research article antiproliferative activity evaluation of...

Research ArticleAntiproliferative Activity Evaluation ofa Series of N-13-Benzothiazol-2-ylbenzamides asNovel Apoptosis Inducers

Filomena Corbo1 Alessia Carocci1 Domenico Armenise1 Nicolino De Laurentis1

Antonio Laghezza1 Fulvio Loiodice1 Patrizia Ancona2 Marilena Muraglia1

Vincenzo Pagliarulo2 Carlo Franchini1 and Alessia Catalano1

1Dipartimento di Farmacia-Scienze del Farmaco Universita degli Studi di Bari ldquoAldo Morordquo Via E Orabona No 4 70126 Bari Italy2Dipartimento di Emergenza e Trapianti drsquoOrgano Unita di Urologia e Andrologia Universita degli Studi di Bari ldquoAldo MorordquoPiazza G Cesare No 11 70124 Bari Italy

Correspondence should be addressed to Alessia Carocci alessiacarocciunibait

Received 21 September 2015 Revised 30 November 2015 Accepted 16 December 2015

Academic Editor Tanaji Talele

Copyright copy 2016 Filomena Corbo 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

A series of N-13-benzothiazol-2-ylbenzamide derivatives were studied for their antiproliferative activity on human liverhepatocellular carcinoma (HepG2) and human breast cancer (MCF-7) cell lines Most of them were found to show a prominentinhibitory effect on cell growth Among the most active compounds 1k emerged for its proapoptotic effect that is particularlyevident towards MCF-7 cancer cell lines

1 Introduction

Cancer a group of diseases characterized by uncontrolledgrowth of abnormal cells is one of the major worldwidehealth problems It is a lethal disease and one of the pri-mary causes of death standing next to the cardiovasculardiseases Currently studies for the identification of potentsafe and selective anticancer drugs are at the forefrontAlthough the tumor-specific action of most anticancer drugshas been attributed to their debilitating effects on activelyproliferating cells several studies conversely suggest thatanticancer agents induce apoptosis a physiological modeof cell death in higher eukaryotes [1ndash3] Apoptosis hasbeen recognized as a basic component in the pathogenesisof cancer It may be considered a defense mechanism toremove potentially dangerous cells such as tumor cells Itsderegulationmay be conceivably involved in the pathogenesisof cancer Many antitumor compounds induce the apoptoticprocess in tumor cells [4] thus development of new drugsthat can effectively trigger apoptosis in tumor cells may

be envisaged A number of benzothiazole containing com-pounds have exhibited interesting biological activities suchas antimicrobial and antitumor activities [5ndash10] Indeed thebenzothiazole nucleus constitutes an important scaffold fordrugs and attracts continuous interest for further molecularexploration to find new useful anticancer agents [11ndash14]Anticancer activity on human carcinoma cell lines has beenreported for a benzothiazole linked to a phthalimide moiety[15] moreover benzothiazole-2-thiol derivatives have beenproposed as novel apoptosis inducers [16] A novel benzoth-iazole derivative has been shown to induce apoptosis viathe mitochondrial apoptosis pathway in vitro with antitumoractivity in solid malignancies [17] Furthermore it has beenreported that antimicrobials often induce cytotoxicity viaapoptotic mechanism thus making themselves candidatesas new tools for anticancer therapy In the last decade ourresearch group was interested in the design synthesis andbiological evaluation of novel benzothiazole derivatives asantimicrobial agents [8 10 18] Thus to further investigatethe panel of activity for this class of compounds we decided

Hindawi Publishing CorporationJournal of ChemistryVolume 2016 Article ID 4267564 5 pageshttpdxdoiorg10115520164267564

2 Journal of Chemistry

1

Cl S

NN

O

HR

2

F S

NN

O

HR

R 4-F or 5-F R 4-Cl or 5-Cl R1 H or difluoro R1 H or difluoro

R1 R1

Figure 1 Structures of compounds 1 and 2

Cl

R

Cl S

NR

Cl S

NN

O

HR

(i) (ii)

m R = 5-Fn R = 4-F

NH2

NH2

1mn4mn3mn

Scheme 1 Synthesis of compounds 1mn Reagents and conditions (i) Br2 KSCN AcOH 30ndash35∘C (ii) benzoyl chloride Et

3N dioxane

50ndash60∘C

to study some of them as potential anticancer agents Basedon the results obtained by Wang et al [16] on a series of ben-zothiazole derivatives that exhibited antiproliferative activityagainst the human hepatocellular carcinoma cell line HepG2and the human mammary carcinoma cell line MCF-7 weselected a small series of compounds among the previouslysynthesized benzothiazoles [18] for biological evaluation aspotential apoptosis inducersThe selected compounds belongto two small series (1 and 2 Figure 1) Then in order toimprove structure-activity relationship (SAR) studies on thisclass of compounds three additional analogues (1mn and 2a)were synthesized and evaluated too

2 Results and Discussion

Nineteen compounds belonging to two small series (1andashn and2andashe Figure 1 Table 1) were synthesized and evaluated fortheir potential antiproliferative and proapoptotic activities asdescribed below

21 Chemistry Compounds 1andashl and 2bndashe were previouslyreported by this group [18] Compounds 1mn and 2a wereprepared as reported in Schemes 1 and 2 respectively Theappropriate aniline was reacted with bromine and potassiumthiocyanate to give the corresponding 2-aminobenzothiazolewhich was reacted with benzoyl chloride to give the finalcompound Novel benzothiazoles were fully characterized byIR both 1H and 13C NMR spectra and GC-MS analysis

22 Biological Results With the aim to develop novel tumorgrowth inhibitors and apoptosis inducers as potential anti-cancer agents two small series of N-13-benzothiazol-2-ylbenzamide derivatives (1andashn and 2andashe Figure 1 Table 2)

Table 1 Structures of compounds 1andashn and 2andashe

Compound R R1

1a

1

Cl S

NN

O

HRR1

4-F 23-F2

1b 4-F 24-F2

1c 4-F 25-F2

1d 4-F 26-F2

1e 4-F 34-F2

1f 4-F 35-F2

1g 5-F 23-F2

1h 5-F 24-F2

1i 5-F 25-F2

1j 5-F 26-F2

1k 5-F 34-F2

1l 5-F 35-F2

1m 5-F mdash1n 4-F mdash2a

2

F S

NN

O

HRR1

4-Cl mdash2b 4-Cl 24-F

2

2c 4-Cl 25-F2

2d 4-Cl 34-F2

2e 4-Cl 35-F2

were investigated Thus the cell growth inhibitory activitiesin cultures of HepG2 and MCF-7 cells were evaluated bymeans of MTT assay In order to select compounds withhigh activity a concentration of 10120583M was chosen for theassays which alsomeets the properties of low solubility of thetested compounds Amongst the two cancer cell lines under

Journal of Chemistry 3

3a 4a 2a

(i) (ii) F S

NN

O

H

Cl

F S

N

Cl

F

Cl

NH2

NH2

Scheme 2 Synthesis of compounds 2a Reagents and conditions (i) Br2 KSCN AcOH 30ndash35∘C (ii) benzoyl chloride Et

3N dioxane 50ndash

60∘C

Table 2 Antiproliferative activity ( inhibition MTT assay) of thetarget compounds 1andashn and 2andashe over HepG2 and MCF-7 cells

HepG2a MCF-7a

Inhibition Inhibition (10120583M) (10 120583M)

1a 34 plusmn 3 20 plusmn 11b 70 plusmn 1 24 plusmn 21c 52 plusmn 3 26 plusmn 151d 0 plusmn 10 0 plusmn 21e 45 plusmn 2 39 plusmn 11f 80 plusmn 2 56 plusmn 21g 36 plusmn 1 40 plusmn 11h 64 plusmn 1 22 plusmn 21i 76 plusmn 1 46 plusmn 11j 39 plusmn 2 31 plusmn 81k 64 plusmn 2 64 plusmn 61l 46 plusmn 7 41 plusmn 81m 33 plusmn 4 10 plusmn 51n 32 plusmn 5 25 plusmn 122a 5 plusmn 3 14 plusmn 52b 23 plusmn 15 28 plusmn 262c 58 plusmn 5 35 plusmn 142d 58 plusmn 3 54 plusmn 242e 20 plusmn 8 40 plusmn 10aData are presented as the means plusmn SD of three independent experiments

evaluation the highest antiproliferative activity values werefound for the HepG2 one In particular three compoundsout of nineteen (1bfi) showed inhibition values of at least70 towards this cell line Since all these compounds belongto series 1 conceivably the presence of the chlorine atom atposition 6 of the benzothiazole nucleus should be crucialfor the antiproliferative activity On the contrary none ofthe compounds bearing a fluorine atom at the same posi-tion (series 2) showed considerable antiproliferative activityAll tested compounds showed low antiproliferative activitytowards MCF-7 cell line except for compounds 1fk and2d with an inhibition value of more than 50 As it isknown the antitumor efficacy of a chemotherapeutic agentcould be related to its apoptosis inducing activity Hencewe examined whether the most active compounds of theseries could induce apoptosis thus we selected compoundsshowing an inhibition value higher than 50 towards HepG2

005

115

225

335

4

Basal 1b 1f 1h 1i 1c 2b 2d 2c 1kMon

o- an

d ol

igon

ucle

osom

es

enric

hmen

tCompound

HepG2MCF-7

Figure 2 ELISA detection of mono- and oligonucleosomes enrich-ment after apoptosis

andor MCF-7 cell lines (1bcfhik and 2cd) In additioncompound 2b was also tested because of its questionableinhibition values (ie high SD) The proapoptotic activityof compounds was performed by measuring the specificenrichment of mono- and oligonucleosomes after treatment(Figure 2) Results on HepG2 cell line suggest a proapoptoticeffect for compounds 1k and 2bc showing about 2-foldmono- and oligonucleosomes enrichment higher than thebasal one A clear-cut apoptotic effect on MCF-7 cell linewas shown by compound 1k followed by 2b and 1f Nosubstantial proapoptotic effect was observed when the othermolecules were tested conceivably suggesting a mechanismof cell growth inhibition not related to apoptosis The mostpromising compounds of the series seem to be 1fik beingthe first two quite selective for HepG2 while compound 1kshows interesting activity on both cell lines conceivably actingas proapoptotic inducer

3 Conclusions

Two series of N-13-benzothiazol-2-ylbenzamides were eval-uated for their antiproliferative activity in vitro The highergrowth inhibition activity in MTT assay was found towardsHepG2 cell line being 1fik the most interesting compoundsIn particular 1k which showed antiproliferative activity onMCF-7 comparable to that of HepG2 cell line may conceiv-ably act via proapoptotic mechanism as demonstrated bymeans of ELISA detection of mono- and oligonucleosomesenrichment Further studies will be required to gain betterinside into the mechanism of their antiproliferative activity


4 Experimental

41 General ExperimentalDetails Chemicalswere purchasedfrom Sigma-Aldrich or Lancaster Yields refer to purifiedproducts and were not optimized The structures of thecompounds were confirmed by routine spectrometric andspectroscopic analyses Only spectra for compounds notpreviously described are given Compounds 4amn and 2bndashewere prepared as previously described [18 19] Melting pointswere determined on a Gallenkamp apparatus in open glasscapillary tubes and are uncorrected Infrared spectra wererecorded on a Perkin-Elmer (Norwalk CT) Spectrum OneFT spectrophotometer and band positions are given in recip-rocal centimeters (cmminus1) 1HNMR spectra were recorded ona Varian VX Mercury spectrometer operating at 300MHzusing CDCl

3and DMSO-d

6(where indicated) as solvents

Chemical shifts are reported in parts per million (ppm) rela-tive to the residual nondeuterated solvent resonance CDCl

3

120575 726 andDMSO-d6 120575 248 119869 values are given inHz GC-MS

was performed on a Hewlett-Packard 6890-5973MSD at lowresolution Chromatographic separations were performed onsilica gel columns by flash chromatography (Kieselgel 600040ndash0063mmMerckDarmstadt Germany) as previouslyreported [20ndash22] TLC analyseswere performed onprecoatedsilica gel on aluminum sheets (Kieselgel 60 F

254 Merck)

411 N-(6-Chloro-5-fluoro-13-benzothiazol-2-yl)benzamide(1m) A mixture of 4m (10 g 50mmol) and triethylamine(050 g 50mmol) in dry dioxane (50mL) was stirred for30min at 50ndash60∘C A solution of benzoyl chloride (070 g50mmol) in dry dioxane (50mL) was added dropwise Themixture was stirred for 2 h and then poured into crushed iceThe resulting solid so separated was collected by filtrationand washed with 1 potassium bicarbonate aqueous solutiongiving 050 g (33) of 1m as a yellow solid mp 246ndash248∘CGC-MS (70 eV electron impact) mz () 306 (M+ 16) and105 (100) IR (KBr) 3218 (NH) 1675 (C=O) cmminus1 1H NMR(DMSO-d

6) 120575 755 (t 119869 = 74Hz 2H Ar) 760ndash770 (m 1H

Ar) 781 (d 119869 = 99Hz 1H Ar) 808ndash816 (m 2H Ar) 830(d 119869 = 74Hz 1H Ar) and 1307 ppm (br s 1H NH exchD2O) 13C NMR (DMSO-d

6) 120575 1084 (1C) 1159 (1C) 1237

(2C) 1291 (2C) 1292 (2C) 1324 (1C) 1337 (1C) 1490 (1C)1584 (1C) 1625 (1C) and 1669 (1C)

412 N-(6-Chloro-4-fluoro-13-benzothiazol-2-yl)benzamide(1n) Prepared as reported above for 1m starting from 4nYield 66 brown solid mp 226-227∘C GC-MS (70 eVelectron impact) mz () 306 (M+ 36) 105 (100) IR (KBr)3241 (NH) 1679 (C=O) cmminus1 1H NMR (DMSO-d

6) 120575 740ndash

780 (m 4H Ar) 762ndash770 (m 1H Ar) 796ndash810 (m 1H Ar)812ndash822 (m 1H Ar) and 132 ppm (br s 1H NH) 13CNMR(DMSO-d

6)120575 1136 (1C) 1185 (1C) 1281 (1C) 1282 (1C) 1291

(3C) 1321 (1C) 1338 (1C) 1363 (1C) 1368 (1C) 1523 (1C)1609 (1C) and 1668 (1C)

413 N-(4-Chloro-6-fluoro-13-benzothiazol-2-yl)benzamide(2a) Prepared as reported above for 1m starting from 4aYield 35 slightly yellowish solid mp 208-209∘C GC-MS(70 eV electron impact) mz () 306 (M+ 16) 105 (100) IR

(KBr) 3252 (NH) 1670 (C=O) cmminus1 1H NMR (DMSO-d6)

120575 742ndash770 (m 5H Ar) 787ndash795 (m 1H Ar) 805ndash815 (m1H Ar) and 131 ppm (br s 1H NH) 13C NMR (DMSO-d

6)

120575 1082 (1C) 1155 (1C) 1254 (1C) 1292 (4C) 1321 (1C) 1338(1C) 1345 (1C) 1432 (1C) 1570 (1C) 1605 (1C) and 1669(1C)

42 Biology

421 MTT Assay for Cell Viability Cell viability was mea-sured using the MTT assay [23 24] The cell lines (humanbreast adenocarcinoma cell lines MCF-7 and human hepa-tocellular carcinoma cell lines HepG2) were obtained fromthe ITCC (Genova Italy) Cells were grown in DMEMmedium supplementedwith 10 fetal bovine serum 10UmLpenicillin 100mgmL streptomycin and 2mM glutamine ina 5 CO

2atmosphere at 37∘C Cells were seeded at a density

of 1ndash5 sdot 104 cellswell into 96-well flat bottom culture platescontaining test compound (100 120583M final concentration) ina final volume of 100120583L Test compounds were dissolvedin DMSO (1 final concentration DMSO carrier had noeffect on cell proliferation) Control wells lacked inhibitorAfter 48 h of incubation at 37∘C in a 5 CO

2atmosphere 3-

(45-dimethylthiazol-2-yl)-25-diphenyltetrazolium bromide(MTT 5mgmL stock solution) was added to a final concen-tration of 05mgmL To control for background absorbancesix wells of cells were lysed by adding Triton X-100 (01vv final concentration) immediately prior to the addition ofMTT reagent After incubation under the same conditions forfurther 3-4 h the culturemediumwas removed the insolubleproduct dissolved by the addition of 100 120583L of solvent (50DMSO 50 EtOH vv) and the absorbance of the well wasmeasured at 570 nm using a PERKINndashELMER Victor V3plate reader Cell growth inhibition was then calculated using

119881 =119860 minus 119860

119887

119860119888minus 119860119887

times 100 (1)

where 119881 is the percentage of cell viability 119860 is theabsorbance of treated cultures 119860

119887is the absorbance of

background control and 119860119888is the absorbance of control

cultures

422 Detection of Mono- and Oligonucleosomes EnrichmentTheMCF-7 and HepG2 cells were seeded into 96-well platesin the absence and presence of known concentrations (10120583M)of a panel of molecules (Table 1) added to a final volumeof 200120583Lwell of standard growth medium and incubatedat 37∘C for 48 h Afterwards the supernatant was removedcarefully and the adherent cells were lysed directly with200120583L of Lysis buffer incubated for 30min at 15ndash25∘C Afterincubation time the lysate was centrifuged at 200timesg for10min and 20120583L of culture supernatants after centrifugationand treatment was transferred into the streptavidin coatedMP of Cell DeathDetection ELISA kit (Roche Basel Switzer-land) to determine the specific enrichment of mono- andoligonucleosomes after inducing cell death according to themanufacturerrsquos protocol The optical density was measuredat 405 nm and 490 nm wavelengths using Multiskan Ascent(Thermo Fischer Scoresby Australia)


Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

This work was accomplished thanks to financial support ofthe Ministero dellrsquoIstruzione dellrsquoUniversita e della Ricerca(MIUR)

References

[1] C Dive and J A Hickman ldquoDrug-target interactions only thefirst step in the commitment to a programmed cell deathrdquoBritish Journal of Cancer vol 64 no 1 pp 192ndash196 1991

[2] J F R Kerr CMWinterford and B V Harmon ldquoApoptosis itssignificance in cancer and cancer therapyrdquo Cancer vol 73 no8 pp 2013ndash2026 1994

[3] C Saturnino C Palladino M Napoli et al ldquoSynthesis and bio-logical evaluation of newN-alkylcarbazole derivatives as STAT3inhibitors preliminary studyrdquo European Journal of MedicinalChemistry vol 60 pp 112ndash119 2013

[4] J Cummings T H Ward M Ranson and C Dive ldquoApop-tosis pathway-targeted drugsmdashfrom the bench to the clinicrdquoBiochimica et Biophysica Acta vol 1705 no 1 pp 53ndash66 2004

[5] P S Yadav Devprakash and G P Senthilkumar ldquoBenzoth-iazole different methods of synthesis and diverse biologicalactivitiesrdquo International Journal of Pharmaceutical Science andDrug Research vol 3 no 1 pp 1ndash7 2011

[6] C BrunoACarocci ACatalano et al ldquoFacile alternative routeto lubeluzole its enantiomer and the racematerdquo Chirality vol18 no 4 pp 227ndash231 2006

[7] I Hutchinson T D Bradshaw C S Matthews M F G Stevensand A D Westwell ldquoAntitumour benzothiazoles Part 20 31015840-cyano and 31015840-alkynyl-substituted 2-(41015840-aminophenyl)benzothi-azoles as new potent and selective analoguesrdquo Bioorganic ampMedicinal Chemistry Letters vol 13 no 3 pp 471ndash474 2003

[8] A Catalano A Carocci I Defrenza et al ldquo2-Aminoben-zothiazole derivatives search for new antifungal agentsrdquo Euro-pean Journal of Medicinal Chemistry vol 64 pp 357ndash364 2013

[9] C Franchini M Muraglia F Corbo et al ldquoSynthesis andanti-cancer activity of benzothiazole containing phthalimide onhuman carcinoma cell linesrdquoArchiv der Pharmazie vol 342 no7 pp 605ndash613 2009

[10] I Defrenza A Catalano A Carocci et al ldquo13-Benzothiazolesas antimicrobial agentsrdquo Journal of Heterociclic Chemistry vol52 pp 1705ndash1712 2015

[11] P C SharmaA Sinhmar A SharmaH Rajak andD P PathakldquoMedicinal significance of benzothiazole scaffold an insightviewrdquo Journal of Enzyme Inhibition and Medicinal Chemistryvol 28 no 2 pp 240ndash266 2013

[12] P Chaudhary P K Sharma A Sharma and J VarshneyldquoRecent advances in pharmacological activity of benzothiazolederivativesrdquo International Journal of Current PharmaceuticalResearch vol 2 no 4 pp 5ndash11 2010

[13] KAhmed S YVVenkataNA KMohammed F Sultana andK R Methuku ldquoRecent advances on structural modificationsof benzothiazoles and their conjugate systems as potentialchemotherapeuticsrdquo Expert Opinion on Investigational Drugsvol 21 no 5 pp 619ndash635 2012

[14] A A Weekes and A D Westwell ldquo2-Arylbenzothiazole asa privileged scaffold in drug discoveryrdquo Current MedicinalChemistry vol 16 no 19 pp 2430ndash2440 2009

[15] S H L Kok R Gambari C H Chui et al ldquoSynthesis andanti-cancer activity of benzothiazole containing phthalimide onhuman carcinoma cell linesrdquoBioorganicampMedicinal Chemistryvol 16 no 7 pp 3626ndash3631 2008

[16] Z Wang X-H Shi J Wang et al ldquoSynthesis structure-activity relationships and preliminary antitumor evaluation ofbenzothiazole-2-thiol derivatives as novel apoptosis inducersrdquoBioorganic amp Medicinal Chemistry Letters vol 21 no 4 pp1097ndash1101 2011

[17] S Xuejiao X Yong W Ningyu et al ldquoA novel benzothiazolederivative YLT322 induces apoptosis via the mitochondrialapoptosis pathway in vitro with anti-tumor activity in solidmalignanciesrdquo PLoS ONE vol 8 no 5 Article ID e63900 2013

[18] D Armenise A Carocci A Catalano et al ldquoSynthesis andantimicrobial evaluation of a new series of N-13-benzothiazol-2-ylbenzamidesrdquo Journal of Chemistry vol 2013 Article ID181758 7 pages 2013

[19] D Armenise N De Laurentis A Reho A Rosato and FMorlacchi ldquoSynthesis and antifungal activity against strains ofCandida albicans of 6-fluoro-4(5 or 7)-chloro-2-(difluoroben-zoyl)aminobenzothiazolesrdquo Journal of Heterocyclic Chemistryvol 41 no 5 pp 771ndash775 2004

[20] A Carocci A Catalano C Bruno et al ldquoSynthesis and in vitrosodium channel blocking activity evaluation of novel homochi-ral mexiletine analogsrdquo Chirality vol 22 no 3 pp 299ndash3072010

[21] A Catalano A Carocci M M Cavalluzzi et al ldquoHydroxylatedanalogs ofmexiletine as tools for structural-requirements inves-tigation of the sodium channel blocking activityrdquo Archiv derPharmazie vol 343 no 6 pp 325ndash332 2010

[22] A Catalano R Budriesi C Bruno et al ldquoSearching for newantiarrhythmic agents evaluation of meta-hydroxymexiletineenantiomersrdquo European Journal of Medicinal Chemistry vol 65pp 511ndash516 2013

[23] A Carocci A Catalano C Bruno et al ldquoN-(phenox-yalkyl)amides as MT

1and MT

2ligands antioxidant properties

and inhibition of Ca2+CaM-dependent kinase IIrdquoBioorganic ampMedicinal Chemistry vol 21 no 4 pp 847ndash851 2013

[24] A Catalano J-F Desaphy G Lentini et al ldquoSynthesis andtoxicopharmacological evaluation ofm-hydroxymexiletine thefirst metabolite of mexiletine more potent than the parent com-pound on voltage-gated sodium channelsrdquo Journal of MedicinalChemistry vol 55 no 3 pp 1418ndash1422 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


1

Cl S

NN

O

HR

2

F S

NN

O

HR

R 4-F or 5-F R 4-Cl or 5-Cl R1 H or difluoro R1 H or difluoro

R1 R1

Figure 1 Structures of compounds 1 and 2

Cl

R

Cl S

NR

Cl S

NN

O

HR

(i) (ii)

m R = 5-Fn R = 4-F

NH2

NH2

1mn4mn3mn

Scheme 1 Synthesis of compounds 1mn Reagents and conditions (i) Br2 KSCN AcOH 30ndash35∘C (ii) benzoyl chloride Et

3N dioxane

50ndash60∘C

to study some of them as potential anticancer agents Basedon the results obtained by Wang et al [16] on a series of ben-zothiazole derivatives that exhibited antiproliferative activityagainst the human hepatocellular carcinoma cell line HepG2and the human mammary carcinoma cell line MCF-7 weselected a small series of compounds among the previouslysynthesized benzothiazoles [18] for biological evaluation aspotential apoptosis inducersThe selected compounds belongto two small series (1 and 2 Figure 1) Then in order toimprove structure-activity relationship (SAR) studies on thisclass of compounds three additional analogues (1mn and 2a)were synthesized and evaluated too

2 Results and Discussion

Nineteen compounds belonging to two small series (1andashn and2andashe Figure 1 Table 1) were synthesized and evaluated fortheir potential antiproliferative and proapoptotic activities asdescribed below

21 Chemistry Compounds 1andashl and 2bndashe were previouslyreported by this group [18] Compounds 1mn and 2a wereprepared as reported in Schemes 1 and 2 respectively Theappropriate aniline was reacted with bromine and potassiumthiocyanate to give the corresponding 2-aminobenzothiazolewhich was reacted with benzoyl chloride to give the finalcompound Novel benzothiazoles were fully characterized byIR both 1H and 13C NMR spectra and GC-MS analysis

22 Biological Results With the aim to develop novel tumorgrowth inhibitors and apoptosis inducers as potential anti-cancer agents two small series of N-13-benzothiazol-2-ylbenzamide derivatives (1andashn and 2andashe Figure 1 Table 2)

Table 1 Structures of compounds 1andashn and 2andashe

Compound R R1

1a

1

Cl S

NN

O

HRR1

4-F 23-F2

1b 4-F 24-F2

1c 4-F 25-F2

1d 4-F 26-F2

1e 4-F 34-F2

1f 4-F 35-F2

1g 5-F 23-F2

1h 5-F 24-F2

1i 5-F 25-F2

1j 5-F 26-F2

1k 5-F 34-F2

1l 5-F 35-F2

1m 5-F mdash1n 4-F mdash2a

2

F S

NN

O

HRR1

4-Cl mdash2b 4-Cl 24-F

2

2c 4-Cl 25-F2

2d 4-Cl 34-F2

2e 4-Cl 35-F2

were investigated Thus the cell growth inhibitory activitiesin cultures of HepG2 and MCF-7 cells were evaluated bymeans of MTT assay In order to select compounds withhigh activity a concentration of 10120583M was chosen for theassays which alsomeets the properties of low solubility of thetested compounds Amongst the two cancer cell lines under


3a 4a 2a

(i) (ii) F S

NN

O

H

Cl

F S

N

Cl

F

Cl

NH2

NH2


3N dioxane 50ndash

60∘C


HepG2a MCF-7a




005

115

225

335

4


o- an

d ol

igon

ucle

osom

es

enric

hmen

tCompound

HepG2MCF-7



3 Conclusions



4 Experimental


3and DMSO-d



3



254 Merck)


6) 120575 755 (t 119869 = 74Hz 2H Ar) 760ndash770 (m 1H


6) 120575 1084 (1C) 1159 (1C) 1237

(2C) 1291 (2C) 1292 (2C) 1324 (1C) 1337 (1C) 1490 (1C)1584 (1C) 1625 (1C) and 1669 (1C)


6) 120575 740ndash


6)120575 1136 (1C) 1185 (1C) 1281 (1C) 1282 (1C) 1291

(3C) 1321 (1C) 1338 (1C) 1363 (1C) 1368 (1C) 1523 (1C)1609 (1C) and 1668 (1C)




6)

120575 1082 (1C) 1155 (1C) 1254 (1C) 1292 (4C) 1321 (1C) 1338(1C) 1345 (1C) 1432 (1C) 1570 (1C) 1605 (1C) and 1669(1C)

42 Biology




2atmosphere 3-


119881 =119860 minus 119860

119887

119860119888minus 119860119887

times 100 (1)




cultures





Acknowledgment


References
























1and MT













Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


3a 4a 2a

(i) (ii) F S

NN

O

H

Cl

F S

N

Cl

F

Cl

NH2

NH2


3N dioxane 50ndash

60∘C


HepG2a MCF-7a




005

115

225

335

4


o- an

d ol

igon

ucle

osom

es

enric

hmen

tCompound

HepG2MCF-7



3 Conclusions



4 Experimental


3and DMSO-d



3



254 Merck)


6) 120575 755 (t 119869 = 74Hz 2H Ar) 760ndash770 (m 1H


6) 120575 1084 (1C) 1159 (1C) 1237

(2C) 1291 (2C) 1292 (2C) 1324 (1C) 1337 (1C) 1490 (1C)1584 (1C) 1625 (1C) and 1669 (1C)


6) 120575 740ndash


6)120575 1136 (1C) 1185 (1C) 1281 (1C) 1282 (1C) 1291

(3C) 1321 (1C) 1338 (1C) 1363 (1C) 1368 (1C) 1523 (1C)1609 (1C) and 1668 (1C)




6)

120575 1082 (1C) 1155 (1C) 1254 (1C) 1292 (4C) 1321 (1C) 1338(1C) 1345 (1C) 1432 (1C) 1570 (1C) 1605 (1C) and 1669(1C)

42 Biology




2atmosphere 3-


119881 =119860 minus 119860

119887

119860119888minus 119860119887

times 100 (1)




cultures





Acknowledgment


References
























1and MT













Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


4 Experimental


3and DMSO-d



3



254 Merck)


6) 120575 755 (t 119869 = 74Hz 2H Ar) 760ndash770 (m 1H


6) 120575 1084 (1C) 1159 (1C) 1237

(2C) 1291 (2C) 1292 (2C) 1324 (1C) 1337 (1C) 1490 (1C)1584 (1C) 1625 (1C) and 1669 (1C)


6) 120575 740ndash


6)120575 1136 (1C) 1185 (1C) 1281 (1C) 1282 (1C) 1291

(3C) 1321 (1C) 1338 (1C) 1363 (1C) 1368 (1C) 1523 (1C)1609 (1C) and 1668 (1C)




6)

120575 1082 (1C) 1155 (1C) 1254 (1C) 1292 (4C) 1321 (1C) 1338(1C) 1345 (1C) 1432 (1C) 1570 (1C) 1605 (1C) and 1669(1C)

42 Biology




2atmosphere 3-


119881 =119860 minus 119860

119887

119860119888minus 119860119887

times 100 (1)




cultures





Acknowledgment


References
























1and MT













Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




Acknowledgment


References
























1and MT













Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article antiproliferative activity evaluation of...

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