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264 Chapter - 5
CHAPTER 5
Synthesis characterization and
pharmacological activity of Nimesulide
based sulphonamides
265 Chapter - 5
5. Synthesis, Characterization and pharmacological
activity of Nimesulide based sulphonamides
5.1 Introduction
Sulfonamides play a versatile role in many medicinal chemistry
analogue programs, these are a very important class of compounds in
the pharmaceutical industry, being widely used anticancer, anti-
inflammatory and antiviral agents. Organic sulfur compounds are
widespread in numerous natural products and widely used as various
artificial chemicals. Not only the medicinal importance the sulfonamides
like Naphtholic naphthalene sulfonate containing sulfonamide group and
its derivatives can be used to synthesize universal dyes, acid dyes, and
cationic dyes.
There is an urgent need for processes involved in structural
modifications of lead compounds that enhance pharmacological activity,
improve pharmacokinetic properties, or reduce unwanted side effects in
the field of drug discovery. Epidemiological and animal model studies
have suggested that nonsteroidal anti-inflammatory drugs (NSAIDs) can
act as chemopreventive agents. A growing body of experimental and
epidemiological evidence suggests that the use of NSAIDs (non-steroidal
anti-inflammatory drugs) may decrease the incidence of mammary
cancer, tumor burden, and tumor volume.
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Celecoxib, a COX-2 (cyclooxygenase 2) selective inhibitor, shows
strong chemopreventive activity against mammary carcinoma in rats in
some studies.
1
In addition to COX inhibition, these small molecules could target
other molecular pathways. The COX-2 inhibitor nimesulide is able to
suppress the development of 2-amino-1-methyl-6-phenylimidazo [4,5-
b]pyridine (PhIP)-induced mammary gland carcinogenesis in rats .
Researchers proved that nimesulide also suppresses aromatase
activity and expression in several breast cancer cell lines In brief, COX-
2 inhibitors benefit breast cancer patients in several ways. Firstly, they
decrease PGE2 production which subsequently promotes tumor
invasiveness, angiogenesis, and progression. Secondly, they inhibit some
kinases which are related with tumor growth. Thirdly, they
decrease aromatase activity which is the key enzyme for
the biosynthesis of estrogen.
The cyclooxygenase-2 (COX-2) inhibitor nimesulide shows
anticancer effects in several cancer cell lines via COX-2-dependent and -
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independent mechanisms. The molecular structure of nimesulide was
used as a starting scaffold to design novel sulfonanilide analogs and
examine the structural features that contribute to this anticancer effect.
2
Other research demonstrated that nimesulide also suppressed
aromatase activity and expression in several breast cancer cell lines.
Nimesulide derivatives which do not have COX-2 inhibitory activity were
more active than nimesulide to target aromatase. Further study reveals
that several nimesulide analogs were able to selectively inhibit Her2
overexpressing breast cancer cell proliferation, which suggests that they
are potentially able to overcome AI resistant breast cancer cell growth.
Because of the unique character of nimesulide derivatives, we propose
that the modification of the structure might change the drug from a
COX-2 inhibitor to an anti-cancer agent.
Garcinol (camboginol) from the fruit rind of Guttiferae species
shows anti-carcinogenic and anti-inflammatory properties.
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Garcinol potently interferes with 5-lipoxygenase and microsomal
prostaglandin (PG) E2synthase enzymes that play pivotal roles
in inflammation and tumorigenesis.
In cell-free assays, garcinol inhibited the activity of purified 5-
lipoxygenase and blocked the mPGES-1-mediated conversion of PGH2 to
PGE2 with IC50 values of 0.1 and 0.3 μM respectively. Garcinol
suppressed 5-lipoxygenase product formation also in intact human
neutrophils and reduced PGE2 formation in interleukin-1β-stimulated
A549 human lung carcinoma cells as well as in human whole blood
stimulated by lipopolysaccharide. In contrast, neither Ca2+-ionophore
(A23187)-induced arachidonic acid release in neutrophils nor COX-2
activity in A549 cells or whole blood measured as formation of 6-keto
PGF1α, or isolated human recombinant COX-2 were significantly affected
by garcinol (≤30 μM). Together the high potency of garcinol to selectively
suppress PGE2 synthesis and 5-lipoxygenase product formation provides
a molecular basis for the anti-inflammatory and anti-carcinogenic effects
of garcinol and rationalizes its therapeutic use (Figure 5.1).
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Figure 5.1 Mechanism of anti-inflammatory and anti-carcenogenic
activity of gercinol
Arachidonic Acid
Gercinol LTA4
PGH2
Leukotrienes
PGI2 PGE2
PGI2 Synthase
mPGES-1
6-Keto PGF1
5-LipoxygenaseCOX-1COX-2
Nimesulide, a preferential COX-2 inhibitor is a non-carboxylic acid
nonsteroidal anti-inflammatory drug (NSAID) that has been in patient’s
use for the treatment of pain for more than 20 years.1 Derivatives of
nimesulide have shown antiviral, anticancer2 and COX-2 inhibiting3
properties.
We anticipated that combination of structural features of these
NSAIDs nimesulide (2) with substituted sulfonyl chlorides in a single
molecule would provide novel agents possessing potent pharmacological
activities. Herein we report the synthesis, structure analysis and in vitro
pharmacological evaluation of a series of hybrid molecules based on
sulfonamides.
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Figure 5.2 Design of novel molecules based on nimesulide and sulfonyl
Chlorides
O
NHSO2CH3
NO2
O
NHSO2CH3
NHSO2Ar
ArSO2Cl
2 A
Pharmacologically active derivatives of Nimesulide
Renard and his team reported4 the synthesis and the
pharmacological evaluation of pyridine analogues of nimesulide, a COX-2
preferential inhibitor. The cyclooxygenases inhibitory activities were
evaluated in vitro using a human whole blood mode. According to the in
vitro results, a selection of compounds exhibiting moderate to high COX-
2/COX-1 selectivity ratio were further evaluated in vivo in a moderate of
λ carrageenan-induced pleurisy in rats. Some of the selected compounds
(3) displayed similar or improved anti-inflammatory properties when
compared to nimesulide and celecoxib.
N
X
NHS
O
O
R
R = CH3, CF3X = O, S, NH
3
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Kavitha and his team have described a simple and rapid synthesis5
of novel cyclic substituted imides (4) from nimesulide. The aromatic
amine prepared from nimesulide was reacted with a variety of cyclic
anhydrides in the presence of sodium acetate to afford the desired
products. Some of the compounds synthesized showed anti-inflammatory
activity when tested in rats.
O
NHSO2CH3
N OO
4
Pyridinic analogues6 of nimesulide were given by Julemont and his
team. Compound 4, N-(3-phenoxy-4-pyridinyl)trifluoromethane
sulfonamide, showed in vitro a strong inhibitory activity on the two
cyclooxygenase enzymes, being more active but less COX-2 selective than
nimesulide. Physicochemical studies and structural analyses indicated
that the anionic sulfonamide species seemed to be the active form of
methanesulfonamides, which optimally interacted with COX enzymes
active sites.
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N
O
NHSO2CF3
5
A series of COX-2 selective inhibitor nimesulide derivatives were
synthesized.7 Their anti-cell proliferation activities were evaluated with a
long term estrogen deprived MCF-7aro (LTEDaro) breast cancer cell line,
which is the biological model of aromatase inhibitor resistance for
hormone dependent breast cancer. Compared to nimesulide which
inhibited LTEDaro cell proliferation with an IC50 at 170.30μM, several
new compounds showed IC50 close to 1.0 μM. The results suggest that A
position as 2, 5 dimethyl or dichloro benzyl is the best fit.
HNO
R2
R1
N
S OO
6
Julemont and his team has synthesized the pyridinic analogues of
nimesulide8 based on their major ionic state at the physiological pH of
7.4 the alkane sulfonamides 7 and the anionic trifluoromethane
sulfonamides 8 compounds. Pharmacological evaluation in vitro showed
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that pyridinium compounds are generally more selective toward COX-2
when compared to their pyridinic analogues. Compound (8) displayed a
better COX-2 selectivity when compared to nimesulide. Compound ()
showed a similar in vivo profile as nimesulide when tested in the rat aw
odema.
N
O
NHO2S
CH3
Cl
N
HN
NHO2S
CF3
7 8
Synthesis of a series of compounds9 structurally related to the
anti-inflammatory agent nimesulide has been accomplished via Pd-
catalyzed C–C bond forming reactions. Thus 4-iodo derivative, prepared
from nimesulide, participated in Sonogashira (9), Heck (10) and Suzuki
(11) coupling reactions to afford the corresponding alkynyl, alkenyl and
aryl substituted products. Some of the compounds synthesized were
tested for anti-inflammatory activities in vivo.
O
NHCOCH3
R
R = C(CH3)2OH, CH2(CH2)4CH3 C(CH3)3
O
NHCOCH3
R'
R' = CO2CH3 CO2C2H5 CO2nBu C2H5 CN
O
NHCOCH3
R'' = OCH3 CH2OH F
R''
9 10 11
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5.2 Present work
We report the synthesis of benzene sulfonamides as hybrid
molecules derived from nimesulide by straight forward sulfonylation of
the key intermediate nimesulide based N-(4-Amino-2-phenoxy-phenyl)-
methane sulfonamide with an appropriate and commercially available
sulfonyl chlorides. Thus reduction of 2 with Sn/HCl10 followed by the
treatment of 12 with sulfonyl chlorides 13 in the presence of chloroform
gave the compound 14a-d (Scheme 1).
Scheme 1
O
NHSO2CH3
NO2
O
NHSO2CH3
NH2
O
NHSO2CH3
HN
Sn/HCl ArSO2Cl (13)
SO2Ar
2 1214a-d
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Table 5.1 Comparison of Time and Yield of products 14a-d
Sl. No. ArSO2Cl
(13)
Product
(14)
Time & Yield
(%)
1.
S
O
O
Cl
CH3
13a
O
NHSO2CH3
HNS
O
O
CH3
14a
9 h / 48
2.
S
O
O
Cl
NHCOCH3
13b
O
NHSO2CH3
HNS
O
O
NHCOCH3
14b
8 h / 51
3.
S
O
O
Cl
Cl
13c
O
NHSO2CH3
HNS
O
O
Cl
14c
14 h / 31
4.
S
O
O
Cl
CH3H3C
13d
O
NHSO2CH3
HNS
O
O
CH3H3C
14d
14 h / 32
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All the compounds were characterized by spectral analysis IR,
MASS, and 1HNMR. Structure of the compound was characterized by X-
ray analysis and was found to be in the form of a monomer.
Figure 5.3 ORTEP view of compound N-[4-(4-methanesulfonylamino-3-
phenoxy phenylsulfamoyl)-phenyl]-acetamide (14b)
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5.3 Conclusion
In conclusion, reduction of nimesulide (2) followed by treating the
N-(4-Amino-2-phenoxy-phenyl)-methane sulfonamide (12) with different
sulfonyl chlorides (13a-d) provided novel benzene sulfonamide
derivatives. But unfortunately we were able to synthesize very few
compounds 14a-d, because of various drawbacks such as long reaction
time, tedious manipulations in the isolation of the pure products, and
very less yield. Many trials were made by changing the solvent, reaction
conditions, and the reagent, but we were not successful in preparing
these sulfonamides in good yield.
5.4 Experimental section
General procedure for the preparation of benzene sulfonamides
N-(4-amino-2-phenoxy phenyl)methanesulfonamide (12, 1 g, 3.56 mmol)
was dissolved in dry chloroform and triethylamine (0.6 mL) was added to
it. The solution was cooled to 0ºC and benzene sulfonyl chloride (13,
3.56 mmol) was added drop wise with stirring. The reaction mixture was
then stirred at room temperature for the time given in Table 5.1, poured
into water (20 mL) and extracted with chloroform (3 × 25 mL). Organic
layers were collected, combined, washed with 10% HCl (10 mL) followed
by water (2 × 10 mL), dried over anhydrous Na2SO4 and concentrated.
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The residue was purified by re-crystallization from chloroform ethyl
acetate mixture.
Preparation of N-(4-methanesulfonylamino-3-phenoxy-phenyl)-4-
methyl-benzenesulfonamide (14a):
O
NHSO2CH3
HNS
O
O
CH3
This compound was prepared according to the general procedure
using N-(4-amino-2-phenoxy phenyl)methanesulfonamide (12, 1 g, 0.003
mol), benzene sulfonyl chloride (13a, 0.52 g, 0.003 mol), triethylamine
(1.0 mL, 0.007 mol) and solvent (15 mL) as described in general
procedure to give 48% of the product as white solid; mp 142 ºC; IR (KBr
cm-1): 3331, 3230, 1659, 1590; MS (ES): m/z 433 (M+, 100%); 1H NMR
(200 MHz, DMSO-d6) δ 10. 2(s, 1H), 9.2 (s, 1H), 7.5-6.5 (m, 12H), 2.9 (s,
3H), 2.3 (s, 3H); Molecular formula: C20H20N2O5S2.
279 Chapter - 5
Synthesis of N-[4-(4-methanesulfonylamino-3-phenoxy
phenylsulfamoyl)-phenyl]-acetamide (14b):
O
NHSO2CH3
HNS
O
O
NHCOCH3
This compound was prepared according to the general procedure
using N-(4-amino-2-phenoxy phenyl)methanesulfonamide (12, 1 g, 0.003
mol), 4-Acetylamino-benzene sulfonyl chloride (13b, 0.696 g, 0.003 mol),
triethylamine (1.0 mL, 0.007 mol) and solvent (15 mL) as described in
general procedure to give 51% of the product as white solid; mp 186 ºC;
IR (KBr cm-1): 3231, 3315, 1658, 1604; MS (ES): m/z 476 (M+, 100%);
1HNMR (200 MHz, DMSO-d6): δ 9.87 (s, 1H), 9.77 (s, 1H), 8.17 (s, 1H),
6.74-7.78 (m, 12H), 2.16 (s, 3H), 2.89 (s, 3H), 9.77 (s, 1H), Molecular
formula: C21H21N3O6S2.
Synthesis of 4-Chloro-N-(4-methanesulfonylamino-3-phenoxy-
phenyl)-benzenesulfonamide (14c):
O
NHSO2CH3
HNS
O
O
Cl
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This compound was prepared according to the general procedure
using N-(4-amino-2-phenoxy phenyl)methanesulfonamide (12, 1 g, 0.003
mol), 4-chloro-benzene sulfonyl chloride (13c, 0.62 g, 0.003 mol),
triethylamine (1.0 mL, 0.007 mol) and solvent (15 mL) as described in
general procedure to give 31% of the product as off white solid; mp:
1580C; IR (KBr cm-1): 3386, 3318, 1692, 1590, 1090; MS (ES) m/z: 453
(M+, 100%), 1HNMR (400 MHz, DMSO-d6): δ 9.71 (bs, 1H, NH, D2O
exchangeable), 7.78 (m, 6H, ArH), 7.55 (d, 1H, J=12Hz), 7.44 (t, 2H,
J=12Hz), 7.23 (t, 1H, J=12Hz), 6.97 (d, 2H, J=12Hz), 6.12 (bs, 1H, NH,
D2O exchangeable), 2.01 (s, 3H); Molecular formula: C19H17ClN2O5S2.
Synthesis of N-(4-methanesulfonylamino-3-phenoxy-phenyl)-2,4-
dimethyl-benzenesulfonamide (14d):
O
NHSO2CH3
HNS
O
O
CH3H3C
This compound was prepared according to the general procedure
using N-(4-amino-2-phenoxy phenyl)methanesulfonamide (12, 1 g, 0.003
mol), 3,5-Dimethyl-benzene sulfonyl chloride (13d, 0.61 g, 0.003 mol),
triethylamine (1.0 mL, 0.007 mol) and solvent (15 mL) as described in
general procedure to give 32% of the product as white solid; mp: 164-
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1660C; IR (KBr cm-1): 3378, 3326, 1653, 1590; MS (ES) m/z: 447 (M+,
100%), 1HNMR (400 MHz, DMSO-d6): δ 10.58 (bs, 1H, NH, D2O
exchangeable), 9.21 (bs, 1H, NH, D2O exchangeable), 8.19 (s, 1H), 7.42
(m, 3H), 7.24-7.12 (M, 3H), 7.01-6.90 (m, 2H), 6.54 (s, 1H), 6.52 (m, 1H),
2.91 (s, 3H), 2.45 (s, 6H); Molecular formula: C21H22N2O5S2.
282 Chapter - 5
5.5 References
1. L. J. Roberts, J. D. Morrow, J. G. Hardman, L. E. eds. Limbird.
2001, 687. McGraw-Hill, New York.
2. S. Karakuş, S. G. Küçükgüzel, I. Küçükgüzel, E. D. Clercq, C.
Pannecouque, G Andrei, R. Snoeck, F. Şahin, O. F. Bayrak, Eur.
J. Med. Chem. 2009, 44, 3591.
3. C. Michaux, C. Charlier, F. Julémont, Leval, X. de Leval, JM.
Dogné, B. Pirotte, F. Durant, Eur. J. Med. Chem. 2005, 40, 1316.
4. R. Jean-Francois, A. Deniz, G. Nancy, B. Pirotte, X. de Levalt. J.
Med. Chem. 2009, 52, 5864–5871.
5. K.Kavitha, V. R. Reddy, K. MukkantI, S. Pal. J. Braz. Chem. Soc.
2010, 21, 6, 1060-1064.
6. F. Julemont, X. de Leval, C. Michaux, J. Damas, C. Charlier, F.
Durant, B. Pirotte, J. M. Dogne. J. Med. Chem. 2002, 45, 5182-
5185.
7. Bin Su, Shiuan Chen. Bioorg. Med. Chem. Lett. 2009, 19(23):
6733–6735
8. F. Julemont, X. de Leval, C. Michaux, R. Jean-Francüois, W. Jean-
Yves, M. Jean-Louis, J. Damas, D. Jean-Michel, B. Pirotte. J. Med.
Chem. 2004, 47, 6749-6759.
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9. D. Shylaprasad, C. Vijay kumar, K. Mukkanti, S. Pal. Appl.
Organometal. Chem. 2010, 24, 680–684.
10. S. Pericherla, J. Mareddy, R .D. P. Geetha, P. V. Gollapudi, S.
Pal, J. Braz. Chem Soc. 2007, 18, 384.
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5.6 Some important spectra of the compounds
Figure 5.4 1HNMR spectrum of N-(4-methanesulfonylamino-3-phenoxy-
phenyl)-4-methyl-benzenesulfonamide (14a)
Figure 5.5 13CNMR spectrum of N-(4-methanesulfonylamino-3-phenoxy-
phenyl)-4-methyl-benzenesulfonamide (14a)
O
NHSO2CH3
HNS
O
O
CH3
O
NHSO2CH3
HNS
O
O
CH3
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Figure 5.6 Mass spectrum of N-(4-methanesulfonylamino-3-phenoxy-phenyl)-
4-methyl-benzenesulfonamide (14a)
Figure 5.7 IR spectrum of N-(4-methanesulfonylamino-3-phenoxy-phenyl)-4-
methyl-benzenesulfonamide (14a)
O
NHSO2CH3
HNS
O
O
CH3
O
NHSO2CH3
HNS
O
O
CH3
286 Chapter - 5
Figure 5.8 1HNMR spectrum of N-[4-(4-methanesulfonylamino-3-phenoxy
phenylsulfamoyl) -phenyl]-acetamide (14b)
O
NHSO2CH3
HNS
O
O
NHCOCH3