Design and synthesis of some substituted 1H-pyrazolyl-oxazolidines or 1H-pyrazolyl-thiazolidines as anti-inflammatory-antimicrobial agents

Article abstract of DOI:10.1002/ardp.200390007

Four series of 1H-pyrazole derivatives have been synthesized. The first series was synthesized starting with the reaction of 3-(5-bromo-2-thienyl)-1 -phenyl-1H-pyrazole-4-carboxaldehyde 1 with L-serine, L-cysteine, or L-penicillamine, followed by N-protection using (Boc)_2O to provide compounds 2. The latter compounds could be N-deprotected by 4N HCl/dioxane to afford the second series 3, or reacted with NH₄OH in the presence of DCC/HOBt to give the corresponding amides 4, followed by N-deprotection giving rise to compounds 5. The newly synthesized compounds were evaluated for their anti-inflammatory-antimicrobial activities. In addition, the ulcerogenic and acute toxicity profiles were determined. Compound 5 b, (2RS, 4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-1H- pyrazol-4-yl]-5-methylthiazolidine-4-carboxamide, proved to be the most active anti-inflammatory-antimicrobial agent in the present study with a good safety margine and no ulcerogenic effect.

Full text of DOI:10.1002/ardp.200390007

Arch. Pharm. Pharm. Med. Chem. 2003, 2, 111–118
1H-Pyrazolyl-thiazolidines 111
Adnan A. Bekhit,
Hesham T.Y. Fahmy
Design and Synthesis of Some Substituted
1H-Pyrazolyl-oxazolidines or
1H-Pyrazolyl-thiazolidines as
Department of Pharmaceutical
Chemistry,
Faculty of Pharmacy,
University of Alexandria,
Alexandria, Egypt
Anti-inflammatory-Antimicrobial Agents
Four series of 1H-pyrazole derivatives have been synthesized.The first series was
synthesized starting with the reaction of 3-(5-bromo-2-thienyl)-1-phenyl-1H-pyr-
azole-4-carboxaldehyde 1 with L-serine, L-cysteine, or L-penicillamine, followed by
N-protection using (Boc)2O to provide compounds 2.The latter compounds could be
N-deprotected by 4N HCl/dioxane to afford the second series 3, or reacted with
NH4OH in the presence of DCC/HOBt to give the corresponding amides 4, followed
by N-deprotection giving rise to compounds 5.The newly synthesized compounds
were evaluated for their anti-inflammatory-antimicrobial activities. In addition, the
ulcerogenic and acute toxicity profiles were determined. Compound 5 b, (2RS,4R)-
2-[3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazol-4-yl]-5-methylthiazolidine-4-carb-
oxamide, proved to be the most active anti-inflammatory-antimicrobial agent in the
present study with a good safety margine and no ulcerogenic effect.
Keywords: Pyrazole; Oxazolidine; Thiazolidine; Anti-inflammatory; Antimicrobial
Received: June 28, 2002 [FP709]
pyrazoles as antimicrobial [7, 8], antiviral [9, 10], and an-
ticancer [11, 12] agents after the discovery of the natural
Introduction
Identification of novel compounds which treat both infec-
tious and inflammatory states more effectively, and
which lack side effects associated with current therapies
remains a major challenge in biomedical research. The
use of several drugs to treat inflammatory conditions as-
sociated with infection is a problem, especially in the
case of patients with impaired liver or kidney functions or
when it is necessary to avoid drug-drug interaction. In
addition, from the pharmacoeconomic cost-effective
stand-point, and seeking better patient compliance, a
dual anti-inflammatory-antimicrobial agent with mini-
mum adverse effects and high safety margin is highly de-
sirable.This prompted us to try to find agents that have a
dual effect as anti-inflammatory-antimicrobial agents.
Compounds containing pyrazole or thiophene function-
ality have been reported to exhibit anti-inflammatory ac-
tivity [1–5]. In addition, among the already marketed cy-
clooxygenase-2 (COX-2) inhibitors that comprise the
pyrazole nucleus, celecoxib (Figure 1) occupies a
unique position as a potent and gastrointestinal (GI) safe
anti-inflammatory and analgesic agent. It is considered
as a typical model of the diaryl heterocycles template
that is known to selectively inhibit the COX-2 enzyme [6].
On the other hand, much attention has been focussed on
pyrazole C-glycoside pyrazofurin (Figure 1). This anti-
biotic was reported to possess a broad spectrum of anti-
microbial and antiviral activities in addition to being ac-
tive against several tumor cell lines [13]. Furthermore,
the antimicrobial activities of thiazolidine derivatives are
well-documented [14, 15]. We previously reported [16]
the anti-inflammatory and the antimicrobial activities of
Correspondence: Adnan A. Bekhit, Department of
Pharmaceutical Chemistry, Faculty of Pharmacy, University of
Alexandria, Alexandria 21521, Egypt. Phone +20 3 4871317,
fax: +20 3 4873273, e-mail: adnbekhit@hotmail.com.
Figure 1
© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
0365-6233/02/0111 $ 17.50+.50/0

112 Bekhit et al.
Arch. Pharm. Pharm. Med. Chem. 2003, 336, 111–118
the lead compounds 3-(5-bromo-2-thienyl)-1-phenyl-
4-(3-substituted-4-oxothiazolidin-2-ylidenehydrazono-
methyl)-1H-pyrazoles as hybrid compounds between
thiazolidine and 1H-pyrazole. Motivated by these find-
ings, and as a continuation of our investigations in the
field of pyrazole chemistry [16–18], it was decided to
synthesize novel series of pyrazole derivatives having in
their structure the thienylpyrazole functionality attached
to either the oxazolidine A or the thiazolidine B moiety
(Figure 1), in order to investigate the effect of such mo-
lecular variation on the anti-inflammatory-antimicrobial
activities. It should be pointed out that, in addition to the
targeted anti-inflammatory and antimicrobial activities,
the ulcerogenic and acute toxicity profiles of the newly
synthesized compounds were determined. The results
revealed that some derivatives showed promising activi-
ties.
Results and Discussion
Chemistry
For the synthesis of the desired compounds, Scheme 1
was adopted. The key intermediate 3-(5-bromo-2-
thienyl)-1-phenyl-1H-pyrazole-4-carboxaldehyde 1 was
prepared by applying the Vilsmeier-Haack reaction [16,
19].The desired series of compounds 2 was synthesized
starting by the reaction of 1 with either L-serine in the
presence of 2N NaOH at 5 °C for 24 h [20], or with L-
cysteine or L-penicillamine under reflux in aqueous eth-
anol [21], followed by N-protection [22] using (Boc)2O.
Compounds 2 were either subjected to N-deprotection
using 4N HCl/dioxane giving rise to series 3 or allowed to
react with NH4OH in the presence of DCC/HOBt to afford
the corresponding amides 4.The latter series upon sub-
jected to N-deprotection afforded series 5. It is worth
Scheme 1

Arch. Pharm. Pharm. Med. Chem. 2003, 336, 111–118
1H-Pyrazolyl-thiazolidines 113
mentioning that all trials to separate diastereomers went
in vain. In 2,4-disubstituted thiazolidines, the cis and
trans diastereomers freely interconvert in solutions [23].
The ratio of diastereomers observed for compounds in
the present study was 1:1 based on 1H NMR spectrosco-
py. Diastereomerization occurs at the C-2 center via an
iminium intermediate [21].This property prevents the in-
dependent examination of the biological activity of the
two diastereomers; hence, the structures will be drawn
and discussed throughout this paper as a diastereomer-
ic mixture.
Acute toxicity
Compounds 2 a–b, 3 a, 4 a–b, and 5 a–b, were further
evaluated for their approximate LD50 in male mice using
the method described in the literature [26, 27]. The re-
sults (Table 1) indicated that most of the tested com-
pounds proved to be non-toxic and well tolerated by the
experimental animals as evidenced by their LD50 values
(>500 mg/kg). Moreover, these compounds were tested
for their toxicity through the parenteral route. A modified
method of Klang was used [28].The results revealed that
all the test compounds were non-toxic up to 100 mg/kg.
Table 1. Anti-inflammatory activity (ED50, µmol)a and ul-
Biological screening
cerogenic activitya, LD50 of the test compounds.
Anti-inflammatory activity
The anti-inflammatory activity of the synthesized com-
pounds 2–5 was evaluated applying the cotton-pellet
granuloma bioassay in rats [24] using indomethacin as a
reference standard. The ED50 values were determined
for each compound. Data were expressed as the mean
SEM. Significant difference between the control and
the treated groups was performed using Student’s t-test
and P values. The difference in results was considered
significant when P > 0.001 (Table 1). In general, com-
pounds having an oxazolidine or thiazolidine moiety
2 a, b; 3 a, b; 4 a, b; 5 a, b (ED50 = 8.97–11.75 µmol, ex-
cept 3 b = 13.68 µmol) are more active than compounds
having a dimethylthiazolidine moiety 2 c, 3 c, 4 c, 5 c
(ED50 = 13.00–15.76 µmol) as anti-inflammatory agents.
Compounds 2 a, 4 a, 4b, 5 a, 5b (ED50 = 8.97–9.57 µmol)
have anti-inflammatory activity comparable to that of in-
domethacin (ED50 = 8.79 µmol).Compound 5 b proved to
be the most active anti-inflammatory agent in the
present study (ED50 = 8.97 µmol).
Test compound
ED50
[µmol]
%
LD50
Ulceration [mg/kg]
Indomethacin
8.79
9.43
100
2 a
2 b
2 c
3 a
3 b
3 c
4 a
4 b
4 c
5 a
5 b
5 c
80
80
>500
>500
ND
>500
ND
11.75
13.00
10.10
13.68
14.82
9.56
9.57
15.76
9.23
NDb
80
ND
ND
10
0.0
ND
0.0
0.0
ND
ND
>500
>500
ND
>500
>500
ND
8.97
14.82
a
All data are significantly different from control
(P > 0.001).
Not determined.
b
Ulcerogenic effects
Compounds 2 a–b, 3 a, 4 a–b, and 5 a–b, which exhibit-
ed anti-inflammatory activity comparable to that of in-
domethacin, were evaluated for their ulcerogenic poten-
tial in rats [25]. All the test compounds proved to have a
superior GI safety profiles (0–80 % ulceration) in the
population of the test animals at the oral doses of
30 µmol/kg per day, when compared with indomethacin;
the reference drug; which was found to cause 100 %
ulceration under the same experimental conditions (Ta-
ble 1). Compounds having the free carboxylic group
2 a–c and 3 a–c showed a high ulcerogenic effect (80 %
ulceration), but still lower than that of indomethacin
(100 % ulceration). Gross observation of the isolated rat
stomachs showed a normal stomach texture for most of
the carboxamide derivatives 4 b and 5 a, b (0 % ulcera-
tion).
Antimicrobial activity
The designed compounds 2–5 have been evaluated for
their antimicrobial activity.The microdilution susceptibili-
ty test in Müller-Hinton Broth (Oxoid) and Sabouraud
Liquid Medium (Oxoid) were used for the determination
of antibacterial and antifungal activity [29]. The minimal
inhibitory concentration (MIC) listed in (Table 2) showed
that all the test compounds have antifungal activity lower
than that of Clotrimazole (Canesten®, Bayer). The test
compounds are more active against S.aureus than
E. coli.Compound 3 c have antimicrobial activity against
S. aureus comparable to that of ampicillin, while the ac-
tivity of compounds 5 b, 5 c is about 50 % of that of ampi-
cillin.

114 Bekhit et al.
Arch. Pharm. Pharm. Med. Chem. 2003, 336, 111–118
(2RS,4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazol-4-yl]-
3-(tert-butyloxycarbonyl)oxazolidine-4-carboxylic acid 2 a
Table 2. Minimal inhibitory concentration (MIC) of test
compounds in µg/mL.
To a solution of L-serine (1.05 g, 10 mmol) in ethanol (20 mL)
were added 2N NaOH (5 mL) and pyrazole aldehyde 1 (3.33 g,
10 mmol) in ethanol (10 mL).The reaction mixture was stirred at
5 °C for 24 h.The pH was adjusted to 9.5 with conc.HCl and the
mixture was then treated with a solution of (Boc)2O (2.34 g,
11 mmol) in 5 mL dioxane. After stirring for 5 h at room temper-
ature, the reaction mixture was diluted with water and washed
with ether (2 × 15 mL). The aqueous phase was acidified with
crystalline citric acid and extracted by ethyl acetate (3 × 15 mL).
The combined organic extract was evaporated under vacuum
and the residue was crystallized from aqueous ethanol (seeTa-
ble 3).
Test compound
E. coli
S. aureus
C. albicans
Ampicilin
Clotrimazole
25
12.5
12.5
>200
>200
>200
100
>200
200
>200
>200
>200
100
2 a
2 b
2 c
3 a
3 b
3 c
4 a
4 b
4 c
5 a
5 b
5 c
>200
200
200
>200
100
100
>200
200
100
200
50
>200
100
25
>200
50
12.5
>200
100
50
>200
25
(2RS,4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazol-4-yl]-
3-(tert-butyloxycarbonyl)-5-methylthiazolidine-4-carboxylic acid
2 b or (2RS,4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazol-
4-yl]-3-(tert-butyloxycarbonyl)-5,5-dimethylthiazolidine-4-
carboxylic acid 2 c
L-Cysteine or L-penicillamine (10 mmol) and pyrazole alde-
hyde 1 (3.33 g, 10 mmol) were suspended in 60 % aqueous
ethanol (20 mL), the mixture was heated under reflux for 5 h,
then cooled and concentrated under vacuum. The resulted
slurry was treated with 2N NaOH (6 mL) and (Boc)2O (2.34 g,
11 mmol) in 5 mL dioxane.After stirring for 5 h at room tempera-
ture, the reaction mixture was diluted with water and washed
with ether (2 × 15 mL). The aqueous phase was acidified with
crystalline citric acid and extracted by ethyl acetate (3 × 15 mL).
The combined organic extract was evaporated under vacuum
and the residue was crystallized from ethyl acetate/n-hexane
(see Table 3).
>200
50
200
25
It can be safely concluded that compound 5 b proved to
be the most active anti-inflammatory-antimicrobial agent
in the present study with no ulcerogenic effect and good
safety margine.Its anti-inflammatory activity is compara-
ble to that of indomethacin (ED50 = 8.97 µmol), no ulcero-
genic effect and LD50 = >500 mg. In addition, the antimi-
crobial activity against S. aureus and E. coli is about
50 % of that of ampicillin.
(2RS,4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazol-4-yl]-
oxazolidine-4-carboxylic acid 3 a, (2RS,4R)-2-[3-(5-bromo-2-
thienyl)-1-phenyl-1H-pyrazol-4-yl]-5-methylthiazolidine-4-car-
boxylic acid 3 b or (2RS,4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-
1H-pyrazol-4-yl]-5,5-dimethylthiazolidine-4-carboxylic acid 3 c
Acknowledgment
To a solution of the appropriate 2 (5.2 mmol) in 4N HCl/Dioxane
(10 mL), anisole (10.4 mmol, 1.1 mL) was added at 0 °C. The
reaction mixture was stirred for 1 h at room temperature. The
solvent was removed in vacuo at room temperature, ether was
added, and the mixture was centrifuged.The obtained product
was crystallized from aqueous ethanol (see Table 3).
The authors wish to thank Ji Young Park, College of
Pharmacy, Sookmyung Women’s University, Seoul
140-742, South Korea and Alaa El-Din A.Bekhit, Depart-
ment of Food Science and Technology, Faculty of Agri-
culture, University of Alexandria, for their assistance dur-
ing the biological screening.
(2RS,4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazol-4-yl]-
3-(tert-butyloxycarbonyl)oxazolidine-4-carboxamide 4 a,
(2RS,4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazol-4-yl]-
3-(tert-butyloxycarbonyl)-5-methylthiazolidine-4-carboxamide
4 b or (2RS,4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazol-
4-yl]-3-(tert-butyloxycarbonyl)-5,5-dimethylthiazolidine-4-car-
boxamide 4 c
Experimental part
Chemistry
Follow up of the reactions and checking the homogeneity of the
compounds were by TLC on silica gel-protected aluminum
sheets (Type 60 F254, Merck) and the spots were detected by
exposure to a UV lamp at λ 254 nm for a few seconds. Melting
points were determined in open glass capillaries using a Tho-
mas capillary melting point apparatus and are uncorrected. –
IR spectra were recorded on 470-Shimadzu infrared spectro-
photometer. 1H NMR spectra were obtained on Varian XL-
200 MHz Spectrometer, and the chemical shifts are given in
δ (ppm) down field from tetramethylsilane (TMS) as an internal
standard. Elemental analysis were performed at the Micro-
analytical Unit, Faculty of Science, Cairo University, Cairo,
Egypt, and were found within 0.4 % of the theoretical values.
To a solution of the selected acid 2 a–c (10 mmol) in DMF
(15 mL), HOBt · H2O (1.84 g, 12 mmol) and DCC. HCl (2.48 g,
12 mmol) were added while stirring at 0 °C, and the mixture was
further stirred at 0 °C for 1 h. Ammonium hydroxide solution
(28 %, 1.56 mL, 40 mmol) was added and the mixture stirred
overnight at room temperature. The mixture was filtered, and
the filtrate was evaporated under reduced pressure and ex-
tracted with AcOEt. The organic layer was washed with 10 %
citric acid, 5 % NaHCO3 and brine, dried over anhydrous
Na2SO4, and filtered. The filtrate was evaporated under re-
duced pressure and the residue was crystallized from ethyl ac-
etate/n-hexane (Table 3).

Arch. Pharm. Pharm. Med. Chem. 2003, 336, 111–118
1H-Pyrazolyl-thiazolidines 115
Table 3. Physical and analytical data of compounds 2–5.
Comp. Yield
Mp
[°C]
Mol. Formula
(Mol. wt.)
IR
1H NMR
(CDCl3)
No.
[%]
(KBr) [cm–1]
2 a
78 172–174 C22H22BrN3O5S
(520.39)
3366 (br., OH),
1.39 (s, 9 H, butyl (CH3)3), 3.26–3.86 (m, 2 H,
1732 (C=O), 1715 oxazol C-5-H), 4.60 (t, J = 7.80, 1 H, oxazol
(C=O), 1635
(C=N), 1204,
1138 (C-O-C)
C-4-H), 6.21 (s, 0.5 H, oxazol C-2-H), 6.30 (s,
0.5 H, oxazol C-2-H), 7.12 (d, J = 3.96 Hz,
1 H, thioph C-3-H), 7.32–7.78 (m, 6 H, phenyl-
H, thioph C-4-H), 8.41 (s, 1 H, pyrazol C-5-H).
2 b
76 183–185 C22H22BrN3O4S2
(536.46)
3372 (br., OH),
1.38 (s, 9 H, butyl (CH3)3), 3.22–3.77 (m, 2 H,
1737 (C=O), 1715 thiazol C-5-H), 4.52 (t, J = 7.80, 1 H, thiazol
(C=O), 1632
(C=N), 1210,
1136 (C-O-C)
C-4-H), 6.06 (s, 0.5 H, thiazol C-2-H), 6.16 (s,
0.5 H, thiazol C-2-H), 7.10 (d, J = 3.96 Hz,
1 H, thioph C-3-H), 7.34–7.82 (m, 6 H, phenyl-
H, thioph C-4-H), 8.43 (s, 1 H, pyrazol C-5-H).
2 c
81 187–189 C24H26BrN3O4S2
(564.52)
3368 (br., OH),
1.40 (s, 12 H, butyl (CH3)3, thiazol C-5- CH3),
1734 (C=O), 1710 1.62 (s, 3 H, thiazol C-5- CH3), 4.10 (s, 1 H,
(C=O), 1630
(C=N), 1206,
1132 (C-O-C)
thiazol C-4- H), 6.04 (s, 0.5 H, thiazol C-2-H),
6.13 (s, 0.5 H, thiazol C-2-H), 7.11 (d, J =
3.96 Hz, 1 H, thioph C-3-H), 7.31–7.82 (m,
6 H, phenyl-H, thioph C-4-H), 8.42 (s, 1 H,
pyrazol C-5-H).
3 a
3 b
3 c
4 a
86 178–180 C17H14BrN3O3S
(420.28)
3371 (br., OH),
3176 (NH), 1715
(C=O), 1635
(C=N)
3.24–3.82 (m, 2 H, oxazol C-5-H), 4.52 (t, J =
7.80, 1 H, oxazol C-4-H), 6.18 (s, 0.5 H, oxazol
C-2-H), 6.27 (s, 0.5 H, oxazol C-2-H), 7.13 (d,
J = 3.96 Hz, 1 H, thioph C-3-H), 7.31–7.82 (m,
6 H, phenyl-H, thioph C-4-H), 8.42 (s, 1 H,
pyrazol C-5-H)
72 167–169 C17H14BrN3O2S2
(436.34)
3362 (br., OH)
3155 (NH), 1710
(C=O), 1630
(C=N)
3.21–3.76 (m, 2 H, thiazol C-5-H), 4.51 (t, J =
7.80, 1 H, thiazol C-4-H), 6.05 (s, 0.5 H, thia-
zol C-2-H), 6.16 (s, 0.5 H, thiazol C-2-H), 7.12
(d, J = 3.96 Hz, 1 H, thioph C-3-H), 7.32–7.81
(m, 6 H, phenyl-H, thioph C-4-H), 8.42 (s, 1 H,
pyrazol C-5-H).
75 186–188 C19H18BrN3O2S2
(464.40)
3367 (br., OH)
3158 (NH), 1712
(C=O), 1632
(C=N)
1.38 (s, 3 H, thiazol C-5-CH3), 1.63 (s, 3 NH,
thiazol C-5-CH3), 4.12 (s, 1 H, thiazol C-4-H),
6.05 (s, 0.5 H, thiazol C-2-H), 6.13 (s, 0.5 H,
thiazol C-2-H), 7.11 (d, J = 3.96 Hz, 1 H,
thioph C-3-H), 7.32–7.79 (m, 6 H, phenyl-H,
thioph C-4-H), 8.41 (s, 1 H, pyrazol C-5-H).
68 191–193 C22H23BrN4O4S
(519.41)
3350, 3170 (NH), 1.38 (s, 9 H, butyl (CH3)3), 3.24–3.87 (m, 2 H,
1737 (C=O), 1689 oxazol C-5-H), 4.57 (t, J = 7.80, 1 H, oxazol
(C=O), 1632
(C=N), 1210,
1136 (C-O-C)
C-4-H), 6.22 (s, 0.5 H, oxazol C-2-H), 6.28 (s,
0.5 H, oxazol C-2-H), 7.11 (d, J = 3.96 Hz,
1 H, thioph C-3-H), 7.31–7.81 (m, 6 H, phenyl-
H, thioph C-4-H), 7.87 (s, 2 H, NH2) 8.42 (s,
1 H, pyrazol C-5-H).

116 Bekhit et al.
Arch. Pharm. Pharm. Med. Chem. 2003, 336, 111–118
Table 3 (continued)
Comp. Yield
Mp
[°C]
Mol. Formula
(Mol. wt.)
IR
(KBr) [cm–1]
1H NMR
(CDCl3)
No.
[%]
4 b
70 185–186 C22H23BrN4O3S2
(535.47)
3346, 3155
1.40 (s, 9 H, butyl (CH3)3), 3.21–3.76 (m, 2 H,
(NH),1734 (C=O), thiazol C-5-H), 4.54 (t, J = 7.80, 1 H, thiazol
1686 (C=O), 1630 C-4-H), 6.07 (s, 0.5 H, thiazol C-2-H), 6.15 (s,
(C=N), 1206,
1132 (C-O-C)
0.5 H, thiazol C-2-H), 7.12 (d, J = 3.96 Hz,
1 H, thioph C-3-H), 7.36–7.83 (m, 6 H, phenyl-
H, thioph C-4-H), 7.90 (s, 2 H, NH2), 8.41 (s,
1 H, pyrazol C-5-H).
4 c
79 195–197 C24H27BrN4O3S2
(563.53)
3348, 3164
1.39 (s, 12 H, butyl (CH3)3, thiazol C-5- CH3),
(NH),1735 (C=O), 1.64 (s, 3 H, thiazol C-5- CH3), 4.13 (s, 1 H,
1684 (C=O), 1630 thiazol C-4- H), 6.05 (s, 0.5 H, thiazol C-2-H),
(C=N), 1208,
1134 (C-O-C)
6.11 (s, 0.5 H, thiazol C-2-H),7.12 (d, J =
3.96 Hz, 1 H, thioph C-3-H), 7.33–7.79 (m,
6 H, phenyl-H, thioph C-4-H), 7.88 (s, 2 H,
NH2), 8.43 (s, 1 H, pyrazol C-5-H).
5 a
5 b
5 c
77 175–177 C17H15BrN4O2S
(419.29)
3335, 3172 (NH), 3.24–3.81 (m, 2 H, oxazol C-5-H), 4.54 (t, J =
1687 (C=O), 1635 7.80, 1 H, oxazol C-4-H), 6.16 (s, 0.5 H, oxazol
(C=N)
C-2-H), 6.23 (s, 0.5 H, oxazol C-2-H), 7.11 (d,
J = 3.96 Hz, 1 H, thioph C-3-H), 7.32–7.80 (m,
6 H, phenyl-H, thioph C-4-H), 7.89 (s, 2 H,
NH2), 8.40 (s, 1 H, pyrazol C-5-H).
82 169–171 C17H15BrN4OS2
(435.36)
3343, 3159 (NH), 3.23–3.78 (m, 2 H, thiazol C-5-H), 4.55 (t, J =
1685 (C=O), 1630 7.80, 1 H, thiazol C-4-H), 6.06 (s, 0.5 H, thi-
(C=N)
azol C-2-H), 6.13 (s, 0.5 H, thiazol C-2-H),
7.13 (d, J = 3.96 Hz, 1 H, thioph C-3-H),
7.34–7.80 (m, 6 H, phenyl-H, thioph C-4-H),
7.92 (s, 2 H, NH2), 8.43 (s, 1 H, pyrazol C-5-H).
83 179–181 C19H19BrN4OS2
(463.41)
3338, 3167 (NH), 1.39 (s, 3 H, thiazol C-5-CH3), 1.62 (s, 3 H,
1683 (C=O), 1633 thiazol C-5-CH3), 4.12 (s, 1 H, thiazol C-4-H),
(C=N)
6.07 (s, 0.5 H, thiazol C-2-H), 6.11 (s, 0.5 H,
thiazol C-2-H), 7.14 (d, J = 3.96 Hz, 1 H, thi-
oph C-3-H), 7.31–7.79 (m, 6 H, phenyl-H,
thioph C-4-H), 7.91 (s, 2 H, NH2), 8.43 (s, 1 H,
pyrazol C-5-H).
(2RS,4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-1H-pyrazol-4-yl]-
oxazolidine-4-carboxamide 5 a, (2RS,4R)-2-[3-(5-bromo-2-
thienyl)-1-phenyl-1H-pyrazol-4-yl]-5-methylthiazolidine-4-car-
boxamide 5 b or (2RS,4R)-2-[3-(5-bromo-2-thienyl)-1-phenyl-
1H-pyrazol-4-yl]-5,5-dimethylthiazolidine-4-carboxamide 5 c
Biological screening
Anti-inflammatory testing
Adult male Sprague-Dawley rats (120–140 g) were used.They
were acclimated 1 week prior to use and allowed unlimited ac-
cess to standard rat chow and water.Prior to the start of experi-
ment, the animals were randomly divided into groups (6 rats
each). Cotton pellets (35 1 mg) cut from dental rolls were im-
pregnated with 0.2 mL (containing 0.01 mmol) of a solution of
the test compound in chloroform or acetone and the solvent
was allowed to evaporate.Each cotton pellet was subsequently
injected with 0.2 mL of an aqueous solution of antibiotics (1 mg
To a solution of the appropriate 4 a–c (5.2 mmol), in 4N HCl/di-
oxane (10 mL), anisole (1.1 mL, 10.4 mmol, 1.1 mL) was added
at 0 °C.The reaction mixture was stirred for 1 h at room temper-
ature.The solvent was removed in vacuo at room temperature,
ether was added, and the mixture was centrifuged. The ob-
tained product was recrystallized from aqueous ethanol (see
Table 3).

Arch. Pharm. Pharm. Med. Chem. 2003, 336, 111–118
1H-Pyrazolyl-thiazolidines 117
azole were used as standards antibacterial and antifungal
agents respectively.Solutions of the test compounds, ampicillin
trihydrate and clotrimazole were prepared in DMSO at concen-
tration of 1600 µg/mL. The twofold dilution of the compounds
were prepared (800, 400,.....6.25 µg/mL). The microorganism
suspensions at 106 CFU/mL (Colony Forming Unit/mL) con-
centration were inoculated to the corresponding wells. Plates
were incubated at 36 °C for 24 h to 48 h.The incubation cham-
ber was kept sufficiently humid.At the end of the incubation pe-
riod, the minimal inhibitory concentrations (MIC) were deter-
mined. Controls for the DMSO microorganisms and media mi-
croorganisms were also done.
penicillin G and 1.3 mg dihydrostreptomycin/mL). Two pellets
were implanted subcutaneously, one in each axilla of the rat,
under mild general anesthesia. One group of animals received
the standard reference indomethacin and the antibiotics at the
same level.Pellets containing only the antibiotics were similarly
implanted in the control rats.Seven days later, the animals were
sacrificed and the two cotton pellets, with adhering granulo-
mas, were removed, dried for 48 h at 60 °C and weighed. The
increment in dry weight (difference between the initial and final
weights) was taken as a measure of granuloma S.E..This was
calculated for each group and the percentage reduction in dry
weight of granuloma from control value was also calculated.
The ED50 values were determined through dose-response
curves, using doses of 4, 7, 10, and 15 µmol for each com-
pound.
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