Design and synthesis of new 4-pyrazolin-3-yl-1,2,3-triazoles and 1,2,3-triazol-4-yl-pyrazolin-1-ylthiazoles as potential antimicrobial agents

Article abstract of DOI:10.1016/j.ejmech.2012.03.023

New pyrazolyl-1,2,3-triazoles and 1,2,3-triazol-4-yl-pyrazolylthiazoles were synthesized through multi step reactions using 1-tolylyl-4-acetyl-5-methyl- 1,2,3-triazole as a precursor. All the newly synthesized compounds were characterized by spectral and elemental analyses. The structure of 11b was evidenced by X-ray crystallographic study. The newly synthesized compounds were evaluated for their antimicrobial activities and also their minimum inhibitory concentration (MIC) against most of test organisms was performed. Amongst the tested compounds 5a, 5c, 11b and 11c displayed excellent antimicrobial activity.

Full text of DOI:10.1016/j.ejmech.2012.03.023

European Journal of Medicinal Chemistry 52 (2012) 263e268
Contents lists available at SciVerse ScienceDirect
European Journal of Medicinal Chemistry
journal homepage: http://www.elsevier.com/locate/ejmech
Original article
Design and synthesis of new 4-pyrazolin-3-yl-1,2,3-triazoles and 1,2,
3-triazol-4-yl-pyrazolin-1-ylthiazoles as potential antimicrobial agents
,
b
a
c
Bakr F. Abdel-Wahab a , Ehab Abdel-Latif , Hanan A. Mohamed , Ghada E.A. Awad
*
a Applied Organic Chemistry Department, National Research Centre, Dokki, 12622 Giza, Egypt
b Department of Chemistry, Faculty of Science, Mansoura University, ET-35516, Mansoura, Egypt
c Chemistry of Natural and Microbial Products, National Research Center, Dokki, 12622 Giza, Egypt
a r t i c l e i n f o
a b s t r a c t
Article history:
New pyrazolyl-1,2,3-triazoles and 1,2,3-triazol-4-yl-pyrazolylthiazoles were synthesized through multi
step reactions using 1-tolylyl-4-acetyl-5-methyl-1,2,3-triazole as a precursor. All the newly synthesized
compounds were characterized by spectral and elemental analyses. The structure of 11b was evidenced
by X-ray crystallographic study. The newly synthesized compounds were evaluated for their antimi-
crobial activities and also their minimum inhibitory concentration (MIC) against most of test organisms
was performed. Amongst the tested compounds 5a, 5c, 11b and 11c displayed excellent antimicrobial
activity.
Received 31 January 2012
Received in revised form
13 March 2012
Accepted 13 March 2012
Available online 23 March 2012
Keywords:
Ó 2012 Elsevier Masson SAS. All rights reserved.
Pyrazolyltriazole
Biheterocycles
Antimicrobial
X-ray crystallography
1. Introduction
copper and copper alloys), photostabilizers, photographic mate-
rials, and agrochemicals [13]. Pyrazole derivatives have showed
Triazole refers to either one of a pair of isomeric chemical
compounds with molecular formula C2H3N3, having five
membered ring of two carbon atoms and three nitrogen atoms. The
two isomers are:
significant biological activities, such as antimicrobial [14], analgesic
[15], anti-inflammatory [16] and anticancer [17] activities. There-
fore it is important to synthesize new compounds having both
1,2,3-triazole and pyrazoline moieties. In this work, and in
continuation of our previous work to discover new biologically
active heterocyclic compounds, [18e25] we aimed to the synthesis
of novel compounds based on 1,2,3-triazoles-linked pyrazolines.
a
N
N
N
N
N
H
N
H
2. Results and discussion
1,2,3-triazole
1,2,4-triazole
2.1. Chemistry
In recent years, the 1,2,3-triazole ring system has been the
subject of considerable research due to its usefulness in synthetic
organic chemistry and also because of the pharmacological prop-
erties. 1,2,3-Triazoles display biological activities such as anti-HIV
activity [1,2], antimicrobial activity against Gram positive bacteria
[3], antiviral [4] and antiproliferative [5]. They are used as inter-
mediates at the synthesis of antibiotics [6e8]. The derivatives of
1,2,3-triazole also are applied as insecticides [9], fungicides [10],
plant growth regulators [11,12]. 1,2,3-Triazoles have also widely
used in industrial applications such as dyes, corrosion inhibition (of
The title compounds 3e14 were prepared from 1-(5-methyl-1-
p-tolyl-1H-1,2,3-triazol-4-yl)ethanone 1. The starting material 1
was prepared starting from p-toluidine and acetylacetone,
according to literature [26]. 4-Acetyltriazole 1 was reacted with
equivalent of aromatic aldehydes 2 in the presence of 10% alcoholic
NaOH in 90% ethanol with stirring at room temperature to give key
intermediates 3. The chalcone 3a was prepared previously by Dong
et al., 2010 (Scheme 1) [27].
According to Scheme 1, the desired pyrazolinyltriazoles 5 have
been prepared by cyclocondensation of hydrazine hydrate with
chalcones 3, which includes formation of hydrazone intermediates
4 and then addition of NH2 of hydrazone to the double bond.
* Corresponding author.
E-mail address: bakrfatehy@yahoo.com (B.F. Abdel-Wahab).
0223-5234/$ e see front matter Ó 2012 Elsevier Masson SAS. All rights reserved.
doi:10.1016/j.ejmech.2012.03.023

264
B.F. Abdel-Wahab et al. / European Journal of Medicinal Chemistry 52 (2012) 263e268
CH3
O
N
N
N
N
N
N
Ar1
Ar2
Ar1
H3C
CH3
O
3
1
2
Ar2CHO ( )
NH2NHCSNH2
NaOH/EtOH
EtOH, NaOH, reflux
N
N
Ar2
N
N
Ar1
Ar2
N
N
N
NH2
N
H3C
O
Ar1
3
S
CH3
O
NH2NH2xH2O
EtOH, reflux
O
9
Br
Cl
Ar3
EtO
10
Ar2
NH2
EtOH / Et3N
EtOH
Ar2
Ar2
N
N
N
N
N
N
Ar2
N
N
N
NH
N
N
H
N
N
Ar1
Ar1
N
N
CH3
4
N
N
CH3
N
Ar1
N
S
N
O
Ar1
CH3
12
6
S
Ar3
CH3
Ar2
N
11
N
N
NH
N
N
Ar1
2,9,11, 12:Ar1= 4-MeC6H4; Ar2= 4-FC6H4
10, 11
CH3
: Ar3 = Ph, 4-ClC6H4, 4-BrC6H4
5
Scheme 2. Synthetic accesses to 1,2,3-triazol-4-yl-pyrazolylthiazoles (11e12).
PhNCS
PhCONCS
EtOH, reflux
Ar2
EtOH, reflux
Ar2
335, 470 and 564 respectively in agreement with the calculated
masses.
X-ray crystallography of this tricyclic system 11b (crystallized
from DMF) confirmed the anticipated structure (Fig. 1).
N
N
N
N
N
S
N
S
N
N
N
Ar1
Ar1
HN
O
CH3
HN
CH3
Ph
7
Ph
8
2.2. Antimicrobial activity
1, 2, 3, 4, 5, 6, 7, 8 : Ar1 = 4-MeC6H4
2, 3, 4, 5, 6,7
8:
a
b
c
d
: Ar2 = Ph, : 4-FC6H4, : 4-NCC6H4, : 4-piperidylC6H4
Ar2 = 4-piperidylC6H4
All the synthesized compounds were screened for their anti-
bacterial and antifungal activities at 100
mg/ml concentration
Scheme 1. Synthetic routes to new pyrazolyl-1,2,3-triazoles (5e8).
against four Gram positive bacteria (Staphylococcus aureus ATCC
29213; Bacillus subtilis ATCC6633; Bacillus megaterium ATCC 9885;
Sarcina lutea), three Gram negative bacteria (Klebseilla pneumoniae
ATCC13883; Pseudomonas aeroginosa ATCC27953; Escherichia coli
ATCC 25922) and two yeast (Saccharomyces cerevisiae and Candida
albicans NRRL Y-477). Ciprofloxacin and Ketoconazole were
respectively used as standard antibacterial and antifungal refer-
ence, respectively. Most of the newly synthesized compounds
showed excellent antimicrobial activities with respect to the
control drugs. The results of antimicrobial activities were shown in
Table 1. Data in Table 1 revealed that most of compounds have
superior significant antifungal potency to antibacterial potency.
Compounds 5a, 5c, 11a and 11c exhibited the highest potency
against all tested organisms with respect to reference drugs.
Compound 5a inhibited the growth of S. aureus ATCC 29213;
B. subtilis ATCC6633 and S. lutea with inhibition zones 34, 32 and
30 mm respectively. While compound 5c showed excellent activity
against K. pneumoniae ATCC13883; E. coli ATCC 25922 and
S. cerevisiae with inhibition zone 30 mm. Also, compound 11c
showed highest activity against S. aureus ATCC 29213, S. cerevisiae
and C. albicans NRRL Y-477 with inhibition zone 30 mm.
Treatment of pyrazolines 5aec with phenyl isothiocyanate in
anhydrous ethanol led to the formation of 3-(1,2,3-triazol-4-yl)-5-
methyl-N-phenyl-pyrazole-1-carbothioamides 7aec in 52e55%
yields. Treatment of 5d with benzoyl isothiocyante in refluxing
ethanol results in the N-(3-(5-methyl-1-p-tolyl-1H-1,2,3-triazol-4-
yl)-5-(4-(piperidin-1-yl)phenyl)-4,5-dihydro-1H-pyrazole-1-carbo
nothioyl)benzamide 8 in 69% yield (Scheme 1).
The reaction between the fluorinated chalcone 3b and the
equivalent amount of thiosemicarbazide was performed in ethanol
in the presence of 2.5 equivalent of sodium hydroxide to yield 3-(5-
methyl-1,2,3-triazol-4-yl)-pyrazole-1-carbothioamide derivative 9.
The resulting product was cyclized to the corresponding 2-(3-
(1,2,3-triazol-4-yl)-5-methyl-1H-pyrazol-1-yl)thiazole derivatives
11aec by reaction with phenacyl bromides 10 in anhydrous
ethanol. Reaction of 9 with ethyl bromoacetate in refluxing ethanol
in the presence of triethylamine gave 2-(3-(1,2,3-triazol-4-yl)-5-
methyl-pyrazol-1-yl)thiazol-4-one 12 in high yield (Scheme 2).
Determination of the reaction product structures was per-
formed by means of IR, NMR, MS spectroscopy, and X-ray diffrac-
tion. For example 1H NMR spectra of
5
contained two
2.3. Minimum inhibitory concentration (MIC)
doubletedoublet and one triplet signals due to the presence of CH2
adjacent asymmetric carbon and presence of a one singlet single at
d
The minimum inhibitory concentration (MIC) of the synthesized
compounds against highly inhibited organisms is reported in
Table 2.
10.19 ppm due to NH proton. While the 1H NMR of compounds 7
and 8 indicate the disappearance of NH signal due to blocking of NH
with carbothioamide. The IR spectrum of 5c exhibits absorption
bands at nmax2224 cmꢀ1 due to the carbonitrile substituent. The
mass spectra of 5b, 7b and 8 showed the molecular ion peaks at m/z
Compounds 5a revealed high MIC (132
B. megaterium ATCC 9885, E. coli ATCC 25922 respectively. On the
other hand, compounds 5a exhibited low MIC (8.25 g/ml) against S.
mg/ml) against
m

B.F. Abdel-Wahab et al. / European Journal of Medicinal Chemistry 52 (2012) 263e268
265
Fig. 1. X-ray structure of compound 11b.
aureus ATCC 29213; B. subtilis ATCC6633; P. aeroginosa ATCC27953;
S. cerevisiae and C. albicans NRRL Y-477 respectively. Compound 5c
showed MIC 8.25 mg/ml against B. subtilis ATCC6633; B. megaterium
ATCC 9885; S. lutea, K. pneumoniae ATCC13883; P. aeroginosa
ATCC27953; E. coli ATCC 25922; S. cerevisiae and C. albicans NRRL Y-
carried from the microanalytical unit, Cairo University, Giza, Egypt.
The IR spectra were recorded in potassium bromide disks on
a JASCO FT/IR-6100. 1H NMR and 13C NMR spectra were run on
JOEL-ECA 500 MHz in deuterated dimethylsulphoxide (DMSO-d6).
Chemical shifts values (d) are given in parts per million (ppm). The
477. Additionally, compounds 11b and 11c exhibited MIC 8.25
against S. aureus ATCC 29213 and also showed MIC 16.5
against K. pneumoniae ATCC13883 (Table 2).
m
m
g/ml
g/ml
mass spectra were performed using mass Varian MAT CH-5 spec-
trometer at 70 eV. 1-(5-Methyl-1-p-tolyl-1H-1,2,3-triazol-4-yl)
ethanone 1 [26] and 4-(piperidin-1-yl)benzaldehyde 2d [28] were
prepared according to literature.
3. Conclusion
4.1.2. General procedure for the preparation of 3bed
A
mixture of the appropriate aromatic aldehydes 2bed
We have synthesized new pyrazolyl-triazole and thiazolyl pyr-
azolyl triazoles with potential antimicrobial activity, from available
4-acetyl-5-methyl-1,2,3-triazole by routine and facile methods. The
new compounds were tested for their antimicrobial activities and
most of them show significant activities.
(12 mmol) and compound 1 (10 mmol, 2.15 g) dissolved in
ethanol (50 ml) was added slowly to an aqueous solution of sodium
hydroxide (12.8 mmol) in water (10 ml). The reaction mixture was
stirred at 20e25 ꢁC for 4 h. The mixture was filtrated and the solid
was washed with cold water. The product was crystallized from
ethanol to give 3bed.
4. Experimental
4.1.2.1. (E)-3-(4-Fluorophenyl)-1-(5-methyl-1-p-tolyl-1H-1,2,3-tria-
4.1. Chemistry
zol-4-yl)prop-2-en-1-one (3b). Yield 70%; m.p. 148e50 ꢁC; IR (KBr)
nmax/cmꢀ1 1652 (C]O); 1H NMR (DMSO-d6)
d 2.38 (s, 3H, CH3), 2.45
4.1.1. General
(s, 3H, CH3), 6.91 (d,1H, CH, J ¼ 18.8 Hz), 7.42 (d,1H, CH, J ¼ 19.1 Hz);
All melting points were taken on Electrothermal IA 9000 series
digital melting point apparatus. Elemental analytical data were
7.29e7.48 (m, 8H, AreH) MS m/z (%): 321 (Mþ, 11), 132 (100).
Table 1
Antimicrobial activity expressed as inhibition diameter zones in millimeters (mm) of chemical compounds against the pathological strains based on well diffusion assay.
Chemical
Gram positive bacteria
Gram negative bacteria
Yeast
compound
Staphylococcus
aureus
ATCC 29213
B. subtilis
ATCC6633
B. megaterium
ATCC 9885
Sarcina
lutea
Klebseilla
pneumoniae
ATCC13883
Pseudomonas
aeroginos
ATCC27953
E. coli
ATCC 25922
Saccharomyces
cerevisiae
Candida albicans
NRRL Y-477
3a
3b
3c
3d
5a
5b
5c
5d
7a
7b
7c
8
9
11a
11b
11c
22
20
23
16
34
20
N.A.
18
18
16
20
16
N.A.
26
28
30
N.A.
20
N.A.
26
26
28
18
32
N.A.
26
16
26
27
N.A.
24
N.A.
24
30
26
N.A.
22
N.A.
24
N.A.
20
16
16
24
N.A.
24
20
N.A.
30
18
24
N.A.
22
30
26
16
24
28
30
18
28
18
20
20
24
23
16
22
22
22
16
20
N.A.
16
16
24
N.A.
N.A.
16
30
N.A.
18
28
16
26
16
28
30
28
N.A.
24
N.A.
22
26
26
28
24
N.A.
20
24
N.A.
32
N.A.
16
28
16
22
23
30
20
28
18
30
18
26
24
24
30
30
22
28
30
18
N.A.
23
24
22
24
18
28
16
28
18
24
22
22
30
26
20
25
30
16
N.A.
22
16
30
N.A.
N.A.
N.A.
N.A.
32
22
16
29
22
22
N.A.
N.A.
N.A.
26
28
24
N.A.
25
N.A.
12
28
23
N.A.
Ciprofloxacin
Ketoconazole
24
N.A.
N.A.
The experiment was carried out in triplicate and the average zone of inhibition was calculated; (N.A. ¼ no activity).

266
B.F. Abdel-Wahab et al. / European Journal of Medicinal Chemistry 52 (2012) 263e268
Table 2
Minimum inhibitory concentration (
m
g/ml) against the pathological strains based on two fold serial dilution technique.
Chemical
Gram positive bacteria
Gram negative bacteria
Yeast
compound
Staphylococcus
aureus
ATCC 29213
B. subtilis
ATCC6633
B. megaterium
ATCC 9885
Sarcina lutea
Klebseilla
pneumoniae
ATCC13883
Pseudomonas
aeroginosa
ATCC27953
E. coli
ATCC 25922
Saccharomyces
cerevisiae
Candida
albicans
NRRL Y-477
3a
3b
3c
3d
5a
5b
5c
5d
7a
7b
7c
8
9
11a
11b
11c
16.5
16.5
16.5
132
8.25
33
33
e
16.5
132
16.5
33
16.5
66
8.25
33
66
16.5
33
66
132
66
66
132
132
16.5
e
8.25
132
8.25
132
8.25
8.25
8.25
e
8.25
e
66
16.5
16.5
16.5
16.5
8.25
132
8.25
132
16.5
16.5
33
8.25
16.5
66
16.5
8.25
132
e
16.5
8.25
33
8.25
e
16.5
e
16.5
8.25
66
8.25
66
132
8.25
132
132
8.25
e
33
132
132
33
e
132
8.25
e
e
33
132
e
8.25
66
132
8.25
132
33
132
e
e
8.25
16.5
e
16.5
16.5
e
132
e
8.25
e
16.5
16.5
8.25
8.25
8.25
33
16.5
8.25
66
16.5
e
66
33
16.5
8.25
16.5
e
e
33
e
8.25
132
33
e
8.25
16.5
132
33
16.5
8.25
16.5
e
e
16.5
8.25
8.25
e
33
8.25
33
33
e
16.5
16.5
e
33
66
12
e
8.25
8.25
e
132
16.5
e
33
16.5
e
Ciprofloxacin
Ketoconazole
8.25
e
8.25
e
16.5
e
e
8.25
8.25
4.1.2.2. (E)-4-(3-(5-Methyl-1-p-tolyl-1H-1,2,3-triazol-4-yl)-3-oxoprop-
1-enyl)benzonitrile (3c). Yield 72%; m.p. 222e3 ꢁC; IR (KBr) nmax
cmꢀ1 1650 (C]O), 2220 (CN); 1H NMR (DMSO-d6)
2.38 (s, 3H,
CH3), 2.48 (s, 3H, CH3), 6.88 (d, 1H, CH, J ¼ 18.7 Hz), 7.45 (d, 1H,
CH, J ¼ 18.9 Hz); 7.31e7.51 (m, 8H, AreH) MS m/z (%): 328 (Mþ, 8),
132 (100).
(s, 3H, CH3), 2.45 (s, 3H, CH3), 2.93, 2.95 (dd, 1H, CH, J ¼ 10.7 Hz,
J ¼ 9.95 Hz), 3.62, 3.65 (dd, 1H, CH, J ¼ 10.7 Hz, J ¼ 10.7 Hz), 4.89 (t,
1H, CH, J ¼ 10.7 Hz, J ¼ 9.95 Hz), 7.38e7.57 (m, 8H, AreH), 10.19 (s,
1H, NH, D2O-exchangeable); MS m/z (%): 342 (Mþ, 7), 90 (100).
/
d
4.1.3.4. 1-(4-(3-(5-Methyl-1-p-tolyl-1H-1,2,3-triazol-4-yl)-4,5-dihydro-
1H-pyrazol-5-yl)phenyl)piperidine (5d). Yield 66%; m.p. 159e61 ꢁC;
4.1.2.3. (E)-1-(5-Methyl-1-p-tolyl-1H-1,2,3-triazol-4-yl)-3-(4-(piper-
IR (KBr) nmax/cmꢀ1 3336 (NH); 1H NMR (DMSO-d6)
d 1.48e1.56 (m,
idin-1-yl)phenyl)prop-2-en-1-one (3d). Yield 68%; m.p.153e4 ꢁC; IR
6H, piperidine), 2.35 (s, 3H, CH3), 2.45 (s, 3H, CH3), 3.08e3.37 (m,
4H, piperidine), 3.38, 3.41 (dd, 1H, CH, J ¼ 10.7 Hz, J ¼ 9.95 Hz), 4.03,
4.05 (dd, 1H, CH, J ¼ 10.7 Hz, J ¼ 10.7 Hz), 5.93 (t, 1H, CH, J ¼ 10.7 Hz,
J ¼ 9.95 Hz), 7.38e7.57 (m, 8H, AreH), 10.19 (s, 1H, NH, D2O-
exchangeable); MS m/z (%): 400 (Mþ, 11), 56 (100).
(KBr) nmax/cmꢀ1 1661 (C]O); 1H NMR (DMSO-d6)
d 1.48e1.56 (m,
6H, piperidine), 3.37e3.42 (m, 4H, piperidine), 2.35 (s, 3H, CH3),
2.46 (s, 3H, CH3), 6.85 (d, 1H, CH, J ¼ 17.8 Hz), 7.46 (d, 1H, CH,
J ¼ 18.0 Hz), 7.16e7.49 (m, 8H, AreH); MS m/z (%): 386 (Mþ, 16), 132
(100).
4.1.4. General procedure for the preparation of 7aec and 8
4.1.3. General procedure for the preparation of 5aed
A mixture of 5aed (2 mmol) and phenyl isothiocyanate
To a solution of appropriate chalcones 3aed (2 mmol) in ethanol
(30 ml), hydrazine hydrate 80% (5 mmol) was added. The reaction
mixture was refluxed for 6 h. Left to cool to room temperature, and
the formed solid product was filtered and washed with ethanol.
(2 mmol, 0.27 g) {or benzoylisothiocyanate (2 mmol, 0.33 g) in case
of 8} in dry ethanol (30 ml) was refluxed for 5 h. Cool to the room
temperature and the formed solid product was collected by filtra-
tion to give products 7aec or 8.
4.1.3.1. 5-Methyl-4-(5-phenyl-4,5-dihydro-1H-pyrazol-3-yl)-1-p-tolyl-
4.1.4.1. 3-(5-Methyl-1-p-tolyl-1H-1,2,3-triazol-4-yl)-N,5-diphenyl-
1H-1,2,3-triazole (5a). Yield 55%; m.p. 139e40 ꢁC; IR (KBr) nmax
/
4,5-dihydro-1H-pyrazole-1-carbothioamide (7a). Yield 55%; m.p.
cmꢀ1 3334 (NH); 1H NMR (DMSO-d6)
d
2.33 (s, 3H, CH3), 2.46 (s, 3H,
197e9 ꢁC; 1H NMR (DMSO-d6)
d 2.39 (s, 3H, CH3), 2.47 (s, 3H, CH3),
CH3), 2.89, 2.93 (dd, 1H, CH, J ¼ 10.7 Hz, J ¼ 9.95 Hz), 3.54, 3.56 (dd,
1H, CH, J ¼ 10.7 Hz, J ¼ 10.7 Hz), 4.80 (t, 1H, CH, J ¼ 10.7 Hz,
J ¼ 9.95 Hz), 7.13e7.43 (m, 9H, AreH), 10.19 (s, 1H, NH, D2O-
exchangeable); MS m/z (%): 317 (Mþ, 9), 65 (100).
3.02, 3.24 (dd, 1H, CH, J ¼ 15.3 Hz, J ¼ 6.9 Hz), 4.08, 4.10 (dd, 1H, CH,
J ¼ 15.3 Hz, J ¼ 6.9 Hz), 6.03 (t, 1H, CH, J ¼ 3.05 Hz, J ¼ 8.04 Hz),
7.15e7.48 (m, 14H, AreH), 9.85 (s, 1H, NH, D2O-exchangeable); MS
m/z (%): 452 (Mþ, 19), 77 (100).
4.1.3.2. 4-(5-(4-Fluorophenyl)-4,5-dihydro-1H-pyrazol-3-yl)-5-methyl-
4.1.4.2. 5-(4-Fluorophenyl)-3-(5-methyl-1-p-tolyl-1H-1,2,3-triazol-
4-yl)-N-phenyl-4,5-dihydro-1H-pyrazole-1-carbothioamide
1-p-tolyl-1H-1,2,3-triazole (5b). Yield 68%; m.p. 135e6 ꢁC; IR (KBr)
nmax/cmꢀ1 3336 (NH); 1H NMR (DMSO-d6)
d
2.33 (s, 3H, CH3), 2.46
(7b). Yield 52%; m.p. 155e7 ꢁC; 1H NMR (DMSO-d6)
d 2.39 (s, 3H,
(s, 3H, CH3), 2.91, 2.94 (dd, 1H, CH, J ¼ 10.7 Hz, J ¼ 9.95 Hz), 3.53,
3.55 (dd, 1H, CH, J ¼ 10.7 Hz, J ¼ 10.7 Hz), 4.82 (t,1H, CH, J ¼ 10.7 Hz,
J ¼ 9.95 Hz), 7.14e7.43 (m, 8H, AreH), 10.11 (s, 1H, NH, D2O-
exchangeable); MS m/z (%): 335 (Mþ, 8), 65 (100).
CH3), 2.47 (s, 3H, CH3), 3.02, 3.24 (dd,1H, CH, J ¼ 15.3 Hz, J ¼ 6.9 Hz),
4.08, 4.10 (dd, 1H, CH, J ¼ 15.3 Hz, J ¼ 6.9 Hz), 6.03 (t, 1H, CH,
J ¼ 3.05 Hz, J ¼ 8.04 Hz), 7.15e7.48 (m, 13H, AreH), 9.85 (s, 1H, NH,
D2O-exchangeable); MS m/z (%): 470 (Mþ, 20), 77 (100).
4.1.3.3. 4-(3-(5-Methyl-1-p-tolyl-1H-1,2,3-triazol-4-yl)-4,5-dihydro-
4.1.4.3. 3-(5-Methyl-1-p-tolyl-1H-1,2,3-triazol-4-yl)-N-phenyl-5-(4-
(piperidin-1-yl)phenyl)-4,5-dihydro-1H-pyrazole-1-carbothioamide
1H-pyrazol-5-yl)benzonitrile (5c). Yield 65%; m.p. 168e70 ꢁC; IR
(KBr) nmax/cmꢀ1 2224 (CN), 3336 (NH); 1H NMR (DMSO-d6)
d
2.35
(7c). Yield 53%; m.p. 168e70 ꢁC; 1H NMR (DMSO-d6)
d 1.48e1.56

B.F. Abdel-Wahab et al. / European Journal of Medicinal Chemistry 52 (2012) 263e268
267
(m, 6H, piperidine), 2.39 (s, 3H, CH3), 2.47 (s, 3H, CH3), 3.08e3.37
(m, 4H, piperidine), 3.39, 3.41 (dd, 1H, CH, 10.7 Hz,
J ¼ 6.85 Hz), 4.08, 4.10 (dd, 1H, CH, J ¼ 10.7 Hz, J ¼ 6.85 Hz), 5.93 (t,
1H, CH, J ¼ 3.05 Hz, J ¼ 8.04 Hz), 7.15e7.48 (m, 13H, AreH), 10.19 (s,
1H, NH, D2O-exchangeable); MS m/z (%): 535 (Mþ, 20), 56 (100).
(m, 12H, AreH); MS m/z (%): 574 (Mþ þ 2, 28), 573 (Mþ þ 1, 18), 572
J
¼
(Mþ, 38), 91 (100).
4.1.6.4. 2-(5-(4-Fluorophenyl)-3-(5-methyl-1-p-tolyl-1H-1,2,3-triazol-
4-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazol-4(5H)-one
58%; m.p. 228e30 ꢁC; IR (KBr) nmax/cmꢀ1 1671 (C]O); 1H NMR
(DMSO-d6) 2.38 (s, 3H, CH3), 2.45 (s, 3H, CH3), 3.90 (s, 2H, thia-
(12). Yield
4.1.4.4. N-(3-(5-Methyl-1-p-tolyl-1H-1,2,3-triazol-4-yl)-5-(4-(piper-
idin-1-yl)phenyl)-4,5-dihydro-1H-pyrazole-1-carbonothioyl)benza-
mide (8). Yield 69%; m.p. 178e80 ꢁC; 1H NMR (DMSO-d6)
d
zolidinone-CH2) 3.17, 3.18 (dd, 1H, CH, J ¼ 11.45 Hz, J ¼ 3.05 Hz),
3.99, 4.03 (dd, 1H, CH, J ¼ 11.45 Hz, J ¼ 3.05 Hz), 5.91 (t, 1H, CH,
J ¼ 3.05 Hz, J ¼ 7.65 Hz), 7.13e7.43 (m, 9H, AreH), MS m/z (%): 434
(Mþ ꢀ 1, 6) 433 (Mþ, 16), 91 (100).
d
1.48e1.56 (m, 6H, piperidine), 2.39 (s, 3H, CH3), 2.47 (s, 3H, CH3),
3.08e3.37 (m, 4H, piperidine), 3.39, 3.41 (dd, 1H, CH, J ¼ 10.7 Hz,
J ¼ 6.85 Hz), 4.08, 4.10 (dd, 1H, CH, J ¼ 10.7 Hz, J ¼ 6.85 Hz), 5.93 (t,
1H, CH, J ¼ 3.05 Hz, J ¼ 8.04 Hz), 6.85e7.90 (m, 13H, AreH), 10.97 (s,
1H, NH, D2O-exchangeable); MS m/z (%): 564 (Mþ þ 1, 50), 70 (100).
4.2. X-ray crystallography
A single crystal of compound 11b was obtained by slow evapo-
ration at room temperature, from dimethylformamide (DMF). The
crystal structure was solved and refined using MaXus (Bruker
Nonius, Deflt and MacScience, Japan) [29] Mo Ka radiation
4.1.5. 5-(4-Fluorophenyl)-3-(5-methyl-1-p-tolyl-1H-1,2,3-triazol-
4-yl)-4,5-dihydro-1H-pyrazole-1-carbothioamide (9)
To a suspension of chalcone 3b (10 mmol, 3.21 g) and sodium
hydroxide (25 mmol, 1.0 g) in ethanol (50 ml), thiosemicarbazide
(12 mmol, 1.1 g) was added. The mixture was refluxed for 6 h, then
left to cool; the solid product was filtered off, washed with ethanol
and dried.
(
l
¼ 0.71073 Ǻ) and a graphite monochromator were used for data
collection. The chemical formula and ring labeling system is shown
in Fig. 1. Crystal data for compound 11b: C28H22ClFN6S, Mr, 529.041;
system, orthorhombic; space group, P212121; unit cell dimensions, a,
Yield 46%; m.p. 240e2 ꢁC; IR (KBr) nmax/cmꢀ1 3475, 3345 (NH2);
11.4339 (2) Å; b,14.1131 (4) Å; c,16.0647 (4) Å; a b g,
, 90.00ꢁ; , 90.00ꢁ;
1H NMR (DMSO-d6)
d
2.38 (s, 3H, CH3), 2.45 (s, 3H, CH3), 3.14, 3.17
90.00ꢁ; V, 2592.32 (11) Å3; Z, 4; Dx, 1.356 Mg mꢀ3
; q range for data
(dd, 1H, CH, J ¼ 3.05 Hz, J ¼ 3.05 Hz), 3.99, 4.03 (dd, 1H, CH,
collection, 2.910e27.485ꢁ;
m
(Mo-Ka), 0.27 mmꢀ1; T ¼ 298 K; inde-
J ¼ 11.45 Hz, J ¼ 11.5 Hz), 5.90 (t, 1H, CH, J ¼ 3.05 Hz, J ¼ 7.65 Hz),
pendent reflections, 3705; measured reflections, 5953; observed
reflections, 1934; Rint, 0.025; R(all), 0.087; R(gt), 0.035; wR(ref),
0.061; wR(all), 0.078; wR(gt), 0.061; S(ref), 1.464; S(all), 1.802; S(gt),
7.13e7.43 (m, 9H, AreH), 8.09 (s, 2H, NH2, D2O-exchangeable);13
C
NMR (DMSO-d6):
d 10.25, 14.46, 19.88, 21.27, 39.71, 39.87, 40.20,
40.36, 41.24, 55.39, 56.41, 75.98, 87.79, 88.55, 93.12, 100.74, 106.17,
109.82, 113.32, 120.18, 125.84, 130.55, 133.58, 135.95, 140.12, 141.13,
152.95, 155.38, 163.63, 168.017, 176.96; MS m/z (%): 394 (Mþ, 36), 91
(100).
1.464;
D/
smax, 0.043, Drmax, 0. 0.48 e Å3; Drmin ꢀ0.45 e Å3.
Crystallographic data for the structures 11b have been deposited
with the Cambridge Crystallographic Data Center (CCDC) under the
number 858991. Copies of the data can be obtained, free of charge,
on application to CCDC 12 Union Road, Cambridge CB2 1EZ, UK
[Fax: þ44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk or at
www.ccdc.cam.ac.uk].
4.1.6. General procedure for the preparation of 11aec and 12
To a suspension of compound 9 (1 mmol, 0.39 g) in ethanol
(15 ml) the appropriate 1-aryl-2-bromoethanones 10aec (1 mmol)
{or ethyl chloroacetate (1 mmol, 0.12 g) in case of 12} was added
and heated under reflux for 1.5 h. After cooling, the precipitate was
collected by suction filtration.
4.3. Antimicrobial activity
Chemical compounds were individually tested against a panel of
gram positive and gram negative bacterial pathogens, yeast and
fungi. Antimicrobial tests were carried out by the agar well diffu-
4.1.6.1. 2-(5-(4-Fluorophenyl)-3-(5-methyl-1-p-tolyl-1H-1,2,3-triazol-
4-yl)-4,5-dihydro-1H-pyrazol-1-yl)-4-phenylthiazole
(11a). Yield
sion method [30] using 100 mL of suspension containing
86%; m.p. 196e8 ꢁC; 1H NMR (DMSO-d6)
d
2.40 (s, 3H, CH3), 2.46 (s,
1 ꢂ108 CFU/ml of pathological tested bacteria and 1 ꢂ106 CFU/ml of
yeast spread on nutrient agar (NA) and Sabourand dextrose agar
(SDA) respectively. After the media had cooled and solidified, wells
(10 mm in diameter) were made in the solidified agar and loaded
3H, CH3), 3.39, 3.41 (dd, 1H, CH, J ¼ 11.45 Hz, J ¼ 12.25 Hz), 4.15, 4.10
(dd, 1H, CH, J ¼ 11.45 Hz, J ¼ 10.33 Hz), 5.64 (t, 1H, CH, J ¼ 5.35 Hz,
J ¼ 6.1 Hz), 7.25 (s, 1H, thiazole-H), 7.29e7.51 (m, 13H, AreH); 13C
NMR (DMSO-d6):
d
10.25, 14.46, 21.27, 125.84, 130.55, 133.11, 133.58,
with 100 mL of tested compound solution prepared by dissolving
140.12, 140.22, 142.23, 145.75, 168.023; MS m/z (%): 494 (Mþ, 12), 91
100 mg of the chemical compound in one ml of dimethyl sulfoxide
(DMSO). The inculcated plates were then incubated for 24 h at 37 ꢁC
for bacteria and 48 h at 28 ꢁC for fungi. Negative controls were
prepared using DMSO employed for dissolving the tested
(100).
4.1.6.2. 4-(4-Chlorophenyl)-2-(5-(4-fluorophenyl)-3-(5-methyl-1-p-
tolyl-1H-1,2,3-triazol-4-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazole
compound. Ciprofloxacin (50 mg/ml) and Ketoconazole (50 mg/ml)
(11b). Yield 88%; m.p. 205e7 ꢁC; 1H NMR (DMSO-d6)
d
2.40 (s, 3H,
were used as standard for antibacterial and antifungal activity
respectively. After incubation time, antimicrobial activity was
evaluated by measuring the zone of inhibition against the test
organisms and compared with that of the standard. The observed
zone of inhibition is presented in Table 1. Antimicrobial activities
were expressed as inhibition diameter zones in millimeters (mm).
The experiment was carried out in triplicate and the average zone
of inhibition was calculated.
CH3), 2.46 (s, 3H, CH3), 3.39, 3.41 (dd, 1H, CH, J ¼ 11.45 Hz,
J ¼ 12.25 Hz), 4.15, 4.10 (dd, 1H, CH, J ¼ 11.45 Hz, J ¼ 10.33 Hz), 5.64
(t, 1H, CH, J ¼ 5.35 Hz, J ¼ 6.1 Hz), 7.27 (s, 1H, thiazole-H), 7.30e7.56
(m, 12H, AreH); MS m/z (%): 530 (Mþ þ 1, 38), 529 (Mþ, 38), 528
(Mþ ꢀ 1, 78), 91 (100).
4.1.6.3. 4-(4-Bromophenyl)-2-(5-(4-fluorophenyl)-3-(5-methyl-1-p-
tolyl-1H-1,2,3-triazol-4-yl)-4,5-dihydro-1H-pyrazol-1-yl)thiazole
(11c). Yield 87%; m.p. 224e5 ꢁC; 1H NMR (DMSO-d6)
d
2.40 (s, 3H,
4.4. Minimal inhibitory concentration (MIC) measurement
CH3), 2.46 (s, 3H, CH3), 3.39, 3.41 (dd, 1H, CH, J ¼ 11.45 Hz,
J ¼ 12.25 Hz), 4.15, 4.10 (dd, 1H, CH, J ¼ 11.45 Hz, J ¼ 10.33 Hz), 5.64
(t, 1H, CH, J ¼ 5.35 Hz, J ¼ 6.1 Hz), 7.27 (s, 1H, thiazole-H), 7.30e7.56
The bacteriostatic activity of the active compounds (having
inhibition zones (IZ) ꢃ 16 mm) was then evaluated using the two

268
B.F. Abdel-Wahab et al. / European Journal of Medicinal Chemistry 52 (2012) 263e268
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fold serial dilution technique [31]. Two fold serial dilutions of the
tested compounds solutions were prepared using the proper
nutrient broth. The final concentration of the solutions was 132; 66;
33; 16.5; and 8.25 mg/ml. The tubes were then inoculated with the
test organisms, grown in their suitable broth at 37 ꢁC for 24 h for
bacteria (about 1 ꢂ 108 CFU/ml), each 5 ml received 0.1 ml of the
above inoculum and incubated at 37 ꢁC for 24 h. The lowest
concentration showing no growth was taken as the minimum
inhibitory concentration (MIC).
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Appendix A. Supplementary data
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[20] B.F. Abdel-Wahab, H.A. Mohamed, J. Sulfur Chem. 32 (2011) 543e556.
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Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.ejmech.2012.03.023.
[22] B.F. Abdel-Wahab, G.E.A. Awad, F.A. Badria, Eur. J. Med. Chem. 46 (2011)
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