Synthesis and antimicrobial evaluation of new 1-{[4-(4-Halogenophenyl)-4H- 1,2,4- triazol-3-yl]sulfanyl}acetyl-4-substituted thiosemicarbazides and products of their cyclization

Article abstract of DOI:10.1002/hc.20758

By the reaction of hydrazides of 4-(4-halogenophenyl)-4H-1,2,4-triazol-3- yl-sulfanyl acetic acid with isothiocyanate, 1-acyl-4-substituted thiosemicarbazide derivatives (7-19) were obtained. The cyclization of compounds (7-19) in the presence of 2% NaOH led to the formation of compounds (20-26) containing two 1,2,4-triazole rings connected by a methylenesulfanyl group. The new compounds were tested for their in vitro antimicrobial activity. Some of the tested compounds (9, 12, 18, 21, 22) showed activity against the reference strains of Gram-positive bacteria with the MIC (minimal inhibitory concentration) = 125 to >1000 μg/mL.

Full text of DOI:10.1002/hc.20758

Heteroatom Chemistry
Volume 23, Number 1, 2012
Synthesis and Antimicrobial Evaluation of New
1-{[4-(4-Halogenophenyl)-4H-1,2,4-
triazol-3-yl]sulfanyl}acetyl-4-substituted
Thiosemicarbazides and Products
of Their Cyclization
Nazar Trotsko,1 Jakub Kro´l,1 Agata Siwek,1 Monika Wujec,1
Urszula Kosikowska,2 and Anna Malm2
1Department of Organic Chemistry, Faculty of Pharmacy, Medical University,
4 Chodzki, 20-093 Lublin, Poland
2Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Medical University,
1 Chodzki, 20-093 Lublin, Poland
Received 17 March 2011; revised 1 August 2011
spectrum of biological activities, such as antibac-
ABSTRACT: By the reaction of hydrazides of
terial [1,2], antifungal [3,4], antitubercular [5,6],
4-(4-halogenophenyl)-4H-1,2,4-triazol-3-yl-sulfanyl
anti-inflammatory [7,8], anticancer [9,10], analgesic
acetic acid with isothiocyanate, 1-acyl-4-substituted
[11], antiviral [12], anticonvulsant [13,14], and cen-
thiosemicarbazide derivatives (7–19) were obtained.
tral nervous system [15] activity. Among them, a
The cyclization of compounds (7–19) in the presence
large number of 1,2,4-triazole-3-thiones have been
of 2% NaOH led to the formation of compounds (20–
reported as antibacterial substances [16–22]. In view
26) containing two 1,2,4-triazole rings connected by
of these facts, in the present paper, we have de-
a methylenesulfanyl group. The new compounds were
scribed several novel thiosemicarbazide derivatives
tested for their in vitro antimicrobial activity. Some
with the 1,2,4-triazole-3-thione moiety at the posi-
of the tested compounds (9, 12, 18, 21, 22) showed
tion 1 for which their products were obtained after
activity against the reference strains of Gram-positive
intramolecular cyclization. The newly synthesized
bacteria with the MIC (minimal inhibitory concentra-
compounds were evaluated for their antimicrobial
ꢀ
C
tion) = 125 to >1000 μg/mL. 2011 Wiley Periodicals,
activity.
Inc. Heteroatom Chem 23:117–121, 2012; View this article
online at wileyonlinelibrary.com. DOI 10.1002/hc.20758
RESULTS AND DISCUSSION
INTRODUCTION
Chemistry
1,2,4-Triazoles and their derivatives represent an in-
In the present work, the ethyl esters of
teresting group of compounds, possessing a wide
4-(4-halogenophenyl)-4H-1,2,4-triazol-3-yl-sulfanyl
acetic acid (1–3) were used as starting mate-
rials, which were obtained by the reaction of
4-(4-halogenophenyl)-4H-1,2,4-triazole-3-thione
with ethyl bromoacetate in the presence of sodium
Correspondence to: Nazar Trotsko; e-mail: nazar.trotsko@
umlub.pl.
2011 Wiley Periodicals, Inc.
c
ꢀ
117

118 Trotsko et al.
In the 1H NMR spectra, all the compounds
showed proton signals that are typical for the CH
group of the 1,2,4-triazole-3-thione ring in the range
of 8.84–8.98 ppm. All the thiosemicarbazide deriva-
tives (7–19) showed three proton signals of the
NHNHC(S)NH group in the 8.85–10.54 ppm range.
The cyclic compounds (20–26) showed proton sig-
nals in the 13.57–13.91 ppm range that are typical
for the NH group of the 1,2,4-triazole ring. All deriva-
tives with a 4-substituted phenyl ring showed typical
signals for two doublets in the 7.12–7.96 ppm range
(J = 7.5–10.0 Hz).
CH3
N
N
N
N
O
NH
NH2
S
S
N
R
N
R
.
H2O
NH2-NH2
O
O
R1NCS
4–6
1–3
S
N
N
N N
NH
R1
NH
N
NH
NH
2% NaOH
S
S
N
R
N
N
O
R1
S
20–26
7–19
R
R = Cl,Br,I
R1
= C6H5, C6H5CH2, 4-CH3-C6H4, 2-CH3C6H4, C6H11, CH3CH2, CH2=CH-CH2
Antimicrobial Evaluation
The in vitro antimicrobial activity of the synthe-
sized compounds (7–10, 12–14, 16–23, 25, 26) was
evaluated by using the broth microdilution method
against the reference strains of Gram-negative and
Gram-positive bacterial species. According to our
screening results, compounds 9, 12, 18, 21, and
22 showed potential antibacterial activity against
Gram-positive bacteria—the Staphylococcus species
or Micrococcus luteus ATCC (American Type Cul-
ture Collection) 10240; no activity against Gram-
negative bacteria was found. Based on data ob-
tained by using the broth microdilution method,
the most effective compounds against Gram-positive
species were thiosemicarbazide derivatives 9 and
12 with the 4-methylphenyl substituent at position
4 for M. luteus ATCC 10240 (minimal inhibitory
concentration [MIC] = 125–250 μg/mL) or for S.
aureus ATCC 25923 (MIC = 250 μg/mL) and S.
epidermidis ATCC 12228 (MIC = 250 μg/mL) (Ta-
ble 1). The compound 18 with a benzyl substi-
tutent at position 4 of thiosemicarbazide deriva-
tives showed somewhat better activity against S. epi-
dermidis ATCC 12228 (MIC = 125 μg/mL), but it
was not active against S. aureus ATCC 25923 (MIC
>1000 μg/mL). Cyclic derivatives 21 and 22 showed
an inhibitory effect against S. epidermidis ATCC
12228 (MIC = 500 μg/mL), but to a lesser extent,
and were not active against S. aureus ATCC 25923
FIGURE 1 Synthesis of 1-acyl-4-substituted thiosemicar-
bazide derivatives (7–19) and products of their cyclization
(20–26).
ethanolate. The reaction of 1,2,4-triazole-3-thione
derivatives with ethyl bromoacetate proceeds
according to the classical mechanism of the second-
order nucleophilic substitution (SN2). The pathway
of this reaction was confirmed by quantum me-
chanical calculations [23]. The structures of these
compounds were confirmed by X-ray analyses [24].
The next stage of investigation was the synthesis of
4-(4-halogenophenyl)-4H-1,2,4-triazol-3-yl-sulfanyl
acetic acid hydrazides. By the reaction of the ethyl
esters of 4-(4-halogenophenyl)-4H-1,2,4-triazol-3-
yl-sulfanyl acetic acid (1–3) with hydrazine hydrate
in anhydrous ethanol, the corresponding hydrazides
(4–6) were obtained. The hydrazides (4–6) were
used as substrates in the reaction with appropriate
isothiocyanates. In this way, 1-acyl-4-substituted
thiosemicarbazide derivatives (7–19) were obtained.
The cyclization of thiosemicarbazide derivatives in
an alkaline medium led to compounds 20–26. The
described reactions are shown in Fig. 1.
The structures of newly obtained compounds (7–
26) were confirmed by using elemental analysis and
the 1H NMR method.
TABLE 1 Influence of Some Newly Synthesized Compounds on the Growth of Gram-Positive Bacteria on the Basis of MIC
(μg/mL) Values Determined by Using the Broth Dilution Method
Staphylococcus aureus
ATCC 25923
Staphylococcus epidermidis
ATCC 12228
Micrococcus Luteus
ATCC 10240
Compound
9
250
250
>1000
>1000
>1000
250
250
125
500
500
250
125
125
12
18
21
22
>1000
250
Heteroatom Chemistry DOI 10.1002/hc

Synthesis and Antimicrobial Evaluation of Thiosemicarbazides and Products of Their Cyclization 119
(MIC >1000 μg/mL). Among cyclic compounds, only
1-({[4-(4-Chlorophenyl)-4H-1,2,4-triazol-3-yl]
sulfanyl}acetyl) - 4 - (4 - methylphenyl)thiosemicarba-
zide (9). Yield 73%, mp 166–168◦C. 1H NMR δ (ppm):
2.35 (s, 3H, CH3); 4.04 (s, 2H, CH2); 7.19 (d, 2H,
4-CH3-C6H4, J = 7.5 Hz); 7.42 (d, 2H, 4-CH3-C6H4,
J = 7.5 Hz); 7.66 (d, 2H, 4-Cl-C6H4, J = 7.5 Hz); 7.76
(d, 2H, 4-Cl-C6H4, J = 7.5 Hz); 8.97 (s, 1H, CH); 9.72,
9.76, 10.45 (3s, 3H, 3× NH). Elemental anal. (%),
Calcd for C18H17ClN6OS2: C 49.94, H 3.96, N 19.41;
Found: C 49.89, H 3.97, N 19.42.
compound 22 showed activity against M. luteus
ATCC 10240 (MIC = 250 μg/mL). According to our
results, the MICs of cefuroxime, which have been
extensively used to treat bacterial infections, were
0.24–1.95 μg/mL for the Staphylococcus species and
0.49–31.25 μg/mL for the other Gram-positive bacte-
ria. Other tested compounds had no effect on Gram-
positive and Gram-negative bacterial species.
1-({[4-(4-Bromophenyl)-4H-1,2,4-triazol-3-yl]
sulfanyl}acetyl)-4-phenylthiosemicarbazide
(10).
1
EXPERIMENTAL
Yield 81%, mp 190–192◦C. H NMR δ (ppm): 3.96
(s, 2H, CH2); 7.12–7.53 (m, 9H, C6H5 & 4-Br-C6H4);
8.89 (s, 1H, CH); 9.71, 9.74, 10.39 (3s, 3H, 3× NH).
Elemental anal. (%) Calcd for C17H15BrN6OS2: C
44.07, H 3.26, N 18.14; Found: C 44.09, H 3.25, N
18.07.
Chemistry
Melting points were determined in a Fischer–Johns
block (Sanyo, Japan) and are uncorrected. The H
1
NMR spectra were recorded on a Bruker Avance
DPX 250 in DMSO-d6 using tetramethylsilane as an
internal standard. The purity of all compounds was
checked by TLC on aluminum oxide 60 F254 plates
(Merck) in a CHCl3/C2H5OH (10:1, v/v) solvent sys-
tem with UV visualization (λ = 254 nm). The ele-
mental microanalysis for C, H, and N was performed
on an AMZ 851 CHX analyzer, and the results were
within 0.4% of the theoretical value.
4 - Benzyl - 1 - ({[4 - (4 - bromophenyl) - 4H - 1, 2, 4 -
triazol-3-yl]sulfanyl}acetyl)thiosemicarbazide (11).
1
Yield 77%, mp 184–186◦C. H NMR δ (ppm): 3.93
(s, 2H, CH2); 4.77 (d, 2H, C6H5CH2, J = 7.5 Hz);
7.25–7.47 (m, 7H, C6H5 and 4-Br-C6H4); 7.80 (d, 2H,
4-Br-C6H4, J = 7.5 Hz); 8.85 (s, 1H, CH); 8.78, 9.49,
10.36 (3s, 3H, 3× NH). Elemental anal. (%), Calcd
for C18H17BrN6OS2: C 45.29, H 3.59, N 17.60; Found:
C 45.22, H 3.60, N 17.54.
Synthesis
of
1-({[4-(4-Halogenophenyl)-
4H - 1,2,4 - triazol - 3 - yl]sulfanyl}acetyl)-4-substituted
Thiosemicarbazides (7–19) General Procedure. To
0.005 mol of substances 4, 5, or 6, 0.005 mol of
corresponding isothiocyanate was added. Then the
mixture was heated in an oil bath at 50–60◦C for
12 h. The obtained product was washed with diethyl
ether, dried, and recrystallized from ethanol. The
compounds 13, 16–19 were recrystallized from the
mixture DMF:H2O (1:1).
1-({[4-(4-Bromophenyl)-4H-1,2,4-triazol-3-yl]
sulfanyl}acetyl)-4-(4-methylphenyl)thiosemicarbazide
1
(12). Yield 71%, mp 176–178◦C. H NMR δ (ppm):
2.27 (s, 3H, CH3); 3.96 (s, 2H, CH2); 7.12 (d, 2H,
4-CH3-C6H4, J = 7.5 Hz); 7.35 (d, 2H, 4-CH3-C6H4,
J = 7.5 Hz); 7.52 (d, 2H, 4-Br-C6H4, J = 7.5 Hz);
7.81 (d, 2H, 4-Br-C6H4, J = 7.5 Hz); 8.89 (s, 1H,
CH); 9.64, 9.68, 10.37 (3s, 3H, 3× NH). Elemental
anal. (%), Calcd for C18H17BrN6OS2: C 45.29, H 3.59,
N 17.60; Found: C 45.20, H 3.57, N 17.58.
1-({[4 - (4 - Chlorophenyl) - 4H-1,2,4-triazol-3-yl]
sulfanyl}acetyl)-4-phenylthiosemicarbazide (7). Yield
1-({[4-(4-Bromophenyl)-4H-1,2,4-triazol-3-yl]
80%, mp 194–196◦C. H NMR δ (ppm): 4.04 (s, 2H,
sulfanyl}acetyl)-4-(2-methylphenyl)thiosemicarbazide
1
1
CH2); 7.23–7.60 (m, 5H, C6H5); 7.67 (d, 2H, 4-Cl-
C6H4, J = 7.5 Hz); 7.76 (d, 2H, 4-Cl-C6H4, J = 7.5
Hz); 8.97 (s, 1H, CH); 9.80, 9.83, 10.47 (3s, 3H, 3×
NH). Elemental anal. (%), Calcd for C17H15ClN6OS2:
C 48.74, H 3.61, N 20.06; Found: C 48.67, H 3.60, N
20.08.
(13). Yield 72%, mp 184–186◦C. H NMR δ (ppm):
2.12 (s, 3H, CH3); 4.00 (s, 2H, CH2); 7.09–7.22
(m, 4H, 2-CH3-C6H4,); 7.50 (d, 2H, 4-Br-C6H4,
J = 7.5 Hz); 7.74 (d, 2H, 4-Br-C6H4, J = 7.5 Hz);
8.84 (s, 1H, CH); 9.51, 9.66, 10.41 (3s, 3H, 3× NH).
Elemental anal. (%), Calcd for C18H17BrN6OS2: C
45.29, H 3.59, N 17.60; Found: C 45.31, H 3.60, N
17.57.
4 - Benzyl - 1 - ({[4 - (4 - chlorophenyl) - 4H - 1,2,4 -
triazol-3-yl]sulfanyl}acetyl)thiosemicarbazide
(8).
Yield 78%, mp 176–178◦C. H NMR δ (ppm): 4.02
(s, 2H, CH2); 4.85 (d, 2H, C6H5CH2, J = 7.5 Hz);
7.25–7.43 (m, 5H, C6H5); 7.63 (d, 2H, 4-Cl-C6H4,
J = 7.5 Hz); 7.76 (d, 2H, 4-Cl-C6H4, J = 7.5 Hz);
8.93 (s, 1H, CH); 8.85, 9.58, 10.42 (3s, 3H, 3× NH).
Elemental anal. (%), Calcd for C18H17ClN6OS2: C
49.94, H 3.96, N 19.41; Found: C 49.90, H 3.94, N
19.39.
4-Allyl-1-({[4-(4-bromophenyl)-4H-1,2,4-triazol-
1
3-yl]sulfanyl}acetyl)thiosemicarbazide (14). Yield
1
68%, mp 168–170◦C. H NMR δ (ppm): 4.01 (s, 2H,
CH2); 4.19–4.24 (m, 2H, CH2CH CH2); 5.05–5.21 (m,
2H, CH2CH CH2); 5.80–5.98 (m, 1H, CH2CH CH2);
7.58 (d, 2H, 4-Br-C6H4, J = 10.0 Hz); 7.89 (d, 2H,
4-Br-C6H4, J = 10.0 Hz); 8.98 (s, 1H, CH); 8.46 (t,
1H, NH, J = 5.0 Hz); 9.50, 10.35 (2s, 2H, 2× NH).
Heteroatom Chemistry DOI 10.1002/hc

120 Trotsko et al.
Elemental anal. (%), Calcd for C14H15BrN6OS2: C
39.35, H 3.54, N 19.67; Found: C 39.32, H 3.56, N
19.61.
ter cooling, the filtrate was acidified by diluted HCl
to a pH of 3–4. The resulting precipitate was recrys-
tallized from ethanol.
1-({[4-(4-Bromophenyl)-4H-1,2,4-triazol-3-yl]
5-({[4-(4-Chlorophenyl)-4H-1,2,4-triazol-3-yl]
sulfanyl}acetyl)-4-cyclohexylthiosemicarbazide (15).
sulfanyl}methyl) - 4 - phenyl - 2,4 - dihydro - 3H - 1,2,4 -
1
1
Yield 73%, mp 187–190◦C. H NMR δ (ppm): 1.02–
triazole-3-thione (20). Yield 78%, mp 177–180◦C. H
1.72 (m, 10H, C6H11); 3.85 (s, 2H, CH2); 4.17 (s, 1H,
C6H11); 7.52 (d, 2H, 4-Br-C6H4, J = 7.5 Hz); 7.82 (d,
2H, 4-Br-C6H4, J = 7.5 Hz); 8.94 (s, 1H, CH); 7.67,
9.25, 10.13 (3s, 3H, 3× NH). Elemental anal. (%),
Calcd for C17H21BrN6OS2: C 43.50, H 4.51, N 17.90;
Found: C 43.37, H 4.50, N 17.86.
NMR δ (ppm): 4.11 (s, 2H, CH2); 7.15–7.70 (m, 9H,
C6H5 & 4-Cl-C6H4); 8.89 (s, 1H, CH); 13.83 (s, 1H,
NH). Elemental anal. (%), Calcd for C17H13ClN6S2: C
50.93, H 3.27, N 20.96; Found: C 50.84, H 3.27, N
20.79.
4 - Benzyl - 5 - ({[4 - (4 - chlorophenyl) - 4H - 1,2,4 -
triazol-3-yl]sulfanyl}methyl)-2,4-dihydro-3H-1,2,4-
triazole-3-thione (21). Yield 81%, mp 143–145◦C.
1H NMR δ (ppm): 4.24 (s, 2H, CH2); 5.24 (s, 2H,
C6H5CH2); 7.17–7.69 (m, 9H, C6H5 and 4-Cl-C6H4);
8.89 (s, 1H, CH); 13.57 (s, 1H, NH). Elemental anal.
(%), Calcd for C18H15ClN6S2: C 52.10, H 3.64, N 20.25;
Found: C 52.03, H 3.59, N 20.26.
5-({[4-(4-Chlorophenyl)-4H-1,2,4-triazol-3-yl]
sulfanyl}methyl)-4-(4-methylphenyl)-2,4-dihydro-3H-
1,2,4-triazole-3-thione (22). Yield 77%, mp 156–
158◦C. 1H NMR δ (ppm): 2.37 (s, 3H, CH3); 4.09
(s, 2H, CH2); 7.12–7.70 (m, 8H, 4-Cl-C6H4 and
4-CH3-C6H4); 8.88 (s, 1H, CH); 13.76 (s, 1H, NH).
Elemental anal. (%), Calcd for C18H15ClN6S2: C
52.10, H 3.64, N 20.25; Found: C 52.01, H 3.61, N
20.20.
1-({[4-(4-Bromophenyl)-4H-1,2,4-triazol-3-yl]
sulfanyl}acetyl)-4-ethylthiosemicarbazide (16). Yield
79%, mp 186–188◦C. 1H NMR δ (ppm): 1.07 (m, 3H,
CH2CH3); 3.52 (m, 2H, CH2CH3); 3.89 (s, 2H, CH2);
7.52 (d, 2H, 4-Br-C6H4, J = 10.0 Hz); 7.82 (d, 2H, 4-
Br-C6H4, J = 10.0 Hz); 8.93 (s, 1H, CH); 8,26 (t, 1H,
NH, J = 5.0 Hz); 9.31, 10.22 (2s, 2H, 2× NH). Ele-
mental anal. (%), Calcd for C13H15BrN6OS2: C 37.59,
H 3.64, N 20.23; Found: C 37.60, H 3.64, N 20.18.
1 - ({[4 - (4 - Iodophenyl) - 4H - 1,2,4 - triazol - 3 - yl]
sulfanyl}acetyl)-4-phenylthiosemicarbazide
(17).
Yield 70%, mp 176–178◦C. 1H NMR δ (ppm): 3.96 (s,
2H, CH2); 7.12–7.52 (m, 7H, C6H5 & 4-I-C6H4); 7.97
(d, 2H, 4-I-C6H4, J = 7.5 Hz); 8.88 (s, 1H, CH); 9.71,
9.75, 10.39 (3s, 3H, 3× NH). Elemental anal. (%),
Calcd for C17H15IN6OS2: C 40.01, H 2.96, N 16.47;
Found: C 39.97, H 2.94, N 16.48.
5-({[4-(4-Bromophenyl)-4H-1,2,4-triazol-3-yl]
4-Benzyl-1-({[4-(4-iodophenyl)-4H-1,2,4-triazol-
sulfanyl}methyl) - 4 - phenyl - 2,4 - dihydro - 3H - 1,2,4 -
1
3-yl]sulfanyl}acetyl)thiosemicarbazide (18). Yield
triazole-3-thione (23). Yield 54%, mp 200–202◦C. H
1
85%, mp 204–206◦C. H NMR δ (ppm): 3.95 (s, 2H,
NMR δ (ppm): 4.17 (s, 2H, CH2); 7.26–7.77 (m, 9H,
C6H5 and 4-Br-C6H4); 8.85 (s, 1H, CH); 13.91 (s, 1H,
NH). Elemental anal. (%), Calcd for C17H13BrN6S2:
C 45.85, H 2.94, N 18.87; Found: C 45.79, H 2.95, N
18.79.
4 - Benzyl - 5 - ({[4 - (4 - bromophenyl) - 4H - 1,2,4 -
triazol-3-yl]sulfanyl}methyl)-2,4-dihydro-3H-1,2,4-
triazole-3-thione (24). Yield 74%, mp 161–164◦C.
1H NMR δ (ppm): 4.20 (s, 2H, CH2); 5.21 (s, 2H,
C6H5CH2); 7.19-7.78 (m, 9H, C6H5 and 4-Br-C6H4);
8.91 (s, 1H, CH); 13.62 (s, 1H, NH). Elemental anal.
(%), Calcd for C18H15BrN6S2: C 47.06, H 3.29, N
18.29; Found: C 47.10, H 3.27, N 18.26.
CH2); 4.77 (d, 2H, C6H5CH2, J = 5.0 Hz); 7.15–7.33
(m, 7H, C6H5 & 4-I-C6H4); 7.97 (d, 2H, 4-I-C6H4,
J = 7.5 Hz); 8.85 (s, 1H, CH); 8,78 (t, 1H, NH,
J = 2.5 Hz); 9.51, 10.34 (2s, 2H, 2× NH). Elemental
anal. (%), Calcd for C18H17IN6OS2: C 41.23, H 3.27,
N 16.03; Found: C 41.20, H 3.30, N 15.97.
1 - ({[4 - (4 - Iodophenyl) - 4H - 1,2,4 - triazol-3-yl]
sulfanyl}acetyl)-4-(4-methylphenyl)thiosemicarbazide
1
(19). Yield 70%, mp 168–170◦C. H NMR δ (ppm):
2.27 (s, 3H, CH3); 3.95 (s, 2H, CH2); 7.12 (d, 2H,
4-CH3-C6H4, J = 7.5 Hz); 7.32–7.36 (m, 4H, 4-I-C6H4
(2H) & 4-CH3-C6H4 (2H)); 7.96 (d, 2H, 4-I-C6H4
J = 10.0 Hz); 8.88 (s, 1H, CH); 9.64, 9.69, 10.37
(3s, 3H, 3× NH). Elemental anal. (%), Calcd for
C18H17IN6OS2: C 41.23, H 3.27, N 16.03; Found: C
43.19, H 3.28, N 15.98.
4-Allyl-5-({[4-(4-bromophenyl)-4H-1,2,4-triazol-
3-yl]sulfanyl}methyl)-2,4-dihydro-3H-1,2,4-triazole-
1
3-thione (25). Yield 81%, mp 152–154◦C. H NMR δ
(ppm): 4.31 (s, 2H, CH2); 4.58 (d, 2H, CH2CH CH2,
J = 5.0 Hz); 5.00 (d, 1H, CH2CH CH2, J = 12.5 Hz);
5.13 (d, 1H, CH2CH CH2, J = 12.5 Hz); 5.73–5.84
(m, 1H, CH2CH CH2); 7.40 (d, 2H, 4-Br-C6H4, J =
10.0 Hz); 7.77 (d, 2H, 4-Br-C6H4, J = 10.0 Hz); 8.92
(s, 1H, CH); 13.68 (s, 1H, NH). Elemental anal. (%),
Calcd for C14H13BrN6S2: C 41.08, H 3.20, N 20.53;
Found: C 40.98, H 3.19, N 20.50.
5-({[4-(4-Halogenephenyl)-4H-1,2,4-triazol-3-
yl]sulfanyl}methyl)-4-substituted-2,4-dihydro-3H-
1,2,4-triazole-3-thiones (20–26). General Procedure.
To 0.005 mol of compounds 7–11, 14, or 15, 10 mL
of a 2% solution of NaOH was added. The mixture
was refluxed for 2 h. The solution was filtered off. Af-
Heteroatom Chemistry DOI 10.1002/hc

Synthesis and Antimicrobial Evaluation of Thiosemicarbazides and Products of Their Cyclization 121
5-({[4-(4-Bromophenyl)-4H-1,2,4-triazol-3-yl]
a twofold dilution of each tested compound were
added to the Mueller–Hinton broth without bacteria
and were incubated under the same conditions.
sulfanyl}methyl)-4-cyclohexyl-2,4-dihydro-3H-1,2,4-
1
triazole-3-thione (26). Yield 70%, mp 144–146◦C. H
NMR δ (ppm): 1.09–1.83 (m, 10H, C6H11); 4.27 (s,
1H, C6H11); 4.53 (s, 2H, CH2); 7.36 (d, 2H, 4-Br-C6H4,
J = 7.5 Hz); 7.78 (d, 2H, 4-Br-C6H4, J = 7.5 Hz); 8.78
(s, 1H, CH); 13.66 (s, 1H, NH). Elemental anal. (%),
Calcd for C17H19BrN6S2: C 45.23, H 4.24, N 18.62;
Found: C 45.19, H 4.21, N 18.58.
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Heteroatom Chemistry DOI 10.1002/hc