Synthesis and studies on antidepressant and anticonvulsant activities of some 3-(2-thienyl)pyrazoline derivatives

Article abstract of DOI:10.1002/ardp.200800068

In this study, the synthesis of twelve 3-(2-thienyl)pyrazoline derivatives are described. The structures of all compounds were confirmed by UV, IR, ¹H-NMR, mass spectral data, and microanalyses. In the pharmacological studies, antidepressant an

Full text of DOI:10.1002/ardp.200800068

Arch. Pharm. Chem. Life Sci. 2008, 341, 701–707
Z. Ozdemir et al.
701
Full Paper
Synthesis and Studies on Antidepressant and Anticonvulsant
Activities of Some 3-(2-Thienyl)pyrazoline Derivatives
Zuhal Ozdemir1, H. Burak Kandilci2, Bulent Gumusel2, Unsal Calis1, and A. Altan Bilgin1
1 Hacettepe University Faculty of Pharmacy, Department of Pharmaceutical Chemistry, Ankara, Turkey
2 Hacettepe University Faculty of Pharmacy, Department of Pharmacology, Ankara, Turkey
In this study, the synthesis of twelve 3-(2-thienyl)pyrazoline derivatives are described. The struc-
1
tures of all compounds were confirmed by UV, IR, H-NMR, mass spectral data, and microanaly-
ses. In the pharmacological studies, antidepressant and anticonvulsant activities of these com-
pounds have been screened. The antidepressant activities of the compounds were investigated
by Porsolt's behavioral despair test (forced swimming) on albino mice and compared with tranyl-
cypromine. Among the compounds examined, the compounds 9 and 12 showed significant anti-
depressant activity. Anticonvulsant activities of the compounds were determined by maximal
electroshock seizure (MES) and subcutaneous pentylenetetrazole (metrazol) (scMet.) tests, neuro-
toxicities were determined by rotarod toxicity test on albino mice. Compound 8 was found to be
protective against MES in the range of 30–300 mg/kg dose levels at four hours. None of the syn-
thesized compounds showed neurotoxicity at 30–300 mg/kg dose levels.
Keywords: Anticonvulsant activity / Antidepressant activity / 3-Pyrazoline derivatives /
Received: April 10, 2008; accepted: July 31, 2008
DOI 10.1002/ardp.200800068
Introduction
The chemistry and the synthesis of 2-pyrazoline deriv-
atives have attracted widespread attention in recent
years. The present popularity of these derivatives is
Figure 1. Structure of isocarboxazid(N'-benzyl-5-methyl-oxa-
zole-3-carbohydrazide).
mainly due to their structural similarity to isocarboxazid
(Fig. 1), a monoamine oxidase (MAO) inhibitor, which is
well known to show prominent antidepressant activity
[1]. In earlier studies, 1,3,5-triphenyl-2-pyrazolines are
reported to possess MAO inhibitory activities by Palmar
et al. [2] and Soni et al. [3]. In a recent paper, Chimenti et
al. [4] reported enantioselective MAO-A and MAO-B inhib-
iting properties of 1-thiocarbamoyl-2-pyrazolines. MAO
inhibitors have been proven to show antidepressant
activity both in laboratory animals and man [5, 6].
So far, we synthesized various substituted pyrazolines
and their some condensed derivatives and investigated
their antidepressant and anticonvulsant activities [7–
13]. Rajendra Prasad et al. [14] also reported the synthesis
and antidepressant activity of the compounds with the
same ring. Promissing antidepressant or anticonvulsant
activities of some derivatives prompted us to investigate
them further. In continuation to our earlier studies, we
attempted to expand our series of compounds by chang-
ing the aryl substituents on the pyrazole ring. In this
study, synthesis, structural elucidation, and antidepres-
sant activity as well as anticonvulsant activity of a new
series of 3-(2-thienyl)-pyrazoline derivatives are reported.
Correspondence: B. Gumusel, PhD, Professor of Pharmacology, Hacet-
tepe University, Faculty of Pharmacy, Department of Pharmacology,
06100 Ankara, Turkey.
E-mail: gumusel@hacettepe.edu.tr
Fax: +90 312 305-2026
Abbreviations: maximal electroshock seizure (MES); monoamine oxi-
dase (MAO); subcutaneous pentylenetetrazole (metrazol) (scMet.)
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702
Z. Ozdemir et al.
Arch. Pharm. Chem. Life Sci. 2008, 341, 701–707
Results and Discussion
As shown in Scheme 1, the starting compound, 1-(2-
thienyl)-3-phenyl/(2-thienyl)-2-propen-1-one was obtained
by the reaction of benzaldehyde and 2-thienylaldehyde
with acetylthiophen in a Claisen–Schmidt condensation
reaction. The reaction of 1-(2-thienyl)-3-phenyl/(2-thienyl)-
2-propen-1-one with phenylhydrazine and thiosemicar-
bazide in presence of sodium hydroxide in ethanol gave
1-phenyl- (1 and 2), and 1-thiocarbamoyl-3-(2-thienyl)-5-
phenyl/(2-thienyl)-2-pyrazolines (3 and 4), respectively.
Treatment of the starting compound with hydrazine
hydrate in ethanol, followed by addition of thiocyanates
in the presence of triethylamine in ether provided 1-N-
substituted
thiocarbamoyl-3-(2-thienyl)-5-phenyl/(2-
thienyl)-2-pyrazolines 5–12. Although compounds 1 and
2 have already been reported previously by Ried and Dan-
kert [15], they have been included in our research pro-
gram to screen their activity. The structures of the iso-
lated compounds were characterized by spectral meth-
ods and microanalyses. All spectral data are in accord-
ance with the assumed structures.
Scheme 1. Synthetic route of the 3-(2-thienyl)-pyrazoline deriv-
atives.
In the UV spectra of the compounds, two absorption
maxima were observed at 206–244 and 327–353 nm due
to C=N and Ar-N-N=C-Ar groups, respectively. In the IR
spectra, all compounds displayed pyrazoline C=N stretch-
ing (1501–1576 cm– 1), C4-H deformation (1362–
1464 cm– 1), C5-N1 streching (1069–1189 cm– 1), thiocarba-
moyl group N-H stretching (3112–3481 cm– 1), and C=S
stretching (1315–1357 cm– 1) bands.
In the1H-NMR spectra of the compounds HA, HB, and HX,
protons of the pyrazoline ring were observed as doublet
of doublet at d = 2.98–3.30 ppm (JAB = 17.44–17.69 Hz),
3.45–3.75 ppm (JAx = 3.43–3.71 Hz), and 5.98–6.97 ppm
(JBx = 11.34–11.66 Hz), respectively. N-H protons of the thi-
ocarbamoyl group were generally seen at 7.23–9.10 ppm
as broad bands. All the other protons belonging methyl,
ethyl, allyl groups, benzene and thiophene rings were
seen accordingly to the expected chemical shift and inte-
gral values.
The mass spectroscopic fragmentation of the com-
pounds was studied under electron ionization. molecu-
lar ion peaks [M+], which were prominent for all the com-
pounds, confirmed the molecular weights of the exam-
ined compounds. The fragmentation pattern was essen-
tially identical. Fragments resulting from the loss of the
SH ion from the thiocarbamoyl group were observed for
all compounds. On the other hand, a-cleavage adjacent
to both sides of the C=S group have also been observed
causing ejection of NHR or CSNHR type of ions. The frag-
ments resulting by loss of C5H4NS and C5H4N2S ions from
the molecular ion were observed for almost all com-
pounds. Additionally, the pyrazoline ring has shown a
fragmentation pattern giving rise to C7H7N2S and C5H4NS
type of ions. Microanalyses results were also in accord-
ance with the theoretical amounts.
In-vivo antidepressant activities of the compounds
were assessed in mice applying the forced swimming
test. The forced swimming test, which is a behavioral
test, used to predict the efficacy of antidepressant treat-
ments [16]. It is used effectively in predicting the activity
of a wide variety of antidepressants such as MAO inhibi-
tors [17] and typical antidepressants [18]. It also has a
good predictive value for the antidepressant potency in
humans [19]. The obtained data on the antidepressant
activity of the compounds and reference drug were given
in Table 1. The compounds 2, 4, 9, 10, 12 bearing a thienyl
group at the 5-position of the pyrazoline ring (except 11)
showed marked antidepressant activity. Among the men-
tioned derivatives, most promising results were obtained
with the compounds carrying 1-N-methylthiocarbamoyl-
(9) and 1-N-phenylthiocarbamoyl- (12) on the pyrazoline
ring. The mentioned derivatives significantly reduced
the duration of immobility times at the 10 mg/kg dose
level when compared to the control (p a 0.05, Table 1).
Anticonvulsant activities of the synthesized com-
pounds were also investigated by maximal electroshock
(MES) and subcutaneous pentylenetetrazole (metrazol)
(scMet.) tests, and results from these experiments are
shown in Table 2. Seizure assays and neurotoxicity were
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Arch. Pharm. Chem. Life Sci. 2008, 341, 701–707
Pyrazoline Derivatives as Antidepressant – Anticonvulsant
703
Table 1. Antidepressant activities of the synthesized com-
pounds.
significant difference in activity was observed depending
on both aryl group at 5-position and the substituents on
the thiocarbamoyl at the first position of the pyrazoline
ring. Compound 4, 1-thiocarbamoyl-3,5-di-(2-thienyl)-2-
pyrazoline, was found ineffective in the dose range of
30–300 mg/kg, while some remarkable activity were
observed with compound 3 having a phenyl at 5-position
in the 300 mg/kg-dose level at four hours. Anticonvulsant
activity of the compounds bearing a phenyl group at the
5-position are taken into consideration, it could be con-
cluded that the substitution of thiocarbamoyl group
always resulted in good activity either at half hour at the
300 mg/kg-dose level (compounds 5 and 7) or at four
hours (compounds 6 and 8). Among the compounds with
phenyl, compound 8 possessed the most prominent and
consistent activity against MES in the range of 30–
300 mg/kg-dose levels at four hours. It is worth saying
that all compounds which exhibited activity were found
to be protective against MES-induces seizures at their
high dose level (300 mg/kg). However, only two com-
pounds (compounds 6 and 12) exhibited activity against
scMet.–induced seizures at the 300 mg/kg-dose level.
Neurotoxicity was observed in none of the synthesized
compounds in the dose range of 30–300 mg/kg.
Compounds
Antidepressant activities
Duration of im- Change
mobility (sec)
from control
(Mean l S.E.M.) * (%)
1
2
3
4
5
6
188 l 7.7
96 l 21.2*
158 l 18.3
84 l 21.5*
174 l 14.2
190 l 10
–6.47
–52.53
–21.39
–58.20
–13.43
–5.47
7
8
9
10
11
12
154 l 19.9
148 l 29.1
43 l 15.3*
88 l 21.2*
182 l 14.9
48 l 18.9*
57 l 11.6
–23.38
–26.36
–78.60
–56.24
–9.45
–76.12
–71.64
Tranylcypromine sulfate
(10 mg/kg, ip)
Control
201 l 8.6
* Values represents the mean l S.E.M. (n = 6–9).
* Significantly compared to control (Dunnet's test; p a 0.05).
determined by rotarod toxicity test according to the
phase-I tests of the anti-epileptic drug development
(ADD) program which were developed by the National
Institute of Neurological and Communicative Disorders
and Stroke (NINCDS) [20, 21]. According to the results of
the in-vivo experiments, it is difficult to extract a definite
structure-anticonvulsant activity relationship between
of the tested compounds 1–12. As shown in Table 2, the
Conclusion
In summary, we have reported the synthesis and biologi-
cal evaluation of 3-(2-thienyl)-5-phenyl/(2-thienyl)-2-pyra-
zoline derivatives as novel candidate antidepressant /
Table 2. Phase I anticonvulsant screening of the compounds.
Compounds
MES*
scMet.a)
Toxicityb)
1/2 h mg/kg
4 h mg/kg
1/2 h mg/kg
4 h mg/kg
1/2 h mg/kg
100
4 h mg/kg
30
100
300
30
100
300
30
100
300
30
100
300
30
300
30
100
300
1
2
3
4
5
6
7
8
9
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
1/1
0/1
1/1
0/1
0/1
0/1
1/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
1/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
1/1
0/1
0/1
0/1
0/1
0/1
0/1
1/1
0/1
0/1
1/1
0/1
1/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
1/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
0/1
1/1
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/2
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
0/4
10
11
12
*
MES: maximal electroshock seizure test.
a)
scMet.: subcutaneous pentylenetetrazole (metrazol) seizure test.
b)
oxicity: rotarod test.
0/1: no activity at dose level, 1/1: noticeable activity at dose level.
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Arch. Pharm. Chem. Life Sci. 2008, 341, 701–707
anticonvulsant compounds. Generally, the synthesized 1-Phenyl-3-(2-thienyl)-5-phenyl/(2-thienyl)-2-pyrazolines
compounds having a phenyl substituent at the 5– posi- 1, 2
The solution of appropriate chalcone (0.01 mol) and phenylhy-
drazine (0.02 mol) in ethanolic sodium hydroxide (0.025 mol,
20 mL) was refluxed for four hours. The product was poured into
ice water and the crude product, which was separated out, was
tion of the pyrazoline ring (compounds 3, 5, 6, 7, 8) pos-
sess remarkable anticonvulsant activity. Among the men-
tioned derivatives, most promising results were obtained
with the compound 8 carrying 1-N-phenylthiocarbamoyl-
against MES in the range of 30–300 mg/kg dose levels at
four hours. On the contrary, however, the componds
bearing a thienyl at the 5-position of the ring (com-
pounds 2, 4, 9, 10, 12, except 11) attract attention with
their antidepressant activity. Two of them (compounds 9
and 12) showed a larger antidepressant activity than tra-
nylcypromine. It is worth saying that the compounds
having a N-phenylthiocarbamoyl at 1-position of pyrazo-
line ring exhibited a remarkable antidepressant and anti-
convulsant activity. Therefore, such compounds would
represent a fruitful matrix for the development of a new
class of antidepressant and anticonvulsant agents and
would deserve further investigation and derivatization
as a promising scaffold.
filtered and crystallized from a proper solvent.
1,5-Diphenyl-3-(2-thienyl)-2-pyrazoline 1
MeOH
Maks
Yield: 65%; m.p.: 128–1298C (Crys. solv.: MeOH); UV k
[nm]:
202 (log e: 4.31), 253 (log e: 4.11), 369 (log e: 4.10); IR m (KBr) [cm–
1]: 1593, 1499 (C=N stretching), 1386 (C4-H-deformation), 1125
(C5-N1 stretching); 1H-NMR d (CDCl3) [ppm]: 3.15 (dd, JAB
17.42 Hz, JAX = 7.11 Hz, 1H, HA), 3.90 (dd, JAB = 17.11 Hz, JBX
=
=
12.41 Hz, 1H, HB), 5.25 (dd, JAX = 7.13 Hz, JBX = 12.15 Hz, 1H, HX),
6.80 (m, 1H, thiophene H4), 7.00–7.45 (m, 12H, thiophene H3, H5
and benzene); MS m/e: 304 [M+] (100%), 227 [M – C6H5] (35%), 91
[C6H5N] (50%), 77 [C6H5] (35%).
1-Phenyl-3,5-di-(2-thienyl)-2-pyrazoline 2
Yield: 88%; m.p.: 107–1088C (Crys. solv.: MeOH / H2O); UV kMMaeOksH
[nm]: 201 (log e: 4.19), 251 (log e: 4.13 ), 365 (log e: 4.07); IR m (KBr)
[cm– 1]: 1591, 1495 (C=N stretching), 1377 (C4-H-deformation),
1
1228 (C5-N1 stretching); H-NMR d (CDCl3) [ppm]: 3.30 (dd, JAB
=
=
16.83 Hz, JAX = 6.35 Hz, 1H, HA), 3.85 (dd, JAB = 16.46 Hz, JBX
This study was supported by Hacettepe University Scientific
Research Foundation (Project no: 0302 30100).
12.15 Hz, 1H, HB), 5.55 (dd, JAX = 6.63 Hz, JBX = 12.21 Hz, 1H, HX),
6.75–7.50 (m, 11H, thiophene and benzene); MS m/e: 310 [M+]
(100%), 277 [M – SH] (28%), 227 [M – C4H3S] (21%), 218 [M –
C6H6N] (41%), 200 [M – C5H4NS] (38%), 91 [C6H5N] (81%).
The authors have declared no conflict of interest.
1-Thiocarbamoyl-3-(2-thienyl)-5-phenyl/(2-thienyl)-2-
pyrazolines 3, 4
1-Thiocarbamoyl-3-(2-thienyl)-5-phenyl/(2-thienyl)-2-pyrazolines
were obtained by heating (2 h) thiosemicarbazide (0.012 mol)
with the appropriate chalcone (0.01 mol) and sodium hydroxide
(0.025 mol in 5 mL water) in ethanol (50 mL). The product was
poured into ice water and the crude product, which was sepa-
rated out, was filtered and crystallized from the proper solvent.
Experimental
Chemistry
All chemicals used in this study were supplied by E. Merck (Ger-
many), Aldrich Chemical Co. (Munich, Germany) and Fluka AG
(Buchs, Switzerland). Melting points were taken in a Thomas
Hoover capillary melting point apparatus (Thomas Hoover, Phil-
adelphia, PA, USA) and are uncorrected. UV spectra were
obtained on Agilent 8453 UV-Visible spectrophotometer in
methanol. IR spectra were recorded in a Bruker Vector 22 IR
Opus Spectroscopic Software Version 2.0 (Bruker Bioscience, Bill-
erica, MA, USA) using KBr pellets. 1H-NMR spectra were recorded
on a Bruker Avance 400 MHz FT spectrometer (Bruker) in CDCl3
using TMS as internal standart. Mass spectra were recorded on
Scientific Instrument Service HPP7-M (SIS, Ringoes, NJ, USA)
direct insertion probe spectrometer using Agilent 5973 network
mass selective electron impact detector (Agilent, Palo Alto, CA,
USA). Microanalyses of the compounds were performed at The
Laboratory of Instrumental Analyses (ATAL). The Scientific and
Technical Research Council of Turkey (Instrument: Leco CHNS-
932; Leco, St. Joseph, MI, USA).
1-Thiocarbamoyl-3-(2-thienyl)-5-phenyl-2-pyrazoline 3
MeOH
Maks
Yield: 63%; m.p.: 178–1798C (Crys. solv.: MeOH). UV k
[nm]:
202 (log e: 4.22), 244 (log e: 4.20), 338 (log e: 3.85); IR m (KBr) [cm–
1]: 3356 (N-H stretching), 1571, 1473 (C=N stretching), 1370 (C=S
stretching), 1294 (C4-H-deformation), 1000 (C5-N1 stretching); 1H-
NMR d (CDCl3) [ppm]: 3.20 (dd, JAB = 17.65 Hz, JAX = 3.68 Hz, 1H,
pyrazoline HA), 3.90 (dd, JAB = 17.61 Hz, JBX = 11.40 Hz, 1H, pyrazo-
line HB), 6.05(dd, JAX = 3.50 Hz, JBX = 11.43 Hz, 1H, pyrazoline HX),
7.00–7.50 (m, 8H, thiophene and benzene); MS m/e: 287 [M+]
(96%), 254 [M – SH] (87%), 227 [M – CSNH2] (72%), 177 [M-C5H4NS]
(100%), 151 [C7H7N2S] (65%), 110 [C5H4NS] (35%). Anal. Calcd. for
C14H13N3S2: C, 58.51; H, 4.56; N, 14.62; S, 22.31. Found: C, 58.69;
H, 5.28; N, 14.75; S, 22.19.
1-Thiocarbamoyl-3,5-di-(2-thienyl)-2-pyrazoline 4
MeOH
Yield: 66%; m.p.: 157–88C (Crys. solv.: EtOH); UV k
[nm]: 243
Maks
(log e: 4.23), 337 (log e: 4.04); IR m (KBr) [cm– 1]: 3438 (N-H stretch-
1-(2-Thienyl)-3-phenyl/(2-thienyl)-2-propen-1-ones
chalcones
ing), 1571, 1519, 1470 (C=N stretching), 1350 (C=S stretching),
1
Chalcone derivatives were obtained from 2-acetylthiophene
(0.01 mol) and appropriate aldehydes (0.01 mol) by known meth-
ods [22–26].
1080 (C5-N1 stretching); H-NMR d (CDCl3) [ppm]: 3.35 (dd, JAB
17.50 Hz, JAX = 3.21 Hz, 1H, HA), 3.90 (dd, JAB = 17.43 Hz, JBX
11.40 Hz, 1H, HB), 6.10 (b, 1H, NH), 6.40 (dd, JAX = 3.45 Hz, JBX
=
=
=
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Arch. Pharm. Chem. Life Sci. 2008, 341, 701–707
Pyrazoline Derivatives as Antidepressant – Anticonvulsant
705
11.27 Hz, 1H, HX), 6.90 (b, 1H, NH), 6.90–7.50 (m, 6H, thiophene);
MS m/e: 293 [M+] (89%), 260 [M – SH] (70%), 233 [M – CSNH2]
(34%), 183 [M – C5H4NS] (75%), 169 [M – C5H4N2S] (100%), 151
[C7H7N2S] (24%), 110 [C5H4NS] (57%). Anal. Calcd. for C12H11N3S3: C,
49.12; H, 3.78; N, 14.32; S, 32.78. Found: C, 49.53; H, 4.20; N,
14.38; S, 32.34.
CSNHC3H5] (77%), 151 [C7H7N2S] (66%), 110 [C5H4NS] (46%), 104
[C7H6N] (86%). Anal. Calcd. for C17H17N3OS2: C, 62.35; H, 5.23; N,
12.83; S, 19.58. Found: C, 62.72; H, 5.18; N, 12.86; S, 19.91.
1-N-Phenylthiocarbamoyl-3-(2-thienyl)-5-phenyl-2-
pyrazoline 8
MeOH
Maks
Yield: 67%; m.p.: 122–38C (Crys. solv.: EtOH); UV k
[nm]: 202
1-N-substituted-thiocarbamoyl-3-(2-thienyl)-5-phenyl/(2-
thienyl)-2-pyrazolines 5–12
(log e: 4.47), 251 (log e: 4.43), 346 (log e: 4.22); IR m (KBr) [cm– 1]
3343 (N-H stretching), 1588, 1513 (C=N stretching), 1451 (C4-H-
deformation), 1343 (C=S stretching), 1169 (C5-N1 stretching); H-
1
Hydrazine hydrate (0.02 mol) was added to an ethanolic solution
of appropriate chalcone (0.01 mol, 10 mL ethanol) and refluxed
for 2 h. The solvent was evaporated at reduced pressure. The resi-
due was dissolved in dry ether. Isothiocyanate (0.01 mol) and
four drops of triethylamine were added and stirred at room tem-
perature for 4 h. The mixture was evaporated to dryness and the
residue was crystallized from the proper solvent.
NMR d (CDCl3) [ppm]: 3.20 (dd, JAB = 17.60 Hz, JAX = 3.40 Hz, 1H,
HA), 3.90 (dd, JAB = 17.62 Hz, JBX = 11.50 Hz, 1H, HB), 6.20 (dd, JAX
=
3.37 Hz, JBX = 11.50 Hz, 1H, HX), 7.10–7.70 (m, 13H, thiophene
and benzene), 9.15 (s, 1H, NH); MS m/e: 363 [M+] (73%), 330 [M –
SH] (75%), 271 [M – C6H5NH] (77%), 253 [M – C5H4NS] (43%), 227
[M – CSNHC6H5] (79%), 162 [C8H6N2S] (100%), 151 [C7H7N2S] (64%),
110 [C5H4NS] (30%). Anal. Calcd. for C20H17N3S2: C, 66.08; H, 4.71;
N, 11.56; S, 17.64. Found: C, 66.47; H, 5.07; N, 11.57; S, 17.50.
1-N-Methylthiocarbamoyl-3-(2-thienyl)-5-phenyl-2-
pyrazoline 5
Yield: 60%; m.p.: 138–1398C (Crys. solv.: EtOH / H2O); UV kMMaeOksH
[nm]: 203 (log e: 4.22), 246 (log e: 4.17), 341 (log e: 3.89); IR m (KBr)
[cm– 1]: 3371 (N-H stretching), 1590, 1435 (C=N stretching), 1388
(C4-H-deformation), 1343 (C=S stretching), 1110 (C5-N1 stretch-
1-N-Methylthiocarbamoyl-3,5-di-(2-thienyl)-2-pyrazoline
9
Yield: 53%; m.p.: 149–1508C (Crys. solv.: EtOH / H2O); UV kMMaeOksH
[nm]: 223 (log e: 4.20 ), 243 (log e: 4.03), 340 (log e: 4.01); IR m (KBr)
[cm– 1]: 3321 (N-H stretching), 1531 (C=N stretching), 1431, 1387
(C4-H-deformation), 1351 (C=S stretching), 1100 (C5-N1 stretch-
ing); 1H-NMR d (CDCl3 ) [ppm]: 3.20 (d, J = 4.65 Hz, 3H, CH3), 3.40
(dd, JAB = 17.32 Hz, JAX = 3.50 Hz, 1H, HA), 3.75 (dd, JAB = 17.40 Hz,
ing); 1H-NMR d (CDCl3) [ppm]: 3.15 (dd, JAB = 17.55 Hz, JAX
3.70 Hz, 1H, HA), 3.25 (d, J = 4.91 Hz, 3H, CH3), 3.82 (dd, JAB
17.52 Hz, JBX = 11.65 Hz, 1H, HB), 6.10 (dd, JAX = 3.63 Hz, JBX
11.68 Hz, 1H, HX), 7.00–7.55 (m, 8H, thiophene and benzene),
7.40 (b, 1H, NH); MS m/e: 301 [M+] (100%), 268 [M – SH] (75%), 227
[M – CSNHCH3] (96%), 191 [M – C5H4NS] (91%), 151 [C7H7N2S]
(87%), 110 [C5H4NS] (37%). Anal. Calcd. for C15H15N3S2: C, 59.77; H,
5.02; N, 13.94; S, 21.28. Found: C, 60.16; H, 5.07; N, 14.00; S,
20.99.
=
=
=
J
BX = 11.48 Hz, 1H, HB), 6.40 (dd, JAX = 3.41 Hz, JBX = 11.32 Hz, 1H,
HX), 6.80–7.50 (m, 6H, thiophene), 7.30 (b, 1H, NH); MS m/e: 307
[M+] (100%), 274 [M – SH] (80%), 233 [M – CSNHCH3] (70%), 218 [M
– C2H5N2S] (37%), 197 [M – C5H4NS] (74%), 183 [M – C5H4N2S]
(81%), 110 [C5H4NS] (51%). Anal. Calcd. for C13H13N3S3: C, 50.78; H,
4.26; N, 13.67; S, 31.29. Found: C, 51.04; H, 4.29; N, 13.60; S,
31.67.
1-N-Ethylthiocarbamoyl-3-(2-thienyl)-5-phenyl-2-
pyrazoline 6
Yield: 60%; m.p.: 112–1138C (Crys. solv.: EtOH / H2O); UV kMMaeOksH
[nm]: 202 (log e: 4.24), 247 (log e: 4.17), 342 (log e: 3.89); IR m (KBr)
[cm– 1]: 3348 (N-H stretching), 1511 (C=N stretching), 1443, 1369
(C4-H-deformation), 1300 (C=S stretching), 1184 (C5-N1 stretch-
ing); 1H-NMR d (CDCl3) [ppm]: 1.35 (t, J = 5.40 Hz, 3H, CH3), 3.15
(dd, JAB = 17.52 Hz, JAX = 3.64 Hz, 1H, HA), 3.60–3.90 (m, 3H, HB and
CH2), 6.10 (dd, JAX = 3.65 Hz, JBX = 11.68 Hz, 1H, HX), 7.05–7.55 (m,
8H, thiophene and benzene), 7.35 (b, 1H, NH); MS m/e: 315 [M+]
(100%), 282 [M – SH] (61%), 227 [M – CSNHC2H5] (95%), 205 [M –
C5H4NS] (47%), 151 [C7H7N2S] (73%), 110 [C5H4NS] (28%). Anal.
Calcd. for C16H17N3S2: C, 60.92; H, 5.43; N, 13.32; S, 20.33. Found:
C, 60.81; H, 6.37; N, 13.23; S, 19.89.
1-N-Ethylthiocarbamoyl-3,5-di-(2-thienyl)-2-pyrazoline 10
Yield: 57%; m.p.: 138–98C (Crys. solv.: MeOH); UV kMaks
MeOH [nm]: 200
(log e: 4.19 ), 244 (log e: 4.03), 341 (log e: 4.01); IR m (KBr) [cm– 1]:
3336 (N-H stretching), 1584, 1511 (C=N stretching), 1440, 1382
(C4-H-deformation), 1105 (C5-N1 stretching); 1H-NMR d (CDCl3)
[ppm]: 1.25 (t, JAB = 6.92, 3H, CH3), 3.30 (dd, JAB = 17.32 Hz, JAX
=
3.41 Hz, 1H, HA), 3.60–3.80 (m, 2H, CH2), 6.40 (dd, JAX = 3.31 Hz,
JBX = 11.20 Hz, 1H, HX), 6.90–7.45 (m, 6H, thiophene), 7.30 (b, 1H,
NH); MS m/e: 321 [M+] (100%), 288 [M – SH] (51%), 278 [M –
C2H5N] (71%), 233 [M – CSNHC2H5] (79%), 218 [M – C3H7N2S]
(44%), 211 [M – C5H4NS] (39%), 110 [C5H4NS] (66%). Anal. Calcd.
for C14H15N3S3: C, 52.30; H, 4.70; N, 13.07; S, 29.92. Found: C,
52.19; H, 4.10; N, 13.17; S, 30.29.
1-N-Allylthiocarbamoyl-3-(2-thienyl)-5-phenyl-2-
pyrazoline 7
1-N-Allylthiocarbamoyl-3,5-di-(2-thienyl)-2-pyrazoline 11
MeOH
Yield: 38%; m.p.: 101-1028C (Crys. solv.: EtOH / H2O); UV kMMaeOksH
[nm]: 204 (log e: 4.78), 248 (log e: 4.72), 342 (log e: 4.43); IR m (KBr)
[cm– 1]: 3370 (N-H stretching), 1508 (C=N stretching), 1441, 1368
(C4-H-deformation), 1311 (C=S stretching), 1160 (C5-N1 stretch-
Yield: 56%; m.p.: 117–1188C (Crys. solv.: MeOH); UV k
[nm]:
Maks
224 (log e: 4.30), 244 (log e: 4.32 ), 341 (log e: 4.02); IR m (KBr)
[cm–1]: 3380 (N-H stretching), 1587, 1506 (C=N stretching), 1441,
1370 (C4-H-deformation), 1158 (C5-N1 stretching); 1H-NMR d
(CDCl3) [ppm]: 3.30 (dd, JAB = 17.31 Hz, JAX = 3.40 Hz, 1H, HA), 3.75
(dd, JAB = 17.40 Hz, JBX = 11.31 Hz, 1H, HB), 4.12–4.40 (m, 2H, -CH2),
ing); 1H-NMR d (CDCl3) [ppm]: 3.20 (dd, JAB = 17.69 Hz, JAX
=
3.68 Hz, 1H, HA), 3.85 (dd, JAB = 17.51 Hz, JBX = 11.67 Hz, 1H, HB),
4.20–4.45 (m, 2H, CH2), 5.15–5.33 (m, 2H, =CH2), 5.90–6.00 (m,
1H, =CH), 6.10 (dd, JAX = 3.56 Hz, JBX = 11.60 Hz, 1H, HX), 7.05–7.50
(m, 8H, thiophene and benzene), 7.42 (b, 1H, NH); MS m/e: 327
[M+] (91%), 294 [M – SH] (18%), 271 [M – NHC3H5] (100%), 227 [M –
5.15–5.20 (m, 2H, =CH2 ), 5.90–6.10 (m, 1H, -CH=), 6.40 (dd, JAX
=
3.40 Hz, JBX = 11.32 Hz, 1H, HX), 6.90–7.50 (m, 6H, thiophene),
7.35 (b, 1H, NH); MS m/e: 333 [M+] (41%), 300 [M – SH] (18%), 277
[M – NHC3H5] (100%), 233 [M – CSNHC3H7] (50%), 218 [M –
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706
Z. Ozdemir et al.
Arch. Pharm. Chem. Life Sci. 2008, 341, 701–707
C4H7N2S] (32%), 209 [M – C5H4N2S] (27%), 168 [C6H4N2S2] (72%),
110 [C5H4NS] (57%). Anal. Calcd. for C15H15N3S3: C, 54.02; H, 4.53;
N, 12.60; S, 28.84. Found: C, 54.36; H, 3.93; N, 12.68; S, 29.30.
used for each compound. The synthesized compounds were sus-
pended in 30% aqueous solution of PEG 400 and administered ip
in a volume of 10 mg/kg at body weight to the mice. Control ani-
mals received 30% aqueous PEG 400. Pentylenetetrazole (metra-
zol) was administered subcutaneously (sc) from the back of the
neck. Rotarod toxicity test was performed on a 1-inch diameter
knurled wooden rod; rotating at 6 rpm.
1-N-Phenylthiocarbamoyl-3,5-di-(2-thienyl)-2-pyrazoline
12
MeOH
Maks
Yield: 72%; m.p.: 147–1488C (Crys. solv.: EtOH); UV k
[nm]:
201 (log e: 4.25), 247 (log e: 4.19), 345 (log e: 4.13); IR m (KBr)
[cm–1]: 3339 (N-H stretching), 1586, 1514 (C=N stretching), 1450,
1344 (C4-H-deformation), 1240 (C5-N1 stretching); 1H-NMR d
(CDCl3) [ppm]: 3.40 (dd, JAB = 17.42 Hz, JAX = 3.30 Hz, 1H, HA), 3.85
(dd, JAB = 17.45 Hz, JBX = 11.24 Hz, 1H, HB), 6.55 (dd, JAX = 3.6 Hz, JBX
= 12.32 Hz, 1H, HX), 6.90–7.85 (m, 11H, thiophene and benzene),
9.10 (s, 1H, NH); MS m/e: 369 [M+] (37%), 336 [M – SH] (36%), 277
[M – NHC6H5] (38%), 233 [M – CSNHC6H5] (43%), 218 [M –
C7H7N2S] (25%), 168 [C6H4N2S2] (100%). Anal. Calcd. for C18H15N3S3:
C, 58.51; H, 4.09; N, 11.37; S, 26.03. Found: C, 58.84; H, 4.51; N,
11.40; S, 25.90.
Maximal electroshock seizure (MES) test
Maximal electroshock seizures are elicited with a 60-cycle alter-
nating current of 50 mA intensity (5–7 times that is required to
elicit minimal electroshock seizures) delivered for 0.2 s via cor-
neal electrodes. A drop of 0.9% saline is instilled in the eye prior
to application of the electrodes in order to prevent the death of
the animal. Abolition of the hind limb tonic extension compo-
nent of the seizure is defined as protection.
Subcutaneous pentylenetetrazole (metrazol) (scMet) test
85 mg/kg of pentylenetetrazole (produces seizures in greater
than 95% of mice) is administered as a 0.5% solution sc in the
posterior midline. The animal was observed for 30 min failure to
observe even a threshold seizure (a single episode of clonic
spasms of at least 5 s duration) was defined as protection.
Pharmacology
The present study was approved by the Hacettepe University Ani-
mal Ethics Committee (# 2003/3-3 and 2003/47-1).
Antidepressant activity
Neurotoxicity
The synthesized compounds were screened for their antidepres-
sant activity using Porsolt's behavioral despair (forced swim-
ming) test [16]. Local breed, male albino mice (20–24 g) were
used in the forced swimming test under standard conditions
with free access to food and water. They were housed in groups
of six. On the test day, mice were dropped one at a time into a
plexiglass cylinder (height 25 cm, diameter 10 cm) containing
10 cm of water at 23–258C [14]. On this day, mice were assigned
into different groups (n = 6–9 for each group). Tranylcypromine
sulfate was supplied by Sigma Chemical Co. The synthesized
compounds (10 mg/kg), and tranylcypromine sulfate, as a refer-
ence antidepressant drug (10 mg/kg), were suspended in a 1%
aqueous solution of Tween 80. The drugs were injected intraper-
itoneally (ip) to mice (22 l 2 g) in a standard volume of 0.5 mL/
20 g body weight, 30 min prior to the test. Control animals
received 1% aqueous solution of Tween 80. Then, the mice were
dropped individually into the plexiglass cylinder and left in the
water for 6 min. After the first 2 min of the initial vigorous
struggling, the animals were immobile. A mouse was judged
immobile if it floated in the water in an upright position and
made only slight movements in order to prevent sinking. The
duration of immobility was recorded during the last 4 min of
the 6-min test.
The rotarod test was used to evaluate neurotoxicity. The animal
was placed on a 1-inch diameter knurled wooden rod rotating at
6 rpm. Normal mice remain on a rod rotating at this speed indef-
initely. Neurologic toxicity was defined as the failure of the ani-
mal to remain on the rod for 1 min.
Statistical analysis
Results are expressed as mean l S.E.M.; n represents the number
of animals. Data obtained from pharmacological experiments
were analyzed with one-way analysis of variance (ANOVA) fol-
lowed by Dunnet's post hoc test, using Pharmacologic Calcula-
tion System Version 4.1. (Microcomputer Specialists). A p-value
of less than 0.05 was considered statistically significant.
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