H, CH ), 7.02-
165.8 (C ), 160.3 (C ), 139.2, 135.5, 129.5,
5 2
2
2
2625 (SH)
7.29 (m, 4H, Ar-H)
126.8 (Ar-C), 55.7 (CH SO )
2 2

116
V. Padmavathi, P. Thriveni, B. Jagan M. Reddy and A. Padmaja
Vol. 42
Table 3 (continued)
1
13
Product
IR
H NMR (δ, ppm)
C NMR (δ, ppm)
14a
1122,1330 (SO ), 1625 (CN),
10.26 (s, 1H, SH), 4.13 (s, 2H, CH ), 4.54
168.3 (C ), 160.7 (C ), 137.8, 131.6, 130.5,
2
2
5
2
2580 (SH)
(s, 2H, Ar-CH ), 6.88-7.29 (m, 5H, Ar-H)
127.3 (Ar-C), 57.4 (PhCH ), 51.3 (CH SO )
2
2 2 2
14b
14c
1134,1328 (SO ), 1632 (CN),
2590 (SH)
2.20 (s, 3H, Ar-CH ), 10.28 (s, 1H, SH),
169.4 (C ), 161.3 (C ), 138.9, 132.2, 130.5,
5 2
2
3
4.15 (s, 2H, CH ), 4.49 (s, 2H, Ar-CH ),
124.9 (Ar-C), 57.6 (ArCH ), 50.8 (CH SO )
2
2
2 2 2
6.76-7.24 (m, 4H, Ar-H)
21.3 (Ar-CH )
3
1125,1336 (SO ), 1630 (CN),
10.29 (s, 1H, SH), 4.19 (s, 2H, CH ), 4.58
170.1 (C ), 161.4 (C ), 135.4, 133.6, 130.7,
2
2
5 2
2600 (SH)
(s, 2H, Ar-CH ), 7.01-7.35 (m, 4H, Ar-H)
125.8 (Ar-C), 57.3 (ArCH ), 51.6 (CH SO )
2 2 2
2
A solution of 10 mmoles of 7/8 in 6 ml of acetic acid was
refluxed for 24 hours. The contents of the flask were cooled and
poured onto crushed ice. The solid obtained was collected by fil-
tration, dried and recrystallized from 2-propanol.
Thus a new class of triazoles, oxadiazoles and thiadia-
zoles were prepared from simple substrates, phenylsul-
fonylacetic acid and benzylsulfonylacetic acid via potas-
sium dithiocarbazate of acid hydrazide.
4-Amino-5-arylsulfonylmethyl-4H-[1,2,4]triazole-3-thiol
(11)/4-Amino5-Aryl-methanesulfonylmethyl-4H-[1,2,4]tria-
zole-3-thiol (12).
EXPERIMENTAL
Melting points were determined on Tempo Mel-Temp appara-
tus and are uncorrected. The IR spectra were recorded on a
Perkin-Elmer grating infrared spectrophotometer model 337 as
To a solution of 10 mmoles of potassium salt (7/8) in 10 ml of
water, 20 mmoles of hydrazine hydrate was added and refluxed
for 8-9 hours. The contents of the flask were cooled, diluted with
water and acidified with 10 ml of acetic acid. The separated solid
was collected by filtration, dried and recrystallized from 2-
propanol.
-1
1
KBr pellets and the wave numbers were given in cm The H
.
NMR spectra were recorded in CDCl /DMSO-d on a Varian EM-
3
6
360 spectrometer (300MHz) with TMS as an internal standard and
13
the C NMR spectra were recorded on a Varian VXR spectrome-
5-Arylsulfonymethyl[1,3,4]oxadiazole-2-thiol (13)/5-Aryl-
methanesulfonylmethyl[1,3,4]oxadiazole-2-thiol (14).
ter operating at 75.5 MHz with CDCl as solvent. Elemental
3
analyses were performed using a Perkin-Elmer 240C elemental
analyzer. The chemical shifts were measured in δ (ppm). The
purity of compounds was checked by TLC using silica gel ‘G’
(BDH) and hexane-ethyl acetate as eluents. The starting com-
pounds arylsulfonylacetic acid (1)/arylmethanesulfonyl acetic
acid (2) were prepared as per the literature procedure [7].
A solution of 10 mmoles of potassium salt (7/8) was dissolved
in 10 ml of water and acidified with 2 ml of conc. HCl. The
regenerated solid was collected by filtration, dried and recrystal-
lized from 2-propanol.
REFERENCES AND NOTES
Arylsulfonylacetic Acid Methyl Ester (3)/Arylmethanesulfonyl-
acetic Acid Methyl Ester (4).
*
To whom correspondence should be addressed. E-mail:
vkpuram2001@yahoo.com
[1] N. F. Eweiss, A. A. Bahajaj and E. A. Elsherbini, J.
Heterocyclic Chem., 23, 1451(1986).
[2] M. A. EL-Dawy, A. M. M. E. Omar, A. M. Ismail and A. A.
B. Hazzaa, J. Pharm. Sci., 43, 45 (1983).
A solution of 10 mmoles 1/2, 10 ml of methanol and 1 ml conc.
H SO was refluxed on a steam bath for 8-10 hours. The contents
2
4
of the flask were cooled and poured onto crushed ice. The solid
that separated was collected by filtration, washed with cold water
and dried. The crude product was recrystallized from methanol.
[3a] V. Dwivedi and P. K. Agarwal, Indian J. Pharm. Sci., 53, 82
(1991); [3b] N. F. Eweiss and A. A. Bahajaj, J. Heterocyclic Chem., 24,
1173 (1987).
Arylsulfonylacetic Acid Hydrazide (5)/Arylmethanesulfonyl-
acetic Acid Hydrazide (6).
[4] K. Kariyone, H. Harada, M. Kuritha and T. Takaano,
Antibiot J., 23, 131 (1970).
To a solution of mixture of 10 mmoles of 3/4 in 6 ml of
methanol, 11 mmoles of hydrazine hydrate and 3 drops of pyri-
dine were added and refluxed for 6-7 hours. The reaction mixture
was cooled and the solid that separated was collected by filtra-
tion, dried and recrystallized from methanol.
[5a] V. Padmavathi, K. Venugopal Reddy, A. Padmaja and D.
Bhaskar Reddy, Synth Commun., 32, 1227 (2002); [5b] V. Padmavathi,
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610 (1999).
Potassium Dithiocarbazate (7/8).
A solution of 10 mmoles of 5 in 20 ml of absolute ethanol and
15 mmoles of KOH was treated with 40 mmoles of CS . The
2
[6a] I. Lalezari, P. Lowlavar and N. Mazhari, J. Med Chem., 15,
115 (1972); [6b] A.Wagenaar, G. Kransen and Jan B. F. N. Engberts, J.
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[7] A. I. Vogel, A Textbook of Practical Organic Chemistry, 5
edition, (Longman’s Green & Co. Ltd, London), 1989.
mixture was sonicated for 4 hours. The separated solid was col-
lected by filtration and dried.
th
5-Arylsulfonylmethyl[1,3,4]thiadiazole-2-thiol (9)/5-Arylmethane-
sulfonylmethyl[1,3,4]thiadiazole-2-thiol (10).