Hindawi Publishing CorporationJournal of ChemistryVolume 2013 Article ID 816769 8 pageshttpdxdoiorg1011552013816769

Research ArticleNimesulide Based Novel Glycolamide EstersTheir Design Synthesis and Pharmacological Evaluation

Kavitha Kankanala12 Vangala Ranga Reddy3 Yumnam Priyadarshini Devi4

Lakshmi Narasu Mangamoori4 Khagga Mukkanti1 and Sarbani Pal2

1 Centre for Chemical Science and Technology IST JNTUH Kukatpally Hyderabad Andhra Pradesh 500085 India2Department of Chemistry MNR Degree and PG College Kukatpally Hyderabad Andhra Pradesh 500085 India3 Dr Reddyrsquos Laboratories Limited Integrated Product Development Bachupally Hyderabad Andhra Pradesh 500055 India4Centre for Biotechnology IST JNTUH Kukatpally Hyderabad Andhra Pradesh 500085 India

Correspondence should be addressed to Sarbani Pal sarbani277yahoocom

Received 16 May 2013 Accepted 31 July 2013

Academic Editor Weiguo Dai

Copyright copy 2013 Kavitha Kankanala et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

The nimesulide based novel glycolamide esters were designed and synthesized for the first time via a three-step methodstarting from nimesulide Structures of the synthesized compounds were confirmed by spectroscopic analysis All the synthesizedcompounds were examined for their cytotoxic effects in vitro some of which showed significant cytotoxic activities against HCT-15human colon cancer cell line

1 Introduction

Cancer is the second leading cause of death [1] worldwideafter cardiovascular diseases according to WHO Indeedlung breast stomach liver and colorectal cancers causethe most cancer deaths worldwide each year and thereforediscovery and development of suitable agents to treat varioustypes of cancer are highly desirable

Over the years glycolamide esters have attracted partic-ular attention as prodrugs of many pharmaceutically impor-tant molecules [2ndash4] because of their ability to undergo quickcleavage in human plasma to deliver the parent drugs Theseinclude glycolamide esters of aspirin [5] ibuprofen [6] niflu-mic acid [7] and scutellarin [8] that are reported as biolabileprodrugs of these drugs However studies have suggestedthat the rate of plasma catalyzed hydrolysis of glycolamideesters can be altered with the change of substituents onamide nitrogen atom [9ndash12] For example monosubstituted(ndashCO

2CH2CONHR) or unsubstituted (ndashCO

2CH2CONH

2)

glycolamide esters were found to be more resistant thanN N-disubstituted glycolamide esters (ndashCO

2CH2CONRR1015840)

Indeed some of these stable prodrugs were found to behavelike new chemical entities (NCEs) and have shown promisingpharmacological effects comparable to the parent drugs For

example Colfenamate (Figure 1) a glycolamide ester hasshown good analgesic and anti-inflammatory properties [13]These observations and our interest in novel cytotoxic agentsprompted us to synthesize and evaluate a library of newglycolamide esters A (Figure 1)

The design of our target molecules A was based on thestructural modifications of nimesulide [14ndash20] We antici-pated that combining the structural features of nimesulideand glycolamide esters in a single molecule may afford noveltemplate for the design and synthesis of new anticanceragents Notably the cyclooxygenase-2 (COX-2) inhibitornimesulide is known to possess anticancer properties [2122] whereas the glycolamide esters are known to impartfavorable pharmacological properties Herein we report thesynthesis and in vitro cytotoxic effects of a series of novelglycolamide esters A derived from nimesulide To the best ofour knowledge synthesis and pharmacological evaluation ofglycolamide esters derived from nimesulide are not known inthe literature

2 Experimental21 General Methods Melting points were determined byopen glass capillary method on a Cintex melting point

2 Journal of Chemistry

F3C NH

O O CONH2

NHSO2Me NHSO2Me

PhO

NO2HN

CO

OC

R

O

O

Colfenamate NimesulideA

Figure 1 Known glycolamide ester Colfenamate COX-2 inhibitor nimesulide and new glycolamide esters A

apparatus and are uncorrected IR spectra were recordedon a Perkin-Elmer spectrometer using KBr pellets 1HNMRspectra were recorded on a Bruker ACF-300 machine anda Varian 300 and 400MHz spectrometer using CDCl

3or

DMSO-d6 with reference to tetramethylsilane as an internal

reference 13CNMR spectra were recorded on a 75MHz spec-trometer Elemental analyses were performed by Varian 3 LVanalyzer series CHN analyzer Mass spectra were recordedon a Jeol JMCD-300 instrument by using electron ionizationat 70 ev All reactions were monitored by TLC on precoatedsilica gel plates Column chromatography was performed on100ndash200 mesh silica gel (SRL India) using 10ndash20 times (byweight) of the crude product All the carboxylic acids usedare commercially available

22 Synthesis of 2-Chloro-N-(4-methanesulfonylamino-3-phe-noxy-phenyl)-acetamide (2) 36mmol (1 g) of compound (1)was taken into a round bottomed flask To this 20mL ofCHCl

3and 06mL of Et

3N were added This mixture was

stirred and then cooled to 0∘C using an ice bath To thismixture 36mmol (05mL) of 120572-chloroacetyl chloride wasadded drop wise The mixture was then cooled to roomtemperature and stirring was continued for an additional30 minutes After completion of the reaction as indicatedby TLC the mixture was diluted with 10ndash15mL of coldwater which was then extracted with CHCl

3(3 times 20mL)

The organic layers were collected combined washed withwater dried over anhydrous Na

2SO4 filtered and concen-

trated under reduced pressure The crude product obtainedwas recrystallised from aqueous EtOH to give the titledcompound as an off-white solid mp 135-136∘C 119877

119891 045

(CHCl3 ethyl acetate = 9 1) IR (KBr) ]maxcm

minus1 3325 32651665 1611 1589 1H NMR (400MHz DMSO-119889

6) 120575 1030

(s 1H NHCO D2O exchangeable) 925 (s 1H NH D

2O

exchangeable) 750ndash740 (m 2H) 738ndash726 (m 2H) 721ndash714(m 2H) 710 (119889 119869 88Hz 2H) 420 (s 2H) 300 (s 3H)13CNMR (100MHz CDCl

3) 120575 1647 1554 1482 1348 1302

1247 1244 1231 1188 1156 1101 527 394 MS (119898119911) 355(M+ 100) 3572 (M++2 33) Elemental analysis found C5084 H 402 N 773 C

15H15ClN2O4S requires C 5078 H

426 N 790

23 General Procedure for the Synthesis of Glycolamide Esters(4a-l) A mixture of N-chloroacetamide (001mol) anappropriate acid (001mol) potassium iodide (0001mol)triethylamine (0011mol) and NN-dimethylformamide(10mL) was stirred for 15ndash45min (depending on the acidderivative) at 90∘C The reaction mixture was poured into

water (50mL) and extracted with ethyl acetate (3 times 50mL)The combined organic extracts were washedwith 2 aqueoussodium bicarbonate (50mL) and water (3 times 50mL) Theorganic layer was collected dried over anhydrous Na

2SO4

and evaporated under reduced pressure The crude productobtained was purified by column chromatography to get thecorresponding glycolamide esters (4a-l)

24 MTT Assay for Cytotoxicity The viability of the cellswas assessed by MTT [3 4 5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide] assay which is based on thereduction of MTT by the mitochondrial dehydrogenase ofintact cells to a purple formazan product Etoposide a knownanticancer drug was used as a reference compound in thisassay Cells (1times104) were plated in a 96-well plate After 24 hthey were treated with different concentrations (0ndash25120583M) ofdifferent test compounds diluted appropriately with culturemedia for 48 h Cells grown in media containing equivalentamount of DMSO served as positive control and cells inmedium without any supplementation were used as negativecontrol After the treatment media containing compoundwere carefully removed by aspiration 100 120583L of 04mgmLMTT in PBS was added to each well and incubated in thedark for 4 h 100 120583L of DMSO was added to each well andkept in an incubator for 4 h for dissolution of the formedformazan crystals The amount of formazan was determinedbymeasuring the absorbance at 540 nm using an ELISA platereaderThe data were presented as percent dead cells whereasabsorbance from nontreated control cells was defined as100 live cells The percent of dead cells was plotted (119910-axis) against concentration (119909-axis) of compounds whereIC50values could be interpolated from the graph

3 Results and Discussion

The key starting material that is 2-chloro-N-(4-meth-anesulfonylamino-3-phenoxy-phenyl)-acetamide (2) re-quired for our synthesis was prepared via chloroacetylationofN-(4-amino-2-phenoxyphenyl) methane sulfonamide [14](1 obtained from nimesulide) in dry CHCl

3in presence of

Et3N (Scheme 1)The chlorocompound 2 was well characterized by using

MS IR 1H and 13C NMR spectroscopic techniques Forexample the IR spectrum showed absorption at 1665 (C=Ostretching) 3325 and 3265 cmminus1 (NH stretching) whereas1HNMR spectrum recorded in DMSO-119889

6displayed two

singlets at 120575 420 and 296 ppm due to CH2and CH

3

groups respectively The presence of NH groups was further

Journal of Chemistry 3

NHSO2Me NHSO2MeNHSO2Me

OPh OPhOPhSnHCl

NO2

Nimesulide

90∘C 3 hNH2

ClCH2COCl

HNCO

ClEt3N CHCl3

0∘C-rt

1 2

Scheme 1 Synthesis of key starting material 2

NHSO2Me NHSO2Me

OPhOPh

OPh

HNCO

HNC

C

O

O

OO

Cl

NHSO2Me

HN N+

NCH3

CH3R

DMAPEt3N rt

RCOOH (3)

2 4 5

Scheme 2 The reaction of chloro compound 2 with carboxylic acids 3

indicated by the disappearance of two peaks at 120575 1046 and922 ppm in D

2O exchange experiment Moreover the 13C

signals at 1647 527 and 394 ppm indicated the presenceof amide carbonyl CH

2and CH

3groups respectively

Having prepared the starting material 2 we then treatedthis chloroderivative with commercially available carboxylicacids in the presence of catalytic amount of 119873 119873-dimethyl-4-aminopyridine [9] using Et

3N as a base (Scheme 2) To

our surprise instead of the desired glycolamide esters (4)we isolated a white solid with the melting point 264-265∘Cirrespective of acid partner employed Based on the spectraldata (IR 1H amp 13C NMR and MS) the isolated solid wasconfirmed as 2-(4-dimethylamino-pyridin-1-yl)-N-(4-meth-anesulfonylamino-3-phenoxy-phenylcarbamoyl)-methylester (5) It was evident that DMAP reacted better thanthe acid 3 with the chloro compound 2 perhaps due to itspredominant role as a nucleophile rather than a base underthe reaction conditions employed We therefore decided toomit its use in our subsequent studies

We then performed the reaction of 2 with 3 under amodified reaction conditions that is in the presence ofpotassium iodide and Et

3N To our satisfaction the desired

product 4 was isolated in good yields and the results aresummarized in Table 1 It is evident from Table 1 that bothaliphatic and aromatic acids participated well in the presentreaction and a range of nimesulide based glycolamide esters(4) were prepared by using this methodology All the com-pounds synthesized were well characterized by spectral dataFor example compound 4a showed IR signals at 1742 (estercarbonyl) and 1677 cmminus1 (amide carbonyl) respectively Theappearance of two singlets at 120575 220 for 3H and 120575 464 for2H in 1H NMR spectrum of 4a confirmed the presenceof ndashCOMe and CH

2groups respectively In 13C NMR

appearance of 15 signals was highly consistent with the 15nonequivalent carbon atoms of the compound 4a Moreoverthe ester and amide carbonyls appear at120575 1699 and 1655 ppmwhereas the CH

2group appeared at 120575 624 ppm

All the glycolamide esters 4 synthesized were tested invitro against HCT-15 human colon cancer cell line basedon an MTT [3-(45-dimethylthiazol-2-yl)-25-diphenyltetra-zolium bromide] assay (Table 2) [23] Defined as a cancerfrom uncontrolled cell growth in the colon or rectum (partsof the large intestine) or in the appendix colon cancer(commonly known as colorectal cancer or bowel cancer) isthe third most commonly diagnosed cancer in the worldIt was estimated in 2008 that worldwide 123 million newcases of colorectal cancer were clinically diagnosed and thatit killed 608000 people [24] This prompted us to focus oncolon cancer In our present assay the percentage of cell deathwas measured for each compound at various concentrationsand finally the IC

50(half maximal inhibitory concentration)

values were determined to measure the cytotoxic activitiesThe IC

50is inversely proportional to the cytotoxicity of a

compound that is the lower the IC50value is the higher the

activity is In general most of the compounds were found tobe active against the HCT-15 colon cancer cell line at 25 120583MNotable among them are 4d (Entry 4 Table 2) 4f (Entry6 Table 2) 4g (Entry 7 Table 2) 4i (Entry 9 Table 2) 4j(Entry 10 Table 2) 4k (Entry 11 Table 2) and 4l (Entry 12Table 2) that showed gt40 inhibition at 25120583M It is evidentthat an aryl group attached to the ester carbonyl moiety wasgenerally more favorable than an alkyl group for activity(eg 4a-b versus 4c-f) While insertion of an olefin moietybetween the ester carbonyl and the aryl group was tolerated(eg 4g) a naphthylmethyl group (eg 4h) attached to thecarbonyl moiety decreased the activity However a benzylgroup having substituent at 119901- or 119900-position (eg 4j-l) wasfavorable for activity A graphical presentation of in vitrocytotoxic activities of compound 4l against HCT-15 humancolon cancer cell line is shown in Figure 2 The IC

50values

of most active compounds that is 4j 4k and 4l werefound to be 2440 2240 and 1892 120583M respectively Thusthe compound 4l (calculated average Log119875 = 283 plusmn 046 andaverage log 119878 = minus604 versus 175 plusmn 026 and minus424 resp ofcompound 1 [25]) was identified as the best active compound

4 Journal of Chemistry

Table 1 Synthesis of nimesulide based glycomide esters 4a

NHSO2MeNHSO2Me

OPh OPh

HNC

OCl

HNC

CO

OO

R

KI Et3NDMF 90∘C

RCOOH (3)

2 4

Entry RCOOH (3)R = Products (4) Time

(min) yieldb

(1)

CH3

3a

NHSO2MeOPh

4a

HNC

CO

OO Me

30 91

(2) 3bCH2CH3

OPh

4b

HNC

C

O

O

O

NHSO2Me

C2H5

30 95

(3)

3c

OPh

4c

HNC

C

OO

O

Ph

NHSO2Me

20 80

(4)

3d

H3COPh

4d

HNC

C

O

O

O

Me

NHSO2Me

30 90

(5)

3eOMe

OPh

4e

HNC

C

O

O

O

OMe

NHSO2Me

30 70

Journal of Chemistry 5

Table 1 Continued

(6)

3fNO2

OPh

4f

HNC

C

O

O

O

NHSO2Me

NO2

15 75

(7)

3g

CCH

HOPh

4g

HNC

C CCH

H

O

O

O

NHSO2Me

10 98

(8)

3hMe

OMe OPh

4h

HNC

C

O

O

OMe

OMe

NHSO2Me

30 78

(9)

3iMe

Me

Me OPh

4i

HNC

C

O

O

OMe

Me

Me

NHSO2Me

45 80

(10)

3j

NH

Cl

Cl

OPh

4j

HNC

C

O

O

ON

H

Cl

Cl

NHSO2Me

15 92

(11)

3k

NH

Me

MeOPh

4k

HNC

C

O

O

OMe

MeHN

NHSO2Me

30 90

6 Journal of Chemistry

Table 1 Continued

(12)

3l

OCOMe

OPh

4l

HNC

C

O

O

O

OCOMe

NHSO2Me

15 90

aAll the reactions were performed using chlorocompound 2 (001mmol) and acid 3 (001mol) in the presence of NaI (0001mol) Et3N (0011mmol) and DMF(15mL) at 90∘CbIsolated yield

Table 2 In vitro cytotoxic activity of compound 4 against HCT-15 human colon cancer cell line

Entry Compounds of cell death at various concentrationsa IC50 (120583M)1 120583M 2 120583M 5120583M 10120583M 25 120583M

1 4a 094 689 815 877 2030 nd2 4b 062 720 750 1850 2850 nd3 4c 031 125 250 752 3100 nd4 4d 343 453 2169 3578 4938 nd5 4e 188 658 1316 1755 2880 nd6 4f 588 1446 2022 2500 4240 nd7 4g 600 796 1446 1862 4191 nd8 4h 031 752 877 1220 1940 nd9 4i 735 1237 1495 1629 4889 nd10 4j 674 943 2561 3590 5122 2440 plusmn 01411 4k 0 596 1220 3070 5579 2240 plusmn 13112 4l 2169 2193 2450 3002 6605 1892 plusmn 009aAll the values are the average of the experiments done in triplicates Etoposide (IC50 = 985120583M) was used as a reference compound nd not done

in this series Notably the IC50value of nimesulide was found

to be gt150120583M [26] whereas its reduced product did not showsignificant activities

Since the colon cancer is common in developed countriesthe present class of glycolamide esters has medicinal valueIt is worthy to mention that nimesulide is a banned drugin many countries because of its potential liver toxicity Theobserved liver toxicity of nimesulide has often been linkedto its uncoupling effects on mitochondria and study hasshown that nimesulide exerts this effect via a protonophoreticmechanism as well as oxidation of mitochondrial NADH andNADPH [27] The nitro group of nimesulide was thoughtto be responsible for its protonophoretic and NAD(P)Hoxidizing properties as chemical reduction of ndashNO

2to ndashNH

2

completely suppressed these activitiesThus the present classof compounds that does not contain a nitro group on the ndashNHSO

2Mebearing phenyl ring is expected to be free from the

liver toxicities of nimesulide We also performed the stabilitystudies using the compound 4l in the presence of 50mMtris buffer (pH 74) initially where 60 of 4l was found toremain unchanged after 2 h incubation in buffer This studyindicated that the present class of compounds perhaps isnot susceptible towards rapid ester hydrolysis Moreover notbeing the direct prodrug of nimesulide these compounds

would not provide nimesulide as such after ester hydrolysisThus these compounds are expected to be free from thegastric ulceration problem of nimesulide or other NSAIDs(nonsteroidal anti-inflammatory drugs)

Recently a nimesulide analogue obtained via its chemicalmodification that is replacing the phenyl ether moiety by anaryl ether and the nitro group by a cyclohexyl carboxamidemoiety showed suppression of three breast cancer cell pro-liferation types in a dose dependent manner [21] While theanticancer molecular target of this compound was not clearlyunderstood the cytochrome 119888 release assay indicated that theapoptosis induced by this compound was mediated throughthe mitochondria Due to the structural similarities with thiscompound present series of glycolamide esters might followsimilar cytochrome 119888 dependent mechanisms Neverthelessour study indicates that the glycolamide esters derived fromnimesulide [28ndash30] are of further interest

4 Conclusions

In conclusion we have successfully accomplished the synthe-sis of several new nimesulide based glycolamide esters via athree-step method starting from nimesulide in good yieldsStructures of the synthesized compounds were confirmed

Journal of Chemistry 7

0 5 10 15 20 25

100

80

60

40

20

0

Viab

le ce

lls (

)

Viable cells ()Death cells ()

Concentration (120583gmL)

Figure 2 Graphical presentation of in vitro cytotoxic activity ofcompound 4l against HCT-15 human colon cancer cell line

by spectroscopic analysis All the synthesized compoundswere examined for their cytotoxic effects in vitro Some ofthe compounds showed significant cytotoxic activities againstHCT-15 human colon cancer cell line Overall the presentnimesulide based glycolamide ester framework appeared tobe a useful template for the design and identification of noveland potential anticancer agents

Acknowledgment

The authors (Kavitha Kankanala and Sarbani Pal) thank MrM N Raju the chairman of M N R Educational Trust forhis constant encouragement

References

[1] D M Parkin F Bray J Ferlay and P Pisani ldquoGlobal cancerstatistics 2002rdquo CA Cancer Journal for Clinicians vol 55 no2 pp 74ndash108 2005

[2] N M Nielsen and H Bundgaard ldquoGlycolamide esters asbiolabile prodrugs of carboxylic acid agents synthesis stabilitybioconversion and physicochemical propertiesrdquo Journal ofPharmaceutical Sciences vol 77 no 4 pp 285ndash298 1988

[3] L K Wadhwa and P D Sharma ldquoGlycolamide esters of 6-methoxy-2-naphthylacetic acid as potential prodrugs-syntheticand spectral studiesrdquo Indian Journal of Chemistry vol 34 pp408ndash415 1995

[4] P D Sharma K J Singh S Gupta and S Chandiran ldquoGly-colamide esters of 4-biphenylacetic acid as potential prodrugs-synthetic and spectral studiesrdquo Indian Journal of Chemistry vol43 no 3 pp 636ndash642 2004

[5] N M Nielsen and H Bundgaard ldquoEvaluation of glycolamideesters and various other esters of aspirin as true aspirinprodrugsrdquo Journal of Medicinal Chemistry vol 32 no 3 pp727ndash734 1989

[6] A K Bansal R K Khar R Dubey and A K Sharma ldquoActiv-ity profile of glycolamide ester prodrugs of ibuprofenrdquo Drug

Development and Industrial Pharmacy vol 27 no 1 pp 63ndash702001

[7] A K Gadad S Bhat V S Tegeli and V V Redasani ldquoSynthesisspectral studies and anti-inflammatory activity of glycolamideesters of niflumic acid as potential prodrugsrdquo Arzneimittel-Forschung vol 52 no 11 pp 817ndash821 2002

[8] F Cao J-X Guo Q-N Ping and Z-G Liao ldquoProdrugsof scutellarin ethyl benzyl and NN-diethylglycolamide estersynthesis physicochemical properties intestinal metabolismand oral bioavailability in the ratsrdquo European Journal of Phar-maceutical Sciences vol 29 no 5 pp 385ndash393 2006

[9] S Khanna M Madan A Vangoori et al ldquoEvaluation of gly-colamide esters of indomethacin as potential cyclooxygenase-2(COX-2) inhibitorsrdquo Bioorganic and Medicinal Chemistry vol14 no 14 pp 4820ndash4833 2006

[10] CNNalini S Ramachandran K Kavitha andV S SaraswathildquoGlycolamide esters of naproxen as potential prodrugsmdashsynthesis spectral studies and preliminary pharmacologicalscreeningrdquo International Journal of Research in Pharmaceuticaland Biomedical Sciences vol 2 pp 1112ndash1117 2011

[11] M Amblard M Rodriguez and J Martinez ldquoN-benzhydryl-glycolamide esters (OBg esters) as carboxyl protecting groupsin pept1de synthesisrdquo Tetrahedron vol 44 no 16 pp 5101ndash51081988

[12] W J Hoekstra ldquoOrally-active nipecotamide glycolamide estersfor the treatment of thrombosis disorderrdquo US patent noUS6066651 2000

[13] KH Boltze andHKreisfeld ldquoOn the chemistry of etofenamatea novel antiinflammatory agent from the series of N arylan-thranilic acid derivativesrdquo Arzneimittel-Forschung vol 27 no6 b pp 1300ndash1312 1977

[14] S Pericherla J Mareddy D P Geetha Rani P V Gollapudi andS Pal ldquoChemical modifications of nimesuliderdquo Journal of theBrazilian Chemical Society vol 18 no 2 pp 384ndash390 2007

[15] L V Reddy M Nakka A Suman et al ldquoSynthesis of novelquinoline analogues of nimesulide an unusual observationrdquoJournal of Heterocyclic Chemistry vol 48 no 3 pp 555ndash5622011

[16] S Durgadas V K Chatare KMukkanti and S Pal ldquoPalladium-mediated synthesis of novel nimesulide derivativesrdquo AppliedOrganometallic Chemistry vol 24 no 10 pp 680ndash684 2010

[17] L V Reddy M Kethavath M Nakka et al ldquoDesign and syn-thesis of novel cytotoxic agents based on combined frameworkof quinoline and nimesuliderdquo Journal of Heterocyclic Chemistryvol 49 no 1 pp 80ndash87 2012

[18] K Kankanala V R Reddy K Mukkanti and S Pal ldquoLewisacid free high speed synthesis of nimesulide-based novel N-substituted cyclic imidesrdquo Journal of the Brazilian ChemicalSociety vol 21 no 6 pp 1060ndash1064 2010

[19] A Bhattacharya S Ghosh K Kankanala et al ldquoCrystal struc-ture and electronic properties of two nimesulide derivatives acombined X-ray powder diffraction and quantum mechanicalstudyrdquo Chemical Physics Letters vol 493 no 1ndash3 pp 151ndash1572010

[20] K Kankanala V Prakash K Mukkanti V R Reddy and S PalldquoN-(4-Methylsulfonamido-3-phenoxyphenyl)-910-dihydro-910-ethanoanthracene-1112-dicarboximiderdquo MolBank vol2011 article M740 2011

[21] B Chen B Su and S Chen ldquoA COX-2 inhibitor nimesulideanalog selectively induces apoptosis in Her2 overexpressingbreast cancer cells via cytochrome c dependent mechanismsrdquoBiochemical Pharmacology vol 77 no 12 pp 1787ndash1794 2009

8 Journal of Chemistry

[22] S Joudieh M Lahiani-Skiba P Bon O Ba J M Le Bretonand M Skiba ldquoNimesulide apparent solubility enhancementwith natural cyclodextrins and their polymersrdquo Letters in DrugDesign and Discovery vol 5 no 6 pp 406ndash415 2008

[23] T Mosmann ldquoRapid colorimetric assay for cellular growth andsurvival application to proliferation and cytotoxicity assaysrdquoJournal of Immunological Methods vol 65 no 1-2 pp 55ndash631983

[24] J Ferlay H R Shin F Bray D Forman C Mathers and DM Parkin ldquoColorectal cancer incidence mortality and prev-alence worldwide in 2008 Summaryrdquo in Proceedings of theGLOBOCAN 2008

[25] The ALOGPS 21 program was used to calculate the aver-age logP and average logs values httpwwwvcclaborglabalogpsstarthtml

[26] R Davis and R N Brogden ldquoNimesulide An update ofits pharmacodynamic and pharmacokinetic properties andtherapeutic efficacyrdquo Drugs vol 48 no 3 pp 431ndash454 1994

[27] F EMingatto ACDos Santos T Rodrigues AA Pigoso S AUyemura and C Curti ldquoEffects of nimesulide and its reducedmetabolite on mitochondriardquo British Journal of Pharmacologyvol 131 no 6 pp 1154ndash1160 2000

[28] B Su and S Chen ldquoLead optimization of COX-2 inhibitornimesulide analogs to overcome aromatase inhibitor resistancein breast cancer cellsrdquo Bioorganic and Medicinal ChemistryLetters vol 19 no 23 pp 6733ndash6735 2009

[29] B Zhong R Lama K M Smith Y Xu and B Su ldquoDesign andsynthesis of a biotinylated probe of COX-2 inhibitor nimesulideanalog JCC76rdquo Bioorganic andMedicinal Chemistry Letters vol21 no 18 pp 5324ndash5327 2011

[30] B Zhong X Cai S Chennamaneni et al ldquoFrom COX-2 inhib-itor nimesulide to potent anti-cancer agent synthesis in vitroin vivo and pharmacokinetic evaluationrdquo European Journal ofMedicinal Chemistry vol 47 no 1 pp 432ndash444 2012

Impact Factor 173028 Days Fast Track Peer ReviewAll Subject Areas of ScienceSubmit at httpwwwtswjcom

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

2 Journal of Chemistry

F3C NH

O O CONH2

NHSO2Me NHSO2Me

PhO

NO2HN

CO

OC

R

O

O

Colfenamate NimesulideA

Figure 1 Known glycolamide ester Colfenamate COX-2 inhibitor nimesulide and new glycolamide esters A

apparatus and are uncorrected IR spectra were recordedon a Perkin-Elmer spectrometer using KBr pellets 1HNMRspectra were recorded on a Bruker ACF-300 machine anda Varian 300 and 400MHz spectrometer using CDCl

3or

DMSO-d6 with reference to tetramethylsilane as an internal

reference 13CNMR spectra were recorded on a 75MHz spec-trometer Elemental analyses were performed by Varian 3 LVanalyzer series CHN analyzer Mass spectra were recordedon a Jeol JMCD-300 instrument by using electron ionizationat 70 ev All reactions were monitored by TLC on precoatedsilica gel plates Column chromatography was performed on100ndash200 mesh silica gel (SRL India) using 10ndash20 times (byweight) of the crude product All the carboxylic acids usedare commercially available

22 Synthesis of 2-Chloro-N-(4-methanesulfonylamino-3-phe-noxy-phenyl)-acetamide (2) 36mmol (1 g) of compound (1)was taken into a round bottomed flask To this 20mL ofCHCl

3and 06mL of Et

3N were added This mixture was

stirred and then cooled to 0∘C using an ice bath To thismixture 36mmol (05mL) of 120572-chloroacetyl chloride wasadded drop wise The mixture was then cooled to roomtemperature and stirring was continued for an additional30 minutes After completion of the reaction as indicatedby TLC the mixture was diluted with 10ndash15mL of coldwater which was then extracted with CHCl

3(3 times 20mL)

The organic layers were collected combined washed withwater dried over anhydrous Na

2SO4 filtered and concen-

trated under reduced pressure The crude product obtainedwas recrystallised from aqueous EtOH to give the titledcompound as an off-white solid mp 135-136∘C 119877

119891 045

(CHCl3 ethyl acetate = 9 1) IR (KBr) ]maxcm

minus1 3325 32651665 1611 1589 1H NMR (400MHz DMSO-119889

6) 120575 1030

(s 1H NHCO D2O exchangeable) 925 (s 1H NH D

2O

exchangeable) 750ndash740 (m 2H) 738ndash726 (m 2H) 721ndash714(m 2H) 710 (119889 119869 88Hz 2H) 420 (s 2H) 300 (s 3H)13CNMR (100MHz CDCl

3) 120575 1647 1554 1482 1348 1302

1247 1244 1231 1188 1156 1101 527 394 MS (119898119911) 355(M+ 100) 3572 (M++2 33) Elemental analysis found C5084 H 402 N 773 C

15H15ClN2O4S requires C 5078 H

426 N 790

23 General Procedure for the Synthesis of Glycolamide Esters(4a-l) A mixture of N-chloroacetamide (001mol) anappropriate acid (001mol) potassium iodide (0001mol)triethylamine (0011mol) and NN-dimethylformamide(10mL) was stirred for 15ndash45min (depending on the acidderivative) at 90∘C The reaction mixture was poured into

water (50mL) and extracted with ethyl acetate (3 times 50mL)The combined organic extracts were washedwith 2 aqueoussodium bicarbonate (50mL) and water (3 times 50mL) Theorganic layer was collected dried over anhydrous Na

2SO4

and evaporated under reduced pressure The crude productobtained was purified by column chromatography to get thecorresponding glycolamide esters (4a-l)

24 MTT Assay for Cytotoxicity The viability of the cellswas assessed by MTT [3 4 5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide] assay which is based on thereduction of MTT by the mitochondrial dehydrogenase ofintact cells to a purple formazan product Etoposide a knownanticancer drug was used as a reference compound in thisassay Cells (1times104) were plated in a 96-well plate After 24 hthey were treated with different concentrations (0ndash25120583M) ofdifferent test compounds diluted appropriately with culturemedia for 48 h Cells grown in media containing equivalentamount of DMSO served as positive control and cells inmedium without any supplementation were used as negativecontrol After the treatment media containing compoundwere carefully removed by aspiration 100 120583L of 04mgmLMTT in PBS was added to each well and incubated in thedark for 4 h 100 120583L of DMSO was added to each well andkept in an incubator for 4 h for dissolution of the formedformazan crystals The amount of formazan was determinedbymeasuring the absorbance at 540 nm using an ELISA platereaderThe data were presented as percent dead cells whereasabsorbance from nontreated control cells was defined as100 live cells The percent of dead cells was plotted (119910-axis) against concentration (119909-axis) of compounds whereIC50values could be interpolated from the graph

3 Results and Discussion

The key starting material that is 2-chloro-N-(4-meth-anesulfonylamino-3-phenoxy-phenyl)-acetamide (2) re-quired for our synthesis was prepared via chloroacetylationofN-(4-amino-2-phenoxyphenyl) methane sulfonamide [14](1 obtained from nimesulide) in dry CHCl

3in presence of

Et3N (Scheme 1)The chlorocompound 2 was well characterized by using

MS IR 1H and 13C NMR spectroscopic techniques Forexample the IR spectrum showed absorption at 1665 (C=Ostretching) 3325 and 3265 cmminus1 (NH stretching) whereas1HNMR spectrum recorded in DMSO-119889

6displayed two

singlets at 120575 420 and 296 ppm due to CH2and CH

3

groups respectively The presence of NH groups was further

Journal of Chemistry 3

NHSO2Me NHSO2MeNHSO2Me

OPh OPhOPhSnHCl

NO2

Nimesulide

90∘C 3 hNH2

ClCH2COCl

HNCO

ClEt3N CHCl3

0∘C-rt

1 2

Scheme 1 Synthesis of key starting material 2

NHSO2Me NHSO2Me

OPhOPh

OPh

HNCO

HNC

C

O

O

OO

Cl

NHSO2Me

HN N+

NCH3

CH3R

DMAPEt3N rt

RCOOH (3)

2 4 5

Scheme 2 The reaction of chloro compound 2 with carboxylic acids 3

indicated by the disappearance of two peaks at 120575 1046 and922 ppm in D

2O exchange experiment Moreover the 13C

signals at 1647 527 and 394 ppm indicated the presenceof amide carbonyl CH

2and CH

3groups respectively

Having prepared the starting material 2 we then treatedthis chloroderivative with commercially available carboxylicacids in the presence of catalytic amount of 119873 119873-dimethyl-4-aminopyridine [9] using Et

3N as a base (Scheme 2) To

our surprise instead of the desired glycolamide esters (4)we isolated a white solid with the melting point 264-265∘Cirrespective of acid partner employed Based on the spectraldata (IR 1H amp 13C NMR and MS) the isolated solid wasconfirmed as 2-(4-dimethylamino-pyridin-1-yl)-N-(4-meth-anesulfonylamino-3-phenoxy-phenylcarbamoyl)-methylester (5) It was evident that DMAP reacted better thanthe acid 3 with the chloro compound 2 perhaps due to itspredominant role as a nucleophile rather than a base underthe reaction conditions employed We therefore decided toomit its use in our subsequent studies

We then performed the reaction of 2 with 3 under amodified reaction conditions that is in the presence ofpotassium iodide and Et

3N To our satisfaction the desired

product 4 was isolated in good yields and the results aresummarized in Table 1 It is evident from Table 1 that bothaliphatic and aromatic acids participated well in the presentreaction and a range of nimesulide based glycolamide esters(4) were prepared by using this methodology All the com-pounds synthesized were well characterized by spectral dataFor example compound 4a showed IR signals at 1742 (estercarbonyl) and 1677 cmminus1 (amide carbonyl) respectively Theappearance of two singlets at 120575 220 for 3H and 120575 464 for2H in 1H NMR spectrum of 4a confirmed the presenceof ndashCOMe and CH

2groups respectively In 13C NMR

appearance of 15 signals was highly consistent with the 15nonequivalent carbon atoms of the compound 4a Moreoverthe ester and amide carbonyls appear at120575 1699 and 1655 ppmwhereas the CH

2group appeared at 120575 624 ppm

All the glycolamide esters 4 synthesized were tested invitro against HCT-15 human colon cancer cell line basedon an MTT [3-(45-dimethylthiazol-2-yl)-25-diphenyltetra-zolium bromide] assay (Table 2) [23] Defined as a cancerfrom uncontrolled cell growth in the colon or rectum (partsof the large intestine) or in the appendix colon cancer(commonly known as colorectal cancer or bowel cancer) isthe third most commonly diagnosed cancer in the worldIt was estimated in 2008 that worldwide 123 million newcases of colorectal cancer were clinically diagnosed and thatit killed 608000 people [24] This prompted us to focus oncolon cancer In our present assay the percentage of cell deathwas measured for each compound at various concentrationsand finally the IC

50(half maximal inhibitory concentration)

values were determined to measure the cytotoxic activitiesThe IC

50is inversely proportional to the cytotoxicity of a

compound that is the lower the IC50value is the higher the

activity is In general most of the compounds were found tobe active against the HCT-15 colon cancer cell line at 25 120583MNotable among them are 4d (Entry 4 Table 2) 4f (Entry6 Table 2) 4g (Entry 7 Table 2) 4i (Entry 9 Table 2) 4j(Entry 10 Table 2) 4k (Entry 11 Table 2) and 4l (Entry 12Table 2) that showed gt40 inhibition at 25120583M It is evidentthat an aryl group attached to the ester carbonyl moiety wasgenerally more favorable than an alkyl group for activity(eg 4a-b versus 4c-f) While insertion of an olefin moietybetween the ester carbonyl and the aryl group was tolerated(eg 4g) a naphthylmethyl group (eg 4h) attached to thecarbonyl moiety decreased the activity However a benzylgroup having substituent at 119901- or 119900-position (eg 4j-l) wasfavorable for activity A graphical presentation of in vitrocytotoxic activities of compound 4l against HCT-15 humancolon cancer cell line is shown in Figure 2 The IC

50values

of most active compounds that is 4j 4k and 4l werefound to be 2440 2240 and 1892 120583M respectively Thusthe compound 4l (calculated average Log119875 = 283 plusmn 046 andaverage log 119878 = minus604 versus 175 plusmn 026 and minus424 resp ofcompound 1 [25]) was identified as the best active compound

4 Journal of Chemistry

Table 1 Synthesis of nimesulide based glycomide esters 4a

NHSO2MeNHSO2Me

OPh OPh

HNC

OCl

HNC

CO

OO

R

KI Et3NDMF 90∘C

RCOOH (3)

2 4

Entry RCOOH (3)R = Products (4) Time

(min) yieldb

(1)

CH3

3a

NHSO2MeOPh

4a

HNC

CO

OO Me

30 91

(2) 3bCH2CH3

OPh

4b

HNC

C

O

O

O

NHSO2Me

C2H5

30 95

(3)

3c

OPh

4c

HNC

C

OO

O

Ph

NHSO2Me

20 80

(4)

3d

H3COPh

4d

HNC

C

O

O

O

Me

NHSO2Me

30 90

(5)

3eOMe

OPh

4e

HNC

C

O

O

O

OMe

NHSO2Me

30 70

Journal of Chemistry 5

Table 1 Continued

(6)

3fNO2

OPh

4f

HNC

C

O

O

O

NHSO2Me

NO2

15 75

(7)

3g

CCH

HOPh

4g

HNC

C CCH

H

O

O

O

NHSO2Me

10 98

(8)

3hMe

OMe OPh

4h

HNC

C

O

O

OMe

OMe

NHSO2Me

30 78

(9)

3iMe

Me

Me OPh

4i

HNC

C

O

O

OMe

Me

Me

NHSO2Me

45 80

(10)

3j

NH

Cl

Cl

OPh

4j

HNC

C

O

O

ON

H

Cl

Cl

NHSO2Me

15 92

(11)

3k

NH

Me

MeOPh

4k

HNC

C

O

O

OMe

MeHN

NHSO2Me

30 90

6 Journal of Chemistry

Table 1 Continued

(12)

3l

OCOMe

OPh

4l

HNC

C

O

O

O

OCOMe

NHSO2Me

15 90

aAll the reactions were performed using chlorocompound 2 (001mmol) and acid 3 (001mol) in the presence of NaI (0001mol) Et3N (0011mmol) and DMF(15mL) at 90∘CbIsolated yield

Table 2 In vitro cytotoxic activity of compound 4 against HCT-15 human colon cancer cell line

Entry Compounds of cell death at various concentrationsa IC50 (120583M)1 120583M 2 120583M 5120583M 10120583M 25 120583M

1 4a 094 689 815 877 2030 nd2 4b 062 720 750 1850 2850 nd3 4c 031 125 250 752 3100 nd4 4d 343 453 2169 3578 4938 nd5 4e 188 658 1316 1755 2880 nd6 4f 588 1446 2022 2500 4240 nd7 4g 600 796 1446 1862 4191 nd8 4h 031 752 877 1220 1940 nd9 4i 735 1237 1495 1629 4889 nd10 4j 674 943 2561 3590 5122 2440 plusmn 01411 4k 0 596 1220 3070 5579 2240 plusmn 13112 4l 2169 2193 2450 3002 6605 1892 plusmn 009aAll the values are the average of the experiments done in triplicates Etoposide (IC50 = 985120583M) was used as a reference compound nd not done

in this series Notably the IC50value of nimesulide was found

to be gt150120583M [26] whereas its reduced product did not showsignificant activities

Since the colon cancer is common in developed countriesthe present class of glycolamide esters has medicinal valueIt is worthy to mention that nimesulide is a banned drugin many countries because of its potential liver toxicity Theobserved liver toxicity of nimesulide has often been linkedto its uncoupling effects on mitochondria and study hasshown that nimesulide exerts this effect via a protonophoreticmechanism as well as oxidation of mitochondrial NADH andNADPH [27] The nitro group of nimesulide was thoughtto be responsible for its protonophoretic and NAD(P)Hoxidizing properties as chemical reduction of ndashNO

2to ndashNH

2

completely suppressed these activitiesThus the present classof compounds that does not contain a nitro group on the ndashNHSO

2Mebearing phenyl ring is expected to be free from the

liver toxicities of nimesulide We also performed the stabilitystudies using the compound 4l in the presence of 50mMtris buffer (pH 74) initially where 60 of 4l was found toremain unchanged after 2 h incubation in buffer This studyindicated that the present class of compounds perhaps isnot susceptible towards rapid ester hydrolysis Moreover notbeing the direct prodrug of nimesulide these compounds

would not provide nimesulide as such after ester hydrolysisThus these compounds are expected to be free from thegastric ulceration problem of nimesulide or other NSAIDs(nonsteroidal anti-inflammatory drugs)

Recently a nimesulide analogue obtained via its chemicalmodification that is replacing the phenyl ether moiety by anaryl ether and the nitro group by a cyclohexyl carboxamidemoiety showed suppression of three breast cancer cell pro-liferation types in a dose dependent manner [21] While theanticancer molecular target of this compound was not clearlyunderstood the cytochrome 119888 release assay indicated that theapoptosis induced by this compound was mediated throughthe mitochondria Due to the structural similarities with thiscompound present series of glycolamide esters might followsimilar cytochrome 119888 dependent mechanisms Neverthelessour study indicates that the glycolamide esters derived fromnimesulide [28ndash30] are of further interest

4 Conclusions

In conclusion we have successfully accomplished the synthe-sis of several new nimesulide based glycolamide esters via athree-step method starting from nimesulide in good yieldsStructures of the synthesized compounds were confirmed

Journal of Chemistry 7

0 5 10 15 20 25

100

80

60

40

20

0

Viab

le ce

lls (

)

Viable cells ()Death cells ()

Concentration (120583gmL)

Figure 2 Graphical presentation of in vitro cytotoxic activity ofcompound 4l against HCT-15 human colon cancer cell line

by spectroscopic analysis All the synthesized compoundswere examined for their cytotoxic effects in vitro Some ofthe compounds showed significant cytotoxic activities againstHCT-15 human colon cancer cell line Overall the presentnimesulide based glycolamide ester framework appeared tobe a useful template for the design and identification of noveland potential anticancer agents

Acknowledgment

The authors (Kavitha Kankanala and Sarbani Pal) thank MrM N Raju the chairman of M N R Educational Trust forhis constant encouragement

References

[1] D M Parkin F Bray J Ferlay and P Pisani ldquoGlobal cancerstatistics 2002rdquo CA Cancer Journal for Clinicians vol 55 no2 pp 74ndash108 2005

[2] N M Nielsen and H Bundgaard ldquoGlycolamide esters asbiolabile prodrugs of carboxylic acid agents synthesis stabilitybioconversion and physicochemical propertiesrdquo Journal ofPharmaceutical Sciences vol 77 no 4 pp 285ndash298 1988

[3] L K Wadhwa and P D Sharma ldquoGlycolamide esters of 6-methoxy-2-naphthylacetic acid as potential prodrugs-syntheticand spectral studiesrdquo Indian Journal of Chemistry vol 34 pp408ndash415 1995

[4] P D Sharma K J Singh S Gupta and S Chandiran ldquoGly-colamide esters of 4-biphenylacetic acid as potential prodrugs-synthetic and spectral studiesrdquo Indian Journal of Chemistry vol43 no 3 pp 636ndash642 2004

[5] N M Nielsen and H Bundgaard ldquoEvaluation of glycolamideesters and various other esters of aspirin as true aspirinprodrugsrdquo Journal of Medicinal Chemistry vol 32 no 3 pp727ndash734 1989

[6] A K Bansal R K Khar R Dubey and A K Sharma ldquoActiv-ity profile of glycolamide ester prodrugs of ibuprofenrdquo Drug

Development and Industrial Pharmacy vol 27 no 1 pp 63ndash702001

[7] A K Gadad S Bhat V S Tegeli and V V Redasani ldquoSynthesisspectral studies and anti-inflammatory activity of glycolamideesters of niflumic acid as potential prodrugsrdquo Arzneimittel-Forschung vol 52 no 11 pp 817ndash821 2002

[8] F Cao J-X Guo Q-N Ping and Z-G Liao ldquoProdrugsof scutellarin ethyl benzyl and NN-diethylglycolamide estersynthesis physicochemical properties intestinal metabolismand oral bioavailability in the ratsrdquo European Journal of Phar-maceutical Sciences vol 29 no 5 pp 385ndash393 2006

[9] S Khanna M Madan A Vangoori et al ldquoEvaluation of gly-colamide esters of indomethacin as potential cyclooxygenase-2(COX-2) inhibitorsrdquo Bioorganic and Medicinal Chemistry vol14 no 14 pp 4820ndash4833 2006

[10] CNNalini S Ramachandran K Kavitha andV S SaraswathildquoGlycolamide esters of naproxen as potential prodrugsmdashsynthesis spectral studies and preliminary pharmacologicalscreeningrdquo International Journal of Research in Pharmaceuticaland Biomedical Sciences vol 2 pp 1112ndash1117 2011

[11] M Amblard M Rodriguez and J Martinez ldquoN-benzhydryl-glycolamide esters (OBg esters) as carboxyl protecting groupsin pept1de synthesisrdquo Tetrahedron vol 44 no 16 pp 5101ndash51081988

[12] W J Hoekstra ldquoOrally-active nipecotamide glycolamide estersfor the treatment of thrombosis disorderrdquo US patent noUS6066651 2000

[13] KH Boltze andHKreisfeld ldquoOn the chemistry of etofenamatea novel antiinflammatory agent from the series of N arylan-thranilic acid derivativesrdquo Arzneimittel-Forschung vol 27 no6 b pp 1300ndash1312 1977

[14] S Pericherla J Mareddy D P Geetha Rani P V Gollapudi andS Pal ldquoChemical modifications of nimesuliderdquo Journal of theBrazilian Chemical Society vol 18 no 2 pp 384ndash390 2007

[15] L V Reddy M Nakka A Suman et al ldquoSynthesis of novelquinoline analogues of nimesulide an unusual observationrdquoJournal of Heterocyclic Chemistry vol 48 no 3 pp 555ndash5622011

[16] S Durgadas V K Chatare KMukkanti and S Pal ldquoPalladium-mediated synthesis of novel nimesulide derivativesrdquo AppliedOrganometallic Chemistry vol 24 no 10 pp 680ndash684 2010

[17] L V Reddy M Kethavath M Nakka et al ldquoDesign and syn-thesis of novel cytotoxic agents based on combined frameworkof quinoline and nimesuliderdquo Journal of Heterocyclic Chemistryvol 49 no 1 pp 80ndash87 2012

[18] K Kankanala V R Reddy K Mukkanti and S Pal ldquoLewisacid free high speed synthesis of nimesulide-based novel N-substituted cyclic imidesrdquo Journal of the Brazilian ChemicalSociety vol 21 no 6 pp 1060ndash1064 2010

[19] A Bhattacharya S Ghosh K Kankanala et al ldquoCrystal struc-ture and electronic properties of two nimesulide derivatives acombined X-ray powder diffraction and quantum mechanicalstudyrdquo Chemical Physics Letters vol 493 no 1ndash3 pp 151ndash1572010

[20] K Kankanala V Prakash K Mukkanti V R Reddy and S PalldquoN-(4-Methylsulfonamido-3-phenoxyphenyl)-910-dihydro-910-ethanoanthracene-1112-dicarboximiderdquo MolBank vol2011 article M740 2011

[21] B Chen B Su and S Chen ldquoA COX-2 inhibitor nimesulideanalog selectively induces apoptosis in Her2 overexpressingbreast cancer cells via cytochrome c dependent mechanismsrdquoBiochemical Pharmacology vol 77 no 12 pp 1787ndash1794 2009

8 Journal of Chemistry

[22] S Joudieh M Lahiani-Skiba P Bon O Ba J M Le Bretonand M Skiba ldquoNimesulide apparent solubility enhancementwith natural cyclodextrins and their polymersrdquo Letters in DrugDesign and Discovery vol 5 no 6 pp 406ndash415 2008

[23] T Mosmann ldquoRapid colorimetric assay for cellular growth andsurvival application to proliferation and cytotoxicity assaysrdquoJournal of Immunological Methods vol 65 no 1-2 pp 55ndash631983

[24] J Ferlay H R Shin F Bray D Forman C Mathers and DM Parkin ldquoColorectal cancer incidence mortality and prev-alence worldwide in 2008 Summaryrdquo in Proceedings of theGLOBOCAN 2008

[25] The ALOGPS 21 program was used to calculate the aver-age logP and average logs values httpwwwvcclaborglabalogpsstarthtml

[26] R Davis and R N Brogden ldquoNimesulide An update ofits pharmacodynamic and pharmacokinetic properties andtherapeutic efficacyrdquo Drugs vol 48 no 3 pp 431ndash454 1994

[27] F EMingatto ACDos Santos T Rodrigues AA Pigoso S AUyemura and C Curti ldquoEffects of nimesulide and its reducedmetabolite on mitochondriardquo British Journal of Pharmacologyvol 131 no 6 pp 1154ndash1160 2000

[28] B Su and S Chen ldquoLead optimization of COX-2 inhibitornimesulide analogs to overcome aromatase inhibitor resistancein breast cancer cellsrdquo Bioorganic and Medicinal ChemistryLetters vol 19 no 23 pp 6733ndash6735 2009

[29] B Zhong R Lama K M Smith Y Xu and B Su ldquoDesign andsynthesis of a biotinylated probe of COX-2 inhibitor nimesulideanalog JCC76rdquo Bioorganic andMedicinal Chemistry Letters vol21 no 18 pp 5324ndash5327 2011

[30] B Zhong X Cai S Chennamaneni et al ldquoFrom COX-2 inhib-itor nimesulide to potent anti-cancer agent synthesis in vitroin vivo and pharmacokinetic evaluationrdquo European Journal ofMedicinal Chemistry vol 47 no 1 pp 432ndash444 2012

Impact Factor 173028 Days Fast Track Peer ReviewAll Subject Areas of ScienceSubmit at httpwwwtswjcom

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

Journal of Chemistry 3

NHSO2Me NHSO2MeNHSO2Me

OPh OPhOPhSnHCl

NO2

Nimesulide

90∘C 3 hNH2

ClCH2COCl

HNCO

ClEt3N CHCl3

0∘C-rt

1 2

Scheme 1 Synthesis of key starting material 2

NHSO2Me NHSO2Me

OPhOPh

OPh

HNCO

HNC

C

O

O

OO

Cl

NHSO2Me

HN N+

NCH3

CH3R

DMAPEt3N rt

RCOOH (3)

2 4 5

Scheme 2 The reaction of chloro compound 2 with carboxylic acids 3

indicated by the disappearance of two peaks at 120575 1046 and922 ppm in D

2O exchange experiment Moreover the 13C

signals at 1647 527 and 394 ppm indicated the presenceof amide carbonyl CH

2and CH

3groups respectively

Having prepared the starting material 2 we then treatedthis chloroderivative with commercially available carboxylicacids in the presence of catalytic amount of 119873 119873-dimethyl-4-aminopyridine [9] using Et

3N as a base (Scheme 2) To

our surprise instead of the desired glycolamide esters (4)we isolated a white solid with the melting point 264-265∘Cirrespective of acid partner employed Based on the spectraldata (IR 1H amp 13C NMR and MS) the isolated solid wasconfirmed as 2-(4-dimethylamino-pyridin-1-yl)-N-(4-meth-anesulfonylamino-3-phenoxy-phenylcarbamoyl)-methylester (5) It was evident that DMAP reacted better thanthe acid 3 with the chloro compound 2 perhaps due to itspredominant role as a nucleophile rather than a base underthe reaction conditions employed We therefore decided toomit its use in our subsequent studies

We then performed the reaction of 2 with 3 under amodified reaction conditions that is in the presence ofpotassium iodide and Et

3N To our satisfaction the desired

product 4 was isolated in good yields and the results aresummarized in Table 1 It is evident from Table 1 that bothaliphatic and aromatic acids participated well in the presentreaction and a range of nimesulide based glycolamide esters(4) were prepared by using this methodology All the com-pounds synthesized were well characterized by spectral dataFor example compound 4a showed IR signals at 1742 (estercarbonyl) and 1677 cmminus1 (amide carbonyl) respectively Theappearance of two singlets at 120575 220 for 3H and 120575 464 for2H in 1H NMR spectrum of 4a confirmed the presenceof ndashCOMe and CH

2groups respectively In 13C NMR

appearance of 15 signals was highly consistent with the 15nonequivalent carbon atoms of the compound 4a Moreoverthe ester and amide carbonyls appear at120575 1699 and 1655 ppmwhereas the CH

2group appeared at 120575 624 ppm

All the glycolamide esters 4 synthesized were tested invitro against HCT-15 human colon cancer cell line basedon an MTT [3-(45-dimethylthiazol-2-yl)-25-diphenyltetra-zolium bromide] assay (Table 2) [23] Defined as a cancerfrom uncontrolled cell growth in the colon or rectum (partsof the large intestine) or in the appendix colon cancer(commonly known as colorectal cancer or bowel cancer) isthe third most commonly diagnosed cancer in the worldIt was estimated in 2008 that worldwide 123 million newcases of colorectal cancer were clinically diagnosed and thatit killed 608000 people [24] This prompted us to focus oncolon cancer In our present assay the percentage of cell deathwas measured for each compound at various concentrationsand finally the IC

50(half maximal inhibitory concentration)

values were determined to measure the cytotoxic activitiesThe IC

50is inversely proportional to the cytotoxicity of a

compound that is the lower the IC50value is the higher the

activity is In general most of the compounds were found tobe active against the HCT-15 colon cancer cell line at 25 120583MNotable among them are 4d (Entry 4 Table 2) 4f (Entry6 Table 2) 4g (Entry 7 Table 2) 4i (Entry 9 Table 2) 4j(Entry 10 Table 2) 4k (Entry 11 Table 2) and 4l (Entry 12Table 2) that showed gt40 inhibition at 25120583M It is evidentthat an aryl group attached to the ester carbonyl moiety wasgenerally more favorable than an alkyl group for activity(eg 4a-b versus 4c-f) While insertion of an olefin moietybetween the ester carbonyl and the aryl group was tolerated(eg 4g) a naphthylmethyl group (eg 4h) attached to thecarbonyl moiety decreased the activity However a benzylgroup having substituent at 119901- or 119900-position (eg 4j-l) wasfavorable for activity A graphical presentation of in vitrocytotoxic activities of compound 4l against HCT-15 humancolon cancer cell line is shown in Figure 2 The IC

50values

of most active compounds that is 4j 4k and 4l werefound to be 2440 2240 and 1892 120583M respectively Thusthe compound 4l (calculated average Log119875 = 283 plusmn 046 andaverage log 119878 = minus604 versus 175 plusmn 026 and minus424 resp ofcompound 1 [25]) was identified as the best active compound

4 Journal of Chemistry

Table 1 Synthesis of nimesulide based glycomide esters 4a

NHSO2MeNHSO2Me

OPh OPh

HNC

OCl

HNC

CO

OO

R

KI Et3NDMF 90∘C

RCOOH (3)

2 4

Entry RCOOH (3)R = Products (4) Time

(min) yieldb

(1)

CH3

3a

NHSO2MeOPh

4a

HNC

CO

OO Me

30 91

(2) 3bCH2CH3

OPh

4b

HNC

C

O

O

O

NHSO2Me

C2H5

30 95

(3)

3c

OPh

4c

HNC

C

OO

O

Ph

NHSO2Me

20 80

(4)

3d

H3COPh

4d

HNC

C

O

O

O

Me

NHSO2Me

30 90

(5)

3eOMe

OPh

4e

HNC

C

O

O

O

OMe

NHSO2Me

30 70

Journal of Chemistry 5

Table 1 Continued

(6)

3fNO2

OPh

4f

HNC

C

O

O

O

NHSO2Me

NO2

15 75

(7)

3g

CCH

HOPh

4g

HNC

C CCH

H

O

O

O

NHSO2Me

10 98

(8)

3hMe

OMe OPh

4h

HNC

C

O

O

OMe

OMe

NHSO2Me

30 78

(9)

3iMe

Me

Me OPh

4i

HNC

C

O

O

OMe

Me

Me

NHSO2Me

45 80

(10)

3j

NH

Cl

Cl

OPh

4j

HNC

C

O

O

ON

H

Cl

Cl

NHSO2Me

15 92

(11)

3k

NH

Me

MeOPh

4k

HNC

C

O

O

OMe

MeHN

NHSO2Me

30 90

6 Journal of Chemistry

Table 1 Continued

(12)

3l

OCOMe

OPh

4l

HNC

C

O

O

O

OCOMe

NHSO2Me

15 90

aAll the reactions were performed using chlorocompound 2 (001mmol) and acid 3 (001mol) in the presence of NaI (0001mol) Et3N (0011mmol) and DMF(15mL) at 90∘CbIsolated yield

Table 2 In vitro cytotoxic activity of compound 4 against HCT-15 human colon cancer cell line

Entry Compounds of cell death at various concentrationsa IC50 (120583M)1 120583M 2 120583M 5120583M 10120583M 25 120583M

1 4a 094 689 815 877 2030 nd2 4b 062 720 750 1850 2850 nd3 4c 031 125 250 752 3100 nd4 4d 343 453 2169 3578 4938 nd5 4e 188 658 1316 1755 2880 nd6 4f 588 1446 2022 2500 4240 nd7 4g 600 796 1446 1862 4191 nd8 4h 031 752 877 1220 1940 nd9 4i 735 1237 1495 1629 4889 nd10 4j 674 943 2561 3590 5122 2440 plusmn 01411 4k 0 596 1220 3070 5579 2240 plusmn 13112 4l 2169 2193 2450 3002 6605 1892 plusmn 009aAll the values are the average of the experiments done in triplicates Etoposide (IC50 = 985120583M) was used as a reference compound nd not done

in this series Notably the IC50value of nimesulide was found

to be gt150120583M [26] whereas its reduced product did not showsignificant activities

Since the colon cancer is common in developed countriesthe present class of glycolamide esters has medicinal valueIt is worthy to mention that nimesulide is a banned drugin many countries because of its potential liver toxicity Theobserved liver toxicity of nimesulide has often been linkedto its uncoupling effects on mitochondria and study hasshown that nimesulide exerts this effect via a protonophoreticmechanism as well as oxidation of mitochondrial NADH andNADPH [27] The nitro group of nimesulide was thoughtto be responsible for its protonophoretic and NAD(P)Hoxidizing properties as chemical reduction of ndashNO

2to ndashNH

2

completely suppressed these activitiesThus the present classof compounds that does not contain a nitro group on the ndashNHSO

2Mebearing phenyl ring is expected to be free from the

liver toxicities of nimesulide We also performed the stabilitystudies using the compound 4l in the presence of 50mMtris buffer (pH 74) initially where 60 of 4l was found toremain unchanged after 2 h incubation in buffer This studyindicated that the present class of compounds perhaps isnot susceptible towards rapid ester hydrolysis Moreover notbeing the direct prodrug of nimesulide these compounds

would not provide nimesulide as such after ester hydrolysisThus these compounds are expected to be free from thegastric ulceration problem of nimesulide or other NSAIDs(nonsteroidal anti-inflammatory drugs)

Recently a nimesulide analogue obtained via its chemicalmodification that is replacing the phenyl ether moiety by anaryl ether and the nitro group by a cyclohexyl carboxamidemoiety showed suppression of three breast cancer cell pro-liferation types in a dose dependent manner [21] While theanticancer molecular target of this compound was not clearlyunderstood the cytochrome 119888 release assay indicated that theapoptosis induced by this compound was mediated throughthe mitochondria Due to the structural similarities with thiscompound present series of glycolamide esters might followsimilar cytochrome 119888 dependent mechanisms Neverthelessour study indicates that the glycolamide esters derived fromnimesulide [28ndash30] are of further interest

4 Conclusions

In conclusion we have successfully accomplished the synthe-sis of several new nimesulide based glycolamide esters via athree-step method starting from nimesulide in good yieldsStructures of the synthesized compounds were confirmed

Journal of Chemistry 7

0 5 10 15 20 25

100

80

60

40

20

0

Viab

le ce

lls (

)

Viable cells ()Death cells ()

Concentration (120583gmL)

Figure 2 Graphical presentation of in vitro cytotoxic activity ofcompound 4l against HCT-15 human colon cancer cell line

by spectroscopic analysis All the synthesized compoundswere examined for their cytotoxic effects in vitro Some ofthe compounds showed significant cytotoxic activities againstHCT-15 human colon cancer cell line Overall the presentnimesulide based glycolamide ester framework appeared tobe a useful template for the design and identification of noveland potential anticancer agents

Acknowledgment

The authors (Kavitha Kankanala and Sarbani Pal) thank MrM N Raju the chairman of M N R Educational Trust forhis constant encouragement

References

[1] D M Parkin F Bray J Ferlay and P Pisani ldquoGlobal cancerstatistics 2002rdquo CA Cancer Journal for Clinicians vol 55 no2 pp 74ndash108 2005

[2] N M Nielsen and H Bundgaard ldquoGlycolamide esters asbiolabile prodrugs of carboxylic acid agents synthesis stabilitybioconversion and physicochemical propertiesrdquo Journal ofPharmaceutical Sciences vol 77 no 4 pp 285ndash298 1988

[3] L K Wadhwa and P D Sharma ldquoGlycolamide esters of 6-methoxy-2-naphthylacetic acid as potential prodrugs-syntheticand spectral studiesrdquo Indian Journal of Chemistry vol 34 pp408ndash415 1995

[4] P D Sharma K J Singh S Gupta and S Chandiran ldquoGly-colamide esters of 4-biphenylacetic acid as potential prodrugs-synthetic and spectral studiesrdquo Indian Journal of Chemistry vol43 no 3 pp 636ndash642 2004

[5] N M Nielsen and H Bundgaard ldquoEvaluation of glycolamideesters and various other esters of aspirin as true aspirinprodrugsrdquo Journal of Medicinal Chemistry vol 32 no 3 pp727ndash734 1989

[6] A K Bansal R K Khar R Dubey and A K Sharma ldquoActiv-ity profile of glycolamide ester prodrugs of ibuprofenrdquo Drug

Development and Industrial Pharmacy vol 27 no 1 pp 63ndash702001

[7] A K Gadad S Bhat V S Tegeli and V V Redasani ldquoSynthesisspectral studies and anti-inflammatory activity of glycolamideesters of niflumic acid as potential prodrugsrdquo Arzneimittel-Forschung vol 52 no 11 pp 817ndash821 2002

[8] F Cao J-X Guo Q-N Ping and Z-G Liao ldquoProdrugsof scutellarin ethyl benzyl and NN-diethylglycolamide estersynthesis physicochemical properties intestinal metabolismand oral bioavailability in the ratsrdquo European Journal of Phar-maceutical Sciences vol 29 no 5 pp 385ndash393 2006

[9] S Khanna M Madan A Vangoori et al ldquoEvaluation of gly-colamide esters of indomethacin as potential cyclooxygenase-2(COX-2) inhibitorsrdquo Bioorganic and Medicinal Chemistry vol14 no 14 pp 4820ndash4833 2006

[10] CNNalini S Ramachandran K Kavitha andV S SaraswathildquoGlycolamide esters of naproxen as potential prodrugsmdashsynthesis spectral studies and preliminary pharmacologicalscreeningrdquo International Journal of Research in Pharmaceuticaland Biomedical Sciences vol 2 pp 1112ndash1117 2011

[11] M Amblard M Rodriguez and J Martinez ldquoN-benzhydryl-glycolamide esters (OBg esters) as carboxyl protecting groupsin pept1de synthesisrdquo Tetrahedron vol 44 no 16 pp 5101ndash51081988

[12] W J Hoekstra ldquoOrally-active nipecotamide glycolamide estersfor the treatment of thrombosis disorderrdquo US patent noUS6066651 2000

[13] KH Boltze andHKreisfeld ldquoOn the chemistry of etofenamatea novel antiinflammatory agent from the series of N arylan-thranilic acid derivativesrdquo Arzneimittel-Forschung vol 27 no6 b pp 1300ndash1312 1977

[14] S Pericherla J Mareddy D P Geetha Rani P V Gollapudi andS Pal ldquoChemical modifications of nimesuliderdquo Journal of theBrazilian Chemical Society vol 18 no 2 pp 384ndash390 2007

[15] L V Reddy M Nakka A Suman et al ldquoSynthesis of novelquinoline analogues of nimesulide an unusual observationrdquoJournal of Heterocyclic Chemistry vol 48 no 3 pp 555ndash5622011

[16] S Durgadas V K Chatare KMukkanti and S Pal ldquoPalladium-mediated synthesis of novel nimesulide derivativesrdquo AppliedOrganometallic Chemistry vol 24 no 10 pp 680ndash684 2010

[17] L V Reddy M Kethavath M Nakka et al ldquoDesign and syn-thesis of novel cytotoxic agents based on combined frameworkof quinoline and nimesuliderdquo Journal of Heterocyclic Chemistryvol 49 no 1 pp 80ndash87 2012

[18] K Kankanala V R Reddy K Mukkanti and S Pal ldquoLewisacid free high speed synthesis of nimesulide-based novel N-substituted cyclic imidesrdquo Journal of the Brazilian ChemicalSociety vol 21 no 6 pp 1060ndash1064 2010

[19] A Bhattacharya S Ghosh K Kankanala et al ldquoCrystal struc-ture and electronic properties of two nimesulide derivatives acombined X-ray powder diffraction and quantum mechanicalstudyrdquo Chemical Physics Letters vol 493 no 1ndash3 pp 151ndash1572010

[20] K Kankanala V Prakash K Mukkanti V R Reddy and S PalldquoN-(4-Methylsulfonamido-3-phenoxyphenyl)-910-dihydro-910-ethanoanthracene-1112-dicarboximiderdquo MolBank vol2011 article M740 2011

[21] B Chen B Su and S Chen ldquoA COX-2 inhibitor nimesulideanalog selectively induces apoptosis in Her2 overexpressingbreast cancer cells via cytochrome c dependent mechanismsrdquoBiochemical Pharmacology vol 77 no 12 pp 1787ndash1794 2009

8 Journal of Chemistry

[22] S Joudieh M Lahiani-Skiba P Bon O Ba J M Le Bretonand M Skiba ldquoNimesulide apparent solubility enhancementwith natural cyclodextrins and their polymersrdquo Letters in DrugDesign and Discovery vol 5 no 6 pp 406ndash415 2008

[23] T Mosmann ldquoRapid colorimetric assay for cellular growth andsurvival application to proliferation and cytotoxicity assaysrdquoJournal of Immunological Methods vol 65 no 1-2 pp 55ndash631983

[24] J Ferlay H R Shin F Bray D Forman C Mathers and DM Parkin ldquoColorectal cancer incidence mortality and prev-alence worldwide in 2008 Summaryrdquo in Proceedings of theGLOBOCAN 2008

[25] The ALOGPS 21 program was used to calculate the aver-age logP and average logs values httpwwwvcclaborglabalogpsstarthtml

[26] R Davis and R N Brogden ldquoNimesulide An update ofits pharmacodynamic and pharmacokinetic properties andtherapeutic efficacyrdquo Drugs vol 48 no 3 pp 431ndash454 1994

[27] F EMingatto ACDos Santos T Rodrigues AA Pigoso S AUyemura and C Curti ldquoEffects of nimesulide and its reducedmetabolite on mitochondriardquo British Journal of Pharmacologyvol 131 no 6 pp 1154ndash1160 2000

[28] B Su and S Chen ldquoLead optimization of COX-2 inhibitornimesulide analogs to overcome aromatase inhibitor resistancein breast cancer cellsrdquo Bioorganic and Medicinal ChemistryLetters vol 19 no 23 pp 6733ndash6735 2009

[29] B Zhong R Lama K M Smith Y Xu and B Su ldquoDesign andsynthesis of a biotinylated probe of COX-2 inhibitor nimesulideanalog JCC76rdquo Bioorganic andMedicinal Chemistry Letters vol21 no 18 pp 5324ndash5327 2011

[30] B Zhong X Cai S Chennamaneni et al ldquoFrom COX-2 inhib-itor nimesulide to potent anti-cancer agent synthesis in vitroin vivo and pharmacokinetic evaluationrdquo European Journal ofMedicinal Chemistry vol 47 no 1 pp 432ndash444 2012

Impact Factor 173028 Days Fast Track Peer ReviewAll Subject Areas of ScienceSubmit at httpwwwtswjcom

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

4 Journal of Chemistry

Table 1 Synthesis of nimesulide based glycomide esters 4a

NHSO2MeNHSO2Me

OPh OPh

HNC

OCl

HNC

CO

OO

R

KI Et3NDMF 90∘C

RCOOH (3)

2 4

Entry RCOOH (3)R = Products (4) Time

(min) yieldb

(1)

CH3

3a

NHSO2MeOPh

4a

HNC

CO

OO Me

30 91

(2) 3bCH2CH3

OPh

4b

HNC

C

O

O

O

NHSO2Me

C2H5

30 95

(3)

3c

OPh

4c

HNC

C

OO

O

Ph

NHSO2Me

20 80

(4)

3d

H3COPh

4d

HNC

C

O

O

O

Me

NHSO2Me

30 90

(5)

3eOMe

OPh

4e

HNC

C

O

O

O

OMe

NHSO2Me

30 70

Journal of Chemistry 5

Table 1 Continued

(6)

3fNO2

OPh

4f

HNC

C

O

O

O

NHSO2Me

NO2

15 75

(7)

3g

CCH

HOPh

4g

HNC

C CCH

H

O

O

O

NHSO2Me

10 98

(8)

3hMe

OMe OPh

4h

HNC

C

O

O

OMe

OMe

NHSO2Me

30 78

(9)

3iMe

Me

Me OPh

4i

HNC

C

O

O

OMe

Me

Me

NHSO2Me

45 80

(10)

3j

NH

Cl

Cl

OPh

4j

HNC

C

O

O

ON

H

Cl

Cl

NHSO2Me

15 92

(11)

3k

NH

Me

MeOPh

4k

HNC

C

O

O

OMe

MeHN

NHSO2Me

30 90

6 Journal of Chemistry

Table 1 Continued

(12)

3l

OCOMe

OPh

4l

HNC

C

O

O

O

OCOMe

NHSO2Me

15 90

aAll the reactions were performed using chlorocompound 2 (001mmol) and acid 3 (001mol) in the presence of NaI (0001mol) Et3N (0011mmol) and DMF(15mL) at 90∘CbIsolated yield

Table 2 In vitro cytotoxic activity of compound 4 against HCT-15 human colon cancer cell line

Entry Compounds of cell death at various concentrationsa IC50 (120583M)1 120583M 2 120583M 5120583M 10120583M 25 120583M

1 4a 094 689 815 877 2030 nd2 4b 062 720 750 1850 2850 nd3 4c 031 125 250 752 3100 nd4 4d 343 453 2169 3578 4938 nd5 4e 188 658 1316 1755 2880 nd6 4f 588 1446 2022 2500 4240 nd7 4g 600 796 1446 1862 4191 nd8 4h 031 752 877 1220 1940 nd9 4i 735 1237 1495 1629 4889 nd10 4j 674 943 2561 3590 5122 2440 plusmn 01411 4k 0 596 1220 3070 5579 2240 plusmn 13112 4l 2169 2193 2450 3002 6605 1892 plusmn 009aAll the values are the average of the experiments done in triplicates Etoposide (IC50 = 985120583M) was used as a reference compound nd not done

in this series Notably the IC50value of nimesulide was found

to be gt150120583M [26] whereas its reduced product did not showsignificant activities

Since the colon cancer is common in developed countriesthe present class of glycolamide esters has medicinal valueIt is worthy to mention that nimesulide is a banned drugin many countries because of its potential liver toxicity Theobserved liver toxicity of nimesulide has often been linkedto its uncoupling effects on mitochondria and study hasshown that nimesulide exerts this effect via a protonophoreticmechanism as well as oxidation of mitochondrial NADH andNADPH [27] The nitro group of nimesulide was thoughtto be responsible for its protonophoretic and NAD(P)Hoxidizing properties as chemical reduction of ndashNO

2to ndashNH

2

completely suppressed these activitiesThus the present classof compounds that does not contain a nitro group on the ndashNHSO

2Mebearing phenyl ring is expected to be free from the

liver toxicities of nimesulide We also performed the stabilitystudies using the compound 4l in the presence of 50mMtris buffer (pH 74) initially where 60 of 4l was found toremain unchanged after 2 h incubation in buffer This studyindicated that the present class of compounds perhaps isnot susceptible towards rapid ester hydrolysis Moreover notbeing the direct prodrug of nimesulide these compounds

would not provide nimesulide as such after ester hydrolysisThus these compounds are expected to be free from thegastric ulceration problem of nimesulide or other NSAIDs(nonsteroidal anti-inflammatory drugs)

Recently a nimesulide analogue obtained via its chemicalmodification that is replacing the phenyl ether moiety by anaryl ether and the nitro group by a cyclohexyl carboxamidemoiety showed suppression of three breast cancer cell pro-liferation types in a dose dependent manner [21] While theanticancer molecular target of this compound was not clearlyunderstood the cytochrome 119888 release assay indicated that theapoptosis induced by this compound was mediated throughthe mitochondria Due to the structural similarities with thiscompound present series of glycolamide esters might followsimilar cytochrome 119888 dependent mechanisms Neverthelessour study indicates that the glycolamide esters derived fromnimesulide [28ndash30] are of further interest

4 Conclusions

In conclusion we have successfully accomplished the synthe-sis of several new nimesulide based glycolamide esters via athree-step method starting from nimesulide in good yieldsStructures of the synthesized compounds were confirmed

Journal of Chemistry 7

0 5 10 15 20 25

100

80

60

40

20

0

Viab

le ce

lls (

)

Viable cells ()Death cells ()

Concentration (120583gmL)

Figure 2 Graphical presentation of in vitro cytotoxic activity ofcompound 4l against HCT-15 human colon cancer cell line

by spectroscopic analysis All the synthesized compoundswere examined for their cytotoxic effects in vitro Some ofthe compounds showed significant cytotoxic activities againstHCT-15 human colon cancer cell line Overall the presentnimesulide based glycolamide ester framework appeared tobe a useful template for the design and identification of noveland potential anticancer agents

Acknowledgment

The authors (Kavitha Kankanala and Sarbani Pal) thank MrM N Raju the chairman of M N R Educational Trust forhis constant encouragement

References

[1] D M Parkin F Bray J Ferlay and P Pisani ldquoGlobal cancerstatistics 2002rdquo CA Cancer Journal for Clinicians vol 55 no2 pp 74ndash108 2005

[2] N M Nielsen and H Bundgaard ldquoGlycolamide esters asbiolabile prodrugs of carboxylic acid agents synthesis stabilitybioconversion and physicochemical propertiesrdquo Journal ofPharmaceutical Sciences vol 77 no 4 pp 285ndash298 1988

[3] L K Wadhwa and P D Sharma ldquoGlycolamide esters of 6-methoxy-2-naphthylacetic acid as potential prodrugs-syntheticand spectral studiesrdquo Indian Journal of Chemistry vol 34 pp408ndash415 1995

[4] P D Sharma K J Singh S Gupta and S Chandiran ldquoGly-colamide esters of 4-biphenylacetic acid as potential prodrugs-synthetic and spectral studiesrdquo Indian Journal of Chemistry vol43 no 3 pp 636ndash642 2004

[5] N M Nielsen and H Bundgaard ldquoEvaluation of glycolamideesters and various other esters of aspirin as true aspirinprodrugsrdquo Journal of Medicinal Chemistry vol 32 no 3 pp727ndash734 1989

[6] A K Bansal R K Khar R Dubey and A K Sharma ldquoActiv-ity profile of glycolamide ester prodrugs of ibuprofenrdquo Drug

Development and Industrial Pharmacy vol 27 no 1 pp 63ndash702001

[7] A K Gadad S Bhat V S Tegeli and V V Redasani ldquoSynthesisspectral studies and anti-inflammatory activity of glycolamideesters of niflumic acid as potential prodrugsrdquo Arzneimittel-Forschung vol 52 no 11 pp 817ndash821 2002

[8] F Cao J-X Guo Q-N Ping and Z-G Liao ldquoProdrugsof scutellarin ethyl benzyl and NN-diethylglycolamide estersynthesis physicochemical properties intestinal metabolismand oral bioavailability in the ratsrdquo European Journal of Phar-maceutical Sciences vol 29 no 5 pp 385ndash393 2006

[9] S Khanna M Madan A Vangoori et al ldquoEvaluation of gly-colamide esters of indomethacin as potential cyclooxygenase-2(COX-2) inhibitorsrdquo Bioorganic and Medicinal Chemistry vol14 no 14 pp 4820ndash4833 2006

[10] CNNalini S Ramachandran K Kavitha andV S SaraswathildquoGlycolamide esters of naproxen as potential prodrugsmdashsynthesis spectral studies and preliminary pharmacologicalscreeningrdquo International Journal of Research in Pharmaceuticaland Biomedical Sciences vol 2 pp 1112ndash1117 2011

[11] M Amblard M Rodriguez and J Martinez ldquoN-benzhydryl-glycolamide esters (OBg esters) as carboxyl protecting groupsin pept1de synthesisrdquo Tetrahedron vol 44 no 16 pp 5101ndash51081988

[12] W J Hoekstra ldquoOrally-active nipecotamide glycolamide estersfor the treatment of thrombosis disorderrdquo US patent noUS6066651 2000

[13] KH Boltze andHKreisfeld ldquoOn the chemistry of etofenamatea novel antiinflammatory agent from the series of N arylan-thranilic acid derivativesrdquo Arzneimittel-Forschung vol 27 no6 b pp 1300ndash1312 1977

[14] S Pericherla J Mareddy D P Geetha Rani P V Gollapudi andS Pal ldquoChemical modifications of nimesuliderdquo Journal of theBrazilian Chemical Society vol 18 no 2 pp 384ndash390 2007

[15] L V Reddy M Nakka A Suman et al ldquoSynthesis of novelquinoline analogues of nimesulide an unusual observationrdquoJournal of Heterocyclic Chemistry vol 48 no 3 pp 555ndash5622011

[16] S Durgadas V K Chatare KMukkanti and S Pal ldquoPalladium-mediated synthesis of novel nimesulide derivativesrdquo AppliedOrganometallic Chemistry vol 24 no 10 pp 680ndash684 2010

[17] L V Reddy M Kethavath M Nakka et al ldquoDesign and syn-thesis of novel cytotoxic agents based on combined frameworkof quinoline and nimesuliderdquo Journal of Heterocyclic Chemistryvol 49 no 1 pp 80ndash87 2012

[18] K Kankanala V R Reddy K Mukkanti and S Pal ldquoLewisacid free high speed synthesis of nimesulide-based novel N-substituted cyclic imidesrdquo Journal of the Brazilian ChemicalSociety vol 21 no 6 pp 1060ndash1064 2010

[19] A Bhattacharya S Ghosh K Kankanala et al ldquoCrystal struc-ture and electronic properties of two nimesulide derivatives acombined X-ray powder diffraction and quantum mechanicalstudyrdquo Chemical Physics Letters vol 493 no 1ndash3 pp 151ndash1572010

[20] K Kankanala V Prakash K Mukkanti V R Reddy and S PalldquoN-(4-Methylsulfonamido-3-phenoxyphenyl)-910-dihydro-910-ethanoanthracene-1112-dicarboximiderdquo MolBank vol2011 article M740 2011

[21] B Chen B Su and S Chen ldquoA COX-2 inhibitor nimesulideanalog selectively induces apoptosis in Her2 overexpressingbreast cancer cells via cytochrome c dependent mechanismsrdquoBiochemical Pharmacology vol 77 no 12 pp 1787ndash1794 2009

8 Journal of Chemistry

[22] S Joudieh M Lahiani-Skiba P Bon O Ba J M Le Bretonand M Skiba ldquoNimesulide apparent solubility enhancementwith natural cyclodextrins and their polymersrdquo Letters in DrugDesign and Discovery vol 5 no 6 pp 406ndash415 2008

[23] T Mosmann ldquoRapid colorimetric assay for cellular growth andsurvival application to proliferation and cytotoxicity assaysrdquoJournal of Immunological Methods vol 65 no 1-2 pp 55ndash631983

[24] J Ferlay H R Shin F Bray D Forman C Mathers and DM Parkin ldquoColorectal cancer incidence mortality and prev-alence worldwide in 2008 Summaryrdquo in Proceedings of theGLOBOCAN 2008

[25] The ALOGPS 21 program was used to calculate the aver-age logP and average logs values httpwwwvcclaborglabalogpsstarthtml

[26] R Davis and R N Brogden ldquoNimesulide An update ofits pharmacodynamic and pharmacokinetic properties andtherapeutic efficacyrdquo Drugs vol 48 no 3 pp 431ndash454 1994

[27] F EMingatto ACDos Santos T Rodrigues AA Pigoso S AUyemura and C Curti ldquoEffects of nimesulide and its reducedmetabolite on mitochondriardquo British Journal of Pharmacologyvol 131 no 6 pp 1154ndash1160 2000

[28] B Su and S Chen ldquoLead optimization of COX-2 inhibitornimesulide analogs to overcome aromatase inhibitor resistancein breast cancer cellsrdquo Bioorganic and Medicinal ChemistryLetters vol 19 no 23 pp 6733ndash6735 2009

[29] B Zhong R Lama K M Smith Y Xu and B Su ldquoDesign andsynthesis of a biotinylated probe of COX-2 inhibitor nimesulideanalog JCC76rdquo Bioorganic andMedicinal Chemistry Letters vol21 no 18 pp 5324ndash5327 2011

[30] B Zhong X Cai S Chennamaneni et al ldquoFrom COX-2 inhib-itor nimesulide to potent anti-cancer agent synthesis in vitroin vivo and pharmacokinetic evaluationrdquo European Journal ofMedicinal Chemistry vol 47 no 1 pp 432ndash444 2012

Impact Factor 173028 Days Fast Track Peer ReviewAll Subject Areas of ScienceSubmit at httpwwwtswjcom

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

Journal of Chemistry 5

Table 1 Continued

(6)

3fNO2

OPh

4f

HNC

C

O

O

O

NHSO2Me

NO2

15 75

(7)

3g

CCH

HOPh

4g

HNC

C CCH

H

O

O

O

NHSO2Me

10 98

(8)

3hMe

OMe OPh

4h

HNC

C

O

O

OMe

OMe

NHSO2Me

30 78

(9)

3iMe

Me

Me OPh

4i

HNC

C

O

O

OMe

Me

Me

NHSO2Me

45 80

(10)

3j

NH

Cl

Cl

OPh

4j

HNC

C

O

O

ON

H

Cl

Cl

NHSO2Me

15 92

(11)

3k

NH

Me

MeOPh

4k

HNC

C

O

O

OMe

MeHN

NHSO2Me

30 90

6 Journal of Chemistry

Table 1 Continued

(12)

3l

OCOMe

OPh

4l

HNC

C

O

O

O

OCOMe

NHSO2Me

15 90

aAll the reactions were performed using chlorocompound 2 (001mmol) and acid 3 (001mol) in the presence of NaI (0001mol) Et3N (0011mmol) and DMF(15mL) at 90∘CbIsolated yield

Table 2 In vitro cytotoxic activity of compound 4 against HCT-15 human colon cancer cell line

Entry Compounds of cell death at various concentrationsa IC50 (120583M)1 120583M 2 120583M 5120583M 10120583M 25 120583M

1 4a 094 689 815 877 2030 nd2 4b 062 720 750 1850 2850 nd3 4c 031 125 250 752 3100 nd4 4d 343 453 2169 3578 4938 nd5 4e 188 658 1316 1755 2880 nd6 4f 588 1446 2022 2500 4240 nd7 4g 600 796 1446 1862 4191 nd8 4h 031 752 877 1220 1940 nd9 4i 735 1237 1495 1629 4889 nd10 4j 674 943 2561 3590 5122 2440 plusmn 01411 4k 0 596 1220 3070 5579 2240 plusmn 13112 4l 2169 2193 2450 3002 6605 1892 plusmn 009aAll the values are the average of the experiments done in triplicates Etoposide (IC50 = 985120583M) was used as a reference compound nd not done

in this series Notably the IC50value of nimesulide was found

to be gt150120583M [26] whereas its reduced product did not showsignificant activities

Since the colon cancer is common in developed countriesthe present class of glycolamide esters has medicinal valueIt is worthy to mention that nimesulide is a banned drugin many countries because of its potential liver toxicity Theobserved liver toxicity of nimesulide has often been linkedto its uncoupling effects on mitochondria and study hasshown that nimesulide exerts this effect via a protonophoreticmechanism as well as oxidation of mitochondrial NADH andNADPH [27] The nitro group of nimesulide was thoughtto be responsible for its protonophoretic and NAD(P)Hoxidizing properties as chemical reduction of ndashNO

2to ndashNH

2

completely suppressed these activitiesThus the present classof compounds that does not contain a nitro group on the ndashNHSO

2Mebearing phenyl ring is expected to be free from the

liver toxicities of nimesulide We also performed the stabilitystudies using the compound 4l in the presence of 50mMtris buffer (pH 74) initially where 60 of 4l was found toremain unchanged after 2 h incubation in buffer This studyindicated that the present class of compounds perhaps isnot susceptible towards rapid ester hydrolysis Moreover notbeing the direct prodrug of nimesulide these compounds

would not provide nimesulide as such after ester hydrolysisThus these compounds are expected to be free from thegastric ulceration problem of nimesulide or other NSAIDs(nonsteroidal anti-inflammatory drugs)

Recently a nimesulide analogue obtained via its chemicalmodification that is replacing the phenyl ether moiety by anaryl ether and the nitro group by a cyclohexyl carboxamidemoiety showed suppression of three breast cancer cell pro-liferation types in a dose dependent manner [21] While theanticancer molecular target of this compound was not clearlyunderstood the cytochrome 119888 release assay indicated that theapoptosis induced by this compound was mediated throughthe mitochondria Due to the structural similarities with thiscompound present series of glycolamide esters might followsimilar cytochrome 119888 dependent mechanisms Neverthelessour study indicates that the glycolamide esters derived fromnimesulide [28ndash30] are of further interest

4 Conclusions

In conclusion we have successfully accomplished the synthe-sis of several new nimesulide based glycolamide esters via athree-step method starting from nimesulide in good yieldsStructures of the synthesized compounds were confirmed

Journal of Chemistry 7

0 5 10 15 20 25

100

80

60

40

20

0

Viab

le ce

lls (

)

Viable cells ()Death cells ()

Concentration (120583gmL)

Figure 2 Graphical presentation of in vitro cytotoxic activity ofcompound 4l against HCT-15 human colon cancer cell line

by spectroscopic analysis All the synthesized compoundswere examined for their cytotoxic effects in vitro Some ofthe compounds showed significant cytotoxic activities againstHCT-15 human colon cancer cell line Overall the presentnimesulide based glycolamide ester framework appeared tobe a useful template for the design and identification of noveland potential anticancer agents

Acknowledgment

The authors (Kavitha Kankanala and Sarbani Pal) thank MrM N Raju the chairman of M N R Educational Trust forhis constant encouragement

References

[1] D M Parkin F Bray J Ferlay and P Pisani ldquoGlobal cancerstatistics 2002rdquo CA Cancer Journal for Clinicians vol 55 no2 pp 74ndash108 2005

[2] N M Nielsen and H Bundgaard ldquoGlycolamide esters asbiolabile prodrugs of carboxylic acid agents synthesis stabilitybioconversion and physicochemical propertiesrdquo Journal ofPharmaceutical Sciences vol 77 no 4 pp 285ndash298 1988

[3] L K Wadhwa and P D Sharma ldquoGlycolamide esters of 6-methoxy-2-naphthylacetic acid as potential prodrugs-syntheticand spectral studiesrdquo Indian Journal of Chemistry vol 34 pp408ndash415 1995

[4] P D Sharma K J Singh S Gupta and S Chandiran ldquoGly-colamide esters of 4-biphenylacetic acid as potential prodrugs-synthetic and spectral studiesrdquo Indian Journal of Chemistry vol43 no 3 pp 636ndash642 2004

[5] N M Nielsen and H Bundgaard ldquoEvaluation of glycolamideesters and various other esters of aspirin as true aspirinprodrugsrdquo Journal of Medicinal Chemistry vol 32 no 3 pp727ndash734 1989

[6] A K Bansal R K Khar R Dubey and A K Sharma ldquoActiv-ity profile of glycolamide ester prodrugs of ibuprofenrdquo Drug

Development and Industrial Pharmacy vol 27 no 1 pp 63ndash702001

[7] A K Gadad S Bhat V S Tegeli and V V Redasani ldquoSynthesisspectral studies and anti-inflammatory activity of glycolamideesters of niflumic acid as potential prodrugsrdquo Arzneimittel-Forschung vol 52 no 11 pp 817ndash821 2002

[8] F Cao J-X Guo Q-N Ping and Z-G Liao ldquoProdrugsof scutellarin ethyl benzyl and NN-diethylglycolamide estersynthesis physicochemical properties intestinal metabolismand oral bioavailability in the ratsrdquo European Journal of Phar-maceutical Sciences vol 29 no 5 pp 385ndash393 2006

[9] S Khanna M Madan A Vangoori et al ldquoEvaluation of gly-colamide esters of indomethacin as potential cyclooxygenase-2(COX-2) inhibitorsrdquo Bioorganic and Medicinal Chemistry vol14 no 14 pp 4820ndash4833 2006

[10] CNNalini S Ramachandran K Kavitha andV S SaraswathildquoGlycolamide esters of naproxen as potential prodrugsmdashsynthesis spectral studies and preliminary pharmacologicalscreeningrdquo International Journal of Research in Pharmaceuticaland Biomedical Sciences vol 2 pp 1112ndash1117 2011

[11] M Amblard M Rodriguez and J Martinez ldquoN-benzhydryl-glycolamide esters (OBg esters) as carboxyl protecting groupsin pept1de synthesisrdquo Tetrahedron vol 44 no 16 pp 5101ndash51081988

[12] W J Hoekstra ldquoOrally-active nipecotamide glycolamide estersfor the treatment of thrombosis disorderrdquo US patent noUS6066651 2000

[13] KH Boltze andHKreisfeld ldquoOn the chemistry of etofenamatea novel antiinflammatory agent from the series of N arylan-thranilic acid derivativesrdquo Arzneimittel-Forschung vol 27 no6 b pp 1300ndash1312 1977

[14] S Pericherla J Mareddy D P Geetha Rani P V Gollapudi andS Pal ldquoChemical modifications of nimesuliderdquo Journal of theBrazilian Chemical Society vol 18 no 2 pp 384ndash390 2007

[15] L V Reddy M Nakka A Suman et al ldquoSynthesis of novelquinoline analogues of nimesulide an unusual observationrdquoJournal of Heterocyclic Chemistry vol 48 no 3 pp 555ndash5622011

[16] S Durgadas V K Chatare KMukkanti and S Pal ldquoPalladium-mediated synthesis of novel nimesulide derivativesrdquo AppliedOrganometallic Chemistry vol 24 no 10 pp 680ndash684 2010

[17] L V Reddy M Kethavath M Nakka et al ldquoDesign and syn-thesis of novel cytotoxic agents based on combined frameworkof quinoline and nimesuliderdquo Journal of Heterocyclic Chemistryvol 49 no 1 pp 80ndash87 2012

[18] K Kankanala V R Reddy K Mukkanti and S Pal ldquoLewisacid free high speed synthesis of nimesulide-based novel N-substituted cyclic imidesrdquo Journal of the Brazilian ChemicalSociety vol 21 no 6 pp 1060ndash1064 2010

[19] A Bhattacharya S Ghosh K Kankanala et al ldquoCrystal struc-ture and electronic properties of two nimesulide derivatives acombined X-ray powder diffraction and quantum mechanicalstudyrdquo Chemical Physics Letters vol 493 no 1ndash3 pp 151ndash1572010

[20] K Kankanala V Prakash K Mukkanti V R Reddy and S PalldquoN-(4-Methylsulfonamido-3-phenoxyphenyl)-910-dihydro-910-ethanoanthracene-1112-dicarboximiderdquo MolBank vol2011 article M740 2011

[21] B Chen B Su and S Chen ldquoA COX-2 inhibitor nimesulideanalog selectively induces apoptosis in Her2 overexpressingbreast cancer cells via cytochrome c dependent mechanismsrdquoBiochemical Pharmacology vol 77 no 12 pp 1787ndash1794 2009

8 Journal of Chemistry

[22] S Joudieh M Lahiani-Skiba P Bon O Ba J M Le Bretonand M Skiba ldquoNimesulide apparent solubility enhancementwith natural cyclodextrins and their polymersrdquo Letters in DrugDesign and Discovery vol 5 no 6 pp 406ndash415 2008

[23] T Mosmann ldquoRapid colorimetric assay for cellular growth andsurvival application to proliferation and cytotoxicity assaysrdquoJournal of Immunological Methods vol 65 no 1-2 pp 55ndash631983

[24] J Ferlay H R Shin F Bray D Forman C Mathers and DM Parkin ldquoColorectal cancer incidence mortality and prev-alence worldwide in 2008 Summaryrdquo in Proceedings of theGLOBOCAN 2008

[25] The ALOGPS 21 program was used to calculate the aver-age logP and average logs values httpwwwvcclaborglabalogpsstarthtml

[26] R Davis and R N Brogden ldquoNimesulide An update ofits pharmacodynamic and pharmacokinetic properties andtherapeutic efficacyrdquo Drugs vol 48 no 3 pp 431ndash454 1994

[27] F EMingatto ACDos Santos T Rodrigues AA Pigoso S AUyemura and C Curti ldquoEffects of nimesulide and its reducedmetabolite on mitochondriardquo British Journal of Pharmacologyvol 131 no 6 pp 1154ndash1160 2000

[28] B Su and S Chen ldquoLead optimization of COX-2 inhibitornimesulide analogs to overcome aromatase inhibitor resistancein breast cancer cellsrdquo Bioorganic and Medicinal ChemistryLetters vol 19 no 23 pp 6733ndash6735 2009

[29] B Zhong R Lama K M Smith Y Xu and B Su ldquoDesign andsynthesis of a biotinylated probe of COX-2 inhibitor nimesulideanalog JCC76rdquo Bioorganic andMedicinal Chemistry Letters vol21 no 18 pp 5324ndash5327 2011

[30] B Zhong X Cai S Chennamaneni et al ldquoFrom COX-2 inhib-itor nimesulide to potent anti-cancer agent synthesis in vitroin vivo and pharmacokinetic evaluationrdquo European Journal ofMedicinal Chemistry vol 47 no 1 pp 432ndash444 2012

Impact Factor 173028 Days Fast Track Peer ReviewAll Subject Areas of ScienceSubmit at httpwwwtswjcom

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

6 Journal of Chemistry

Table 1 Continued

(12)

3l

OCOMe

OPh

4l

HNC

C

O

O

O

OCOMe

NHSO2Me

15 90

aAll the reactions were performed using chlorocompound 2 (001mmol) and acid 3 (001mol) in the presence of NaI (0001mol) Et3N (0011mmol) and DMF(15mL) at 90∘CbIsolated yield

Table 2 In vitro cytotoxic activity of compound 4 against HCT-15 human colon cancer cell line

Entry Compounds of cell death at various concentrationsa IC50 (120583M)1 120583M 2 120583M 5120583M 10120583M 25 120583M

1 4a 094 689 815 877 2030 nd2 4b 062 720 750 1850 2850 nd3 4c 031 125 250 752 3100 nd4 4d 343 453 2169 3578 4938 nd5 4e 188 658 1316 1755 2880 nd6 4f 588 1446 2022 2500 4240 nd7 4g 600 796 1446 1862 4191 nd8 4h 031 752 877 1220 1940 nd9 4i 735 1237 1495 1629 4889 nd10 4j 674 943 2561 3590 5122 2440 plusmn 01411 4k 0 596 1220 3070 5579 2240 plusmn 13112 4l 2169 2193 2450 3002 6605 1892 plusmn 009aAll the values are the average of the experiments done in triplicates Etoposide (IC50 = 985120583M) was used as a reference compound nd not done

in this series Notably the IC50value of nimesulide was found

to be gt150120583M [26] whereas its reduced product did not showsignificant activities

Since the colon cancer is common in developed countriesthe present class of glycolamide esters has medicinal valueIt is worthy to mention that nimesulide is a banned drugin many countries because of its potential liver toxicity Theobserved liver toxicity of nimesulide has often been linkedto its uncoupling effects on mitochondria and study hasshown that nimesulide exerts this effect via a protonophoreticmechanism as well as oxidation of mitochondrial NADH andNADPH [27] The nitro group of nimesulide was thoughtto be responsible for its protonophoretic and NAD(P)Hoxidizing properties as chemical reduction of ndashNO

2to ndashNH

2

completely suppressed these activitiesThus the present classof compounds that does not contain a nitro group on the ndashNHSO

2Mebearing phenyl ring is expected to be free from the

liver toxicities of nimesulide We also performed the stabilitystudies using the compound 4l in the presence of 50mMtris buffer (pH 74) initially where 60 of 4l was found toremain unchanged after 2 h incubation in buffer This studyindicated that the present class of compounds perhaps isnot susceptible towards rapid ester hydrolysis Moreover notbeing the direct prodrug of nimesulide these compounds

would not provide nimesulide as such after ester hydrolysisThus these compounds are expected to be free from thegastric ulceration problem of nimesulide or other NSAIDs(nonsteroidal anti-inflammatory drugs)

Recently a nimesulide analogue obtained via its chemicalmodification that is replacing the phenyl ether moiety by anaryl ether and the nitro group by a cyclohexyl carboxamidemoiety showed suppression of three breast cancer cell pro-liferation types in a dose dependent manner [21] While theanticancer molecular target of this compound was not clearlyunderstood the cytochrome 119888 release assay indicated that theapoptosis induced by this compound was mediated throughthe mitochondria Due to the structural similarities with thiscompound present series of glycolamide esters might followsimilar cytochrome 119888 dependent mechanisms Neverthelessour study indicates that the glycolamide esters derived fromnimesulide [28ndash30] are of further interest

4 Conclusions

In conclusion we have successfully accomplished the synthe-sis of several new nimesulide based glycolamide esters via athree-step method starting from nimesulide in good yieldsStructures of the synthesized compounds were confirmed

Journal of Chemistry 7

0 5 10 15 20 25

100

80

60

40

20

0

Viab

le ce

lls (

)

Viable cells ()Death cells ()

Concentration (120583gmL)

Figure 2 Graphical presentation of in vitro cytotoxic activity ofcompound 4l against HCT-15 human colon cancer cell line

by spectroscopic analysis All the synthesized compoundswere examined for their cytotoxic effects in vitro Some ofthe compounds showed significant cytotoxic activities againstHCT-15 human colon cancer cell line Overall the presentnimesulide based glycolamide ester framework appeared tobe a useful template for the design and identification of noveland potential anticancer agents

Acknowledgment

The authors (Kavitha Kankanala and Sarbani Pal) thank MrM N Raju the chairman of M N R Educational Trust forhis constant encouragement

References

[1] D M Parkin F Bray J Ferlay and P Pisani ldquoGlobal cancerstatistics 2002rdquo CA Cancer Journal for Clinicians vol 55 no2 pp 74ndash108 2005

[2] N M Nielsen and H Bundgaard ldquoGlycolamide esters asbiolabile prodrugs of carboxylic acid agents synthesis stabilitybioconversion and physicochemical propertiesrdquo Journal ofPharmaceutical Sciences vol 77 no 4 pp 285ndash298 1988

[3] L K Wadhwa and P D Sharma ldquoGlycolamide esters of 6-methoxy-2-naphthylacetic acid as potential prodrugs-syntheticand spectral studiesrdquo Indian Journal of Chemistry vol 34 pp408ndash415 1995

[4] P D Sharma K J Singh S Gupta and S Chandiran ldquoGly-colamide esters of 4-biphenylacetic acid as potential prodrugs-synthetic and spectral studiesrdquo Indian Journal of Chemistry vol43 no 3 pp 636ndash642 2004

[5] N M Nielsen and H Bundgaard ldquoEvaluation of glycolamideesters and various other esters of aspirin as true aspirinprodrugsrdquo Journal of Medicinal Chemistry vol 32 no 3 pp727ndash734 1989

[6] A K Bansal R K Khar R Dubey and A K Sharma ldquoActiv-ity profile of glycolamide ester prodrugs of ibuprofenrdquo Drug

Development and Industrial Pharmacy vol 27 no 1 pp 63ndash702001

[7] A K Gadad S Bhat V S Tegeli and V V Redasani ldquoSynthesisspectral studies and anti-inflammatory activity of glycolamideesters of niflumic acid as potential prodrugsrdquo Arzneimittel-Forschung vol 52 no 11 pp 817ndash821 2002

[8] F Cao J-X Guo Q-N Ping and Z-G Liao ldquoProdrugsof scutellarin ethyl benzyl and NN-diethylglycolamide estersynthesis physicochemical properties intestinal metabolismand oral bioavailability in the ratsrdquo European Journal of Phar-maceutical Sciences vol 29 no 5 pp 385ndash393 2006

[9] S Khanna M Madan A Vangoori et al ldquoEvaluation of gly-colamide esters of indomethacin as potential cyclooxygenase-2(COX-2) inhibitorsrdquo Bioorganic and Medicinal Chemistry vol14 no 14 pp 4820ndash4833 2006

[10] CNNalini S Ramachandran K Kavitha andV S SaraswathildquoGlycolamide esters of naproxen as potential prodrugsmdashsynthesis spectral studies and preliminary pharmacologicalscreeningrdquo International Journal of Research in Pharmaceuticaland Biomedical Sciences vol 2 pp 1112ndash1117 2011

[11] M Amblard M Rodriguez and J Martinez ldquoN-benzhydryl-glycolamide esters (OBg esters) as carboxyl protecting groupsin pept1de synthesisrdquo Tetrahedron vol 44 no 16 pp 5101ndash51081988

[12] W J Hoekstra ldquoOrally-active nipecotamide glycolamide estersfor the treatment of thrombosis disorderrdquo US patent noUS6066651 2000

[13] KH Boltze andHKreisfeld ldquoOn the chemistry of etofenamatea novel antiinflammatory agent from the series of N arylan-thranilic acid derivativesrdquo Arzneimittel-Forschung vol 27 no6 b pp 1300ndash1312 1977

[14] S Pericherla J Mareddy D P Geetha Rani P V Gollapudi andS Pal ldquoChemical modifications of nimesuliderdquo Journal of theBrazilian Chemical Society vol 18 no 2 pp 384ndash390 2007

[15] L V Reddy M Nakka A Suman et al ldquoSynthesis of novelquinoline analogues of nimesulide an unusual observationrdquoJournal of Heterocyclic Chemistry vol 48 no 3 pp 555ndash5622011

[16] S Durgadas V K Chatare KMukkanti and S Pal ldquoPalladium-mediated synthesis of novel nimesulide derivativesrdquo AppliedOrganometallic Chemistry vol 24 no 10 pp 680ndash684 2010

[17] L V Reddy M Kethavath M Nakka et al ldquoDesign and syn-thesis of novel cytotoxic agents based on combined frameworkof quinoline and nimesuliderdquo Journal of Heterocyclic Chemistryvol 49 no 1 pp 80ndash87 2012

[18] K Kankanala V R Reddy K Mukkanti and S Pal ldquoLewisacid free high speed synthesis of nimesulide-based novel N-substituted cyclic imidesrdquo Journal of the Brazilian ChemicalSociety vol 21 no 6 pp 1060ndash1064 2010

[19] A Bhattacharya S Ghosh K Kankanala et al ldquoCrystal struc-ture and electronic properties of two nimesulide derivatives acombined X-ray powder diffraction and quantum mechanicalstudyrdquo Chemical Physics Letters vol 493 no 1ndash3 pp 151ndash1572010

[20] K Kankanala V Prakash K Mukkanti V R Reddy and S PalldquoN-(4-Methylsulfonamido-3-phenoxyphenyl)-910-dihydro-910-ethanoanthracene-1112-dicarboximiderdquo MolBank vol2011 article M740 2011

[21] B Chen B Su and S Chen ldquoA COX-2 inhibitor nimesulideanalog selectively induces apoptosis in Her2 overexpressingbreast cancer cells via cytochrome c dependent mechanismsrdquoBiochemical Pharmacology vol 77 no 12 pp 1787ndash1794 2009

8 Journal of Chemistry

[22] S Joudieh M Lahiani-Skiba P Bon O Ba J M Le Bretonand M Skiba ldquoNimesulide apparent solubility enhancementwith natural cyclodextrins and their polymersrdquo Letters in DrugDesign and Discovery vol 5 no 6 pp 406ndash415 2008

[23] T Mosmann ldquoRapid colorimetric assay for cellular growth andsurvival application to proliferation and cytotoxicity assaysrdquoJournal of Immunological Methods vol 65 no 1-2 pp 55ndash631983

[24] J Ferlay H R Shin F Bray D Forman C Mathers and DM Parkin ldquoColorectal cancer incidence mortality and prev-alence worldwide in 2008 Summaryrdquo in Proceedings of theGLOBOCAN 2008

[25] The ALOGPS 21 program was used to calculate the aver-age logP and average logs values httpwwwvcclaborglabalogpsstarthtml

[26] R Davis and R N Brogden ldquoNimesulide An update ofits pharmacodynamic and pharmacokinetic properties andtherapeutic efficacyrdquo Drugs vol 48 no 3 pp 431ndash454 1994

[27] F EMingatto ACDos Santos T Rodrigues AA Pigoso S AUyemura and C Curti ldquoEffects of nimesulide and its reducedmetabolite on mitochondriardquo British Journal of Pharmacologyvol 131 no 6 pp 1154ndash1160 2000

[28] B Su and S Chen ldquoLead optimization of COX-2 inhibitornimesulide analogs to overcome aromatase inhibitor resistancein breast cancer cellsrdquo Bioorganic and Medicinal ChemistryLetters vol 19 no 23 pp 6733ndash6735 2009

[29] B Zhong R Lama K M Smith Y Xu and B Su ldquoDesign andsynthesis of a biotinylated probe of COX-2 inhibitor nimesulideanalog JCC76rdquo Bioorganic andMedicinal Chemistry Letters vol21 no 18 pp 5324ndash5327 2011

[30] B Zhong X Cai S Chennamaneni et al ldquoFrom COX-2 inhib-itor nimesulide to potent anti-cancer agent synthesis in vitroin vivo and pharmacokinetic evaluationrdquo European Journal ofMedicinal Chemistry vol 47 no 1 pp 432ndash444 2012

Impact Factor 173028 Days Fast Track Peer ReviewAll Subject Areas of ScienceSubmit at httpwwwtswjcom

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

Journal of Chemistry 7

0 5 10 15 20 25

100

80

60

40

20

0

Viab

le ce

lls (

)

Viable cells ()Death cells ()

Concentration (120583gmL)

Figure 2 Graphical presentation of in vitro cytotoxic activity ofcompound 4l against HCT-15 human colon cancer cell line

by spectroscopic analysis All the synthesized compoundswere examined for their cytotoxic effects in vitro Some ofthe compounds showed significant cytotoxic activities againstHCT-15 human colon cancer cell line Overall the presentnimesulide based glycolamide ester framework appeared tobe a useful template for the design and identification of noveland potential anticancer agents

Acknowledgment

The authors (Kavitha Kankanala and Sarbani Pal) thank MrM N Raju the chairman of M N R Educational Trust forhis constant encouragement

References

[1] D M Parkin F Bray J Ferlay and P Pisani ldquoGlobal cancerstatistics 2002rdquo CA Cancer Journal for Clinicians vol 55 no2 pp 74ndash108 2005

[2] N M Nielsen and H Bundgaard ldquoGlycolamide esters asbiolabile prodrugs of carboxylic acid agents synthesis stabilitybioconversion and physicochemical propertiesrdquo Journal ofPharmaceutical Sciences vol 77 no 4 pp 285ndash298 1988

[3] L K Wadhwa and P D Sharma ldquoGlycolamide esters of 6-methoxy-2-naphthylacetic acid as potential prodrugs-syntheticand spectral studiesrdquo Indian Journal of Chemistry vol 34 pp408ndash415 1995

[4] P D Sharma K J Singh S Gupta and S Chandiran ldquoGly-colamide esters of 4-biphenylacetic acid as potential prodrugs-synthetic and spectral studiesrdquo Indian Journal of Chemistry vol43 no 3 pp 636ndash642 2004

[5] N M Nielsen and H Bundgaard ldquoEvaluation of glycolamideesters and various other esters of aspirin as true aspirinprodrugsrdquo Journal of Medicinal Chemistry vol 32 no 3 pp727ndash734 1989

[6] A K Bansal R K Khar R Dubey and A K Sharma ldquoActiv-ity profile of glycolamide ester prodrugs of ibuprofenrdquo Drug

Development and Industrial Pharmacy vol 27 no 1 pp 63ndash702001

[7] A K Gadad S Bhat V S Tegeli and V V Redasani ldquoSynthesisspectral studies and anti-inflammatory activity of glycolamideesters of niflumic acid as potential prodrugsrdquo Arzneimittel-Forschung vol 52 no 11 pp 817ndash821 2002

[8] F Cao J-X Guo Q-N Ping and Z-G Liao ldquoProdrugsof scutellarin ethyl benzyl and NN-diethylglycolamide estersynthesis physicochemical properties intestinal metabolismand oral bioavailability in the ratsrdquo European Journal of Phar-maceutical Sciences vol 29 no 5 pp 385ndash393 2006

[9] S Khanna M Madan A Vangoori et al ldquoEvaluation of gly-colamide esters of indomethacin as potential cyclooxygenase-2(COX-2) inhibitorsrdquo Bioorganic and Medicinal Chemistry vol14 no 14 pp 4820ndash4833 2006

[10] CNNalini S Ramachandran K Kavitha andV S SaraswathildquoGlycolamide esters of naproxen as potential prodrugsmdashsynthesis spectral studies and preliminary pharmacologicalscreeningrdquo International Journal of Research in Pharmaceuticaland Biomedical Sciences vol 2 pp 1112ndash1117 2011

[11] M Amblard M Rodriguez and J Martinez ldquoN-benzhydryl-glycolamide esters (OBg esters) as carboxyl protecting groupsin pept1de synthesisrdquo Tetrahedron vol 44 no 16 pp 5101ndash51081988

[12] W J Hoekstra ldquoOrally-active nipecotamide glycolamide estersfor the treatment of thrombosis disorderrdquo US patent noUS6066651 2000

[13] KH Boltze andHKreisfeld ldquoOn the chemistry of etofenamatea novel antiinflammatory agent from the series of N arylan-thranilic acid derivativesrdquo Arzneimittel-Forschung vol 27 no6 b pp 1300ndash1312 1977

[14] S Pericherla J Mareddy D P Geetha Rani P V Gollapudi andS Pal ldquoChemical modifications of nimesuliderdquo Journal of theBrazilian Chemical Society vol 18 no 2 pp 384ndash390 2007

[15] L V Reddy M Nakka A Suman et al ldquoSynthesis of novelquinoline analogues of nimesulide an unusual observationrdquoJournal of Heterocyclic Chemistry vol 48 no 3 pp 555ndash5622011

[16] S Durgadas V K Chatare KMukkanti and S Pal ldquoPalladium-mediated synthesis of novel nimesulide derivativesrdquo AppliedOrganometallic Chemistry vol 24 no 10 pp 680ndash684 2010

[17] L V Reddy M Kethavath M Nakka et al ldquoDesign and syn-thesis of novel cytotoxic agents based on combined frameworkof quinoline and nimesuliderdquo Journal of Heterocyclic Chemistryvol 49 no 1 pp 80ndash87 2012

[18] K Kankanala V R Reddy K Mukkanti and S Pal ldquoLewisacid free high speed synthesis of nimesulide-based novel N-substituted cyclic imidesrdquo Journal of the Brazilian ChemicalSociety vol 21 no 6 pp 1060ndash1064 2010

[19] A Bhattacharya S Ghosh K Kankanala et al ldquoCrystal struc-ture and electronic properties of two nimesulide derivatives acombined X-ray powder diffraction and quantum mechanicalstudyrdquo Chemical Physics Letters vol 493 no 1ndash3 pp 151ndash1572010

[20] K Kankanala V Prakash K Mukkanti V R Reddy and S PalldquoN-(4-Methylsulfonamido-3-phenoxyphenyl)-910-dihydro-910-ethanoanthracene-1112-dicarboximiderdquo MolBank vol2011 article M740 2011

[21] B Chen B Su and S Chen ldquoA COX-2 inhibitor nimesulideanalog selectively induces apoptosis in Her2 overexpressingbreast cancer cells via cytochrome c dependent mechanismsrdquoBiochemical Pharmacology vol 77 no 12 pp 1787ndash1794 2009

8 Journal of Chemistry

[22] S Joudieh M Lahiani-Skiba P Bon O Ba J M Le Bretonand M Skiba ldquoNimesulide apparent solubility enhancementwith natural cyclodextrins and their polymersrdquo Letters in DrugDesign and Discovery vol 5 no 6 pp 406ndash415 2008

[23] T Mosmann ldquoRapid colorimetric assay for cellular growth andsurvival application to proliferation and cytotoxicity assaysrdquoJournal of Immunological Methods vol 65 no 1-2 pp 55ndash631983

[24] J Ferlay H R Shin F Bray D Forman C Mathers and DM Parkin ldquoColorectal cancer incidence mortality and prev-alence worldwide in 2008 Summaryrdquo in Proceedings of theGLOBOCAN 2008

[25] The ALOGPS 21 program was used to calculate the aver-age logP and average logs values httpwwwvcclaborglabalogpsstarthtml

[26] R Davis and R N Brogden ldquoNimesulide An update ofits pharmacodynamic and pharmacokinetic properties andtherapeutic efficacyrdquo Drugs vol 48 no 3 pp 431ndash454 1994

[27] F EMingatto ACDos Santos T Rodrigues AA Pigoso S AUyemura and C Curti ldquoEffects of nimesulide and its reducedmetabolite on mitochondriardquo British Journal of Pharmacologyvol 131 no 6 pp 1154ndash1160 2000

[28] B Su and S Chen ldquoLead optimization of COX-2 inhibitornimesulide analogs to overcome aromatase inhibitor resistancein breast cancer cellsrdquo Bioorganic and Medicinal ChemistryLetters vol 19 no 23 pp 6733ndash6735 2009

[29] B Zhong R Lama K M Smith Y Xu and B Su ldquoDesign andsynthesis of a biotinylated probe of COX-2 inhibitor nimesulideanalog JCC76rdquo Bioorganic andMedicinal Chemistry Letters vol21 no 18 pp 5324ndash5327 2011

[30] B Zhong X Cai S Chennamaneni et al ldquoFrom COX-2 inhib-itor nimesulide to potent anti-cancer agent synthesis in vitroin vivo and pharmacokinetic evaluationrdquo European Journal ofMedicinal Chemistry vol 47 no 1 pp 432ndash444 2012

Impact Factor 173028 Days Fast Track Peer ReviewAll Subject Areas of ScienceSubmit at httpwwwtswjcom

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

8 Journal of Chemistry

[22] S Joudieh M Lahiani-Skiba P Bon O Ba J M Le Bretonand M Skiba ldquoNimesulide apparent solubility enhancementwith natural cyclodextrins and their polymersrdquo Letters in DrugDesign and Discovery vol 5 no 6 pp 406ndash415 2008

[23] T Mosmann ldquoRapid colorimetric assay for cellular growth andsurvival application to proliferation and cytotoxicity assaysrdquoJournal of Immunological Methods vol 65 no 1-2 pp 55ndash631983

[24] J Ferlay H R Shin F Bray D Forman C Mathers and DM Parkin ldquoColorectal cancer incidence mortality and prev-alence worldwide in 2008 Summaryrdquo in Proceedings of theGLOBOCAN 2008

[25] The ALOGPS 21 program was used to calculate the aver-age logP and average logs values httpwwwvcclaborglabalogpsstarthtml

[26] R Davis and R N Brogden ldquoNimesulide An update ofits pharmacodynamic and pharmacokinetic properties andtherapeutic efficacyrdquo Drugs vol 48 no 3 pp 431ndash454 1994

[27] F EMingatto ACDos Santos T Rodrigues AA Pigoso S AUyemura and C Curti ldquoEffects of nimesulide and its reducedmetabolite on mitochondriardquo British Journal of Pharmacologyvol 131 no 6 pp 1154ndash1160 2000

[28] B Su and S Chen ldquoLead optimization of COX-2 inhibitornimesulide analogs to overcome aromatase inhibitor resistancein breast cancer cellsrdquo Bioorganic and Medicinal ChemistryLetters vol 19 no 23 pp 6733ndash6735 2009

[29] B Zhong R Lama K M Smith Y Xu and B Su ldquoDesign andsynthesis of a biotinylated probe of COX-2 inhibitor nimesulideanalog JCC76rdquo Bioorganic andMedicinal Chemistry Letters vol21 no 18 pp 5324ndash5327 2011

[30] B Zhong X Cai S Chennamaneni et al ldquoFrom COX-2 inhib-itor nimesulide to potent anti-cancer agent synthesis in vitroin vivo and pharmacokinetic evaluationrdquo European Journal ofMedicinal Chemistry vol 47 no 1 pp 432ndash444 2012

Impact Factor 173028 Days Fast Track Peer ReviewAll Subject Areas of ScienceSubmit at httpwwwtswjcom

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal

Impact Factor 173028 Days Fast Track Peer ReviewAll Subject Areas of ScienceSubmit at httpwwwtswjcom

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawi Publishing Corporation httpwwwhindawicom Volume 2013

The Scientific World Journal