Synthesis and antimicrobial activity of new derivatives of 1,3,4-thiadiazoles and 1,2,4-triazoles with 5-nitroindazole as support

Article abstract of DOI:10.1002/jhet.1738

The synthesis of new derivatives of 1,3,4-thiadiazoles and 1,2,4-triazoles was achieved using the 1,4-disubstituted thiosemicarbazides as intermediaries.

Full text of DOI:10.1002/jhet.1738

366
Synthesis and Antimicrobial Activity of New Derivatives of 1,3,4-
Thiadiazoles and 1,2,4-Triazoles with 5-Nitroindazole as Support
Vol 50
a
c
d
Corina Cheptea,a,b,c Valeriu Sunel, Jacques Desbrieres, and Marcel Popa
*
a“Grigore T. Popa” Medicine and Pharmacy University, Faculty of Medical Bioengineering, Department of Biomedical
Sciences, 9-13 Kogalniceanu Street, RO-700454, Iasi, Romania
b“Al. I. Cuza” University, Faculty of Chemistry, Department of Organic Chemistry, 11 Carol I Blv., RO-700506, Iasi, Romania
cPau et des Pays de l’Adour University, IPREM/EPCP, Helioparc Pau Pyrenees, 2 Avenue P. Angot, 64053, Pau cedex 9, France
d“Gheorghe Asachi” Technical University of Iaşi, Faculty of Chemical Engineering and Environmental Protection, 73,
Prof.dr.docent Dimitrie Mangeron Bvd, 700050, Iaşi, Romania
*
E-mail: jacques.desbrieres@univ-pau.fr
Received February 23, 2012
DOI 10.1002/jhet.1738
Published online 4 April 2013 in Wiley Online Library (wileyonlinelibrary.com).
The synthesis of new derivatives of 1,3,4-thiadiazoles and 1,2,4-triazoles was achieved using the
1,4-disubstituted thiosemicarbazides as intermediaries.
J. Hetercycl Chem., 50, 366 (2013).
INTRODUCTION
triazole, all in an attempt to enhance the biological activity
of the resulting compounds.
The observation that compounds like thiadiazoles and
triazoles have an essential role in the structure and function
of certain molecules of importance from a biological point
of view was only the beginning for the search of such
compounds with significant pharmacological application.
Research in this direction showed the importance of the
heterocycle structures in the composition of drugs with
antibacterial [1–6], antifungal [3,5,7–10], tuberculostatic
[11,12], analgesic [3,7,9,13], anti-inflammatory [3,7,9,14–17],
cardioprotective [18], antidepressant [19] as well as
antitumoural [6] activity.
The literature and various articles seem to indicate that
indazole molecule has a wide range of biological properties,
such as anti-inflammatory [20], hepatoprotective [21],
analgesic [20], antibacterial [22], antiangiogenic [23],
cytostatic [24] as well as tuberculostatic [25] activity. These
are just some of the reasons why we directed our research
towards the study of the thiadiazoles and triazoles.
RESULTS AND DISCUSSIONS
The synthesis of new derivatives of 1,3,4-thiadiazoles and
1,2,4-triazoles was achieved using the N-acylhydrazinecar-
bothioamides as intermediaries.
To this purpose, the 5-nitroindazole-1-yl-acethydrazide (I)
[25] was treated with phenyl-, p-tolyl, p-methoxyphenyl-,
p-bromophenyl-, p-chlorophenyl-, and p-iodophenyl-
isothiocyanate in absolute methyl alcohol on reflux for 2 h,
leading to new 2-[(50-nitro-1H-indazol-1-yl)acetyl]-N-acyl-
hydrazinecarbothioamide (II–VII) (Scheme 1).
The chemical structures of the synthesized compounds
(II–XIX) were confirmed by means of elemental and spec-
1
tral analysis (FTIR, H-NMR, 13C-NMR, SM).
FTIR spectra present an intense absorption band at
3120cmꢀ1, specific for the NH group. The absorption band
from 1621 cmꢀ1 is specific for the CO group, and the C═S
group is revealed by an absorption band at 1137 cmꢀ1. The
NO2 group is identified by υNO2 symmetric at 1343cmꢀ1
The aim of our research is the synthesis of new heterocyclic
compounds that would contain in their structure both the
5-nitroindazole and the 1,3,4-thiadiazole and/or the 1,2,4-
© 2013 HeteroCorporation

March 2013
Synthesis and Antimicrobial Activity of New Derivatives of 1,3,4-
Thiadiazoles and 1,2,4-Triazoles with 5-Nitroindazole as Support
367
Scheme 1. Synthesis of aryl-hydrazincarbothioamides (II–VII), aryl-1,3,4-thiadiazole-2-amides (VIII–XIII), and aryl-1,2,4-triazole-5-thiones (XIV–XIX).
and by υNO2 asymmetric at 1525 cmꢀ1, whereas for the com-
specific for N-H bond in position 5 from the side chain of
thiadiazole. There are also medium intensity bands at
1240cmꢀ1 as well as at 1436cmꢀ1 because of the specific
thiadiazole ring vibrations. For the compounds (XI–XIII),
this reaches a peak around at 749–753 cmꢀ1 corresponding
to the C-halogen bonds.
pounds (V–VII), the absorption band appears at 630cmꢀ1
.
The 1H-NMR spectra confirm the presence of the protons
bound at nitrogen, showing signals at 9.66–11.02 ppm and at
7.17–8.95ppm, respectively, aromatic protons. The protons
from methyl group show signals at 2.30 ppm (s, 1H) and at
3.36 ppm (s, 2H).
1
In the H-NMR spectra for all thiadiazoles, aromatics
In the 13C-NMR spectra, C═S appears at 176.63–
187.16 ppm and at 165.58–168.89 ppm for C═O.
The mass spectrum analysis confirms the expected
chemical structures. In all N-acylhydrazinecarbothioamide,
the signals of sodium containing adducts (M + Na),
appear at values of m/z 393, 408, 423, 472, 833, 519.
Protonated ionic species [1 + H]+ were also identified in
the same spectra.
New 2,5-disubstituted-5-aryl-amino-1,3,4-thiadiazoles
(VIII–XIII) were obtained by intramolecular cyclization
of 2-[(50-nitro-1H-indazol-1-yl)acetyl]-N-acylhydrazine-
carbothioamide (II–VII) in strong acid medium, as
described in the literature [2,15,26,27].
protons show signals at 6.89–9.01 ppm. The protons from
CH2 group in position 10 of indazole ring show signals
for singlets at 6.08–6.13 ppm, and the proton bound to
nitrogen was detected as a singlet at 10.16–10.62 ppm.
The methyl group protons from thiadiazoles (IX) and
(X) show signals at 2.24 ppm (s, 1H) and 3.71 ppm
(1, 2H), respectively.
In the 13C-NMR spectra, signals for C-S appear
at 165.84–173 ppm and for C-N group at 142.56–
149.70 ppm.
The mass spectrum base peak recorded for thiadiazoles
(VIII–XII) is situated at m/z 353, 367, 383, 432, 388,
479, which correspond to the (M + H) ion.
The main change in IR spectra of thiadiazoles compared
with those of 2-[(50-nitro-1H-indazol-1-yl)acetyl]-N-
acylhydrazinecarbothioamide (II–VII) from which they
come consists in the disappearance of the intense absorption
band at 1137 cmꢀ1 (specific for C═S group of thiourea
function) and the appearance of a new absorption band at
1070cmꢀ1 (specific for C-S-C in the thiadiazole heterocy-
cle). There is also a wide absorption band at 3200cmꢀ1
The series of indazole derivatives was thus enlarged, as a
result of obtaining new compounds that contain the triazole
heterocycle.
The conversion of 2-[(50-nitro-1H-indazol-1-yl)ace-
tyl]-N-acylhydrazinecarbothioamide (II–VII) into their
corresponding triazoles (XIV–XIX) was achieved
following a method indicated in the literature [2,15,28]
under hydroxyl ions catalytic action (Scheme 1).
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C. Cheptea, V. Sunel, J. Desbrieres, and M. Popa
Vol 50
The chemical structures of the synthesized compounds
The germs were grown on Mueller–Hinton agar and
were incubated at 37ꢁC for 18 h. To assess the microbes’
sensitivity to the action of compounds (VIII–XIX), we
used powders of the substances analyzed, in concentrations
of 1000 mg/disk. The results of antimicrobial effect for
compounds were expressed as the inhibition zone
diameter, determined by the diffusimetric method
Kirby-Bauer [29] (Table 1), using as reference the active
substance kanamycin.
The 1,3,4- thiadiazoles (VIII–XIII) are effective against
the S. aureus and are moderately effective against E. coli.
The B. subtilis, B. cereus, and S. enteritidis cultures are resis-
tant to compounds (VIII–XIII). The 1,2,4-triazole derivatives
(XIV–XIX) show high activity against B. subtilis and B.
cereus, but they are inactive against S. aureus, E. coli, and
S. enteritidis. From the compounds tested, the heterocyclic
derivatives containing in their structure residuals of p-bromo-
phenyl (XI, XVII) and residuals of p-iodophenyl, respec-
tively (XIII, XIX), have proved to be the most active. The
antimicrobial activity of tested compounds is, nevertheless,
lower than that of the reference active substance, kanamycin.
To determine the minimal inhibitory concentration (MIC)
by microdilution method, the compounds (VIII–XIX) were
dissolved in DMSO to 100mg/L. We further used solutions
of different concentrations (dilutions of the initial solutions)
for our tests. Following a preliminary sterilization at 120ꢁC
for 30min, these solutions were placed in the culture
medium. The readings were performed for 24 h (the control
contained only the solvent) (Table 2).
were also confirmed by elemental and spectral analysis
1
(FTIR, H-NMR, 13C-NMR, SM).
The absorption bands in the IR spectra for the cyclic C═S
group appear at 1492–1494 cmꢀ1, which means that in solid
state, the triazoles (XIV–XIX) have an ionic structure. In the
region 3097cmꢀ1, there are absorption bands characteristic
for NH group, whereas the C═N group leads to characteristic
absorption bands at 1622 cmꢀ1. The NO2 group presents
two absorption bands at 1336 cmꢀ1 and 1522 cmꢀ1, whereas
C-halogen groups from (XVII–XIX) compounds present
absorption bands at around 750 cmꢀ1
.
1
The (XIV–XIX) compounds H-NMR spectra show a
signal at 13.40–14.09 ppm as a singlet because of the
proton of SH group, and at 7.11–8.21 ppm, there are
signals specific for aromatic protons. The protons of
methyl group of (XV) and (XVI) compounds appear
at 2.12 ppm and 3.61 ppm.
In the 13C-NMR spectra, the C-S group appears in the
region 172.82–173.79 ppm, and the signals of C-N group
were picked up at 142.09–149.88 ppm.
The mass spectrum of the triazole derivative (XVII) shows
the base peak m/z at 431 that corresponds to the (M+) ion.
The mercapto-triazoles (XIV) and (XVIII) have the base
peak at m/z 375 and 410, respectively, assigned to sodium
containing adducts (M + Na), whereas the compounds
(XV), (XVI), and (XIX) present their base peak at m/z
367, 383, and 479, again, assigned to (M + H) ions.
Evaluation of antibacterial activity of compounds
VIII–XIX.
Antibacterial activity of 1,3,4-thiadiazoles
The values of MIC confirm the results obtained by measur-
ing the inhibition zone diameter of bacterial cultures tested.
The values of MIC for 1,3,4-triazoles (VIII–XIII) are recorded
against S. aureus followed by those for E. coli. The thiadiazole
containing residual of p-iodophenol (XIII) is most active
against S. aureus, whereas the one containing the residual of
p-bromophenyl (XI) has the highest degree of inhibition for
(VIII–XIII) and 1,2,4-triazoles derivatives (XIV–XIX)
was studied by in vitro tests using the following reference
bacterial strains: Staphylococcus aureus ATCC 25923,
Bacillus subtilis ATCC6638, Bacillus cereus ATCC
10876, Escherichia coli ATCC25922, and Salmonella
enteritidis P1131.
Table 1
The antimicrobial activity of compounds VIII–XIX at concentration of 1000 mg/disk.
The inhibition zone diameter (mm)
Compound
Staphylococcus aureus
Bacillus subtilis
Bacillus cereus
Escherichia coli
Salmonella enteritidis
VIII
IX
X
XI
XII
XIII
XIV
XV
XVI
XVII
XVIII
XIX
Kanamicyn
16–17
18–19
19–20
20–21
19–20
23–24
7–8
6–7
8–9
6–7
5–6
4–5
5–6
6–7
8–9
6–7
6–7
8–10
6–7
9–10
6–7
11–12
12–13
14–15
15–16
13–14
16–17
6–7
7–8
7–8
9–10
10–11
6–7
5–6
8–9
7–8
9–10
7–8
8–9
5–6
6–7
5–6
9–10
7–8
6–7
7–8
18–19
20–21
19–20
23–24
21–22
25–26
27–28
19–20
19–20
18–19
22–23
20–21
23–24
30–31
9–10
31–32
8–9
28–29
29–30
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Synthesis and Antimicrobial Activity of New Derivatives of 1,3,4-
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369
Table 2
The minimal inhibitory concentration for compounds VIII–XIX (MIC mg/L).
MIC mg/L
Compound
Staphylococcus aureus
Bacillus subtilis
Bacillus cereus
Escherichia coli
Salmonella enteritidis
VIII
IX
X
XI
XII
XIII
XIV
XV
XVI
XVII
XVIII
XIX
280
138
171
114
125
104
850
532
730
640
750
460
1143
636
618
622
618
585
148
130
132
120
152
116
1128
716
714
780
885
890
168
148
149
126
198
124
269
228
193
170
196
178
760
770
890
870
630
852
1132
829
630
785
790
760
620
1150
1210
1140
560
530
MIC, minimal inhibitory concentration.
the hydrazide (I) (0.005 moles), mildly heating and stirring the
solution until it becomes clear. Afterwards, we added isothiocyanate
(0.005 moles in 5 mL absolute methyl alcohol). The mixture was
refluxed on water bath for 3 h separating an abundant precipitate.
This was filtered in vacuum, was dried, and finally purified by
recrystallization from methyl alcohol.
E. coli strain. The 1,2,4-triazole derivatives (XIV–XIX) show
lower values of MIC for B. subtilis and B. cereus. Out of these,
the compounds (XVII) and (XIX) containing in their molecule
p-bromophenyl residual and p-iodophenyl residual, respec-
tively, stand out in this respect—values of MIC.
0
2-[(5 -Nitro-1H-indazol-1-yl)acetyl]-N-phenylhydrazinecarbothioamide
(II). Yellowish white solid, yield 82.06% (1, 51 g); mp = 186–
188ꢁC. IR (g, cmꢀ1): 3096 (NH); 1623 (CO); 749 (CHAr); 1137
(C═S); 1492 (CH2); 1338 (NO2 sym.); 1535 (NO2 asym.). H-
CONCLUSIONS
1
We obtained 2-[(50-nitro-1H-indazol-1-yl)acetyl]-N-
acylhydrazinecarbothioamide (II–VII) intermediaries used
in the synthesis of both 1,3,4-thiadiazoles (VIII–XIII) and
1,2,4-triazoles (XIV–XIX). We synthesized six N-acyl
hydrazine carbo thio amides (II–VII) that were never
mentioned in the literature before.
NMR (DMSO-d6, 400MHz), d(ppm): 5.42 (s, 2H, CH2); 7.18–
7.21 (d, 1H, Ar); 7.35–7.44 (m, 4H, Ar); 7.75–7.83 (d, 1H, Ar);
8.01–8.04 (d, 1H, Ar); 8.26 (s, 1H, Ar); 8.44 (s, 1H, Ar); 9.76–
9.82 (d, 2H, NH); 10.53–10.60 (d, 1H, NH). 13C-NMR (DMSO-
d6, 400MHz), d(ppm): 56.18 (CH2); 102.88; 110.12; 118.55;
122.24; 124.98; 129.56; 131.08 (Ar); 133.47; 135.81; 139.76;
142.14 (C-N); 166.62 (C═O); 183.08 (C═S). SM, m/z: 371
(M+ H, PB); 393 (M+ Na, 12%); 409 (M + K,7%). Anal. Calcd
for C16H14N6O3S: 51.88% C; 3.81% H; 22.69% N; 8.66% S.
Found: 52.04% C; 4.11% H; 22.87% N; 8.82% S.
The intramolecular cyclization of 2-[(50-nitro-1H-indazol-
1-yl)acetyl]-N-acylhydrazinecarbothioamide (II–VII) in acidic
and alkaline solution leads to new derivatives of 1,3,4-thiadia-
zoles and 1,2,4-triazoles, respectively, with 5-nitroindazole as
support. The chemical structure of the newly synthesized
compounds was confirmed by the results of elemental and
spectral analysis (FTIR, 1H-NMR, 13C-NMR, MS).
Some of the newly synthesized compounds present
promising antimicrobial activity especially against S.
aureus and E. coli, whereas others are more efficient
against B. subtilis and B. cereus, their activity being very
close similar to that of kanamicyn.
0
2-[(5 -Nitro-1H-indazol-1-yl)acetyl]-N-(p-tolyl)-hydrazinecarbothioamide
(III). Creamy-white solid, yield 86.97% (1.67 g); mp = 187–
189ꢁC. IR (g, cmꢀ1): 3098 (NH); 1709 (CO); 750, 785
(CHAr); 1224 (C═S); 1498 (CH2); 1342 (NO2 sym.); 1525
(NO2 asym.). 1H-NMR (DMSO-d6, 400 MHz), d(ppm): 2.30
(s, 3H, CH3); 5.35 (s, 2H, CH2); 7.15–7.17 (d, 2H, Ar); 7.25–7.27
(d, 2H, Ar); 7.80–7.82 (d, 1H, Ar); 8.30–8.32 (d, 1H, Ar); 8.44
(s, 1H, Ar); 8.85 (s, 1H, Ar); 9.69–9.75 (d, 2H, NH); 10.50–10.57
(d, 1H, NH). 13C-NMR (DMSO-d6, 400MHz), d(ppm): 18.34
(CH3); 52.79 (CH2); 102.79; 111.31; 119.16; 121.55;
124.17; 131.67; 139.81 (Ar); 133.26; 136.83; 138.15; 143.44
(C-N); 168.64 (C═O); 184.19 (C═S). SM, m/z: 385 (M + H, PB);
408 (M+ Na, 10%); 793 (2M+ Na, 9%); 831 (2M+ Na + K,
15%). Anal. Calcd for C17H16N6O3S: 53.11% C; 4.19% H;
21.86% N; 8.34% S. Found: 53.39% C; 4.38% H; 22.26% N;
8.43% S.
The presence of a halogen atom in p-position of the
aromatic ring enhances the antibacterial activity.
EXPERIMENTAL
2-[(50-Nitro-1H-indazol-1-yl)acetyl]-N-(p-methoxyphenyl)-
hydrazinecarbothioamide (IV). White solid, yield 79.39%
(1.58 g); mp= 202–204ꢁC. IR (g, cmꢀ1): 3100 (NH); 1621 (CO);
750 (CHAr); 1245 (C═S); 1495 (CH2); 1342 (NO2 sym.); 1535
(NO2 asym.). 1H-NMR (DMSO-d6, 400 MHz), d(ppm): 3.36
(s, 3H, OCH3); 5.35 (s, 2H, CH2); 6.92–6.96 (d, 2H, Ar); 7.25–7.28
Synthesis of 5-nitroindazole-1-yl-acethydrazide (I).
This
synthesis was performed by treating of ethyl ester of 5-nitroindazol-
1-yl-acetic acid with hydrazine hydrate 98% [25].
Synthesis of 2-[(50-nitro-1H-indazol-1-yl)acetyl]-N-
acylhydrazinecarbothioamide (II–VII) (general procedure). In a
reaction flask containing absolute methyl alcohol (50 mL), we added
Journal of Heterocyclic Chemistry
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C. Cheptea, V. Sunel, J. Desbrieres, and M. Popa
Vol 50
(d, 2H, Ar); 7.79–7.82 (d, 1H, Ar); 8.26–8.29 (d, 1H, Ar); 8.43 (s, 1H,
Ar); 8.95 (s, 1H, Ar); 9.66–9.71 (d, 2H, NH); 10.48 (s, 1H, NH). 13C-
NMR (DMSO-d6, 400 MHz), d(ppm): 50.91 (CH3); 55.69 (CH2);
108.70; 111.56; 118.45; 119.49; 121.25; 123.39; (Ar); 132.20;
137.06; 142.45; 149.40 (C-N); 137.43; 166.70 (C═O); 176.63
(C═S). SM, m/z: 401 (M + H, 99%); 423 (M + Na, PB);
439 (M + K, 15%); 823 (2M + Na, 90%). Anal. Calcd
for C17H16N6O4S: 50.99% C; 4.02% H; 21.98% N; 8.00% S.
Found: 51.37% C; 4.26% H; 21.31% N; 8.39% S.
until the pH of washing water became 7. The washed precipitate
was dried under vacuum at 50–55ꢁC and then purified by repeated
recrystallization from boiling ethylic ethanol 96%.
5-[(50-Nitro-1H-indazol-1-yl)methyl]-N-phenyl-1,3,4-thiadiazole-
2-amine (VIII). Creamy-white solid, yield 74.43% (1.31 g);
mp = 184–186ꢁC. IR (g, cmꢀ1): 3242 (NH); 1335 (NO2 sym.);
1573 (NO2 asym.); 1456 (N═C-S); 1072 (C-S-C); 1240, 1436,
1517 (thiadiazolic ring); 815 (CHAr). 1H-NMR (DMSO-d6,
400 MHz), d(ppm): 6.13 (s, 2H, CH2); 7.0–7.10 (t, 1H, Ar); 7.31–
7.34 (m, 2H, Ar); 7.53–7.56 (m, 2H, Ar); 8.02 (s, 1H, Ar); 8.30
(s, 1H, Ar); 8.50–8.51 (d, 1H, Ar); 8.86–8.89 (d, 1H, Ar); 10.36
(s, 1H, NH). 13C-NMR (DMSO-d6, 400MHz), d(ppm): 53.89
(CH2); 113.31; 117.90; 120.57; 121.31; 122.01 (Ar); 137.85;
140.79; 141.77; 142.56 (C-N); 154.65; 165.84 (C═S); SM, m/z:
353 (M + H, PB); 727 (2M + Na, 52%); 391 (M + K, 25%). Anal.
Calcd for C16H12N6O2S: 54.53% C; 3.42% H; 23.84% N; 9.09% S.
Found: 54.87% C; 3.68% H; 24.05% N; 9.35% S.
5-[(50-Nitro-1H-indazol-1-yl)methyl]-N-p-tolyl-1,3,4-thiadiazole-
2-amine (IX). Scarlet color solid, yield 75.95% (1.39 g);
mp = 152–154ꢁC. IR (g, cmꢀ1): 2944 (NH); 1338 (NO2 sym.);
1570 (NO2 asym.); 1449 (N═C-S); 1070 (C-S-C); 1246, 1449,
1517 (thiadiazolic ring); 826 (aromatic ring p-disubstituted).
1H-NMR (DMSO-d6, 400 MHz), d(ppm): 2.24 (s, 3H, CH3);
6.11 (s, 2H, CH2); 7.11–7.13 (d, 2H, Ar); 7.41–7.44 (d, 2H,
Ar); 8.02 (s, 1H, Ar); 8.30 (s, 1H, Ar); 8.49–8.50 (d, 1H, Ar);
8.86–8.87 (d, 1H, Ar); 10.26 (s, 1H, NH). 13C-NMR (DMSO-
d6, 400 MHz), d(ppm): 23.56 (CH3); 54.17 (CH2); 111.89;
119.22; 121.14; 123.38; 130.67; 133.62 (Ar); 134.71; 139.23;
145.15; 149.70 (C-N); 157.72; 171.16 (C-S); SM, m/z: 367 (M + H,
PB); 389 (M + Na, 18%); 755 (2M + Na, 11%). Anal. Calcd for
C17H14N6O2S: 55.73% C; 3.84% H; 22.93% N; 8.75% S. Found:
55.93% C; 4.03% H; 23.16% N; 8.99% S.
5-[(50-Nitro-1H-indazol-1-yl)methyl]-N-p-methoxyphenyl-1,3,4-
thiadiazole-2-amine (X). Brown solid, yield 74.35% (1.42 g);
mp = 113–115ꢁC. IR (g, cmꢀ1): 2900 (NH); 1337 (NO2 sym.);
1509 (NO2 asym.); 1438 (N═C-S); 1070 (C-S-C); 1247, 1519,
1615 (thiadiazolic ring); 784, 827 (aromatic ring p-disubstituted).
1H-NMR (DMSO-d6, 400 MHz), d(ppm): 3.71 (s, 3H, CH3); 6.01
(s, 2H, CH2); 6.89–6.93 (d, 2H, Ar); 7.43–7.48 (d, 2H, Ar);
8.01–8.05 (d, 1H, Ar); 8.29–8.32 (d, 1H, Ar); 8.49 (s, 1H, Ar);
9.0 (s, 1H, Ar); 10.16 (s, 1H, NH). 13C-NMR (DMSO-d6,
400 MHz), d(ppm): 53.58 (CH2); 57.12 (CH3); 111.73; 117.25;
119.84; 123.71; 124.52 (Ar); 135.17; 135.93; 146.29; 149.17
(C-N); 155.18; 172.61 (C-S); SM, m/z: 383 (M + H, PB); 787
(2M + Na, 25%). Anal. Calcd for C17H14N6O3S: 53.39% C;
3.68% H; 21.97% N; 8.38% S. Found: 53.56% C; 3.85% H;
22.19% N; 8.56% S.
5-[(50-Nitro-1H-indazol-1-yl)methyl]-N-bromophenyl-1,3,4-
thiadiazole-2-amine (XI). Brown solid, yield 77.20% (1.66 g);
mp= 205–207ꢁC. IR (g, cmꢀ1): 2900 (NH); 1335 (NO2 sym.);
1540 (NO2 asym.); 1490 (N═C-S); 1070 (C-S-C); 1240, 1440,
1518 (thiadiazolic ring); 828 (aromatic ring p-disubstituted); 750
(C-Br). 1H-NMR (DMSO-d6, 400MHz), d(ppm): 6.01 (s, 2H,
CH2); 7.48–7.50 (d, 2H, Ar); 7.53–7.55 (d, 2H, Ar); 8.02–8.05 (d,
1H, Ar); 8.50–8.53 (d, 1H, Ar); 8.86 (s, 1H, Ar); 8.87 (s, 1H, Ar);
10.52 (s, 1H, NH). 13C-NMR (DMSO-d6, 400 MHz), d(ppm):
54.78 (CH2); 121.73; 122.12; 124.58; 132.44; 134.41 (Ar);
137.74; 141.15; 146.08; 149.28 (C-N); 157.25; 173.11 (C-S);
117.66 (C-Br). SM, m/z: 432 (M + H, PB); 885 (2M + Na, 14%).
Anal. Calcd for C16H11BrN6O2S: 44.56% C; 2.56% H; 19.48% N;
7.43% S. Found: 44.72% C; 2.76% H; 19.71% N; 7.62% S.
2-[(50-Nitro-1H-indazol-1-yl)acetyl]-N-(p-bromophenyl)-
hydrazinecarbothioamide (V). Creamy-white solid, yield
80.71% (1.80 g); mp = 145–147ꢁC. IR (g, cmꢀ1): 3096 (NH);
1619 (CO); 749 (CHAr); 1249 (C═S); 1484 (CH2); 1343 (NO2
sym.); 1526 (NO2 asym.); 629 (C-Br). 1H-NMR (DMSO-d6,
400 MHz), d(ppm): 5.36 (s, 2H, CH2); 7.42–7.44 (d, 2H,
Ar); 7.54–7.56 (d, 2H, Ar); 7.80–7.82 (d, 1H, Ar); 8.26–8.29
(d, 1H, Ar); 8.42 (s, 1H, Ar); 8.84 (s, 1H, Ar); 9.85–9.93 (d,
2H, NH); 10.54 (s, 1H, NH). 13C-NMR (DMSO-d6,
400 MHz), d(ppm): 51.50 (CH2); 103.17 (Ar); 118.58 (C-Br) ;
121.15; 123.24; 124.29; 132.20; 133.17 (Ar); 133.77; 137.69;
139.15; 142.83 (C-N); 168.89 (C═O); 187.16 (C═S). SM, m/z:
450 (M + H, 8%); 472 (M + Na, PB); 488 (M + K, 20%). Anal.
Calcd for C16H13BrN6O3S: 42.77% C; 2.91% H; 17.78% Br;
18.70% N; 7.13% S. Found: 42.87% C; 3.15% H; 18.13% Br;
19.03% N; 7.31% S.
2-[(50-Nitro-1H-indazol-1-yl)acetyl]-N-(p-chlorophenyl)-
hydrazinecarbothioamide (VI). Creamy-white solid, yield
78.80% (1.60 g); mp = 203–205ꢁC. IR (g, cmꢀ1): 3123 (NH); 1620
(CO); 750 (CHAr); 1250 (C═S); 1499 (CH2); 1338 (NO2 sym.);
1525 (NO2 asym.); 664, 721 (C-Cl). 1H-NMR (DMSO-d6,
400 MHz), d(ppm): 5.35 (s, 2H, CH2); 7.43–7.46 (m, 4H, Ar); 7.75–
7.82 (d, 1H, Ar); 8.44 (s, 2H, Ar); 8.60 (s, 1H, Ar); 9.80–9.86 (d,
2H, NH); 10.54 (s, 1H, NH). 13C-NMR (DMSO-d6, 400MHz),
d(ppm): 52.12 (CH2); 102.89; 111.62 118.38; 123.67; 130.15;
133.36 (Ar); 134.82 (C-Cl); 136.15; 138.81; 139.43; 142.17 (C-N);
168.13 (C═O); 187.05 (C═S). SM, m/z: 405 (M+, 50%); 444
(M + K, PB); 833 (2M + Na, 16%). Anal. Calcd for C16H13ClN6O3S:
47.47% C; 3.23% H; 8.75% Cl; 20.75% N; 7.92% S. Found:
47.69% C; 3.47% H; 8.99% Cl; 21.11% N; 8.19% S.
2-[(50-Nitro-1H-indazol-1-yl)acetyl]-N-(p-iodophenyl)-
hydrazinecarbothioamide (VII). Yellowish white solid,
yield 80.16% (1.98 g); mp = 179–181ꢁC. IR (g, cmꢀ1): 3120 (NH);
1620 (CO); 780 (CHAr); 1240 (C═S); 1490 (CH2); 1340 (NO2
sym.); 1526 (NO2 asym.); 630 (C-I). 1H-NMR (DMSO-d6,
400 MHz), d(ppm): 5.35 (s, 2H, CH2); 7.40–7.44 (m, 4H, Ar); 7.68–
7.73 (d, 1H, Ar); 8.02–8.04 (d, 1H, Ar); 8.44–8.48 (d, 2H, Ar);
9.80–9.85 (d, 2H, NH); 11.02 (s, 1H, NH). 13C-NMR (DMSO-d6,
400 MHz), d(ppm): 51.95 (CH2); 103.31; 111.27; 118.74; 122.58;
122.91; 138.44 (Ar); 131.89; 136.27; 139.13; 142.41 (C-N); 165.58
(C═O); 183.98 (C═S); 89.32 (C-I). SM, m/z: 496 (M+, PB); 519
(M + Na, 14%); 1015 (2M + Na, 8%). Anal. Calcd for
C16H13IN6O3S: 38.72% C; 2.63% H; 25.57% I; 16.93% N; 6.46%
S. Found: 39.06% C; 2.89% H; 25.78% I; 17.2% N; 6.71% S.
Synthesis of 5-[(50-nitro-1H-indazol-1-yl)methyl]-N-aryl-1,3,4-
thiadiazoles-2-amine (VIII–XIII) (general procedure). In a
reaction flask, we added 6 mL concentrated sulfuric acid 0.005 mol of
2-[(50-nitro-1H-indazol-1-yl)acetyl]-N-acylhydrazinecarbothioamide
(II–VII), stirring until the solution becomes clear. The mixture was
kept at room temperature for 30–40 min for finalization of
cyclization. Once that was achieved, the solution was poured over
crushed ice when an abundant precipitate was separated, and then
filtered under vacuum, was dried, and washed with distilled water
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

March 2013
Synthesis and Antimicrobial Activity of New Derivatives of 1,3,4-
Thiadiazoles and 1,2,4-Triazoles with 5-Nitroindazole as Support
371
5-[(50-Nitro-1H-indazol-1-yl)methyl]-N-p-chlorophenyl-1,3,4-
thiadiazole-2-amine (XII). Brown solid, yield 73.71% (1.43 g);
mp = 204–206ꢁC. IR (g, cmꢀ1): 3326 (NH); 1342 (NO2 sym.); 1542
(NO2 asym.); 1493 (N═C-S); 1071 (C-S-C); 1260, 1470,
1520 (thiadiazolic ring); 828 (aromatic ring p-disubstituted); 753 (C-Cl).
1H-NMR (DMSO-d6, 400 MHz), d(ppm): 6.13 (s, 2H, CH2);
7.36–7.40 (d, 2H, Ar); 7.58–7.61 (d, 2H, Ar); 8.0–8.02 (d, 1H,
Ar); 8.29–8.30 (d, 1H, Ar); 8.86 (s, 1H, Ar); 9.01 (s, 1H, Ar);
10.50 (s, 1H, NH). 13C-NMR (DMSO-d6, 400 MHz), d(ppm):
54.18 (CH2); 110.98; 119.88; 123.67; 124.13; 128.83 (Ar);
136.31; 139.77; 146.25; 149.39 (C-N); 159.70; 172.36 (C-S);
128.83 (C-Cl). SM, m/z: 388 (M + H, PB); 410 (M + Na, 8%); 775
(2M + H, 6%); 797 (2M + Na, 11%). Anal. Calcd for
C16H11ClN6O2S: 49.68% C; 2.86% H; 9.16% Cl; 21.72% N;
8.28% S. Found: 49.88% C; 3.03% H; 9.4% Cl; 22.03% N; 8.57% S.
5-[(50-Nitro-1H-indazol-1-yl)methyl]-N-p-iodophenyl-1,3,4-
thiadiazole-2-amine (XIII). Brown solid, yield 73.22% (1.75 g);
mp = 185–187ꢁC. IR (g, cmꢀ1): 2917 (NH); 1338 (NO2 sym.); 1518
(NO2 asym.); 1492 (N═C-S); 1070 (C-S-C); 1260, 1438, 1615
(thiadiazolic ring); 824 (aromatic ring p-disubstituted); 749 (C-I).
1H-NMR (DMSO-d6, 400MHz), d(ppm): 6.12 (s, 2H, CH2);
7.40–7.42 (d, 2H, Ar); 7.63–7.65 (d, 2H, Ar); 8.03–8.04 (d, 1H,
Ar); 8.30–8.33 (d, 1H, Ar); 8.50 (s, 1H, Ar); 8.80 (s, 1H, Ar);
10.60–10.62 (d, 1H, NH). 13C-NMR (DMSO-d6, 400MHz),
d(ppm): 53.79 (CH2); 111.34; 118.69; 119.83; 123.50; 136.44
(Ar); 139.45; 141.48; 147.18 (C-N); 155.72; 171.72 (C-S); 87.34
(C-I). SM, m/z: 479 (M + H, 35%); 501 (M +Na, PB); 517
(M + K, 21%). Anal. Calcd for C16H11IN6O2S: 40.18% C; 2.31%
H; 26.53% I; 17.57% N; 6.70% S. Found: 40.44% C; 2.60% H;
26.74% I; 17.90% N; 6.92% S.
133.65; 135.72 (Ar); 139.32; 143.85; 145.16; 147.25; 147.89
(C-N); 173.79 (C-S). SM, m/z: 367 (M + H, PB); 755 (2M + Na,
8%). Anal. Calcd for C17H14N6O2S: 55.73% C; 3.84% H; 22.93%
N; 8.75% S. Found: 56.01% C; 4.12% H; 23.17% N; 9.11% S.
3-[(50-Nitro-1H-indazol-1-yl)methyl]-N-p-methoxyphenil-1,2,4-
triazole-5-thione (XVI). Dark brown solid, yield 73.40%
(0.69 g); mp = 232–234ꢁC. IR (g, cmꢀ1): 1339 (NO2 sym.);
1514 (NO2 asym.); 2590 (SH); 1613 (C═N); 821, 837 (aromatic
ring p-disubstituted). 1H-NMR (DMSO-d6, 400MHz), d(ppm):
3.61 (s, 3H, OCH3); 5.72 (s, 2H, CH2); 6.71–6.73 (d, 2H, Ar);
6.94–6.96 (d, 2H, Ar); 7.50–7.55 (d, 1H, Ar); 8.08–8.11 (d, 1H, Ar);
8.35 (s, 1H, Ar); 8.73 (s, 1H, Ar); 13.90 (s, 1H, SH). 13C-NMR
(DMSO-d6, 400 MHz), d(ppm): 44.32 (CH3); 55.65 (CH2); 110.97;
114.75; 121.29; 123.0 (Ar); 128.97; 137.86; 142.09 (C-N); 159.94
(C-S); 13.90 (C-O). SM, m/z: 383 (M + H, PB); 405 (M + Na, 50%).
Anal. Calcd for C17H14N6O3S: 53.39% C; 3.68% H; 21.97% N;
8.38% S. Found: 53.53% C; 3.84% H; 22.19% N; 8.55% S.
3-[(50-Nitro-1H-indazol-1-yl)methyl]-N-p-bromophenyl-1,2,4-
triazole-5-thione (XVII). Brown-red solid, yield 76.86%
(0.88 g); mp = 210–212ꢁC. IR (g, cmꢀ1): 1341 (NO2 sym.);
1520 (NO2 asym.); 2486 (SH); 1616 (C═N); 804, 918 (aromatic
1
ring p-disubstituted); 752 (C-Br). H-NMR (DMSO-d6, 400 MHz),
d(ppm): 6.12 (s, 2H, CH2); 7.45–7.47 (d, 2H, Ar); 7.50–7.54
(d, 2H, Ar); 8.10–8.12 (d, 1H, Ar); 8.30–8.32(d, 1H, Ar) 8.50
(s, 1H, Ar); 8.90 (s, 1H, Ar); 13.40 (s, 1H, SH). 13C-NMR
(DMSO-d6, 400MHz), d(ppm): 54.23 (CH2); 119.72 (C-Br);
123.25; 125.88; 129.34; 133.30; 133.89 (Ar); 135.66; 145.09;
146.58; 147.35; 147.96 (C-N); 173.42 (C-S). SM, m/z: 431 (M+,
PB); 454 (M + Na, 17%); 470 (M + K, 43%). Anal. Calcd for
C16H11BrN6O2S: 44.56% C; 2.56% H; 18.52% Br; 19.48% N;
7.43% S. Found: 44.82% C; 2.81% H; 18.70% Br; 19.74% N;
7.67% S.
3-[(50-Nitro-1H-indazol-1-yl)methyl]-N-p-chlorophenyl-1,2,4-
triazole-5-thione (XVIII). Brown solid, yield 77.88% (0.81 g);
mp= 228–230ꢁC. IR (g, cmꢀ1): 1341 (NO2 sym.); 1522 (NO2
asym.); 2339 (SH); 1615 (C═N); 898 (aromatic ring p-
disubstituted); 748 (C-Cl). 1H-NMR (DMSO-d6, 400 MHz),
d(ppm): 5.77 (s, 2H, CH2); 7.09–7.11 (d, 2H, Ar); 7.25–7.27 (d,
2H, Ar); 7.53–7.55 d, 1H, Ar); 8.11–8.14 (d, 1H, Ar); 8.34
(s, 1H, Ar); 8.72 (s, 1H, Ar); 14.09 (s, 1H, SH). 13C-NMR
(DMSO-d6, 400 MHz), d(ppm): 53.85 (CH2); 111.58; 119.24;
123.68; 129.55; 131.02 (Ar); 135.12 (C-Cl); 137.52; 145.22;
146.09; 149.18; 149.79 (C-N); 172.97 (C-S). SM, m/z: 388
(M + H, 30%); 410 (M + Na, PB); 426 (M + K, 9%). Anal.
Calcd for C16H11ClN6O2S: 49.68% C; 2.86% H; 9.16% Cl;
21.72% N; 8.28% S. Found: 49.85% C; 3.02% H; 9.55% Cl;
21.90% N; 8.60% S.
3-[(50-Nitro-1H-indazol-1-yl)methyl]-N-p-iodophenyl-1,2,4-
triazole-5-thione (XIX). Brown-red solid, yield 72.09%
(0.93 g); mp = 220–222ꢁC. IR (g, cmꢀ1): 1336 (NO2 sym.);
1518 (NO2 asym.); 2347 (SH); 1614 (C═N); 944 (aromatic
ring p-disubstituted); 749 (C-I). 1H-NMR (DMSO-d6,
400 MHz), d(ppm): 5.73 (s, 2H, CH2); 7.44–7.47 (m, 4H, Ar);
7.73–7.75 (d, 1H, Ar); 8.20–8.21 (d, 1H, Ar); 8.31 (s, 1H, Ar); 8.70
(s, 1H, Ar); 13.80 (s, 1H, SH). 13C-NMR (DMSO-d6, 400 MHz),
d(ppm): 54.47 (CH2); 97.34 (C-I); 111.36; 119.69; 123.52; 133.64;
133.37 (Ar); 139.71; 144.12; 145.22; 146.49; 149.13; 149.88
(C-N); 173.21 (C-S). SM, m/z: 479 (M + H, PB); 501 (M + Na,
75%); 517 (M + K, 12%). Anal. Calcd for C16H11IN6O2S:
40.18% C; 2.31% H; 26.53% I; 17.57% N; 6.70% S. Found:
40.52% C; 2.45% H; 26.84% I; 17.88% N; 6.91% S.
Synthesis of 5-[(50-nitro-1H-indazol-1-yl)methyl]-N-acyl-
1,2,4-triazole-5-thione (XIV–XIX) (general procedure). In a
reaction flask containing 15 mL 2N sodium hydroxide, we
added 0.0027 mol of 2-[(50-nitro-1H-indazol-1-yl)acetyl]-N-
acylhydrazinecarbothioamide (II–VII). The mixture was heated
to boiling point for 1 h. Cooling and dilution with water was
followed by the addition of a dilute hydrochloric acid solution,
in small quantities until pH = 4,5; at which point, the 1,2,4-
triazoles begun to separate as a precipitate. Purification was
performed from ethyl alcohol on boiling.
3-[(50-Nitro-1H-indazol-1-yl)methyl]-N-phenyl-1,2,4-triazole-5-
thione (XIV). Brown-red solid, yield 55.78% (0.53 g); mp = 247–
249ꢁC. IR (g, cmꢀ1): 1337 (NO2 sym.); 1508 (NO2 asym.); 2496
(SH); 1622 (C═N); 822 (CHAr). 1H-NMR (DMSO-d6, 400 MHz),
d(ppm): 5.74 (s, 2H, CH2); 7.11–7.14 (d, 2H, Ar); 7.24–7.26
(d, 2H, Ar); 7.50–7.53 (t, 1H, Ar); 7.72–7.75 (d, 1H, Ar); 8.08
(s, 1H, Ar); 8.18 (s, 1H, Ar); 8.20–8.21 (d, 1H, Ar); 13.85 (s, 1H,
SH). 13C-NMR (DMSO-d6, 400 MHz), d(ppm): 54.70 (CH2);
111.31; 119.23; 123.65; 131.77; 133.45 (Ar); 134.38; 146.17;
147.98; 148.15; 148.88 (C-N); 172.82 (C-S). SM, m/z: 352 (M+,
90%); 375 (M + Na, PB); 727 (2M + Na, 5%). Anal. Calcd for
C16H12N6O2S: 54.53% C; 3.42% H; 23.84% N; 9.09% S. Found:
54.71% C; 3.53% H; 24.08% N; 9.40% S.
3-[(50-Nitro-1H-indazol-1-yl)methyl]-N-p-tolyl 1,2,4-triazole-
5-thione (XV). Brown solid, yield 72.45% (0.71g); mp= 249–
251ꢁC. IR (g, cmꢀ1): 1338 (NO2 sym.); 1514 (NO2 asym.); 2560
1
(SH); 1622 (C═N); 896 (aromatic ring p-disubstituted). H-NMR
(DMSO-d6, 400MHz), d(ppm): 2.12 (s, 3H, CH3); 5.72 (s, 2H,
CH2); 6.91–6.93 (d, 2H, Ar); 6.98–7.0 (d, 2H, Ar); 7.47–7.49
(d, 1H, Ar); 7.73–7.75 (d, 1H, Ar); 8.30 (s, 1H, Ar); 8.71 (s, 1H,
Ar); 13.75 (s, 1H, SH). 13C-NMR (DMSO-d6, 400MHz), d(ppm):
25.21 (CH3); 55.14 (CH2); 111.76; 119.23; 123.82; 131.02;
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

372
C. Cheptea, V. Sunel, J. Desbrieres, and M. Popa
Vol 50
[14] Megeed, A.; Rahman, M.H.; Alkaramany, E.G.; Gendy, A.M.
Eur J Med Chem 2009, 44, 117.
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Peptu, C. Molecules 2009, 14, 2621.
Acknowledgments. The authors thank A. Khoukh (IPREM) for
his help in NMR experiments.
[16] Castro, A.; Castano, T.; Encinas, A.; Porcal, W.; Gil, C.
Bioorg Med Chem 2006, 14, 1644.
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet