V. Sekar et al /J. Pharm. Sci. & Res. Vol.3(10), 2011,

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1 V. ekar et al /J. Pharm. ci. & es. Vol.3(10), 2011, CEEIG F ATICACE ACTIVITY I EWLY YTHEIZED BEZTHIAZLE DEIVATIVE V. ekar *, P. Perumal, Arunachalam,. Gandhimathi. Department of Pharmaceutical Chemistry, J.K.K.ataraja College of Pharmacy, Komarapalayam, amakkal Dt., Tamilnadu , India. Abstract: In present study novel series of benzothiazole derivatives were synthesized and their anti cancer efficacy was analyzed using cancer cell lines (Human Chronic Myelogenous Leukemia). The compounds were synthesized by simple and facile procedures and characterized by I, 1 H-M and Mass spectra study. The synthesized compounds were screened for anti cancer activity using in vitro assays. The compounds were found to exhibit anti cancer activity in cell line. Among the synthesized six compounds, 2 showed significant activity in cell line. Keywords: Benzothiazole, Anticancer, Tryphan Blue Assay. 1. Introduction: In view of the fact, that a large number of derivatives of benzoxazoles, benzothiazoles and benzimidazoles have been found to exhibit a wide variety of pharmacological activities. From these derivatives the anti-cancer agents discovered in recent years, the identification of various 2-(4- aminophenyl) benzothiazoles as potent and selectively antitumor drugs against breast, ovarian, colon and renal cell lines has stimulated remarkable interest 1-5. Moreover, there is experimental evidence suggesting a novel mechanism of action for these benzothiazole compounds and our interest in the benzothiazole nucleus 6-10, it was considered worthwhile to synthesize compounds bearing benzothiazole nucleus and their anti cancer activities were screened. ubstituted 1, 3, 4-oxadiazole are the heterocyclic system that have been found to exhibit diverse biological activities such as antibacterial, antifungal, anti-inflammatory, analgesic and anticancer activity. 2. Materials and Methods: 2.1. General The melting range of the synthesized compounds was performed by LAB IDIA visual melting point apparatus and is uncorrected. The I spectra of the compounds were recorded on Perkin Elmer FT-I spectrometer with potassium bromide pellets. Mass spectra were recorded on himadzu GCM QP The 1 H-M and spectra of the synthesized compounds were recorded on a Bruker 300 M spectrometer in MeD. X-ray diffraction study of synthesized derivatives was performed by PA analytical technique with model PW3040/60 X pert P with the help of source X-ray tube 3kW with copper and gobalt target. The I, 1 H-M, and mass spectra were consistent with the assigned structure General procedure for preparation of compounds tep I A mixture of aniline (0.01mol) and potassium thiocyanate (0.01mol) in glacial acetic acid (20 ml) was cooled and stirred. To this solution bromine (0.01mol) was added drop wise at such a rate to keep the temperature below 10 0 C throughout the addition. tirring was continued for an additional 3h and the separated hydrochloride salt was filtered, washed with acetic acid and dried. It was dissolved in hot water and neutralized with aqueous ammonia solution (25%), filtered, washed with water and dried, recrystallized with ethanol to obtain 6- substituted-1, 3-benzothiazol-2-amine (I) tep II To the solution of cyanate (0.5g) in minimum quantity of water, glacial acetic acid (5ml) was added. This solution was heated with respective 6-substituted-1,3-benzothiazol-2-amine (I) (1.7g, 0.01mol) in alcohol, until the contents of the mixture became turbid and volume remained half of the original volume. The contents were added to ice cold water. The solid (II) obtained was filtered off and dried tep III To a solution of compound II (0.01mol) in ethanol/glacial acetic acid (25ml) was added hydrazine hydrate (99%, 0.01mol). The reaction mixture was heated at reflux for 6hrs and the solvent was removed under reduced pressure. The separated solid was recrystallized from ethanol (III). 1520

2 V. ekar et al /J. Pharm. ci. & es. Vol.3(10), 2011, CHEME i (1) ii H iii (2) H H (3) iv H C H H C H Cl,Br,F,CH 3, 2, 2 4 v (4) i ii KC,Br 2,H 3,CH 3 CH ac,ch 3 CH H (5) H iii.h 2,C 2 H 5 H iv C 6 H 5 C v Con:H

3 V. ekar et al /J. Pharm. ci. & es. Vol.3(10), 2011, tep IV To a solution of compound III 20 ml ethanol and Phenyl isothiocyanate (1.49 g, 0.01 mol) was added. The mixture was refluxed for 5-6hrs, the reaction mixture was cooled and the product separated was filtered, dried and recrystallized from ethanol (IV) tep V The solution of compound IV was added to concentrated ulphuric acid (1.5 ml) with stirring and the temperature was kept below 0 0, the temperature was maintained at 0 0 for another 1 hour after which the reaction mixture was allowed to stand at room temperature overnight. The contents were warmed to 50 0, cooled and poured in to the crushed ice. The solid separated was filtered, washed with water and neutralized with dilute solution ammonia, the solid obtained was collected and recrystallized from ethanol(v) Compound AA1: -(6-fluoro-1,3- M.Pt ºC; I (KBr) (v cm -1 ): 1257(C-F tretching), 3388(-H tretching), 1194 (C- tretching), 1335 (C- tretching); EI-M m/z: ; 1 H-M (MeD) (δ ppm): 8.2 (1H,s,Hetero-H), (3H,Ar-CH), 4.0 (Ar-H) Compound AA2: -(6-chloro-1,3- M. Pt ºC; I (KBr) (v cm -1 ): 763(C-Cl tretching), 3457(-H tretching), 1098 (C- tretching),1276(c- tretching); EI-M m/z: ; 1 H-M (MeD) (δ ppm): 8.28 (1H,, Hetero-H), (3H,Ar-CH), 4.0(Ar-H) Compound AA3: -(4,6-dinitro-1,3- M. Pt ºC; I (KBr) (v cm -1 ): 1258(C- tretching),3449(-h tretching), 1065 (C- tretching),1584(c- 2 tretching); EI-M m/z: ; 1 H-M (MeD) (δ ppm): 8.34(1H,s,Hetero-H),7.12(Ar-CH), 4.0(Ar-H) Compound AA4: -(6-nitro-1,3- M.Pt ºC; I (KBr) (v cm -1 ): 1332(C- tretching),3374(-h tretching),1130 (C- tretching),1532(c- 2 tretching); EI-M m/z: ; 1 H-M (MeD) (δ ppm): 8.28(1H,s,Hetero-H),8.6(Ar-CH), 4.0(Ar-H) Compound AA5: -(6-methoxy-1,3- M.Pt ºC; I (KBr) (v cm -1 ): 1303(C- tretching), 3379 (-H tretching), 1048(C- tretching); EI-M m/z: ; 1 H-M (MeD) (δ ppm): 7.7(1H,s,Hetero-H), 4.0(Ar- H) Compound AA6: -(6-bromo-1,3- M.Pt ºC; I (KBr) (v cm -1 ): 537(C-Br tretching), 1304(C- tretching), 3448(-H tretching),1050(c- tretching); EI-M m/z: ; 1 H-M (MeD) (δ ppm): 8.25(1H,s,Hetero-H), (Ar-CH), 4.0(Ar- H) Biological Assay Biological evaluation of the compounds was performed to test a potent anti cancer activity. In this study, the influence of a different concentration of each compound on proliferation of cancer and normal cell lines was examined. 0.1ml of the cell suspension (containing cells/100 l) and 0.1ml of the test solution (6.25 g g in 1% DM such that the final concentration of DM in media is less than 1%) were added to the 96 well plates and kept in 5% C 2 incubator at 37 0 C for 72 hours. Blank contains only cell suspension and control wells contain 1% DM and cell suspension After 72 hours, 20 l of Tryphan blue was added and kept in carbondioxide incubator for 24 hours followed by TPVG 50 l. The plate was covered with aluminum foil to protect it from light. Then the 96 well plates are kept in rotary shaker for minutes. After minutes, the 96 well plates were processed on ELIA reader for absorption at 562nm. Each result is a mean value from three separate experiments, performed in triplicate. The readings were averaged and viability of the test samples was compared with DM control. 1522

4 V. ekar et al /J. Pharm. ci. & es. Vol.3(10), 2011, Table 1: Characterization data of the compounds Compound Id Molecular Formula Molecular weight Yield (%) Melting point ( o C) 1 4-F C 17 H Cl Br C 16 H 11 5 FCl Cl C 16 H 11 5 Cl CH 3 C 16 H 11 5 BrCl C 16 H Cl ,6-Dinitro C 16 H Cl esults and Discussion: 3.1. Chemistry ynthetic scheme summarizes the general synthetic approach that we employed for the synthesis of novel benzothiazole derivatives (AA1 AA6) and the characterization datas are given in Table 1. Among these compounds, the highest yield was observed with compound AA4, but the others were also given good yields Biological activity All the synthesized compounds (AA1 AA6) were screened for their anti cancer activity against the cell line (Human Chronic Myelogenous Leukemia). The IC 50 of the synthesized compounds was determined using Tryphan blue assay method. DM was used as solvent and blank. It was observed that compound AA5 was more effective against all the cell lines. The best IC 50 values were achieved with other compounds with slight difference among them. ther examined compounds exhibited a moderate inhibitory effect, depending on type of the cells. All the compounds (AA1 to AA6) were found to exhibit good to moderate anti cancer activities in all cell lines and the results were summarized in Table 2. Table 2: IC 50 of the synthesized compounds Compounds IC 50 tatus 1 4 μm Active μm Active 3 3 μm Active μm Moderately Active 5 5 μm Active μm Active 4. Conclusion: The present study was carried out with the aim of synthesis and in vitro anticancer screening of some novel benzothiazole derivatives. The spectral studies were performed for all the title compounds for their conformation. The compounds were purified by column and purity was determined by TLC method by using an appropriate solvent system. The purified compounds were further subjected to I, Mass, 1 H M and X-ray diffraction study for conformation of functional group, molecular weight, number of protons present in the environment and to examine the crystalline or amorphous nature of the compounds. 1523

5 V. ekar et al /J. Pharm. ci. & es. Vol.3(10), 2011, The anticancer screening of title compounds (AA1 AA6) were evaluated against human cell lines and the title compounds were found to exhibit mild to moderate anticancer activities in all cell lines. In conclusion, AA5 > AA1 >AA2 > AA3 > AA4 >AA6. -CH 3 Fluoro, pharmacophore containing compounds shows significant lead optimization. o further beneficial pharmacophore modifications in the design of benzothiazole as promising anti-cancer agent. Generally the anticancer activity of the synthesized compounds may be due to the presence of versatile pharmacophores like - CH 3, fluoro. eferences: [1] hi DF, Bradshaw TD, Wrigley, Carol J, Mccall PL, Malcolm FG, tevens, ynthesis of 2-(4- Aminophenyl) benzothiazoles and Evaluation of Their Activities against Breast Cancer Cell lines in Vitro and in Vivo, J. Med. Chem, 39: , [2] Bradshaw T D, Wrigley, hi D F, chultz J, Paul K D, tevens M F G, 2-(4- aminophenyl)benzothiazoles: novel agents with selective profiles of in vitro anti-tumor activity, Brit. J. Cancer, 77: , [3] Kashiyama E, Hutchinson I, Chua M, tinson F, Phillips L, Kaur G, ausville EA, Bradshaw TD, Westwell AD, tevens MFG, Antitumor Benzothiazoles. 8. Metabolic formation and Biological Properties of the C- and -xidation Products of Antitumor 2-(4- Aminophenyl)benzothiazoles, J. Med. Chem, 42: , [4] Masao Yoshida, Ichiro Hayakawa, oriyuki Hayashi, Toshinori Agatsuma, Youko da, Fumie Tanzawa, hiho Iwasaki, Kumi Ko Koyama, Hidehiko Furukawa, hinichi Kurakata, Yuichi ugano, ynthesis and Biological evaluation of benzothiazole derivatives as Potent Antitumor agents, Bioorg. Med. Chem, 15: , [5] Caleta I, Grdisa M, Mrvos-ermek D, Cetina M, Tralic-Kulenovic VK, Pavelic G, Karminski-Zamola., yntehsis, crystal structure and antiproliferative evaluation of some new substituted benzothiazoles and styryl benzothiazoles, II Farmaco, 59: , [6] Menta E, Palumbo M, ovel Antineoplastic Agents, Exp. pin. Ther. Patents, 7: , [7] Hutchinson I, Chua M, Browne HL, Trapani V, Bradshaw TD, Westwell AD, tevens MFG, ynthesis and in Vitro Biological Properties of Fluorinated 2-(4- Aminophenyl) benzothiazoles, J. Med. Chem, 44: , [8] Das J, Moquin V, Lin J, Chunjianliu, Doweyko AM, Defex HF, Fang Q, Pang, hen D, chieven GL, Barrish JC, Wityak J, Molecular Design, ynthesis and tructure-activity elationships Leading to the Potent and elective P56 lck Inhibitor BM Bioorg. Med. Chem. Lett, 13: , [9] Ian Hutchinson, Bradshaw TD, Matthews C, Malcolm FG, tevens, Westwell AD, Antitumor Benzothiazoles, Part 20: 3 -Cyano and 3 -Alkynylsubstituted 2-(4 -Aminophenyl) Benzothiazoles as ew Potent and elective Analogues, Bioorg. Med. Chem. Lett., 13: , [10] Chua M, hi DF, Wrigley, Bradshaw TD, Hutchinson I, haw P, Barrett DA, tanley LA, tevens MFG, ynthesis of 2-(4- acylaminophenyl) benzothiazoles and investigations into the role of acetylation in the antitumor activities of the parent amines, J. Med. Chem, 42: , [11] Pattan, arendra Babu and Angadi J, ynthesis and biological activity of 7-chloro-(6- fluoro-benzothiazole)-2-amino (substituted) acetanilides. Indian drugs, 39: 515, [12] Arpana ana, adeem idduiq, Khan A, Mashooq A Bhat, ynthesis of benzothiazole semicarbazones as novel anticonvulsants The role of hydrophobic domain. Bioorg. Med. Chem. Lett, 17: , [13] angapure and aga Basawaraj, ynthesis and Biological Activities of some, 1,3,4 oxadiazoles, thiadiazoles, thiazoles and related compounds possessing benzofuram moiety. Indian Journal of Pharmaceutical sciences, Mar: , [14] Trapani G, Massimo F, Latrofa A, Antonia, Gaetano L. ynthesis, invitro and invivo cytotoxicity and predicition of the intestinal absorption of substitiuted 2-ethoxycabonyl imidazo[2,1-b] benzothiazoles. Eur. J. Pharm. ci, 14: ,