Synthesis of some new 1,3,4-thiadiazol-2-ylmethyl-1,2,4-triazole derivatives and investigation of their antimicrobial activities

Article abstract of DOI:10.1016/j.ejmech.2008.12.005

4-Amino-2-[(5-arylamino-4,5-dihydro-1,3,4-thiadiazol-2-yl)methyl]-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-ones (3a-c) were obtained in acidic media via the formation of 2-[(4-amino-3-aryl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)acetyl]-N-arylhyd

Full text of DOI:10.1016/j.ejmech.2008.12.005

European Journal of Medicinal Chemistry 44 (2009) 2896–2903
Contents lists available at ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Synthesis of some new 1,3,4-thiadiazol-2-ylmethyl-1,2,4-triazole derivatives
and investigation of their antimicrobial activities
,
a
a
b
Ahmet Demirbas a , Deniz Sahin , Neslihan Demirbas , Sengu¨l Alpay Karaoglu
*
a Department of Chemistry, Karadeniz Technical University, 61080 Trabzon, Turkey
b Department of Biology, Rize University, 53100 Rize, Turkey
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 3 July 2008
Received in revised form
10 November 2008
Accepted 8 December 2008
Available online 16 December 2008
4-Amino-2-[(5-arylamino-4,5-dihydro-1,3,4-thiadiazol-2-yl)methyl]-5-(4-methylphenyl)-2,4-dihydro-3H-
1,2,4-triazol-3-ones(3a–c)were obtained inacidicmediaviatheformation of2-[(4-amino-3-aryl-5-oxo-4,5-
dihydro-1H-1,2,4-triazol-1-yl)acetyl]-N-arylhydrazinecarbothioamides (2a–c), and then, compound 3b was
converted to methylated derivative, 4. The basic treatment of carbothioamide derivatives, 2a–c, afforded
4-amino-2-[(4-aryl-5-sulphanyl-4H-1,2,4-triazol-3-yl)methyl]-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,
4-triazol-3-ones (5a–c). The alkylation reactions of compounds 4H-1,2,4-triazol-3-ylmethyl-5-(4-methyl-
phenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one derivatives (5a–c) were performed by using methyl iodide or
ethyl bromide in the presence of sodium ethoxide, while the treatment of the same intermediates, 5a–c, with
aromatic aldehydes produced 2-{[4-(4-aryl)-5-sulphanyl-4H-1,2,4-triazol-3-yl]methyl}-4-(arylmethyle-
ne)amino-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-ones (8a–d). The synthesis of 4-amino-(or
arylideneamino)-5-(4-methylphenyl)-2-{[(4-methylpiperazin-1-yl or morpholin-4-ylethyl)methyl]-4-aryl-
5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl}methyl-2,4-dihydro-3H-1,2,4-triazol-3-ones (7a, b and 9) was
performed by a one pot three-component Mannich reaction involving the corresponding compounds,
4-(substituted)amino-4H-1,2,4-triazol-3-ylmethyl-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-
one derivatives 5a, b and 8a, methylpiperazine or 2-(4-morpholino)ethylamine and formaldehyde.
The newly synthesized compounds were well characterized by elemental analyses, IR, 1H NMR, 13C NMR
and mass spectral studies. They were also screened for their microbial activities. The antimicrobial
activity study revealed that some of which 2a, c, 3c, 5a–c, 8a–d showed good activity against a variety of
microorganisms.
Keywords:
1,2,4-Triazole
1,3,4-Thiadiazole
Mannich base
Schiff base
Antimicrobial activity
Ó 2008 Elsevier Masson SAS. All rights reserved.
1. Introduction
infections, contains a piperazine and one or more azole ring in their
structures [9] (Fig. 1, Chart 1).
In the past decades, the problem of multi-drug resistant
microorganisms has reached on alarming level around the world.
For the treatment of microbial infections, the synthesis of new anti-
infectious compounds has become an urgent need. For this
purpose, several compounds that contain a piperazine or mor-
pholine nucleus possessing antimicrobial activity have been
synthesized; some of which contains an azole ring as well [1–6]. For
instance, while eperezolid, which are the members of oxazolidi-
none class antibiotics, consist of morpholine and oxazolidinone
rings linked each other via a fluorophenilene linkage, another
antibiotic, Linezolid, contains a piperazine ring instead of mor-
pholine [7,8]. On the other hand, Itraconazole, posaconazole and
ketoconazole that are being used for the treatment of fungal
The 1,2,4-triazole nucleus has been incorporated into a wide
variety of therapeutically important agents. Ribavirin (antiviral),
Rizatriptan (antimigraine), Alprazolam (anxiolytic), Vorozole,
Letrozole and Anastrozole (antitumoral) are some examples of
drugs containing 1,2,4-triazole moiety [10–14] (Chart 2).
1,2,4-Thiadiazole derivatives are another important class of
heterocycles due to their biological activities. Although the only
commercially available 1,2,4-thiadiazole drug is the antibiotic
cefozopram (Chart 3), there are a number of thiadiazole derivatives
possessing a broad range of biological activities. For instance, KC
12291 has been found to possess a cardioprotective activity, while
another thiadiazole derivative, SCH-202676, has been reported as
allosteric modulator of G-protein coupled receptors [15]. Other
thiadiazolidinones (TDZD) have been described as non-ATP
competitive glycogen synthase kinase 3ß inhibitors [15] (Chart 3).
Multicomponent reactions are a major part of synthetic organic
chemistry with advantages ranging from lower reaction times and
* Corresponding author. Tel.: þ90 462 3772600; fax: þ90 4623253196.
E-mail address: ndemirbas651@mynet.com (A. Demirbas).
0223-5234/$ – see front matter Ó 2008 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2008.12.005

A. Demirbas et al. / European Journal of Medicinal Chemistry 44 (2009) 2896–2903
2897
O
O
S
CH3
N
N
NHNH2
NHNH
C
NHR
N
N
N
N
N
)
R= C H F(p
R= C6H5
2a:
6
4
O
O
N
N
RNCS
N
2b:
2c:
NH
NH
2
2
R= C6H4OCH3(p
)
S
CH3
CH3
1
N
2a-c
N
N
O
N
N
H2SO4
NaOH
N
CH3
CH
F
N
N
N
SH
N
NH
R
N
N
S
N
N
)
R= C6H4F(p
3a, 5a:
3b, 5b:
R
F
R= C H
O
6
5
N
5a-c
O
N
9
)
3c, 5c: R= C6H4OCH3(p
NH2
NH
2
CH3
CH3
3a-c
HCHO
methyl piperazine
HCHO
methyl piperazine or
2-(4-morpholino)ethylamine
R'CHO
R'X
EtO-, CH3I
N
N
N
N
R
SH
SR'
N
N
N
N
N
N
N
N
N
N
N
R'
R
S
N
N
O
N
N
S
O
N
N
N
N
CH3
NH2
O
N
O
CH3
CH
R
N
CH3
NH2
NH2
8a-d
8a: R= C6H4F(p ), R'= C6H4F(p
CH3
7a: R=
6a-c
7a,b
CH3
4
)
R=
6a:
4-fluoro-Ph, R'= Et
N
N
CH3
),
)
C H F(p
6
R= C H OCH (p
R'=
8b:
8c:
8d:
4
6
4
3
Ph, R'= Me
6b: R=
R= C H F(p ), R'=
C6H5
6
4
7b: R= NHCH2CH2
N
O
6c: R= 4-MeO-Ph, R'= Me
R= C H OCH (p ), R'=
C6H5
6
4
3
Fig. 1.
O
O
F
F
HO
O
O
N
O
N
N
N
N
O
NHAC
NHAC
Linezolid
Eperezolid
CH3
N
O
O
N
O
N
N
N
N
N
N
Cl
O
Cl
Itraconazole
O
CH3
.HCl
CH3O
CH3O
N
N
N
C
N
N
N
O
O
N
N
N
N
N
O
OH
N
F
O
NH2
Posaconazole
Prazosin
F
F
CH3
NH
O
H
CH3
N
N
N
CH3
N
O
N
N
O
N
CH3
CH3
Urapidil
Lidoflazin
F
Chart 1.

2898
A. Demirbas et al. / European Journal of Medicinal Chemistry 44 (2009) 2896–2903
N
CH3
NH2
H
N
N
N
N
N
N
O
N
O
N
N
HOCH2
CH3
N
N
Cl
CH3
OH
OH
Rizatriptan
Ribavirin
Alprazolam
N
N
N
N
N
N
N
N
CH3
N
H3C
CN
CH3
N
N
N
Cl
CN
CN
Anastrozole
Vorozole
Letrozole
CH3
CH3
CN
Chart 2.
temperatures to higher yields. Mannich reactions are three-
component condensation reactions involving carbonyl compounds,
which exist as enol–keto tautomeric forms, formaldehyde and
a primary or secondary amine. The amino alkylation of aromatic
compounds by Mannich reaction has been reported to have
a considerably importance for designing efficient bioactive mole-
cules [16]. A number of Mannich base has been reported as anti-
tubercular, antimalarial, vasorelaxing, anticancer and analgesic
drugs [16–19]. Mannich bases of 1,2,4-triazole derivatives con-
taining N-methylpiperazine or morpholine moiety have been
reported to possess antibacterial activity. Prazosin [20], Lidoflazine
[21] and Urapidil [22], that are efficient cardiovascular drugs used
in current treatment, are containing a piperazine nucleus in their
structures (Chart 1). Moreover, organic compounds including
a fluorine atom in their structures have found application in the
pharmaceutical field owing to their diverse biological properties
[23].
In recent years, various antitumor drugs have been developed
for the treatment of cancer. Among these, we prepared some 1,2,4
triazole derivatives incorporating Schiff base structure as antitumor
agents. [24–27]. However, cancer is still a major health problem
because of the insufficiency of the conventional methods. In addi-
tion, some 1,2,4-triazole derivatives have been found to possess
antimicrobial activity [27–32].
As a continuation of our studies on obtaining bioactive molecules,
we have herein synthesized some 1,3,4-thiadiazolyl-1,2,4-triazoles
and Mannich bases of 1,2,4-triazolyl-1,2,4-triazole derivatives con-
taining piperazine or morpholine ring beside schiff bases, some of
which contains fluorophenyl moiety in their structures.
2. Chemistry
2-{[4-Amino-3-(4-methylphenyl)-5-oxo-4,5-dihydro-1H-1,2,4-
triazol-1-yl]acetyl}-N-arylhydrazinecarbothioamides (2a–c) were
obtained from the reaction of compound 2-[4-amino-3-(4-methyl-
phenyl)-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]acetohydrazide (1)
with 4-fluorophenyl-(for compound 2a), phenyl-(for 2b) or
4-methoxyphenyl (for 2c) isothiocyanate. The cyclization of
compounds 2a–c in the presence of sodium hydroxide resulted in the
formation of 5a–c. The alkylations of compounds 5a and 5b
were performed by the reaction with methyl iodide or ethyl
bromide in basic media, thus compounds 6a and 6b were obtained.
On the other hand, the reactions of the same precursors 5a, 5b
with methyl piperazine or 2-(4-morpholino)ethylamine in the
presence of formaldehyde solution afforded the corresponding
Mannichbasederivatives7a, b. Thetreatmentof4-amino-2-([4-aryl-
5-sulphanyl-4H-1,2,4-triazol-3-yl]methyl)-5-(4-methylphenyl)-2,4-
dihydro-3H-1,2,4-triazol-3-ones (5a–c) with 4-fluoro- or 4-methoxy
Bn
Me
N
N
OMe
OMe
O
O
O
N
N
S
Me
N
S
KC 12291
TDZD-8
S
N
Me
N
CONH
O
S
H2N
N
N
HCl
N
N
S
N
N
N
N
MeO
COO
SCH-202676
Cefozopram
Chart 3.

A. Demirbas et al. / European Journal of Medicinal Chemistry 44 (2009) 2896–2903
2899
Table 1
benzaldehyde produced 2-([4-aryl-5-sulphanyl-4H-1,2,4-triazol-3-
Screening for antimicrobial activity of the compounds (mm).
yl]methyl)-4-arylmethyleneamino-5-(4-methylphenyl)-2,4-dihy-
dro-3H-1,2,4-triazol-3-ones (8a–d). The treatment of compound 8a
with methyl piperazine in the presence of formaldehyde resulted in
the formation of compound 9.
Compounds 3a–c were prepared by the treatment of carbo-
thioamide derivatives 2a–c with concentrated sulfuric acid. Then,
compound 3b was converted to its methylated derivative, 4 by
treatment with methyl iodide in the presence of sodium ethoxide.
The structures were confirmed by IR, 1H NMR, 13C NMR and Mass
spectral data (except 3b, 6c, 7b, 8b and 9), and elemental analyses.
Comp. No. E. coli Y. ps. P. aur. E. fec. S. au. B. cer. C. trop. C. alb
2a
2b
2c
34
–
24
–
28
–
25
–
35
–
35
–
30
–
28
–
30
6
28
–
22
–
22
–
–
–
–
–
–
–
6
–
–
–
6
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
6
–
–
–
–
–
–
–
–
–
–
3a
3b
3c
4
–
30
–
–
22
–
–
>30
–
–
20
–
–
28
–
–
23
7
5a
5b
5c
30
25
28
–
26
22
22
–
35
30
30
–
30
20
25
–
26
24
30
8
25
20
25
9
6a
3. Antimicrobial activity
6b
6c
–
–
–
–
–
–
–
–
–
–
–
–
7a
–
–
–
–
–
–
3.1. Antimicrobial activity assessment
7b
8a
8b
8c
8d
9
–
–
–
–
–
–
25
30
25
28
–
22
30
25
25
–
30
35
30
30
–
20
24
20
25
–
24
26
28
30
–
20
22
20
25
8
All bacterial and yeast strain were obtained from the Hifzissihha
Institute of Refik Saydam (Ankara, Turkey) and were as follows:
Escherichia coli ATCC 25922, Yersinia pseudotuberculosis ATCC 911,
Pseudomonas aeruginosa ATCC 27853, Enterococcus faecalis ATCC
29212, Staphylococcus aureus ATCC 25923, Bacillus cereus 709
ROMA, Candida tropicalis ATCC 13803 and Candida albicans ATCC
60193. All the newly synthesized compounds were dissolved in
dimethylsulphoxide (DMSO) and ethanol to prepare chemicals
stock solution of 10 mg/mL.
DMSO
Amp.
Flu.
–
10
–
18
–
18
–
10
–
35
–
15
25
25
Ec: Escherichia coli ATCC 25922, Yp: Yersinia pseudotuberculosis ATCC 911, Pa: Pseu-
domonas aeruginosa ATCC 27853, Ef: Enterococcus faecalis ATCC 29212, Sa: Staphy-
lococcus aureus ATCC 25923, Bc: Bacillus cereus 702 Roma, Ct: Candida tropicalis ATCC
13803, Ca: Candida albicans ATCC 60193. Amp.: Ampicillin, Flu.: Fluconazole, (–): no
activity, solvent is DMSO.
3.1.1. Agar-well diffusion method
Simple susceptibility screening test using agar-well diffusion
method [34] as adapted earlier [35] was used. Each microorganism
was suspended in Mueller Hinton (MH) (Difco, Detroit, MI) broth
and diluted approximately 106 colony forming units (cfu) per mL.
They were ‘‘flood-inoculated’’ onto the surface of MH agar and
Sabouraud Dextrose Agar (SDA) (Difco, Detroit, MI) and then dried.
For C. albicans and C. tropicalis, SDA were used. Five-millimeter
diameter wells were cut from the agar using a sterile cork-borer,
and 50 ml of the extract substances were delivered into the wells.
The plates were incubated for 18 h at 35 ꢀC. Antimicrobial activity
was evaluated by measuring the zone of inhibition against the test
organism. Ampicillin (10 mg) and Fluconazole (5 mg) were standard
drugs. Dimethylsulphoxide was used as solved control. The anti-
microbial activity results were summarized in Table 1.
spectra. Compounds 5a–c displayed moderate activity towards the
microbial strain used in this study except C. tropicalis and C. albi-
cans. It is known that sulphanyl triazoles exist as thioxo-sulphanyl
tautomeric forms. This sulphanyl group in type 5 compounds is
acidic enough for further reactions; for example, alkylation reac-
tions could be achieved [33]. The reaction of compound 5a–c with
methyl iodide (for compounds 6b and 6c) or ethyl bromide (for
compound 6a) in the presence of sodium hydroxide produced 4-
amino-2-{[5-(alkylthio)-4-aryl-4,5-dihydro-1H-1,2,4-triazol-3-yl]
methyl}-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-ones
(6a–c). In the 1H NMR spectra of compounds 6b and 6c there is no
peak derived from –NH– or –SH group. Instead, new signals due to
methyl group appeared at 2.53 ppm, while ethyl substituent of
compound 6a resonated at 1.28 (CH3CH2) and 3.08 ppm (CH3CH2).
In addition, the FT-IR spectra of compounds 6a and 6b do not
contain a peak due to –NH– or –SH group. Mþ (for 6a) or M þ 1 (for
6b) peak exists in the mass spectra of compound 6a, b. Further-
more, compounds 6a, b gave good elemental analysis results.
The Mannich base derivatives of compound 5b were obtained in
relatively mild conditions. The 1H and 13C NMR spectra of
compounds 7a, b displayed additional signals originated from
methyl piperazine or morpholinoethylamine residue and methy-
lene linkage, while the –NH– signal belonging to 5-thioxo-1,2,4-
triazole ring was disappeared. Due to less solubility in any NMR
solvent, 13C NMR spectra of compounds 7a and 7b were not
recorded. A peak representing a stable molecular ion was present in
the mass spectra of 7a. Moreover, the elemental analysis data of 7a,
b are consistent with their structures.
4. Results and discussion
It is known that the –NH2 group on 4,5-dihydro-1H-1,2,4-triazol-
5-ones resonate between 5.20 and 5.50 ppm in the 1H NMR spec-
trum [5,8,11–16]. As expected, the 1H NMR spectra of compounds
2a–c displayed a signal belonging to –NH2 group at 5.54–5.57 ppm.
Moreover, three –NH– signals recorded between 9.62 and 10.38 ppm
(controlled by changed with D2O) in the 1H NMR spectra of
compounds 2a–c. Moreover, the stretching bands derived from
NH þ NH2 groups were seen in the FT-IR spectra of compounds 2a–c.
The elemental analyses data of these compounds are consistent with
the assigned structures. A stable molecular ion peak was seen for 2b,
while compounds 2a and 2c gave peaks derived from M þ 2 (for 2a)
or M þ K (for 2c) in the Mass spectra. Among compounds 2a–c, 2a
and 2c, which are containing a 4-substituted phenyl ring in the
carbothioamide structure, displayed moderate activity against the
test microorganisms except C. tropicalis and C. albicans.
In the 1H NMR spectra of compounds 8a–d, the –NH2 signal
disappeared, while additional signals belonging to aldehyde
residue appeared at aromatic region. The 1H NMR spectra of
compound 9 displayed new peaks owing to methylene linkage and
methyl piperazine moiety at 5.14 and 2.31–2.50 ppm. Due to less
solubility in any deuterated solvent, a satisfactory 13C NMR spec-
trum was not taken for compound 9. Compounds 8a–d were found
to possess moderate activity against the bacterial strain used in the
study except C. tropicalis and C. albicans.
The signal observed at 13.91–14 ppm in the 1H NMR spectra of
compounds 5a–c was attributed to –SH group. This group was
observed at 2760–2768 cmꢁ1 in the FT-IR spectra of compounds
5a–c. The elemental analyses data are consistent with the assigned
structures of compounds 5a–c. Furthermore, 5a–c gave stable
molecular ion peak (5a and 5c) or M þ Na peak (for 5b) in the mass

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A. Demirbas et al. / European Journal of Medicinal Chemistry 44 (2009) 2896–2903
The acidic treatmentofcompounds 2a–c afforded4-amino-2-({5-
n
, cmꢁ1): 3335, 3274 and 3159 (NH2 þ 3NH), 1693 (C]O), 1611
[(4-fluorophenyl)amino]-1,3,4-thiadiazol-2-yl}methyl)-5-(4-meth-
ylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-ones (3a–c). Compound
3b was ethylated by using ethyl bromide in the presence of sodium
hydride. Compounds 3a–c and 4 gave satisfactory spectroscopic and
elemental analysis data. Among compounds 3a–c, antimicrobial
activity was showed for 3c.
(C]N), 1191 (C]S); 1H NMR (DMSO-d6)
d
(ppm): 2.35 (3H, s, CH3),
4.60 (2H, s, CH2), 5.54 (2H, s, NH2), 7.13–7.46 (6H, m, arH), 7.88 (2H,
d, arH, J ¼ 8.0 Hz), 9.68 (H, s, NH), 9.80 (H, s, NH), 10.36 (H, s, NH);
13C NMR (DMSO-d6)
d (ppm): 20.85 (CH3), 46.82 (CH2), arC: [114.45
(2CH), 114.88 (2CH), 123.64 (C), 127.32 (2CH), 128.79 (2CH), 135.19
(2C), 139.57 (C)], 144.84 (triazole C-3), 153.74 (triazole C-5), 166.30
(C]O), 180.97 (C]S); MS (ESI): m/z (%) 413.28 (M þ 2) (16), 384.12
(18), 331.12 (19), 301.08 (16), 273.99 (21), 252.90 (25), 251.90 (33),
232.94 (37), 231.94 (27), 202.84 (54), 190.83 (44), 163.80 (30),
162.80 (94), 145.71 (88), 144.78 (50), 120.81 (100).
5. Conclusion
This study reports the successful synthesis of some new 5-sul-
phanyl-4H-1,2,4-triazol-2-ylmethyl-2,4-dihydro-3H-1,2,4-triazol-
3-ones, 1,3,4-thiadiazol-2-ylmethyl-2,4-dihydro-3H-1,2,4-triazol-
3-ones, and conversion some of them into the corresponding Shiff
and Mannich bases and alkylated derivatives. The antimicrobial
screening studies were also performed in the study. 1,2,4-Triazole
nucleus is one of the active components present in many standard
drugs and it is known to increase the pharmacological activity of the
molecules. The presence of N-methylpiperazine or morpholine
moiety is also instrumental in contributing to the net biological
activity of a system. Also we already reported antimicrobial activi-
ties of some biheterocyclic compounds incorporating 1,2,4-triazole
and 1,3,4-thiadiazole rings, in addition to some alkylated derivatives
of 1,2,4-triazole compounds. Hence herein we combined all these
three potential units, namely 1,2,4-triazole and 1,3,4-thiadiazole
nucleus (or second 1,2,4-triazole moiety), methyl piperazine/mor-
pholine ring. The antimicrobial screening suggests that among the
newly synthesized compounds, 2a–c, 3c, 5a–c and 8a–d exhibited
moderate activity against all the tested microorganisms except C.
tropicalis and C. albicans. On the contrary to expected, the intro-
duction of third heterocyclic ring (methyl piperazine or morpho-
line) to the structure of compounds 5a–c by a Mannich reaction
caused no antimicrobial activity. But, it might be speculated that
these results were obtained probably due to slight solubility of
compounds 7a, b and 9 in known organic solvents.
6.1.3. 2-{[4-Amino-3-(4-methylphenyl)-5-oxo-4,5-dihydro-1H-1,
2,4-triazol-1-yl]acetyl}-N-phenylhydrazinecarbothioamide (2b)
Yield 76%, m.p. 190–191 ꢀC. Anal. Calcd. (%) for: C18H19N7O2S: C,
54.39; H, 4.82, N, 24.67. Found; C, 54.47; H, 4.90; N, 24.53; IR (KBr, n,
cmꢁ1): 3311, 3210 (3NH þ NH2), 1685 and 1718 (2C]O), 1597
(C]N), 1202 (C]S); 1H NMR (DMSO-d6)
d (ppm): 2.36 (3H, s, CH3),
4.61 (2H, s, CH2), 5.57 (2H, s, NH2), 7.18 (2H, t, arH, J ¼ 7.0 Hz), 7.32
(3H, t, arH, J ¼ 8.4 Hz), 7.39–7.45 (2H, m, arH), 7.89 (2H, d, arH,
J ¼ 8.0 Hz), 9.70 (H, s, NH), 9.79 (H, s, NH), 10.38 (H, s, NH); 13C NMR
(DMSO-d6)
d (ppm): 21.03 (CH3) 47.07 (CH2), arC: [123.82 (C),
125.07 (CH), 127.44 (3CH), 127.96 (2CH), 128.75 (3CH), 138.97 (C),
139.53 (C)], 144.98 (triazole C-3), 153.89 (triazole C-5), 166.35
(C]O), 180.77 (C]S); MS (ESI): m/z (%) 398.06 (Mþ, 26), 277.98
(15), 241.00 (14), 202.84 (44), 190.82 (15), 161.79 (23), 156.72 (100),
144.77 (59), 132.76 (17), 117.74 (21).
6.1.4. 2-{[4-Amino-3-(4-methylphenyl)-5-oxo-4,5-dihydro-1H-1,2,
4-triazol-1-yl]acetyl}-N-(4-methoxyphenyl) hydrazinecarbothioa-
mide (2c)
Yield 74%, m.p. 196–199 ꢀC. Anal. Calcd. (%) for: C19H21N7O3S: C,
53.38; H, 4.95, N, 22.94. Found; C, 53.51; H, 5.03; N, 22.90; IR (KBr, n,
cmꢁ1): 3292, 3153 (3NH þ NH2), 1695 (2C]O), 1598 (C]N), 1188
(C–S); 1H NMR (DMSO-d6)
d (ppm): 2.29 (3H, s, CH3), 2.36 (3H, s,
OCH3), 4.61 (2H, s, CH2), 5.56 (2H, s, NH2), 7.14 (2H, d, arH,
J ¼ 8.4 Hz), 7.29 (4H, d, arH, J ¼ 8.8 Hz), 7.89 (2H, d, arH, J ¼ 8.2 Hz),
9.62 (H, s, NH), 9.72 (H, s, NH), 10.34 (H, s, NH); 13C NMR (DMSO-d6)
6. Experimental
6.1. Chemistry
d
(ppm): 20.47 (CH3), 20.88 (OCH3), 46.84 (CH2); arC: [123.71 (C),
125.61 (CH), 127.34 (2CH), 128.49 (3CH), 128.82 (2CH), 134.35 (C),
136.30 (C), 139.60 (C)], 144.84 (triazole C-3), 153.76 (triazole C-5),
166.33 (C]O), 180.69 (C]S); MS (ESI): m/z (%) 466.11 (M þ K, 9),
434.14 (16), 412.12 (14), 300.92 (11), 262.97 (11), 202.87 (20),193.81
(79), 192.80 (100), 178.83 (56), 166.94 (18), 156.74 (38), 144.78 (19),
118.67 (68).
Melting points were determined on a Bu¨chi B-540 melting point
apparatus and are uncorrected. 1H NMR and 13C NMR spectra were
recorded on a Varian-Mercury 200 MHz spectrometer. The IR
spectra were measured as potassium bromide pellets using a Per-
kin–Elmer 1600 series FT-IR spectrometer. Mass spectra were
obtained at a Quattro LC-MS (ESI, 70 eV) Instrument (except
compounds 3b, 6c, 7b, 8b and 9). Combustion analysis was per-
formed on a Costech Elemental Combustion System CHNS-O
elemental analyzer. All the chemicals were obtained from Fluka
Chemie AG Buchs (Switzerland). Compound 1 was prepared by the
way reported earlier [27].
6.2. General method for the synthesis of compounds 3a–c
A mixture of corresponding carbothioamide 2 (10 mmol) in cold
concentrated sulfuric acid (28 mL) was stirred for 10 min then, the
mixture was allowed to reach room temperature. After stirring for
an additional 30 min, the resulting solution was poured into ice-
cold water and made alkaline to pH 8 with ammonia. The precip-
itated product was filtered, washed with water and recrystallized
from ethanol to afford pure compounds.
6.1.1. General method for the synthesis of compounds 2a–c
A mixture of compound 1 (10 mmol) and 4-fluorophenyl iso-
thiocyanate (1.53 g, 10 mmol) (for compound 2a), phenyl
isothiocyanate (1.35 g, 10 mmol) (for compound 2b) or 4-methox-
yphenyl isocyanate (1.65 g, 10 mmol) (for compound 2c) was
refluxed in ethanol for 3 h. Then, the solution was cooled to room
temperature and a white solid appeared. This was filtered and
recrystallized from ethanol to afford the desired compound.
6.2.1. 4-Amino-2-({5-[(4-fluorophenyl)amino]-1,3,4-thiadiazol-2-yl}
methyl)-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (3a)
Yield 79%, m.p. 234–235 ꢀC. Anal. Calcd. (%) for: C18H16 FN7OS: C,
54.40; H, 4.06, N, 24.67. Found; C, 54.54; H, 4.12; N, 24.61; IR (KBr, n,
6.1.2. 2-{[4-Amino-3-(4-methylphenyl)-5-oxo-4,5-dihydro-1H-1,2,
4-triazol-1-yl]acetyl}-N-(4-fluorophenyl)hydrazinecarbothioamide
(2a)
Yield 96%, m.p. 224–225 ꢀC. Anal. Calcd. (%) for: C18H18FN7O2S:
C, 52.04; H, 4.37, N, 23.60. Found; C, 52.12; H, 4.38; N, 23.57; IR (KBr,
cmꢁ1): 3275 and 3156 (NH þ NH2), 1725 (C]O), 1619, 1550 and
1503 (3C]N); 1H NMR (DMSO-d6)
d (ppm): 2.23 (3H, s, CH3), 5.14
(2H, s, CH2), 5.56 (2H,s, NH2), 7.18 (2H, t, arH, J ¼ 8.6 Hz), 7.30 (2H, d,
arH, J ¼ 8.0 Hz), 7.62 (2H, q, arH, J ¼ 4.6 Hz), 7.89 (2H, d, arH,
J ¼ 8.0 Hz) 10.37 (H, s, NH); 13C NMR (DMSO-d6)
d (ppm): 22.20

A. Demirbas et al. / European Journal of Medicinal Chemistry 44 (2009) 2896–2903
2901
(CH3), 45.42 (CH2), arC: [116.80 (CH), 117.24 (CH),120.48 (CH),
124.88 (C), 128.83 (CH), 128.99 (2CH), 130.32 (2CH), 138.24 (C),
141.32 (2C)], 146.92 (triazole C-3), 154.46 (triazole C-5), 155.72
(thiadiazole C-2), 166.85 (thiadiazole C-5); MS (ESI): m/z (%) 420.08
(M þ Na, 18), 394.18 (6), 335.05 (26), 316.96 (12), 294.06 (12),
293.00(41), 278.05 (14), 196.70 (35), 193.76 (84), 179.75 (30),
156.72(100), 148.71(16), 118.74 (54), 116.62 (16).
253.83 (19), 242.88 (16), 240.88 (34); 194.83 (16), 193.83 (100),
192.83 (65), 178.81 (28), 156.72 (34).
6.3.2. 4-Amino-2-[(5-sulphanyl-4-phenyl-4H-1,2,4-triazol-3-yl)
methyl]-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one
(5b)
Yield 91%, m.p. 277–278 ꢀC. Anal. Calcd. (%) for: C18H17N7OS: C,
56.98; H, 4.52; N, 25.84 Found; C, 57.23; H, 4.55; N, 25.77; IR (KBr, n,
6.2.2. 4-Amino-2-[(5-anilino-1,3,4-thiadiazol-2-yl)methyl]-5-
(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (3b)
Yield 98%, m.p. 212–213 ꢀC. Anal. Calcd. (%) for: C18H17N7OS: C,
cmꢁ1): 3274 and 3199 (NH2), 1702 (C]O), 2768 (SH),1615,1578 and
1495 (3C]N); Anal. Calcd. (%) for: C18H17N7OS: C, 56.98; H, 4.52, N,
25.84. Found; C, 57.06; H, 4.56; N, 25.67; 1H NMR (DMSO-d6)
56.98; H, 4.52; N, 25.84. Found; C, 57.18; H, 4.55; N, 24.73; IR (KBr,
cmꢁ1): 3317–3201 (NH2), 1704 (C]O), 3137 (NH), 1602, 1574 and
1504 (3C]N); 1H NMR (DMSO-d6)
(ppm): 2.36 (3H, s, CH3), 5.26
n
,
d ppm: 2.35 (3H, s, CH3), 4.95 (2H, s, NCH2), 5.318 (2H, s, NH2), 7.26–
7.34 (4H, m, arH), 7.43–7.50 (3H, m, arH), 7.74 (2H, d, arH,
d
J ¼ 8.4 Hz), 14.00 (s, SH); 13C NMR (DMSO-d6)
d ppm: 20.87 (CH3),
(2H, s, CH2), 5.56 (2H, s, NH2), 6.98 (1H, t, arH, J ¼ 7.2 Hz), 7.21–7.36
38.09–40.70 (DMSO-d6 þ CH2), arC: [123.30 (C), 132.79 (C), 139.69
(C), 127.56 (2CH), 127.41 (2CH), 128.77 (2CH), 129.42 (CH), 129.09
(2CH)], 145.057 (triazole C-3), 152.59 (triazole C-5), 147.50 (sul-
phanyl triazole C-2), 168.25 (sulphanyl triazole C-5); MS (ESI): m/z
(%) 403.06 (Mþ Na, 32), 380.08 (M þ 1), 277.96 (23), 240.90 (20),
190.89 (26), 181.64 (20), 156.72 (86), 148.67 (22), 134.70 (22), 118.78
(94), 103.62(100).
(4H, m, arH), 7.59 (2H, d, arH, J ¼ 7.60 Hz), 7.91 (2H, d, arH,
J ¼ 8.4 Hz), 10.36 (H, s, NH); 13C NMR (DMSO-d6)
d (ppm): 20.96
(CH3), 44.06 (CH2), arC: [117.33 (2CH), 121.84 (CH), 123.53 (C),
127.47 (2CH), 128.80 (2CH), 128.95 (2CH), 139.77 (C), 140.39 (C)],
153.07 (triazole C-3), 154.14 (triazole C-5, thiadiazole C-2), 165.39
(thiadiazole C-5).
6.2.3. 4-Amino-2-({5-[(4-methoxyphenyl)amino]-1,3,4-thiadiazol-
2-yl}methyl)-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-
one (3c)
6.3.3. 4-Amino-2-{[4-(4-methoxyphenyl)-5-sulphanyl-4H-1,2,4-
triazol-3-yl]methyl}-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-
triazol-3-one (5c)
Yield: 81%, m.p. 231–232 ꢀC. Anal. Calcd. (%) for: C19H19N7O2S: C,
55.73; H, 4.68; N, 23.95. Found; C, 55.86; H, 4.75; N, 23.88; IR (KBr,
Yield 92%, m.p. 268–269 ꢀC. Anal. Calcd. (%) for: C19H19N7O2S: C,
55.73; H, 4.68; N, 23.95. Found; C, 55.79; H, 4.71; N, 23.88; IR (KBr,
cmꢁ1): 3275 and 3176 (NH2), 2760 (SH), 1698 (C]O), 1629, 1568
and 1516 (3C]N); 1H NMR (DMSO-d6)
ppm: 2.27(3H, s, CH3), 2.33
n,
n
, cmꢁ1): 3329, 3267 (NH2 þ NH), 1713 (C]O), 1618, 1543 and 1501
(3C]N); 1H NMR (DMSO-d6)
d
(ppm): 2.22 (3H, s , CH3), 2.33 (3H, s,
d
OCH3), 5.23 (2H, s, CH2), 5.56 (2H, s, NH2), 7.12 (2H, d, arH,
J ¼ 8.4 Hz), 7.28 (2H, d, arH, J ¼ 8.4 Hz), 7.44 (2H, d, arH, J ¼ 8.4 Hz),
7.87 (2H, d, arH, J ¼ 8.0 Hz), 10.26 (1H, s, NH); 13C NMR (DMSO-d6)
(3H, s, OCH3), 4.91 (2H, s, CH2), 5.33 (2H, s, NH2), 7.14–7.28 (6H, m,
arH), 7.70 (2H, d, arH, J ¼ 8.4 Hz), 13.91 (H, s, SH); 13C NMR (DMSO-
d6)
d
ppm: 20.63 (CH3), 20.87 (CH3), 38.03–40.94 (CH2 þ DMSO-d6),
d
(ppm): 20.23 (CH3), 20.87 (OCH3), 44.01 (CH2), arC: [117.44 (2CH),
arC: [123.34 (C), 127.37 (3CH), 128.74 (3CH), 129.59 (2CH), 130.26
(C), 139.06 (C), 139.64 (C)], 144.88 (triazole C-3), 147.53 (triazole C-
3), 152.65 (triazole C-3), 168.35 (triazole C-5); MS (ESI): m/z (%)
409.25 (Mþ, 41), 409.13 (100), 409.00 (32), 393.62 (19), 365.16 (17),
334.90 (19), 304.19(78), 241.85(22), 189.70 (19).
123.44 (C), 127.42 (2CH), 128.83 (2CH), 129.37 (2CH), 130.87 (C),
137.95 (C), 139.82 (C)], 145.41 (triazole C-3), 152.99 (thiadiazole C-
2), 153.82 (triazole C-5), 165.54 (thiadiazole C-5); MS (ESI): m/z (%)
407.21 (Mþ, 26), 395.38 (16), 394.24 (49), 317.03 (33), 301.86 (20),
292.99 (36), 291.98(31), 279.21 (25), 277.95 (100), 270.96 (41),
264.86 (28), 240.82 (88), 214.95 (25), 203.81 (33). 193.81 (83),
178.77(53), 156.68 (39).
6.4. General method for the synthesis of compounds 8a–d
An equivalent amount of 4-fluorobenzaldehyde (for compounds
8a and 8c) or 4-methoxy benzaldehyde (for compounds 8b, 8d) was
added to a solution of corresponding compounds 5a and 5b
(10 mmol) (for compounds 8a–d) in absolute ethanol, and the
mixture was heated until a clear solution was obtained. Then, a few
drops of concentrated sulfuric acid were added as a catalyst and the
solution was allowed to reflux for 3–4 h. On cooling the reaction
content to room temperature, a solid appeared. The product was
filtered-off and recrystallized from dimethyl sulfoxide/water (1:1)
(for 8a, 8b, 8d) or ethanol (for 8c) to yield the desired compound.
6.3. General method for the synthesis of compounds 5a–c
A solution of corresponding carbothioamide 2a–c (10 mmol) in
equivalent amount of 2 N NaOH solution was refluxed for 3 h. The
resulting solution was cooled to room temperature and acidified to
pH 3–4 with 37% HCl. The precipitate formed was filtered, washed
with water and recrystallized from dimethyl sulfoxide/water (1:1)
to afford the desired compound.
6.3.1. 4-Amino-2-{[4-(4-fluorophenyl)-5-sulphanyl-4H-1,2,4-
triazol-3-yl]methyl}-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-
triazol-3-one (5a)
6.4.1. 2-{[4-(4-Fluorophenyl)-5-sulphanyl-4H-1,2,4-triazol-3-yl]
methyl}-4-{[(4-fluorophenyl)-methylene]amino}-5-
Yield 84%, m.p. 254–256 ꢀC. Anal. Calcd. (%) for: C18H16 FN7OS: C,
(4-methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (8a)
Yield 90%, m.p. 240–242 ꢀC. Anal. Calcd. (%) for: C25H19F2 N7OS:
C, 59.63; H, 3.80; N, 19.47 Found; C, 59.77; H, 3.92; N, 19.48; IR (KBr,
54.40; H, 4.06; N, 24.67. Found; C, 54.57; H, 4.18; N, 24.62; IR (KBr,
cmꢁ1): 3316, 3145 (NH2), 2763 (SH), 1682 (C]O), 1583, 1508 and
1505 (C]N), 1224 (C]S); 1H NMR (DMSO-d6)
ppm: 2.35 (3H, s,
n,
d
n
, cmꢁ1): 2920 (SH), 3168 (NH), 1725 (C]O), 1602 (C]N), 1508
CH3), 4.95 (2H, s, CH2), 5.36 (2H, s, NH2), 7.26–7.43 (6H, m, arH), 7.75
(C]N), 1223 (C]S); 1H NMR (DMSO-d6)
d ppm: 2.38 (3H, s, CH3),
(2H, d, arH, J ¼ 8.4 Hz), 13.97 (H, s, SH); 13C NMR (DMSO-d6)
d
ppm:
5.09 (2H, s, CH2), 7.27–7.44 (6H, m, arH), 7.66 (2H, d, arH, J ¼ 8.0 Hz),
20.77 (CH3), 38.09–40.69 (NCH2 þ DMSO-d6), arC: [115.82 (CH),
116.29 (CH), 123.21 (C), 127.31 (2CH), 128.68 (2CH), 129.09 (C),
129.91 (CH), 130.09 (CH),139.63 (C), 145.00 (C)], 147.37 (triazole C-
3), 152.50 (triazole C-3), 159.62 (triazole C-5), 164.52 (triazole C-3),
168.45 (triazole C-5); MS (ESI): m/z (%) 397.99 (Mþ, 23), 394.30 (31),
293.06 (18), 277.86 (28), 271.91 (100), 270.91 (67), 269.91 (19),
7.83 (2H, dd, arH, J ¼ 8.6 Hz), 7.87 (2H, dd, arH, J ¼ 5.4 Hz), 9.35 (H, s,
N]CH), 14.05 (H, s, SH); 13C NMR (DMSO-d6)
d ppm: 20.79 (CH3),
38.08–40.60 (CH2 þ DMSO-d6), 96.41 (N]CH), arC: [115.82 (CH),
116.34 (CH), 122.52 (C), 127.86 (CH), 128.98 (2CH), 129.10 (2CH),
129.42 (C),129.72 (CH),129.90 (CH) 130.11 (CH),130.28 (CH), 140.25
(C), 143.93 (C), 147.22 (C), 148.51 (C), 155.48 (CH), 159.10 (triazole

2902
A. Demirbas et al. / European Journal of Medicinal Chemistry 44 (2009) 2896–2903
C-3), 161.52 (triazole C-3), 164.55 (triazole C-5), 166.50 (triazole C-
5); MS (ESI): m/z (%) 503.13 (Mþ, 38), 502.38 (28), 442.68(60),
405.64(29), 400.14(66), 381.99(100), 364.72(25), 343.19(69), 309.59
(49), 309.40 (39), 276.12 (27), 222.18 (24), 182.88 (33), 167.05 (29),
126.88 (31), 112.43 (64).
mixture was stirred at room temperature for 2 h. Then, distilled
water was added and kept overnight in cold. The solid separated
was collected by filtration and recrystallized from dimethyl sulf-
oxide to yield the target compounds.
6.5.1. 4-Amino-5-(4-methylphenyl)-2-({4-methyl-1-[(4-
6.4.2. 2-{[4-(4-Methoxyphenyl)-5-sulphanyl-4H-1,2,4-triazol-3-
yl]methyl}-4-{[(4-fluorophenyl)-methylene]amino}-5-(4-
methylphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (8b)
Yield 87%, m.p. 237–239 ꢀC. Anal. Calcd. (%) for: C26H22F N7OS: C,
methylpiperazin-1-yl)methyl]-4-phenyl-5-thioxo-4,5-dihydro-1H-
1,2,4-triazol-3-yl}methyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (7a)
Yield 42%, m.p. 247–248 ꢀC. Anal. Calcd. (%) for: C24H29 N9OS: C,
58.63; H, 5.95; N, 25.64. Found; C, 58.67; H, 6.05; N, 25.61; IR (KBr,
60.57; H, 4.30; N, 19.02. Found; C, 60.68; H, 4.33; N, 18.84; IR (KBr,
n
,
n
, cmꢁ1): 3455 and 3324 (NH2), 1717 (C]O), 1613 and 1580 (C]N),
cmꢁ1): 3164 (NH), 1726 (C]O), 1599, 1508 (C]N), 1260 (C–O), 1222
(C]S); 1H NMR: 2.39 (3H, s, CH3), 3.84 (3H, s, OCH3), 5.04 (2H, s,
NCH2), 7.03 (2H, d, arH, J ¼ 8.8 Hz), 7.27–7.37 (6H, m, arH) 7.69 (4H,
t, arH, J1 ¼8.0 Hz, J2 ¼ 8.8 Hz), 9.19 (1H, s, N]CH), 14.00 (1H, s, SH);
1326 (C]S); 1H NMR: 2.32 (3H, s, CH3), 2.49 (3H, s, CH3), 3.28 (8H,
m, 4CH2-piperazine), 4.55 (2H, s, NCH2), 5.12 (2H, s, NCH2N), 5.45
(2H, s, NH2), 6.85–6.97 (2H, m, arH), 7.20–7.70 (5H, m, arH), 7.98
(2H, d, arH, J ¼ 8.2 Hz); MS (ESI): m/z (%) 491.04 (Mþ, 26), 451.70
(31), 449.69 (11), 437.68 (20), 421.79 (18), 420.72 (58), 414.09 (19),
395.19 (19), 394.32 (53), 392.00 (100), 386.68 (27), 381.86 (42),
381.68 (36), 376.86 (22), 365.85 (28), 365.03 (50), 358.77 (44),
349.76 (29), 348.76 (34), 335.00 (24), 332.93 (30), 320.79 (31),
317.98 (42), 316.85 (64), 305.84 (25), 304.90 (56), 301.83 (66).
13C NMR (DMSO-d6)
d ppm: 20.77 (CH3), 20.93 (OCH3), 44.27 (CH2),
96.88 (N]CH), arC: [117.15 (CH), 119.41 (CH), 122.57 (C), 125.49
(CH), 128.31 (2CH), 129.11 (2CH), 129.76 (C), 129.82 (CH), 129.94
(CH) 132.32 (CH), 133.43 (CH), 141.61 (C), 144.07 (C), 145.80 (C),
148.51 (C), 147.34 (CH)], 148.33 (triazole C-3), 157.84 (triazole C-3),
164.45 and 164.50 (2triazole C-5).
6.5.2. 4-Amino-5-(4-methylphenyl)-2-{[4-methyl-1-(morpholin-4-
ylmethyl)-4-phenyl-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl]
methyl}-2,4-dihydro-3H-1,2,4-triazol-3-one (7b)
6.4.3. 2-{[4-(4-Fluorophenyl)-5-sulphanyl-4H-1,2,4-triazol-3-
yl]methyl}-4-[(phenyl-methylene)-amino]-5-(4-methylphenyl)-2,4-
dihydro-3H-1,2,4-triazol-3-one (8c)
Yield: 42%, m.p. 228–230 ꢀC; Anal. Calcd. (%) for: C25H31 N9O2S:
C, 57.56; H, 5.99; N, 24.17; Found; C, 57.68; H, 5.93; N, 24.11; IR (KBr,
Yield 92%, m.p. 210–211 ꢀC. Anal. Calcd. (%) for: C25H20 N7OS: C,
61.84; H, 4.15; N, 20.19 Found; C, 62.05; H, 4.22; N, 20.07; IR (KBr,
cmꢁ1): 2746 (SH), 1721 (C]O), 1567, 1600 and 1503 (3C]N); 1H
NMR (DMSO-d6) (ppm): 2.38 (3H, s, CH3), 5.09 (2H, s, NCH2), 7.32–
n
,
n
, cmꢁ1): 3457 and 3320 (NH2), 1717 (C]O), 1616 and 1581 (C]N),
1331 (C]S); 1H NMR (DMSO-d6)
d (ppm): 2.46 (3H, s, CH3), 3.40
d
(8H, bs, 4CH2), 4.24 (2H, bs, NCH2), 4.71–5.10 (4H, m, 2CH2), 5.43
(4H, bs, NCH2N þ NH2), 7.01 (2H, bs, arH), 7.31 (2H, d, arH,
J ¼ 7.6 Hz), 7.42–7.75 (3H, m, arH), 8.00 (2H, d, arH, J ¼ 7.8 Hz).
7.36 (5H, m, arH), 7.38–7.51 (4H, m, arH), 7.64 (2H, d, arH,
J ¼ 8.2 Hz), 7.83-7.90 (2H, m, arH), 9.31 (1H, s, N]CH), 14.05 (1H, s,
SH); 13C NMR (DMSO-d6)
d ppm: 21.03 (CH3), 38.06–40.67
(CH2 þ DMSO-d6), 98.27 (N]CH), arC: [117.56 (CH), 118.52 (CH),
121.66 (C), 127.83 (CH), 128.12 (2CH), 129.19 (2CH), 129.56 (C),
130.63 (CH), 130.85 (CH) 130.11 (2CH), 130.48 (CH), 135.80 (CH),
140.27 (C), 143.67 (C), 147.20 (C)], 155.13 (triazole C-3), 160.91
(triazole C-3), 164.62 (triazole C-5), 166.89 (triazole C-5); MS (ESI):
m/z (%) 486.11 (M þ 1, 16), 274.04 (16), 261.01 (16), 231.94 (18),
162.78 (15), 161.90 (46), 156.74 (100), 144.78 (43), 132.76 (30),
118.67 (56).
6.5.3. 4-[(4-Fluorobenzylidene)amino]-5-(4-methylphenyl)-2-({4-
methyl-1-[(4-methylpiperazin-1-yl)methyl]-4-(4-fluorophenyl)-5-
thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl}methyl)-2,4-dihydro-3H-
1,2,4-triazol-3-one (9)
Yield 55% m.p. 166–168 ꢀC, Anal. Calcd. (%) for: C31H31F2N9OS: C,
60.47; H, 5.07; N, 20.47 Found; C, 60.61; H, 5.16; N, 20.36; IR (KBr,
cmꢁ1): 1713 (C]O), 1600 and 1509 (2C]N), 1224 (C]S), 1H NMR
(DMSO-d6) (ppm): 2.14 (3H, s, CH3), 2.31 (4H, bs, 2CH2), 2.37 (3H,
n,
d
s, CH3), 2.50 (4H, bs, 2CH2), 5.10 (2H, s, CH2), 5.14 (2H, s, NCH2N),
9.34 (1H, s, N]CH), 7.27–7.46 (6H, m, arH), 7.65 (3H, d, arH,
J ¼ 6.4 Hz), 7.85 (3H, q, arH, J ¼ 5.8 Hz).
6.4.4. 2-{[4-(4-Methoxyphenyl)-5-sulphanyl-4H-1,2,4-triazol-3-
yl]methyl}-4-[(methylene)-amino]-5-(4-methylphenyl)-2,4-
dihydro-3H-1,2,4-triazol-3-one (8d)
Yield 86%, m.p. 245–246 ꢀC. Anal. Calcd. (%) for: C26H23N7O2S: C,
6.6. General method for the synthesis of compounds 4 and 6a–c
62.76; H, 4.66; N, 19.71 Found; C, 62.78; H, 4.79; N, 62.75; IR (KBr,
cmꢁ1): 2835 (SH), 1722 (C]O), 1257 (C]S); 1H NMR (DMSO-d6)
(ppm): 2.36 (3H, s, CH3), 2.50 (3H, s, OCH3), 3.83 (2H, s, CH2), 7.07
n,
To a solution of corresponding compound 3b or 5a, b (10 mmol)
in absolute ethanol, equivalent amount of methyl iodide (for
compounds 4 and 6a) or ethyl bromide (for compound 6b) was
added and the reaction content was refluxed in the presence of
sodium ethoxide (10 mmol) for 3–4 h (completion of the reaction
was controlled by TLC). After removing of the reaction solvent
under reduced pressure, a solid was obtained. This was recrystal-
lized from DMSO:water (1:1) to afford the desired compound.
d
(2H, d, arH, J ¼ 8.6 Hz), 7.32 (2H, d, arH, J ¼ 8.2 Hz), 7.43–7.47 (4H,
m, arH), 7.62-7.76 (5H, m, arH), 9.14 (1H, s, N]CH), 13.97 (1H, s,
SH); 13C NMR (DMSO-d6)
d ppm: 21.62 (CH3), 22.45 (OCH3), 44.88
(CH2), 101.11 (N]CH), arC: [120.34 (CH), 121.28 (CH), 122.87 (C),
125.19 (2CH), 127.46 (CH), 129.68 (CH), 128.94 (C), 129.66 (2CH),
129.47 (CH) 133.08 (CH), 133.61 (2CH), 138.17 (CH), 141.66 (C),
144.43 (C), 144.96 (C), 147.85 (C)], 148.33 (triazole C-3), 157.84
(triazole C-3), 164.50 (triazole C-5), 164.45 (triazole C-5); MS (ESI):
m/z (%) 498.08 (M þ 1, 6), 394.24 (9),194.88 (12),193.87 (80),192.80
(100), 178.77 (54), 156.74 (38), 151.77 (16), 118.60 (53).
6.6.1. 4-Amino-5-(4-methylphenyl)-2-({5-[methyl(phenyl)amino]-
4,5-dihydro-1,3,4-thiadiazol-2-yl}methyl)-2,4-dihydro-3H-1,2,4-
triazol-3-one (4)
Yield 68%, m.p. 173–175 ꢀC. Anal. Calcd. (%) for: C19H19N7OS: C,
58.00; H, 4.87; N, 24.92. Found; C, 58.23; H, 4.89; N, 24.90; IR (KBr,
6.5. General method for the synthesis of compounds 7a–b and 9
n
, cmꢁ1): 3298, 3199 (NH2), 1705 (C]O), 1618, 1575 and 1505
Methyl piperazine (for compounds 7a and 9) (10 mmol) or 2-(4-
morpholinoethylamine) (for compound 7b) (10 mmol) and form-
aldehyde (40%, 1.5 mL) were added to a solution of corresponding
compound 5b or 8a (10 mmol) in dimethyl formamide, and the
(3C]N); 1H NMR (DMSO-d6)
d (ppm): 2.37 (3H, s, CH3), 3.22 (3H, s,
NCH3), 5.21 (2H, s, NCH2), 5.45 (2H, s, NH2), 6.93 (1H, q, arH,
J1 ¼7.4 Hz, J2 ¼ 7.8 Hz), 7.21–7.27 (4H, m, arH), 7.32 (1H, bs, arH),
7.41 (1H, d, arH, J ¼ 7.8 Hz), 7.89 (2H, t, arH, J1 ¼8.4, Hz, J2 ¼ 8.4 Hz);

A. Demirbas et al. / European Journal of Medicinal Chemistry 44 (2009) 2896–2903
2903
13C NMR (DMSO-d6)
d
(ppm): 20.96 (CH3), 22.68 (CH3), 44.48 (CH2),
(C), 140.51 (C)], 145.46 (triazole C-3), 151.81 (thiadiazole C-2),
153.05 (triazole C-5), 153.43 (thiadiazole C-5).
arC: [120.41 (CH), 121.64 (CH), 125.53 (3CH), 127.06 (C), 128.17
(2CH), 128.63 (2CH), 137.84 (C), 139.11 (C)], 154.66 (triazole C-3),
156.07 (triazole C-5), 157.32 (thiadiazole C-2), 167.47 (thiadiazole C-
5); MS (ESI): m/z (%) 416.02 (M þ Na, 26), 394.12 (M þ 1, 51), 252.90
(34), 251.89 (47), 240.88 (23), 204.76 (22), 203.81 (100),190.79 (25),
164.80 (18), 117.72 (54).
Acknowledgement
This project was supported by Karadeniz Technical University,
BAP, Turkey (Ref. No. 2005.111.002.3) and is gratefully acknowledged.
6.6.2. 4-Amino-2-{[5-(ethylthio)-4-(4-fluorophenyl)-4H-1,2,4-
triazol-3-yl]methyl}-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-
triazol-3-one (6a)
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56.46; H, 4.74; N, 23.04. Found; C, 56.53; H, 4.77; N, 22.94; IR (KBr,
cmꢁ1): 3314 and 3198 (NH2), 1706 (C]O), 1638, 1603 and 1513
(C]N); 1H NMR (DMSO-d6)
n,
d
(ppm): 1.28 (3H, t, CH3, J ¼ 7.4 Hz),
2.35 (3H, s, CH3), 3.08 (2H, q, CH2, J ¼ 7.4 Hz), 5.04 (2H, s, CH2), 5.35
(2H, s, NH2), 7.27 (2H, d, arH, J ¼ 8.2 Hz), 7.32–7.48 (4H, m, arH), 7.76
(2H, d, arH, J ¼ 8 Hz); 13C NMR (DMSO-d6)
d (ppm): 14.57 (CH3),
20.75 (CH3), 26.34 (SCH2), 38.08-40.59 (NCH2 þ DMSO-d6) arC:
[116.19 (CH), 116.65 (CH), 123.30 (C), 127.28 (2CH), 128.60 (C) 128.65
(2CH), 129.23 (CH), 129.41 (CH), 139.55 (C), 144.75 (C)], 150.90
(triazole C-3), 152.52 (triazole C-3), 159.83 (triazole C-5), 164.76
(triazole C-5); MS (ESI): m/z (%) 449.11 (M þ Na, 29), 426.09 (M þ 1,
100), 235.81 (20).
6.6.3. 4-Amino-5-(4-methylphenyl)-2-{[5-(methylthio)-4-phenyl-
4H-1,2,4-triazol-3-yl] methyl}-2,4-dihydro-3H-1,2,4-triazol-3-one
(6b)
Yield 66%, m.p. 257–259 ꢀC. Anal. Calcd. (%) for: C19H19N7OS: C,
58.00; H, 4.87; N, 24.92 Found; C, 58.16; H, 4.88; N, 24.87; IR (KBr,
cmꢁ1): 3312 and 3198 (NH2), 1704 (C]O), 1642, 1599 and 1499
(C]N); 1H NMR (DMSO-d6)
(ppm): 2.53 (3H, t, CH3), 2.32 (3H, s,
n,
d
CH3), 5.12 (2H, s, CH2), 5.33 (2H, s, NH2), 7.23 (2H, d, arH, J ¼ 8.2 Hz),
7.25–7.32 (5H, m, arH), 7.68 (2H, d, arH, J ¼ 8.0 Hz); 13C NMR
(DMSO-d6)
d (ppm): 17.41 (CH3), 20.77 (CH3), 47.12 (NCH2), arC:
[118.33 (CH), 118.62 (CH), 126.67 (C), 127.48 (2CH), 128.00 (CH)
128.62 (2CH), 128.83 (CH), 129.40 (CH), 135.55 (C), 142.81 (C)],
151.99 (triazole C-3), 154.44 (triazole C-3), 155.83 (triazole C-5),
162.11 (triazole C-5); MS (ESI): m/z (%) 416.08 (M þ Na, 14), 394.05
(M þ 1, 43), 303.95 (18), 283.99 (38), 269.91 (100), 268.91 (18),
253.96 (56), 252.89 (89), 251.89 (51), 240.88 (26), 193.83 (34),
179.87 (19), 164.73 (59), 148.84 (39), 120.68 (28), 104.85 (52).
6.6.4. 4-Amino-2-{[4-(4-methoxyphenyl)-5-(methylthio)-4H-1,2,4-
triazol-3-yl]methyl}-5-(4-methylphenyl)-2,4-dihydro-3H-1,2,4-
triazol-3-one (6c)
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C, 56.72; H, 5.00; N, 23.15 Found; C, 56.80; H, 5.17; N, 23.05; IR (KBr,
_
_
_
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_
n
, cmꢁ1): 3298, 3204 (NH2), 1713 (C]O), 1635, 1514, 1454 (3C]N),
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1114–1120.
1H NMR (DMSO-d6)
d (ppm): 2.32 (3H, s, CH3), 2.35 (3H, s, OCH3),
_
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2.55 (3H, s, SCH3), 5.02 (2H, s, CH2) 5.34 (2H, s, NH2), 7.21–7.32 (6H,
m, arH), 7.74 (2H, d, arH, J ¼ 8 Hz); 13C NMR (DMSO-d6)
d (ppm):
14.95 (SCH3), 21.41 (CH3), 21.66 (OCH3), arC: [124.23 (C), 127.32
(2CH), 128.15 (2CH), 129.54 (2CH), 130.37(C), 130.82 (2CH), 140.38