Antinociceptive properties of chloromaleinimides and their sulphonyl derivatives

Article abstract of DOI:10.1002/ardp.200300826

This report describes the synthesis of new cyclic imides obtained from the reaction between aniline and dichloromaleic anhydride with further chlorosulphonation as well as the reaction between different amines and 4-methoxyphenol for the synthesis of imid

Full text of DOI:10.1002/ardp.200300826

Arch. Pharm. Pharm. Med. Chem. 2004, 337, 201−206
Antinociceptive Properties of Chloromaleinimides 201
Maria Elena Waltera,
Antinociceptive Properties of
Chloromaleinimides and their Sulphonyl
Derivatives
Cristiano Moraa,
Karoline Mundstocka,
a
b
´
Marcia M de Souza ,
´
Andreia de Oliveira
Pinheirob,
This report describes the synthesis of new cyclic imides obtained from the reac-
tion between aniline and dichloromaleic anhydride with further chlorosulphon-
ation as well as the reaction between different amines and 4-methoxyphenol for
the synthesis of imidobenzenesulphonyl derivatives. These compounds were
tested as antinociceptive agents using the writhing test on mice. Some com-
pounds, when intraperitoneally injected, proved to be potent and dose-related
antinociceptives, being several times more active than many known reference
drugs.
Rosendo Augusto Yunesa,
Ricardo J. Nunesa
a
´
´
Laboratorio de Sıntese e
Estrutura Atividade
(LabSEAt), Departamento de
´
Quımica, Universidade
Federal de Santa Catarina
´
(UFSC), Florianopolis/SC,
Brazil
Keywords: Chloromaleinimides; Sulphonamides; Antinociception; Writhing
test; Mice
b
´
˜
Nucleo de Investigac¸oes
Quımico Farmaceuticas
(NIQFAR)/CCS, Universidade
Received: June 30, 2003; Accepted: November 25, 2003 [FP826]
DOI 10.1002/ardp.200300826
ˆ
´
´
do Vale do Itajaı (UNIVALI),
´
Itajaı/SC, Brazil
The results summarized in Table 1 reveal that the
compounds synthesized show a significant antino-
ciceptive effect as compared to nonsteroidal drugs
Introduction
Studies carried out in this laboratory previously have
shown that both, cyclic imides [1, 2] and sulphon-
amides have potent analgesic action, exceeding the
anti-inflammatory potency observed under the same
conditions by either aspirin or paracetamol. Kalgutkar
et al. [3] have demonstrated that some N-substituted
maleinimides inhibit the prostaglandine endoperoxide
synthase (PGHS). The cyclooxygenase activity of
PGHS is inhibited by several compounds known as
nonsteroidal anti-inflammatory drugs (NSAIDs). In this
context, the scope of the present investigation was the
synthesis of new imidic and imidobenzenesulphonyl
compounds aiming at the development of novel active
compounds related to cyclic imides. We also investi-
gated whether the maleinimides in this study act by
the same mechanism of those indicated by Kalgutkar
et al. [3]. The analgesic potential of the synthesized
compounds was tested using a writhing test in mice.
such as aspirin and paracetamol, based on the acetic
acid-induced abdominal contortion model. The N-
phenylsuccinimide displayed quite a different activity
behavior with respect to maleinimides. The former ex-
hibited a very low activity compared with that of
maleinimides. It was also observed that the substi-
tution of the double bond hydrogens of the imido ring
by chlorine atoms increased the activity of the N-phen-
ylmaleinimide significantly.
Acetic acid releases several inflammatory mediators,
including prostaglandines [4, 5], when administered in
the peritonaeum of animals. It has been suggested
that the analgesic and anti-inflammatory effects of
NSAIDs result, at least in part, from suppression of
prostaglandin synthesis due to PGHS inhibition [6, 7].
Considering the structural similarity of the maleinim-
ides in this study with those studied by Kalgutkar et al.
along with the fact that both, the former (in vivo) and
the latter (in vitro) studies, found succinimides to be
almost inactive in comparison to maleinimides, it is
reasonable to assume that these maleinimides are
acting by the same mechanism: inhibition of PGHS.
However, it should be noted that some differences ex-
ist between the effects of the compounds used in this
study and those of Kalgutkar’s which are probably due
to the distinct behavior of the compounds involved in
in vivo and in vitro experiments. According to Kalgut-
kar et al., N-(carboxyheptyl)-maleinimide inhibits en-
zyme activity within seconds after mixing with a stoi-
Results and discussion
The synthesis method used is represented in Scheme
2. The compounds (1-22) were readily characterized
by conventional spectral data.
´
´
Correspondence: Ricardo Jose Nunes, Laboratorio de
´
Sıntese e Estrutura Atividade (LabSEAt), Departamento de
´
Quımica, Universidade Federal de Santa Catarina (UFSC),
´
88040-900, Florianopolis/SC, Brazil. Phone: +55 483 319-
219, Fax: +55 483 319-711; e-mail: nunes@qmc.ufsc.br
 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

202 Nunes et al.
Arch. Pharm. Pharm. Med. Chem. 2004, 337, 201−206
Scheme 1.
chiometric amount of PGHS protein. The lack of
PGHS inhibition of N-(carboxyheptyl)-succinimide sug-
gests that this inhibition results from a covalent modifi-
cation of the enzyme. Compound 1 shows very rapid
reaction with some nucleophilic reagents that replace
one of the chlorine atoms. This fact supports the hy-
pothesis of Kalgutkar, who proposed that maleinimides
2-4 suggests that a covalent bond modification takes
place by displacement of a chlorine atom of the imido
ring. However, when a chlorine atom from 1 is re-
placed by nitrogen bases, as in compounds 2Ϫ4, a
nucleophilic attack on the double bond along with the
substitution of the second chlorine atom is not ex-
pected to occur, as can be inferred from the resonance
structures in Scheme 2, resulting in a low activity. The
reaction of compounds 2Ϫ4 with different amines at
room temperature did not take place.
inactivate
prostaglandin-endoperoxide
synthase
(PGHS) due to a covalent modification of the protein
[3]. The high activity of 1 compared with compounds
 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Arch. Pharm. Pharm. Med. Chem. 2004, 337, 201−206
Antinociceptive Properties of Chloromaleinimides 203
pounds 7 and 8) reacted with nitrogen bases produc-
ing compounds 11Ϫ22. The chlorosulphonation of
compound 1 with subsequent synthesis of compounds
9 and 10 was also carried out successfully.
The activity of the sulphonamides 9, 11Ϫ22 and the
ester 10 improved with respect to their corresponding
parent compounds (compounds 2Ϫ5). Compound 22
was approximately 13 times more active than aspirin,
suggesting additional non-covalent interactions be-
tween imidobenzenesulphonyl compounds and the
residues of aminoacid present in the active site of
PGHS. This implied that non-covalent interactions
played an important role in determining the activity of
11Ϫ22 which lead us to think that the mechanism of
Scheme 2.
Compounds 2Ϫ5 were submitted to chlorosulphon-
ation in an attempt to improve their activity. In the pro-
cess, compounds 4 and 5 produced multiple products
that could not be isolated. On the other hand, com-
pounds 2 and 3 were successfully processed and the
corresponding benzenesulphonyl chlorides (com-
Table 1. Effect of imides, sulphonyl compounds, and reference drugs given intraperitoneally against acetic acid-
induced abdominal constriction (writhing test) in mice.
Compounds
Dosage range (mg/kg)
ID50 (mg/kg)
ID50 (µmol/kg)
1
2
0.5Ϫ10
10Ϫ60
3Ϫ10
3Ϫ30
1Ϫ10
10Ϫ60
1Ϫ10
3Ϫ30
10Ϫ60
3Ϫ30
3Ϫ30
3Ϫ30
3Ϫ30
3Ϫ30
3Ϫ30
3Ϫ30
10Ϫ60
3Ϫ30
3Ϫ30
0.67 (0.48Ϫ0.77)†
22.65 (14.36Ϫ22.84)
11.24 (3.23Ϫ15.40)
25.41 (16.28Ϫ29.36)
4.38 (3.58Ϫ5.36)
2.80 (2.00Ϫ3.20)†
81.88 (51.93Ϫ82.54)
38.66 (11.14Ϫ53.00)
86.84 (55.62Ϫ100.33)
13.31 (10.86Ϫ16.26)
64.95 (41.86Ϫ102.29)
7.36 (5.81Ϫ13.37)
3
4
5
9
28.90 (18.49Ϫ45.20)
3.45 (2.99Ϫ6.89)
10
11
12
13
14
15
16
17
18
19
20
21
22
12.23 (8.97Ϫ16Ϫ67)
29.40 (12.27Ϫ36.69)
17.88 (13.55Ϫ23.59)
11.71 (9.96Ϫ13.75)
8.30 (8.05Ϫ8.55)
26.24 (19.25Ϫ35.76)
50.66 (29.44Ϫ79.45)
44.96 (34.08Ϫ59.31)
22.75 (19.36Ϫ26.72)
18.87 (18.30Ϫ19.44)
10.92 (8.77Ϫ13.65)
19.10 (8.99Ϫ25.88)
25.66 (17.83Ϫ48.70)
12.78 (10.41Ϫ27.18)
50.25 (10.20Ϫ71.53)
13.94 (4.75Ϫ31.75)
10.36 (5.24Ϫ22.42)
321.1(280.10Ϫ480.2)
5.36 (3.91Ϫ6.10)
9.09 (4.27Ϫ12.31)
11.80 (8.20Ϫ22.39)
5.66 (4.43Ϫ11.57)
20.59 (4.18Ϫ29.31)
6.30 (2.14Ϫ14.34)
4.61 (2.33Ϫ9.99)
NϪPhenylsuccinimide
([8], unpublished results)
NϪPhenylmaleinimide [9]
Aspirin [10]
19.00 (11.50Ϫ31.80)
133.00 (73.Ϫ247.00)
125.00 (104.Ϫ250.00)
Paracetamol [10]
†
95% confidence limit.
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204 Nunes et al.
Arch. Pharm. Pharm. Med. Chem. 2004, 337, 201−206
3-Choro-4-morpholin-4-yl-1-phenyl-1H-pyrrol-2,5-dione (4)
mp (°C) 160-161 (lit. [12] 160Ϫ161°C); Yield: 67%.
inhibition of the PGHS, involving compounds 11Ϫ22,
might occur without the formation of a covalent inter-
action, since the substitution of the nitrogen bases
and/or the remaining chlorine atom is not expected to
occur as discussed previously.
3-Chloro-4-(4-metoxyphenoxy)-1-phenyl-1H-pyrrole-2,5-
dione (5)
1H-NMR (CDCl3, ppm) δ: 7.46Ϫ7.35 (m, 5H, ArH), 7.16Ϫ6.89
(m, 4H, ArH-OC6H4OMe-p), 3.83 (s, 3H, OCH3); IR
(KBr ,cm1) = 1782, 1726, 1656 (C=0), 1598 (Ar C=C);
C17H12ClNO4 requires C, 61.92; H, 3.67; N, 4.25; found C,
61.58; H, 4.00; N, 4.45%; mp (°C): 128.6Ϫ129.8 (dry-flash
chromatography, ethyl acetate : hexane, 1:1); Yield: 67%.
Acknowledgments
This work was supported by grants from CNPq, UFSC,
and NIQFAR/UNIVALI.
4-(3,4-Dichloro-2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-
benzenesulphonyl chloride (6)
Experimental
m.s. 339, 341, 343, 345 (M+), 304, 306, 308 (M+-Cl), 240,
242, 244 (M+-SO2Cl), 184, 166, 122, 118, 87; mp (°C):
186,5Ϫ187,5; Yield: 85%.
Chemistry
Compound 1 was directly obtained from the reaction of 3,4-
dichloromaleic anhydride and aniline with acetic acid under
reflux, according to a methodology described elsewhere [11].
Compounds 2Ϫ4 were obtained from the reaction of com-
pound 1 (1 mol) and appropriate amines (2 mol) in dichloro-
methane at room temperature. Compound 5 was obtained
from the reaction of compound 1 (1 mol) with 4-methoxyphe-
nol (1mol) in the presence of triethylamine (2 mol) at room
temperature. Compounds 6Ϫ8 were obtained from the reac-
tion of compounds 1, 2 and 3 (1 mol) with chlorosulphonic
acid (6.0 mol). Compound 10 was obtained from the reaction
of compound 6 (1 mol) with 4-methoxy-phenol (1 mol) also in
the presence of triethylamine (2 mol) in dichloromethane at
room temperature. Compounds 9, 11Ϫ22 were obtained from
the reaction between compounds 6, 7 and 8 (1 mol) and am-
ines (morpholine, piperidine, pyrrolidine, and substituted ani-
lines, 2 mol) in methanol at 0°C. The mixture was allowed to
warm to room temperature for 2 hours and was then poured
onto ice-water. The precipitate was filtered off, washed with
water and dried under an infrared lamp. All the compounds
were characterized by 1H-NMR, IR, and microanalysis. The
purity of these compounds was determined by TLC using
several solvent systems of different polarity. Infrared spectra
were determined with a Perkin Elmer 16PC spectrophoto-
meter (Perkin Elmer, Wellesley, MA, USA). Nuclear magnetic
resonance spectra were recorded with a Bruker AC-200F
spectrometer (Bruker BioSpin GmbH, Karlsruhe, Germany)
using tetramethylsilane as internal standard. Mass spectra
were obtained with a Shimadzu GC-MS-2000A instrument
(Shimadzu, Kyoto, Japan). Microanalyses were carried out
with a Perkin Elmer 2400 instrument.
4-(3-Chloro-2,5-dioxo-4-pyrrolidin-1-yl-2,5-dihydro-1H-pyrrol-
1-yl)benzenesulphonyl chloride (7)
m.s. 378, 376, 374 (M+), 341, 339 (M+-Cl); C14H12Cl2N2O4S
requires C, 44.81; H, 3.22; N, 7.47; found C, 44.38; H, 3.60;
N, 7.73%; mp (°C): 122-123; Yield: 90%.
4-(3-Chloro-2,5-dioxo-4-piperidin-2,5-dihydro-1H-pyrrol-1-
yl)benzenesulphonyl chloride (8)
m.s. 392, 390, 388, (M+), 355, 353, (M+-Cl), 289, 291(M+-
SO2Cl), 218, 108, 87; C15H14Cl2N2O4S requires C, 46.28; H,
3.63; N, 7.20; found C, 46.50; H, 3.45; N, 7.05%. mp (°C):
88 decomp.; Yield: 74%.
3-Chloro-4-morpholin-4-yl-1-[4-(morpholin-4-ylsulphonyl)-
phenyl]-1H-pyrrole-2,5-dione (9)
1H-NMR (CDCl3, ppm) δ: 7.85- 7.60 (m, 4H, ArH); 4.08Ϫ3.01
(m, 16H, morpholino); IR (KBr, cm1) = 3470 (NH), 1772, 1716,
1632 (C=O), 1592 (Ar C=C), 1343,1166 (SO2);
C18H20ClN3O6S requires C, 48.92; H, 4.56; N, 9.51; found C,
48.50; H, 4.34; N, 9.72%; mp (°C): 150-151 (from ethanol);
Yield: 58%.
4-Metoxyphenyl-4-[3-chloro-4-(4-metoxyphenoxy)-2,5-dioxo-
2,5-dihydro-1H-pyrrol-1-yl]benzenesulphonate (10)
1H-NMR (CDCl3, ppm) δ: 7.93Ϫ7.65 (m, 4H, ArH); 7.15Ϫ6.73
(m, 8H, ArH, C6H4OMe-p); 3.84 (s, 3H, OCH3); 3.77 (s, 3H,
OCH3); IR (KBr, cm1) = 3502 (NH), 1754, 1738, 1658 (C=O),
1594 (Ar C=C), 1340, 1146 (SO2); C24H18ClNO8Srequires C,
55.87; H, 3.52; N, 2.71; found C, 55.39; H, 3.70; N, 2.95%;
mp (°C): 140-141 (dry-flash chromatography, ethyl acetate :
hexane, 1:1); Yield: 12%.
Physico-chemical data of synthesized compounds
3,4-Dichloro-1 phenyl-1H-pyrrole-2,5-dione (1)
mp (°C): 204Ϫ205 (lit. [11] 204Ϫ206°C); Yield: 70%.
3-Chloro-1-phenyl-4-pyrrolidin-1-yl-1H-pyrrole-2,5-dione (2)
4-(3-Chloro-2,5-dioxo-4-pyrrolidin-1-yl-2,5-dihydro-1H-pyrrol-
1H-NMR (CDCl3, ppm) δ: 7,40- 7,34 (m, 5H, ArH); 4,00 (t, 4H,
N(CH2)2); 1,96 (t, 4H, 2 ϫ CH2); IR (KBr, cm1) = 1762, 1706,
1634 (C=O), 1590 (Ar C=C); C14H13ClN2O2 requires C,60.77;
H,4.74; N,10.12; found C, 60.50; H, 5.00; N, 9.85%; mp (°C)
135Ϫ136 (dry-flash chromatography, ethyl acetate:hexane,
1:1); Yield: 76.5%.
1-yl)-N-(4-chlorophenyl) benzenesulphonamide (11)
1H-NMR (CDCl3, ppm) δ: 7.72-7.55 (m, 5H, ArH, NH);
7.10Ϫ6.50 (m, 4H, ArH, C6H4Cl-p); 3.90Ϫ4.10 [m, 4H,
N(CH2)2]; 1.90Ϫ2.10 (m, 4H, 2 ϫ CH2); IR (KBr, cm1) = 3458
(NH),1766, 1704, 1640 (C=O),1592 (Ar C=C), 1342,1164
(S02); C20H17Cl2N3O4S requires C, 51.51; H, 3.67; N, 9.01;
found C, 51.30; H, 3.93; N, 8.75%; mp (°C): 177 decomp
(dry-flash chromatography, ethyl acetate : hexane, 1:1);
Yield: 56%.
3-Chloro-1-phenyl-4-piperidin-1-yl-1H-pyrrole-2,5-dione (3)
mp (°C) 126-127 (lit. [12] 127Ϫ128°C); Yield: 87%.
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Arch. Pharm. Pharm. Med. Chem. 2004, 337, 201−206
Antinociceptive Properties of Chloromaleinimides 205
4-(3-Chloro-2,5-dioxo-4-pyrrolidin-1-yl-2,5-dihydro-1H-pyrrol-
1-yl)-N-(4-metoxyphenyl) benzenesulphonamide (12)
C, 57.45; H, 4.82; N, 9.14; found C, 57.62; H, 4.45; N, 9.50%;
mp (°C) :189-190 (dry-flash chromatography, ethyl acet-
ate:hexane, 1:1); Yield: 32%.
1H-NMR (CDCl3, ppm) δ: 7.71-7.54 (m, 4H, ArH); 6.96Ϫ6.60
(m, 4H, ArH, C6H4OMe-p); 6.30 (s, 1H, NH); 3.90Ϫ4.10 [m,
4H, N(CH2)2]; 3.76 (s, 3H, OCH3); 1.97Ϫ2.10 (m, 4H, 2 ϫ
CH2); C21H20ClN3O5S requires C, 54.60; H, 4.36; N, 9.10;
found C, 54.20; H, 4.67; N, 9.46%; mp (°C): 148-149 (dry-
flash chromatography, ethyl acetate: hexane, 1:1); Yield:
58.5%.
3-Chloro-1-[4-(morpholin-4-ylsulphonyl)phenyl]-4-pyrrolidin-
1-yl-1H-pyrrole-2,5-dione (19)
1H-NMR (CDCl3, ppm) δ: 7.83-7.63 (m, 4H, ArH); 4.00-4.10
[m, 4H, N(CH2)2]); 3.70Ϫ3,80 [m, 4H, O(CH2)2], 3.00-3.08 [m,
4H, N(CH2)2], 1.92Ϫ2.02 (m, 4H, 2 ϫ CH2); IR (KBr, cm1) =
1766, 1718, 1642 (C=O), 1586 (Ar C=C), 1340, 1162 (SO2);
C18H23ClN4O5S requires C, 48.81; H, 5.23; N, 12.65; found
C, 48.63; H, 5.30; N, 12.48%; mp (°C): 147.8-149.0 (dry-
flash chromatography, ethyl acetate : hexane, 1:1); Yield:
63%.
4-(3-Chloro-2,5-dioxo-4-piperidin-1-yl-2,5-dihydro-1H-pyrrol-
1-yl)-N,N-dimethylbenzenesulphonamide (13)
mp (°C): 217,5Ϫ219,5 (lit. [1] 218Ϫ219°C); Yield: 47.5%.
4-(3-Chloro-2,5-dioxo-4-piperidin-1-yl-2,5-dihydro-1H-pyrrol-
1-yl)-N-(3,4-dichlorophenyl) benzenesulphonamide (14)
3-Chloro-4-pyrrolidin-1-yl-1-[4-pyrrolidin-1-yl-sulphonyl)-
phenyl]-1H-pyrrole-2,5-dione (20)
1H-NMR (CDCl3, ppm) δ: 8.70 (s, 1H, NH),.8.0-6.9 (m, 7H,
ArH), 3.80-4.10 [m, 4H, N(CH2)2], 1.50Ϫ2.00 (m, 6H, 3 ϫ
CH2 ); IR (KBr, cm1) = 3450 (NH), 1758,1706, 1620 (C=O),
1594 (Ar C=C), 1332, 1164 (SO2); C21H18Cl3N3O4S requires
C, 48.99; H, 3.52; N, 8.16; found C, 49.23; H, 3.15; N, 8.39%;
mp (°C) 205-206 (dry-flash chromatography, ethyl acetate :
hexane, 1:1); Yield: 44.5%.
1H-NMR (CDCl3, ppm) δ: 7.91Ϫ7.58(m, 4H, ArH); 4.01Ϫ4.10
[m, 4H, N(CH2)2]; 3.30Ϫ3.20 [m, 4H, SO2N(CH2)2];
2.10Ϫ1.97 (m, 4H, 2 ϫ CH2); 1.80-1.70 (m, 4H, 2 ϫ CH2);
IR (KBr, cm1) = 3458 (NH), 1766, 1716, 1632 (C=O), 1594
(Ar C=C), 1344,1158 (SO2); C18H20ClN3O4S requires C,
52.74; H, 4.92; N, 10.25; found C, 52.46; H, 4.68; N, 9.95%;
mp (°C): 178.7-180.0 (from ethanol); Yield: 70%.
3-ChIoro-1-[4-(morpholin-4yl-sulphonyl)phenyl]-4-piperidin-1-
yl-1H-pyrrole-2,5-dione (15)
3-Chloro-1-[4-(piperidin-1-yl-sulphonyl)benzyl]-4-piperidin-1-
yl-1H-pyrrol-2,5-dione (21)
1H-NMR (CDCl3, ppm) δ: 7.71Ϫ7.45(m, 4H, ArH); 4.00Ϫ3.88
[m, 4H, N(CH2)2]; 3.00Ϫ2.99 [m, 4H, SO2N(CH2)2]; 1.73-1.50
(m, 12H, 6 ϫ CH2); IR (KBr, cm1) = 3452 (NH), 1764, 1709,
1628 (C=O), 1344, 1166 (S02). C21H26ClN3O4S requires C,
55.81; H, 5.80; N, 9.30; found C, 56.05; H, 5.46; N, 9.62%;
mp (°C): 87-88 (from ethanol); Yield: 60%.
1H-NMR (CDCl3, ppm) δ: 7.83- 7.61 (m, 4H, ArH); 4.10-3.90
[m, 4H, N(CH2)2]; 3.80Ϫ3.70 [m, 4H, O(CH2)2], 2.90-3.10 [m,
4H, N(CH2)2], 1.65Ϫ1.75 (m, 6H, 3 ϫ CH2); IR (KBr, cm1) =
1766, 1718, 1642 (C=O), 1586 (Ar C=C), 1340, 1162 (SO2);
C19H22ClN3O5S requires C, 51.87; H, 5.04; N, 9.55; found C,
51.46; H, 5.43; N, 9.32%; mp (°C): 207 (dry-flash chromatog-
raphy, ethyl acetate : hexane, 1:1); Yield: 55%.
4-(3-Chloro-2,5-dioxo-4-pyrrolidin-1-yl-2,5-dihydro-1H-pyrrol-
1-yl)-N-(4-methylphenyl) benzenesulphonamide (22)
4-(3-Chloro-2,5-dioxo-4-piperidin-1-yl-2,5-dihydro-1H-pyrrol-
1-yl)-N-pyridin-2-yl-benzenesulphonamide (16)
1H-NMR (CDCl3, ppm) δ: 7.80Ϫ7.55 (m, 4H, ArH); 7.10Ϫ6.90
(m, 4H, ArH, C6H4Me-p); 6.35 (s, 1H, NH); 4,10Ϫ4.00 [m, 4H,
N(CH2)2]; 2.28 (s, 3H, CH3); 2.00Ϫ1.95 (m, 4H, 2 ϫ CH2); IR
(KBr, cm1) = 3452 (NH), 1762, 1712, 1638 (CO), 1594 (Ar C=
C), 1336, 1160 (SO2); C21H20ClN3O4S requires C, 56.56; H,
4.52; N, 9.42, found C, 56.15; H, 4.78; N, 9.73%; mp (°C):
219-220 (dry-flash chromatography, ethyl acetate : hexane,
1:1); Yield: 43%.
1H-NMR (C3D6O/DMSO, ppm) δ: 7.40-7.80 (m, 4H, ArH);
8.10Ϫ7.90 and 7.1Ϫ6.8 (m, 4H, 2-pyridyl); 4.00-3,90 [m, 4H,
N(CH2)2]; 1.80Ϫ1,60 (m, 6H, 3 ϫ CH2); IR (KBr, cm1) = 3318
(NH), 1764, 1710, 1634 (C=O), 1670(Ar C=C), 1398,1182
(S02); C20H19ClN4O4S requires C, 53.75; H, 4.29; N, 12.54;
found C, 53.48; H, 4.70; N%, 12.42; mp (°C): 194-196 (from
ethanol); Yield:17%.
Pharmacology
Writhing test
4-(3-Chloro-2,5-dioxo-4-piperidin-1-yl-2,5-dihydro-1H-pyrrol-
1-yl)-N-(4-metoxyphenyl) benzenesulphonamide (17)
1H-NMR (CDCl3, ppm) δ: 7.75-7.48 (m, 4H, ArH); 7.00-6.75
(m, 4H, ArH, C6H4OMe-p); 6.37 (s, 1H, NH); 4.00Ϫ3.90 [m,
4H, N(CH2)2]; 3.76 (s, 3H, OCH3); 1.80Ϫ1.70 (m, 6H, 3 ϫ
CH2); IR (KBr, cmϪ1) = 3284 (NH), 1760, 1708, 1622 (C=O),
1340, 1160 (SO2); C22H22ClN3O5S requires C, 55.52; H, 4.66;
N, 8.83; found C, 55.21; H, 4.75; N, 8.75%; mp (°C) 172-
173 (dry-flash chromatography, ethyl acetate : hexane, 1:1);
Yield: 73%.
Male Swiss mice (25Ϫ30 g, N = 6Ϫ8 animals for each dose)
were used. The abdominal constriction induced by intraperi-
toneal injection of acetic acid (0.6%) was carried out accord-
ing to the previously described procedures [13, 14] with minor
modifications. Within each of the dose ranges (Table 1) of
the studied compounds, three doses were selected and the
animals were pre-treated intraperitoneally with them 30 min
before the injection of acetic acid. The vehicle used for in-
jecting of the test compounds was 0.9% NaCl solution. When
necessary, an aqueous solution of DMSO (2%) was used in
order to dissolve some of the compounds. Control animals
received a similar volume of vehicle (10 mL kg-1, i.p.). All
experiments were carried out at 23 2°C. Pairs of mice were
placed in separate boxes and the number of abdominal con-
strictions of the abdominal muscles together with a stretching,
were cumulatively counted over a period of 20 min. Antino-
4-(3-Chloro-2,5-dioxo-4-piperidin-1-yl-2,5-dihydro-1H-pyrrol-
1-yl)-N-(4-methylphenyl) benzenesulphonamide (18)
1H-NMR (CDCl3, ppm) δ: 7.75Ϫ7.55 (m, 4H, ArH); 7.10Ϫ6.90
(m, 4H, ArH, C6H4CH3-p); 6.35 (s, 1H,NH); 4.00Ϫ3.90 [m,
4H, N(CH2)2]; 2.26 (s, 3H, CH3); 1.80Ϫ1.70 (m, 6H, 3 ϫ
CH2); IR (KBr, cmϪ1) = 3450 (NH), 1758, 1706, 1620 (C=O),
1594 (Ar C=C), 1332, 1164 (SO2); C22H22ClN3O4S requires
 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

206 Nunes et al.
Arch. Pharm. Pharm. Med. Chem. 2004, 337, 201−206
[4] A. Dray, Br. J. Anesth. 1995, 75, 125Ϫ131.
ciceptive activity was expressed as the reduction of the num-
ber of abdominal contractions between control animals and
mice pre-treated with the studied compound.
[5] A. Dray, S. Bevan, Trends Pharmacol. Sci., 1993, 14,
287-290.
Statistical Analysis
[6] H. P. Rang, S. Bevan, A. Dray, Brit. Med. Bull. 1991,
47, 534Ϫ548.
The results are presented as mean s.e.m., and the statisti-
cal significance between the groups was analyzed by means
of variance followed by Dunnett’s multiple comparison test. P
values less than 0.05 were considered as indicative of signifi-
cance. The ID50 values (concentration of the compound that
reduced responses by 50% with respect to control values)
were estimated by graphical interpolation from individual
experiments. ID50’s are presented as mean values with the
95% confidence interval.
[7] J. R. Vane, Nature, 1971, 231, 232Ϫ35.
ˆ
[8] R. Correa, Y. Tomazoni, C. P. Korobinki, Universidade
´
do Vale do Itajaı, unpublished results.
[9] V. Cechinel Filho, Z. Vaz, R. J. Nunes, J. B. Calixto, R.
A. Yunes, Pharmacol. Sci., 1996, 2, 1Ϫ3.
[10] V. Cechinel Filho, Z. R. Vaz, L. Zunino, J. B. Calixto, R. A
Yunes, Arzneim. Forsch./Drug Res. 2000, 50, 281Ϫ285.
[11] E. L. Martin, C. L. J. Dickson, J. Org. Chem., 1961, 26,
2032Ϫ2037.
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 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim