Research Article Synthesis and Anticancer Activity of N

Research ArticleSynthesis and Anticancer Activity ofN-Aryl-5-substituted-134-oxadiazol-2-amine Analogues

Mohamed Jawed Ahsan1 Jyotika Sharma1 Monika Singh1

Surender Singh Jadav2 and Sabina Yasmin2

1 Department of Pharmaceutical Chemistry Maharishi Arvind College of Pharmacy Jaipur Rajasthan 302 023 India2Department of Pharmaceutical Chemistry Birla Institute of Technology Mesra Ranchi Jharkhand 835 215 India

Correspondence should be addressed to Mohamed Jawed Ahsan jawedpharmagmailcom

Received 12 February 2014 Revised 4 April 2014 Accepted 12 May 2014 Published 26 May 2014

Academic Editor Leonel Rojo

Copyright copy 2014 Mohamed Jawed Ahsan et alThis 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

In continuance of our search for anticancer agents we report herein the synthesis and anticancer activity of some novel oxadiazoleanalogues The compounds were screened for anticancer activity as per National Cancer Institute (NCI US) protocol on leukemiamelanoma lung colon CNS ovarian renal prostate and breast cancers cell linesN-(24-Dimethylphenyl)-5-(4-methoxyphenyl)-134-oxadiazol-2-amine (4s) showed maximum activity with mean growth percent (GP) of 6261 and was found to be the mostsensitive on MDA-MB-435 (melanoma) K-562 (leukemia) T-47D (breast cancer) and HCT-15 (colon cancer) cell lines with GPof 1543 1822 3427 and 3977 respectively Maximum GP was observed on MDA-MB-435 (melanoma) cell line (GP = 682) bycompound N-(24-dimethylphenyl)-5-(4-hydroxyphenyl)-134-oxadiazol-2-amine (4u)

1 Introduction

An estimated 141 million cancer cases and 82 million deathsoccurred globally in 2012 and the annual new cases willjump to 193 million by 2025 Cancer deaths were up tonearly 8 percent from 76 million in a previous survey in2008 An urgent need in cancer control today is to developeffective and affordable approaches to the early detectiondiagnosis and treatment of cancer Tobacco use is the greatestsingle avoidable risk factor for cancer mortality worldwidecausing an estimated 22 of cancer deaths per annum 22of mouth and oropharynx cancers in men are attributableto alcohol Almost 22 of cancer deaths in the developingworld and 6 in industrialized countries are due to infectiousagents and environmental pollution of air water and soilwith carcinogenic chemicals accounts for 1ndash4 of all cancersResidential exposure to radon gas from soil and buildingmaterials is estimated to cause 3ndash14 of all lung cancersmaking it the second cause of lung cancer after tobaccosmoke Ultraviolet (UV) radiation in particular solar radi-ation is carcinogenic to humans causing all major types of

skin cancer which includes basal cell carcinoma squamouscell carcinoma and melanoma Breast cancer is the mostfrequently diagnosed cancer and the leading cause of cancerdeath among females accounting for 23 of the total cancercases and 14 of the cancer deaths [1ndash3] The therapeuticapproach of cancer includes chemotherapy radiotherapysurgery immunotherapy monoclonal antibody therapy hor-monal therapy targeted therapy and angiogenesis inhibitionThe drugs used for the treatment of cancer are generallycytotoxic and their use is often coupled with various adverseeffects including bonemarrow depression alopecia and druginduced cancer Resistance cytotoxicity and genotoxicity ofanticancer drugs are the reasons that warrant the searchfor newer anticancer agents and researchers from variouslaboratories throughout the world are ardently engaged tofind a more pleasant solution for the treatment of cancer

The widespread use of 134-oxadiazoles as a scaffold inmedicinal chemistry establishes this moiety as a memberof the privileged structural class due to their remarkablebiological and pharmacological properties such as anticancer[4ndash7] antitubercular [8 9] antibacterial [8] antifungal [10]

Hindawi Publishing CorporationBioMed Research InternationalVolume 2014 Article ID 814984 9 pageshttpdxdoiorg1011552014814984

2 BioMed Research International

anti-HIV [11] anti-inflammatory [12] and insecticidal [13]activities Zibotentan an endothelin receptor A (ETA) antag-onist is an anticancer agent which contains 134-oxadiazolering [14] Inspired by all these facts we have designed basedon themolecular properties prediction byMolinspiration andtoxicity risk prediction by Osiris software and synthesizedoxadiazole analogues for anticancer screening [15 16] Thenumber of rotatable bonds (NROTB) and Lipinskirsquos rule offive were also calculated [17] The rule of five states thatmost molecules with good membrane permeability havelog P (partition coefficient) le 5 molecular weight (MW)le 500 number of hydrogen bond acceptors le 10 andnumber of hydrogen bond donors le 5 This rule is widelyused as a filter for drug-like properties Furthermore noneof the compounds violated Lipinskirsquos parameters makingthem potentially promising agents The pharmacokineticparameters important for good oral bioavailability ofN-aryl-5-substituted-134-oxadiazol-2-amine analogues (4andashx) aregiven in Table 1 and the toxicity risk prediction (mutagenicirritant and reproductive effect) calculated with Osiris isgiven in Table 2 The toxicity risk prediction showed thatall these oxadiazoles are comparatively less toxic than thestandard drug fluorouracil andmethotrexate Good intestinalabsorption reduced molecular flexibility (measured by thenumber of rotatable bonds) low polar surface area and totalhydrogen bond count (sum of donors and acceptors) areimportant predictors of good oral bioavailability [18 19]Membrane permeability and bioavailability are always asso-ciated with some basic molecular descriptors such as log P(partition coefficient) molecular weight (MW) or hydrogenbond acceptors and donors counts in amoleculeThe numberof rotatable bonds is important for conformational changes ofmolecules under study and ultimately for the binding withreceptors or channels It is revealed that for passing oralbioavailability criteria the number of rotatable bond shouldbe le10 [18] In the present studies the title compounds havelog P value varied from 273 to 472 (lt5) MW varied from203 to 375 (lt500) number of hydrogen bond acceptors variedfrom 4 to 6 (le10) number of hydrogen bond donors variedfrom 1 to 2 (le5) and number of rotatable bond varied from 3to 5 (le10)

2 Materials and Methods

21 Chemistry All chemicals were procured from E MerckCDH Drug laboratory and SD Fine Chemicals Meltingpoints were determined by open tube capillary method andwere uncorrected Purity of the compounds was checkedby elemental analysis and the progress of reactions wasmonitored by TLC plates (silica gel G) using mobile phasechloroform methanol (9 1) and acetone n-hexane (8 2)and the spots were identified by iodine vapours or UV lightIR spectra were recorded on a Shimadzu 8201 PC FT-IRspectrometer (KBr pellets) NMR spectra were recorded ona Bruker AC 300MHz spectrometer using TMS as internalstandard in DMSO d6 Mass spectra were recorded on aBruker Esquire LCMS using ESI and elemental analyses wereperformed on Perkin-Elmer 2400 Elemental Analyzer

22 General Method for the Synthesis of Substituted PhenylUrea Analogues (2andashd) Aromatic anilines (01mol) weredissolved in 20mL of glacial acetic acid and 10mL of hotwater and sodium cyanate (65 g 01mol) in 80mL of hotwater was added with stirring It was allowed to stand for 30min then cooled in ice bath filtered with suction dried andrecrystallized from boiling water to obtain substituted phenylurea (2andashd) [20ndash22]

23 General Method for the Synthesis of Semicarbazide Ana-logues (3andashd) Equimolar quantities (005mol) of substitutedphenyl urea (2andashd) and hydrazine hydrate (AR 99-100)(25mL 005mol) in ethanol were refluxed for 48 h withstirring The two-thirds volume of alcohol was distilled byvacuum distillation and then poured into the crushed iceThe resultant precipitate was filtered washed with water anddried The solid mass was recrystallized from 50mL absoluteethanol to obtain semicarbazide analogues (3andashd) [20ndash22]

24 General Method for the Synthesis of 5-Substituted-N-aryl-134-oxadiazol-2-amine Analogues (4andashx) Substitutedphenyl semicarbazide (0005mol) (3andashd) and aromatic alde-hydes (0005mol) were refluxed for 10ndash12 h using 20molNaHSO

3and ethanol-water system (1 2 vv) solvent [23]

After completion of reaction the excess solvent was removedand the concentrate was poured into crushed ice filterwashed with water dried and recrystallized with absoluteethanol to obtain the final product (4andashx) The reaction wasmonitored throughout by thin layer chromatography (TLC)using chloroform methanol (9 1) and acetone n-hexane(8 2) as mobile phase

241 N-(4-Methylphenyl)-5-(4-methoxyphenyl)-134-oxadia-zol-2-amine (4a) Yield 72Mp 178ndash180∘C IR (KBr) cmminus13219 (NH) 1523 (C=N) 1173 (CndashOndashC) 1H NMR (300MHzDMSO-119889

6) 120575 225 (3H s CH

3) 379 (3H s OCH

3) 695ndash

698 (2H d J = 78Hz ArH) 707ndash709 (2H d J = 72HzArH) 750ndash752 (2H d J = 75Hz ArH) 773ndash776 (2H d J =78Hz ArH) 867 (1H s NH) 13C NMR (75Hz DMSO-119889

6)

120575 2431 5592 11482 11621 11855 12812 12852 1299214009 15212 16071 16455 mz = 281 (M+) 282 (M+1)+CalAna [C (6822) 6831H (545) 537N (1482) 1494]

242 N-(4-Methylphenyl)-5-(4-chlorophenyl)-134-oxadia-zol-2-amine (4b) Yield 68Mp 214ndash216∘C IR (KBr) cmminus13191 (NH) 1531 (C=N) 1203 (CndashOndashC) 694 (CndashCl) 1HNMR(300MHz DMSO-119889

6) 120575 203 (3H s CH

3) 682ndash685 (2H d

J = 84Hz ArH) 708ndash712 (2H d J = 81Hz ArH) 721ndash724(2H d J = 81Hz ArH) 731ndash734 (2H d J = 84Hz ArH)844 (1H s NH) mz = 285 (M+) 287 (M+2)+ CalAna [C(6301) 6305H (419) 423N (1473) 1471]

243 N-(4-Methylphenyl)-5-(4-hydroxyphenyl)-134-oxadia-zol-2-amine (4c) Yield 74 Mp 182ndash185∘C IR (KBr) cmminus13402 (OH) 3199 (NH) 1511 (C=N) 1119 (CndashOndashC) 766 (CndashCl) 1H NMR (300MHz DMSO-119889

6) 120575 224 (3H s CH

3)

678ndash681 (2H d J =63HzArH) 706ndash708 (2H d J = 54Hz

BioMed Research International 3

Table 1 Pharmacokinetic parameters important for good oral bioavailability ofN-aryl-5-substituted-134-oxadiazol-2-amine analogues (4andashx)

NH O

N NR

NH NHO

N N

O

R

4e 4k 4r 4x

O

N NR

4f 4l

R1

4andashd 4gndashj 4mndashq 4sndashw

Compound R R1 ABS Volume (1198603) TPSA (1198602) NROTB HBA HBD clog119875 MW Lipinskirsquos violationRule mdash mdash mdash mdash mdash le10 lt10 lt5 le5 lt500 le14a 4-Methyl- 4-Methoxy- 8823 254625 6018 4 5 1 366 281 04b 4-Methyl- 4-Chloro- 9142 242615 5095 3 4 1 433 285 04c 4-Methyl- 4-Hydroxy- 8444 237097 7118 3 5 2 338 267 04d 4-Methyl- 34-Dimethoxy- 8505 280171 6941 5 6 1 359 311 04e 4-Methyl- mdash 8689 210647 6409 3 5 1 295 241 04f 4-Methyl- mdash 9142 210647 5095 3 4 1 273 203 04g 4-Bromo- 4-Methoxy- 8823 255949 6018 4 5 1 404 345 04h 4-Bromo- 4-Chloro- 9142 243939 5095 3 4 1 472 349 04i 4-Bromo- 4-Hydroxy- 8444 238421 7118 3 5 2 376 331 04j 4-Bromo- 34-Dimethoxy- 8505 281495 6941 5 6 1 397 375 04k 4-Bromo- mdash 8689 211972 6409 3 5 1 334 305 04l 4-Bromo- mdash 9142 192358 5095 3 4 1 312 267 04m 4-Chloro- 4-Methoxy- 8823 2516 6018 4 5 1 392 301 04n 4-Chloro- 4-Fluoro- 9142 230985 5095 3 4 1 409 289 04o 4-Chloro- 4-Chloro- 9142 23959 5095 3 4 1 460 305 04p 4-Chloro- 4-Hydroxy- 8444 234072 7118 3 5 2 364 287 04q 4-Chloro- 34-Dimethoxy- 8505 277145 6941 5 6 1 385 331 04r 4-Chloro- mdash 8689 207622 6409 3 5 1 322 261 04s 24-Dimethyl- 4-Methoxy- 8823 271186 6018 4 5 1 400 295 04t 24-Dimethyl- 4-Fluoro- 9142 271186 5095 3 4 1 417 283 04u 24-Dimethyl- 4-Chloro- 9142 259176 5095 3 4 1 468 299 04v 24-Dimethyl- 4-Hydroxy- 8444 253658 7118 3 5 2 373 281 04w 24-Dimethyl- 34-Dimethoxy 8505 296732 6941 5 6 1 393 325 04x 24-Dimethyl- mdash 8689 207622 6409 3 5 1 330 255 0ABS percentage of absorption TPSA topological polar surface area NROTB number of rotatable bonds MW molecular weight Log P logarithm ofcompound partition coefficient between n-octanol and water HBD number of hydrogen bond donors HBA number of hydrogen bond acceptors

ArH) 749ndash751 (2H d J = 6Hz ArH) 762ndash764 (2H d J =63Hz ArH) 862 (1H s NH) 1036 (1H s OH) mz = 267(M+) CalAna [C (6731) 6740H (486) 490N (1576) 1572]

244 N-(4-Methylphenyl)-5-(34-dimethoxyphenyl)-134-ox-adiazol-2-amine (4d) Yield 70 Mp 176ndash178∘C IR (KBr)cmminus1 3212 (NH) 1521 (C=N) 1119 (CndashOndashC) 1H NMR(300MHz DMSO-119889

6) 120575 224 (3H s CH

3) 379 (6H s

OCH3) 677ndash680 (2H d J = 64Hz ArH) 706ndash708 (2H d

J = 54Hz ArH) 753ndash755 (2H d J = 61Hz ArH) 761 (1Hs ArH) 844 (1H s NH) 13C NMR (75Hz DMSO-119889

6) 120575

2432 5621 11231 11581 11623 11951 12082 12842 1299914019 14211 14981 15031 16451 mz = 311 (M+) CalAna[C (6541) 6558H (546) 555N (1376) 1350]

245 N-(4-Methylphenyl)-5-(2-furyl)-134-oxadiazol-2-amine (4e) Yield 66 Mp 182ndash184∘C IR (KBr) cmminus13219 (NH) 1523 (C=N) 1109 (CndashOndashC) 1H NMR (300MHz

DMSO-1198896) 120575 223 (3H s CH

3) 686ndash689 (2H d J = 61Hz

ArH) 696ndash699 (2H d J = 54Hz ArH) 736ndash741 (3H mArH) 833 (1H s NH)mz = 241 (M+) CalAna [C (6466)6472 H (456) 460N (1752) 1742]

246 N-(4-Methylphenyl)-5-ethyl-134-oxadiazol-2-amine(4f) Yield 70 Mp 210ndash212∘C IR (KBr) cmminus1 3222 (NH)1529 (C=N) 1116 (CndashOndashC) 1HNMR (300MHz DMSO-119889

6)

120575 132ndash135 (3H t J = 64Hz CH3) 224 (3H s CH

3) 262

(2H m CH2) 689ndash692 (2H d J = 61Hz ArH) 693ndash696

(2H d J = 64Hz ArH) 862 (1H s NH) mz = 203 (M+)CalAna [C (6494) 6501 H (646) 645N (2076) 2068]

247 N-(4-Bromophenyl)-5-(4-methoxyphenyl)-134-oxadia-zol-2-amine (4g) Yield 81Mp 198ndash200∘C IR (KBr) cmminus13212 (NH) 1521 (C=N) 1119 (CndashOndashC) 635 (CndashBr) 1H NMR(300MHz DMSO-119889

6) 120575 379 (3H s OCH

3) 677ndash680 (2H


Table 2 Prediction of toxicity risk of theN-aryl-5-substituted-134-oxadiazol-2-amine analogues (4andashx)

Compound Prediction of toxicity risk by OsirisMUT IRRI REP

4a mdash mdash mdash4b mdash mdash mdash4c mdash mdash mdash4d mdash mdash mdash4e + mdash mdash4f mdash mdash +4g mdash mdash mdash4h mdash mdash mdash4i mdash mdash mdash4j mdash mdash mdash4k + mdash mdash4l mdash mdash +4m mdash mdash mdash4n mdash mdash mdash4o mdash mdash mdash4p mdash mdash mdash4q + mdash mdash4r mdash mdash mdash4s mdash +a mdash4t mdash +a mdash4u mdash +a mdash4v mdash +a mdash4w mdash +a mdash4x mdash +a mdashMethotrexate +a mdash +a

Fluorouracil + + +MUT mutagenic IRRI irritant REP reproductive effect A dash (mdash)indicates no effect a plus (+) indicates the effect and (+a) indicates slighteffect

d J = 61Hz ArH) 696ndash698 (2H d J = 51Hz ArH) 741ndash743 (2H d J = 6Hz ArH) 752-753 (2H d J = 66Hz ArH)843 (1H s NH) mz = 345 (M+) 347 (M++2) CalAna [C(5211) 5204 H (346) 349N (1218) 1214]

248 N-(4-Bromophenyl)-5-(4-chlorophenyl)-134-oxadia-zol-2-amine (4h) Yield 70 Mp 177-178∘C IR (KBr) cmminus13211 (NH) 1519 (C=N) 1112 (CndashOndashC) 643 (CndashBr) 787(C-Cl)1H NMR (300MHz DMSO-119889

6) 120575 671ndash673 (2H d J

= 62Hz ArH) 692ndash694 (2H d J = 60Hz ArH) 712ndash714(2H d J = 6Hz ArH) 732ndash734 (2H d J = 61Hz ArH)853 (1H s NH) mz = 348 (M+) 350 (M++2) 352 (M++4)CalAna [C (4791) 4796 H (256) 259N (1196) 1199]

249 N-(4-Bromophenyl)-5-(4-hydroxyphenyl)-134-oxadia-zol-2-amine (4i) Yield 67 Mp 190ndash192∘C IR (KBr) cmminus13402 (OH) 3192 (NH) 1525 (C=N) 1119 (CndashOndashC) 634 (CndashBr) 1H NMR (300MHz DMSO-119889

6) 120575 673ndash675 (2H d J

= 61Hz ArH) 695ndash697 (2H d J = 51Hz ArH) 739ndash741(2H d J = 6Hz ArH) 747ndash750 (2H d J = 66Hz ArH) 844(1H s NH) 1042 (1H s OH) mz = 331 (M+) 333 (M++2)CalAna [C (6541) 6558H (546) 555N (1376) 1350]

2410 N-(4-Bromophenyl)-5-(34-dimethoxyphenyl)-134-ox-adiazol-2-amine (4j) Yield 75 Mp 186ndash188∘C IR (KBr)cmminus1 3218 (NH) 1513 (C=N) 1112 (CndashOndashC) 637 (CndashBr) 1HNMR (300MHz DMSO-119889

6) 120575 379 (6H s OCH

3) 679ndash681

(2H d J = 62Hz ArH) 692ndash695 (2H d J = 61Hz ArH)744ndash747 (2H d J = 6Hz ArH) 751 (1H s ArH) 842 (1Hs NH) 13C NMR (75Hz DMSO-119889

6) 120575 5612 11233 11311

11583 11851 11912 12082 13253 14211 14908 14951 1620216459mz = 375 (M+) 377 (M++2) CalAna [C (5111) 5108H (372) 375N (1116) 1117]

2411 N-(4-Bromophenyl)-5-(2-furyl)-134-oxadiazol-2-amine (4k) Yield 78 Mp 138ndash140∘C IR (KBr) cmminus1 3212(NH) 1501 (C=N) 1121 (CndashOndashC) 634 (CndashBr) 1H NMR(300MHz DMSO-119889

6) 120575 680ndash682 (2H d J = 62Hz ArH)

692ndash694 (2H d J = 51Hz ArH) 741ndash744 (3H m ArH)814 (1H s NH) mz = 305 (M+) 307 (M++2) CalAna [C(4701) 4708H (266) 263N (1376) 1373]

2412 N-(4-Bromophenyl)-5-ethyl-134-oxadiazol-2-amine(4l) Yield 70 Mp 178ndash180∘C IR (KBr) cmminus1 3210 (NH)1524 (C=N) 1116 (CndashOndashC) 634 (CndashBr) 1HNMR (300MHzDMSO-119889

6) 120575 134 (3H s CH

3) 259 (2H m CH

2) 733ndash735

(2H d J = 63Hz ArH) 756ndash758 (2H d J = 63Hz ArH)866 (1H s NH) mz = 267 (M+) 269 (M++2) CalAna [C(4479) 4480H (373) 376N (1565) 1567]

2413 N-(4-Chlorophenyl)-5-(4-methoxyphenyl)-134-oxa-diazol-2-amine (4m) Yield 82 Mp 188ndash190∘C IR (KBr)cmminus1 3211 (NH) 1523 (C=N) 1129 (CndashOndashC) 695 (CndashCl)1H NMR (300MHz DMSO-119889

6) 120575 383 (3H s OCH

3)

696ndash698 (2H d J = 75Hz ArH) 731ndash733 (2H d J = 75HzArH) 768ndash771 (2H d J = 75Hz ArH) 778ndash781 (2H d J =78Hz ArH) 861 (1H s NH) mz = 301 (M+) 303 (M++2)CalAna [C (5966) 5971H (397) 401N (1398) 1393]

2414 N-(4-Chlorophenyl)-5-(4-fluorophenyl)-134-oxadia-zol-2-amine (4n) Yield 71 Mp 185ndash187∘C IR (KBr)cmminus1 3214 (NH) 1521 (C=N) 1115 (CndashOndashC) 787 (CndashF) 694(CndashCl)1H NMR (300MHz DMSO-119889

6) 120575 721ndash724 (2H d J

= 87Hz ArH) 731ndash734 (2H d J = 87Hz ArH) 767ndash770(2H d J = 87Hz ArH) 789ndash792 (2H d J = 57Hz ArH)865 (1H s NH) mz = 289 (M+) 291 (M++2) CalAna [C(5808) 5804H (311) 313N (1446) 1451]

2415 N-(4-Chlorophenyl)-5-(4-chlorophenyl)-134-oxadia-zol-2-amine (4o) Yield 72 Mp 162ndash164∘C IR (KBr)cmminus1 3212 (NH) 1511 (C=N) 1102 (CndashOndashC) 699 (CndashCl)1HNMR (300MHz DMSO-119889

6) 120575 727ndash729 (2H d J = 61Hz

ArH) 739ndash741 (2H d J = 60Hz ArH) 762ndash764 (2H d J= 61Hz ArH) 781ndash783 (2H d J = 62Hz ArH) 805 (1H


s NH) mz = 305 (M+) 307 (M++2) CalAna [C (5485)5492H (291) 296N (1386) 1373]

2416 N-(4-Chlorophenyl)-5-(4-hydroxyphenyl)-134-oxa-diazol-2-amine (4p) Yield 69 Mp 140ndash142∘C IR (KBr)cmminus1 3402 (OH) 3192 (NH) 1521 (C=N) 1118 (CndashOndashC) 697(CndashCl) 1H NMR (300MHz DMSO-119889

6) 120575 723ndash725 (2H d

J = 61Hz ArH) 732ndash734 (2H d J = 62Hz ArH) 768ndash770(2H d J = 61Hz ArH) 783ndash785 (2H d J = 57Hz ArH)795 (1H s NH) 1041 (1H s OH) mz = 287 (M+) 289(M++2) CalAna [C (5841) 5845H (346) 350N (1466)1461]

2417 N-(4-Chlorophenyl)-5-(34-dimethoxyphenyl)-134-ox-adiazol-2-amine (4q) Yield 76 Mp 170ndash172∘C IR (KBr)cmminus1 3218 (NH) 1518 (C=N) 1116 (CndashOndashC) 699 (CndashCl) 1HNMR (300MHz DMSO-119889

6) 120575 378 (6H s OCH

3) 120575 729ndash

731 (2H d J = 61Hz ArH) 741ndash743 (2H d J = 61Hz ArH)769ndash773 (2H d J = 72Hz ArH) 795 (1H s ArH) 842 (1Hs NH) 13C NMR (75Hz DMSO-119889

6) 120575 5629 11231 11508

11771 11951 12081 12433 12982 14121 14981 15033 1620216459mz = 331 (M+) 333 (M++2) CalAna [C (5798) 5793H (422) 425N (1256) 1267]

2418 N-(4-Chlorophenyl)-5-(2-furyl)-134-oxadiazol-2-amine (4r) Yield 78 Mp 108ndash112∘C IR (KBr) cmminus1 3216(NH) 1511 (C=N) 1119 (CndashOndashC) 694 (CndashCl) 1H NMR(300MHz DMSO-119889

6) 120575 727ndash729 (2H d J = 60Hz ArH)


2419 N-(24-Dimethylphenyl)-5-(4-methoxyphenyl)-134-oxadiazol-2-amine (4s) Yield 72 Mp 180ndash182∘C IR(KBr) cmminus1 3209 (NH) 1523 (C=N) 1171 (CndashOndashC) 1HNMR (300MHz DMSO-119889

6) 120575 221 (6H s CH

3) 378 (3H s

OCH3) 695ndash697 (2H t J = 75Hz ArH) 725ndash727 (2H d


6) 120575

1588 2463 5623 11232 11581 11611 11853 12082 1269312832 12892 13179 13911 14981 15032 16271 16455 mz= 295 (M+) CalAna [C (6912) 6914H (585) 580N (1419)1423]

2420 N-(24-Dimethylphenyl)-5-(4-fluorophenyl)-134-ox-adiazol-2-amine (4t) Yield 68 Mp 190ndash192∘C IR (KBr)cmminus1 3191 (NH) 1521 (C=N) 1198 (CndashOndashC) 788 (CndashF) 1HNMR (300MHz DMSO-119889

6) 120575 223 (6H s CH

3) 697-692

(2H t J = 75Hz ArH) 721ndash723 (2H d J = 63Hz ArH)714ndash744 (2H d J = 66Hz ArH) 791 (1H s ArH) 845 (1Hs NH) mz = 283 (M+) 285 (M+2)+ CalAna [C (6787)6783H (491) 498N (1480) 1483]

2421 N-(24-Dimethylphenyl)-5-(4-chlorophenyl)-134-oxa-diazol-2-amine (4u) Yield 68 Mp 204ndash206∘C IR (KBr)cmminus1 3192 (NH) 1539 (C=N) 1173 (CndashOndashC) 697 (CndashCl) 1HNMR (300MHz DMSO-119889

6) 120575 249 (6H s CH

3) 639ndash741

(7H t J = 87Hz ArH) 731ndash734 (2H d J = 87Hz ArH)767ndash770 (2H d J = 87Hz ArH) 795 (1H s ArH) 898 (1Hs NH) mz = 299 (M+) 301 (M+2)+ CalAna [C (6405)6411 H (467) 471 N (1401) 1402]

2422 N-(24-Dimethylphenyl)-5-(4-hydroxyphenyl)-134-oxadiazol-2-amine (4v) Yield 74 Mp 200ndash202∘C IR(KBr) cmminus1 3412 (OH) 3197 (NH) 1511 (C=N) 1179 (CndashOndashC) 1H NMR (300MHz DMSO-119889

6) 120575 222 (6H s CH

3)

699ndash701 (2H t J = 75Hz ArH) 720ndash722 (2H d J = 63HzArH) 741ndash743 (2H d J = 66Hz ArH) 766 (1H s ArH)845 (1H s NH) 1062 (1H s OH)mz = 281 (M+) CalAna[C (6825) 6831H (529) 537N (1499) 1494]

2423 N-(24-Dimethylphenyl)-5-(34-dimethoxyphenyl)-134-oxadiazol-2-amine (4w) Yield 70 Mp 178ndash180∘CIR (KBr) cmminus1 3202 (NH) 1521 (C=N) 1139 (CndashOndashC) 1HNMR (300MHz DMSO-119889

6) 120575 223 (6H s CH

3) 379 (6H

s OCH3) 694ndash697 (2H d J = 84Hz ArH) 712ndash714 (1H

d J = 71Hz ArH) 747 (1H s ArH) 754ndash756 (1H d J =6Hz ArH) 785 (1H m ArH) 840 (1H s NH) 13C NMR(75Hz DMSO-119889

6) 120575 1583 2467 5623 11231 11589 11616

11859 12081 12699 12830 12892 13170 13919 1498315032 16271 16455 mz = 325 (M+) CalAna [C (6641)6645H (586) 589N (1286) 1291]

2424 N-(24-Dimethylphenyl)-5-(2-furyl)-134-oxadiazol-2-amine (4x) Yield 66 Mp 190ndash192∘C IR (KBr) cmminus13219 (NH) 1523 (C=N) 1109 (CndashOndashC) 1H NMR (300MHzDMSO-119889

6) 120575 223 (6H s CH

3) 691ndash693 (2H t J = 75Hz

ArH) 725ndash727 (2H d J = 61Hz ArH) 734ndash736 (2H d J =66Hz ArH) 779 (1H s ArH) 841 (1H s NH) mz = 255(M+) CalAna [C (6576) 6587H (509) 513N (1652) 1646]

25 Anticancer Activity The compounds were submitted tothe National Cancer Institute (NCI US) and were screenedon NCI 60 cell lines initially at a single high dose (10minus5M)on leukemia melanoma lung colon CNS ovarian renalprostate and breast cancers cell linesThe one-dose data werereported as a mean graph of the percent growth (GP) oftreated cells The number reported for the one-dose assay isgrowth relative to the no-drug control and relative to the timezero number of cells The anticancer screening was carriedout as per the NCI US protocol reported elsewhere [24ndash27]We have discussed the anticancer screening method in ourprevious work [6 28]

3 Results and Discussions

31 Chemistry In the first step aromatic anilines (1andashd)were treated with sodium cyanate in glacial acetic acidto obtain substituted phenyl ureas (2andashd) which was thentreated with hydrazine hydrate to obtain substituted phenylsemicarbazides (3andashd) In the final step substituted phenylsemicarbazides (3andashd) and aromatic aldehydes were refluxedfor 12ndash14 h using 20mol NaHSO

3and ethanol-water sys-

tem (1 2 vv) solvent to obtain oxadiazole analogues (4andashx) The reaction was monitored throughout by thin layer


Table 3 In vitro anticancer activity of N-aryl-5-substituted-134-oxadiazol-2-amine analogues (4andashx)

Compound60 cell lines assay in one dose 10minus5M conc

NSC Code Mean GP Range of GP The most sensitive cell lines GP of the mostsensitive cell lines

4a 776721 9888 7288 to 11464NCI-H522 (non-small-cell lung cancer)

SNB-75 (CNS cancer)MCF7 (breast cancer)A498 (renal cancer)

7288804483988588

4b 776720 10209 8459 to 12342A498 (renal cancer)T-47D (breast cancer)UO-31 (renal cancer)MCF7 (breast cancer)

8459864692109237

4c 777952 9855 7667 to 11771SR (leukemia)

K-562 (leukemia)HL-60 (TB) (leukemia)SNB-75 (CNS cancer)

7667810582028385

4d 776719 10071 8346 to 12718UO-31 (renal cancer)

MDA-MB-231ATCC (breast cancer)SK-OV-3 (ovarian cancer)MCF7 (breast cancer)

8346866389428992

4e 776722 10059 8087 to 11708HOP-92 (non-small-cell lung cancer)

UO-31 (renal cancer)HL-60 (TB) (leukemia)

NCI-H522 (non-small-cell lung cancer)

8087831087928813

4f 777951 9850 6575 to 11026SR (leukemia)

MOLT-4 (leukemia)UO-31 (renal cancer)

HCT-116 (colon cancer)

6575825887208820

4h 776724 9730 6045 to 11198SK-MEL-2 (melanoma)

MDA-MB-231ATCC (breast cancer)UO-31 (renal cancer)MCF7 (breast cancer)

6045674280028297

4i 777954 9793 7533 to 11840HL-60 (TB) (leukemia)

K-562 (leukemia)SR (leukemia)


7533818885638868

4j 776723 9703 7506 to 12027HOP-92 (non-small-cell lung cancer)

MOLT-4 (leukemia)NCI-H522 (non-small-cell lung cancer)

SNB-75 (CNS cancer)

7506763179428173

4k 776725 9780 7329 to 11630PC-3 (prostate cancer)UO-31 (renal cancer)MOLT-4 (leukemia)

HOP-92 (non-small-cell lung cancer)

7329822183758414

4l 777953 9710 7662 to 11224A498 (renal cancer)

MALME-3M (melanoma)MOLT-4 (leukemia)

SR (leukemia)

7662779679518294

4m 776715 10109 7980 to 12896A498 (renal cancer)

SK-MEL-2 (melanoma)HL-60 (TB) (leukemia)MCF7 (breast cancer)

7980807880818112

4n 776716 10042 5921 to 11624SK-MEL-2 (melanoma)UO-31 (renal cancer)MOLT-4 (leukemia)BT-549 (breast cancer)

5921828484218627


Table 3 Continued



4s 777948 6261 1543 to 8849MDA-MB-435 (melanoma)

K-562 (leukemia)T-47D (breast cancer)HCT-15 (colon cancer)

1543182234273977

4u 777949 7846 682 to 10657MDA-MB-435 (melanoma)

K-562 (leukemia)NCI-H522 (non-small-cell lung cancer)


682248041034474

4w 777950 10129 8097 to 11523T-47D (breast cancer)A498 (renal cancer)

HCT-116 (colon cancer)UO-31 (renal cancer)

8097874489019055

RNaCNO

AcOH

N

O

H

RN N

O

H H

REtOH

EtOH

N O

N N

Ar

H

R

NH2

NH2NH2

NaHSO3

NH2NH2 middot H2O

ArCHOR998400CHO

1andashd 2andashd 3andashd

4andashx

Scheme 1 Protocol for the synthesis of 5-substituted-N-aryl-134-oxadiazol-2-amine analogues (4andashx)

chromatography (TLC) using chloroform methanol (9 1)and acetone n-hexane (8 2) as mobile phase and the purityof the compounds was checked by elemental analysis Thereaction sequence is shown in Scheme 1 The synthesizedcompounds were characterized by spectral analysis and allthe compounds were in full harmony with the proposedstructures In general the IR spectra afforded absorption3191ndash3222 cmminus1 band due to NH band 1511ndash1531 cmminus1 banddue to C=N and 1109ndash1203 cmminus1 band due to oxadiazolestretching In 1H NMR the signals of the respective protonsof the synthesized title compounds were verified on the basisof their chemical shifts and multiplicities in DMSO d6 Thespectra showed a triplet at 120575 132ndash134 ppm correspondingto CH

3 a singlet at 120575 222ndash237 ppm corresponding to

aromatic CH3 a singlet at 373ndash379 ppm corresponding to

OCH3 a singlet at 120575 805ndash895 ppm corresponding to NH

singlet doublets triplet and multiplet at 120575 671ndash795 ppmcorresponding to aromatic protons and a singlet at 120575 1036ndash1062 ppm corresponding to OH

32 Anticancer Activity All compounds submitted to theNCI 60 cell screen were tested initially at a single highdose (10minus5M) on leukemia melanoma lung colon CNSovarian renal prostate and breast cancers cell lines nearly60 in number Compound N-(24-dimethylphenyl)-5-(4-methoxyphenyl)-134-oxadiazol-2-amine (4s) showed max-imum activity with mean growth percent (GP) of 6262 fol-lowed by N-(24-dimethylphenyl)-5-(4-chlorophenyl)-134-oxadiazol-2-amine (4u) with mean GP of 7846 while restof the compounds showed less mean GP of more than9703 The compound 4s was highly active on MDA-MB-435 (melanoma) [GP = 1543] K-562 (leukemia) [GP =1822] T-47D (breast cancer) [GP = 3427] and HCT-15(colon cancer) [GP = 3977] The compound 4u showedmaximum activity on MDA-MB-435 (melanoma) [GP =682] K-562 (leukemia) [GP= 2480] NCI-H522 (non-small-cell lung cancer) [GP = 4103] andHCT (colon cancer) [GP =4474] N-(4-Bromophenyl)-5-(34-dimethoxyphenyl)-134-oxadiazol-2-amine (4j) showed anticancer activity with GP


of 7506 (HOP-92 non-small-cell lung cancer) 7631 (MOLT-4 leukemia) 7942 (NCI-H522 non-small-cell lung can-cer) and 8173 (SNB-75 CNS cancer) N-(4-Bromophenyl)-5-ethyl-134-oxadiazol-2-amine (4l) showed GP of 7662(A498 renal cancer) 7796 (MALME-3M melanoma)and 7951 (MOLT-4 leukemia) N-(4-Bromophenyl)-5-(4-chlorophenyl)-134-oxadiazol-2-amine (4h) showed GP of8294 (SR leukemia) 6045 (SK-MEL-2 melanoma) 6742(MDA-MB-231ATCC breast cancer) 8002 (UO-31 renalcancer) and 8297 (MCF7 breast cancer) Rest of the com-pounds had less average GP albeit showing good activityagainst some cell lines namely compound 4f [GP = 6575SR (leukemia)] compound 4a [GP = 7288 NCI-H522 (non-small-cell lung cancer)] and compound 4c [GP = 7667SR (leukemia)] The maximum activity was observed onMDA-MB-435 (melanoma) with GP of 632 while rest of thecompounds showed GP of gt5921 The anticancer activityof the compounds is given in Table 3 The structure activityrelationship obtained from the screening results showed thatN-aryl with 24-dimethyl substitution was more promis-ing than methyl substitution and 4-dimethoxyphenyl 34-dimethoxyphenyl and ethyl substitution at position 5 ofoxadiazole showed more activity

4 Conclusion

A series of newer oxadiazole analogues were subjected tomolecular properties prediction by Molinspiration and tox-icity risk prediction by Osiris software and synthesized insatisfactory yields All the compounds followed the Lipinskirule of five which makes them potentially active agentsand were also found to be less toxic than the standardanticancer drug methotrexate and fluorouracil (as per Osirisprediction) 16 compounds were evaluated for their anti-cancer activity in one-dose assay and showed moderateactivity on various cell lines N-(24-Dimethylphenyl)-5-(4-methoxyphenyl)-134-oxadiazol-2-amine could be con-sidered as lead for further discovery and could be mod-ified to potentiate the anticancer activity Further studiesto acquire more information about quantitative structureactivity relationships (QSAR) and molecular docking studiesare currently in progress in our laboratory

Conflict of Interests

The authors confirm that this paper has no conflict ofinterests

Acknowledgments

Anticancer data were provided by National Cancer InstituteBethesda MD USA The authors are grateful for all helpprovided by Professor Doug Smallwood and Dr MohammedNayel NCI US The management of Maharishi Arvind Col-lege of Pharmacy Jaipur Rajasthan India is acknowledgedfor providing research facilities

References

[1] httpwwwnydailynewscomlife-stylehealth14-million-peo-ple-cancer-2012-article-11545738

[2] httpwwwwhointcancerpreventionen[3] A Jemal F Bray M M Center J Ferlay E Ward and

D Forman ldquoGlobal cancer statisticsrdquo CA Cancer Journal forClinicians vol 61 no 2 pp 69ndash90 2011

[4] T Akhtar S Hameed N A Al-Masoudi R Loddo and PL Colla ldquoIn vitro antitumor and antiviral activities of newbenzothiazole and 134-oxadiazole-2-thione derivativesrdquo ActaPharmaceutica vol 58 no 2 pp 135ndash149 2008

[5] M J Ahsan J Sharma S Bhatia P K Goyal K Shankhalaand M Didel ldquoSynthesis of 2 5-disubstituted-1 3 4-oxadiazoleanalogs as novel anticancer and antimicrobial agentsrdquo Letters inDrug Design and Discovery vol 11 no 4 pp 413ndash419 2013

[6] M J Ahsan R V P SinghM Singh et al ldquoSynthesis anticancerand molecular docking studies of 2-(4-chlorophenyl)-5-aryl-13 4-oxadiazole analoguesrdquo Medicinal Chemistry vol 33 no 3pp 294ndash297 2013

[7] Salahuddin M Shaharyar A Majumdar and M J AhsanldquoSynthesis characterization and anticancer evaluation of2-(naphthalen-1-ylmethylnaphthalen-2-yloxymethyl)-1-[5-(substituted phenyl)-[134]oxadiazol-2-ylmethyl]-1H-benzimidazolerdquo Arabian Journal of Chemistry 2013

[8] M J Ahsan J G Samy H Khalilullah et al ldquoMolecularproperties prediction and synthesis of novel 134-oxadiazoleanalogues as potent antimicrobial and antitubercular agentsrdquoBioorganic and Medicinal Chemistry Letters vol 21 no 24 pp7246ndash7250 2011

[9] M J Ahsan J G Samy C B Jain K R Dutt H Khalilul-lah and M S Nomani ldquoDiscovery of novel antitubercu-lar 15-dimethyl-2-phenyl-4-([5-(arylamino)- 134-oxadiazol-2-yl]methylamino)-12-dihydro-3H-pyrazol-3-one analoguesrdquoBioorganic and Medicinal Chemistry Letters vol 22 no 2 pp969ndash972 2012

[10] M A Bakht M S Yar S G Abdel-Hamid S I Al Qasoumiand A Samad ldquoMolecular properties prediction synthesis andantimicrobial activity of some newer oxadiazole derivativesrdquoEuropean Journal of Medicinal Chemistry vol 45 no 12 pp5862ndash5869 2010

[11] M Khan T Akhtar N A Al-Masoudi H Stoeckli-Evans andS Hameed ldquoSynthesis crystal structure and anti-HIV activ-ity of 2-adamantyladamantylmethyl-5-aryl-134-oxadiazolesrdquoMedicinal Chemistry vol 8 no 6 pp 1190ndash1197 2012

[12] G C Ramaprasad B Kalluraya B Sunil Kumar and SMallya ldquoSynthesis of new oxadiazole derivatives as anti-inflammatory analgesic and antimicrobial agentsrdquo MedicinalChemistry Research vol 22 no 11 pp 5381ndash5389 2013

[13] Y Li H Zhu K Chen et al ldquoSynthesis insecticidal activity andstructure-activity relationship (SAR) of anthranilic diamidesanalogs containing oxadiazole ringsrdquoOrganic and BiomolecularChemistry vol 11 no 24 pp 3979ndash3988 2013

[14] httpclinicaltrialsgovshowNCT00554229[15] Molinspiration Chemoinformatics

httpwwwmolinspirationcomcgi-binproperties[16] httpwwworganic-chemistryorgprogpeo[17] C A Lipinski F Lombardo B W Dominy and P J Feeney

ldquoExperimental and computational approaches to estimate sol-ubility and permeability in drug discovery and developmentsettingsrdquo Advanced Drug Delivery Reviews vol 46 no 1ndash3 pp3ndash26 2001


[18] D F Veber S R Johnson H Cheng B R Smith K W Wardand K D Kopple ldquoMolecular properties that influence theoral bioavailability of drug candidatesrdquo Journal of MedicinalChemistry vol 45 no 12 pp 2615ndash2623 2002

[19] H H F Refsgaard B F Jensen P B Brockhoff S B PadkjaeligrM Guldbrandt and M S Christensen ldquoIn silico predictionof membrane permeability from calculated molecular parame-tersrdquo Journal of Medicinal Chemistry vol 48 no 3 pp 805ndash8112002

[20] S N Pandeya P Yogeeswari and J P Stables ldquoSynthesisand anticonvulsant activity of 4-bromophenyl substituted arylsemicarbazonesrdquo European Journal of Medicinal Chemistry vol35 no 10 pp 879ndash886 2000

[21] M J Ahsan H Khalilullah S Yasmin S S Jadav J P Stablesand J Govindasamy ldquoSynthesis and anticonvulsant evalua-tion of 2-(substituted benzylideneethylidene)-N-(substitutedphenyl)hydrazinecarboxamide analoguesrdquo Medicinal Chem-istry Research vol 22 no 6 pp 2746ndash2754 2013

[22] M J Ahsan and J P Stable ldquoPsychomotor seizure test neu-rotoxicity and in vitro neuroprotection assay of some semicar-bazone analoguesrdquo CNS Agents in Medicinal Chemistry vol 13no 2 pp 141ndash147 2013

[23] J N Sangshetti A R Chabukswar and D B ShindeldquoMicrowave assisted one pot synthesis of some novel 25-disubstituted 134-oxadiazoles as antifungal agentsrdquo BioorganicandMedicinal Chemistry Letters vol 21 no 1 pp 444ndash448 2011

[24] httpdtpncinihgov[25] A Monks D Scudiero P Skehan et al ldquoFeasibility of a high-

flux anticancer drug screen using a diverse panel of culturedhuman tumor cell linesrdquo Journal of theNational Cancer Institutevol 83 no 11 pp 757ndash766 1991

[26] M R Body and K D Paull ldquoSome practical considerations andapplications of the national cancer institute in vitro anticancerdrug discovery screenrdquoDrug Development Research vol 34 no2 pp 91ndash109 1995

[27] R H Shoemaker ldquoThe NCI60 human tumour cell line anti-cancer drug screenrdquo Nature Reviews Cancer vol 6 no 10 pp813ndash823 2006

[28] M J Ahsan H Khalilullah S Yasmin S S Jadav and J Govin-dasamy ldquoSynthesis characterisation and in vitro anticanceractivity of curcumin analogues bearing pyrazolepyrimidinering targeting EGFR tyrosine kinaserdquo BioMed Research Interna-tional vol 2013 Article ID 239354 14 pages 2013

Submit your manuscripts athttpwwwhindawicom

PainResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

ToxinsJournal of

VaccinesJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AntibioticsInternational Journal of

ToxicologyJournal of


StrokeResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Drug DeliveryJournal of



Advances in Pharmacological Sciences

Tropical MedicineJournal of


Medicinal ChemistryInternational Journal of


AddictionJournal of



BioMed Research International

Emergency Medicine InternationalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Autoimmune Diseases


Anesthesiology Research and Practice

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of


Pharmaceutics


MEDIATORSINFLAMMATION

of


anti-HIV [11] anti-inflammatory [12] and insecticidal [13]activities Zibotentan an endothelin receptor A (ETA) antag-onist is an anticancer agent which contains 134-oxadiazolering [14] Inspired by all these facts we have designed basedon themolecular properties prediction byMolinspiration andtoxicity risk prediction by Osiris software and synthesizedoxadiazole analogues for anticancer screening [15 16] Thenumber of rotatable bonds (NROTB) and Lipinskirsquos rule offive were also calculated [17] The rule of five states thatmost molecules with good membrane permeability havelog P (partition coefficient) le 5 molecular weight (MW)le 500 number of hydrogen bond acceptors le 10 andnumber of hydrogen bond donors le 5 This rule is widelyused as a filter for drug-like properties Furthermore noneof the compounds violated Lipinskirsquos parameters makingthem potentially promising agents The pharmacokineticparameters important for good oral bioavailability ofN-aryl-5-substituted-134-oxadiazol-2-amine analogues (4andashx) aregiven in Table 1 and the toxicity risk prediction (mutagenicirritant and reproductive effect) calculated with Osiris isgiven in Table 2 The toxicity risk prediction showed thatall these oxadiazoles are comparatively less toxic than thestandard drug fluorouracil andmethotrexate Good intestinalabsorption reduced molecular flexibility (measured by thenumber of rotatable bonds) low polar surface area and totalhydrogen bond count (sum of donors and acceptors) areimportant predictors of good oral bioavailability [18 19]Membrane permeability and bioavailability are always asso-ciated with some basic molecular descriptors such as log P(partition coefficient) molecular weight (MW) or hydrogenbond acceptors and donors counts in amoleculeThe numberof rotatable bonds is important for conformational changes ofmolecules under study and ultimately for the binding withreceptors or channels It is revealed that for passing oralbioavailability criteria the number of rotatable bond shouldbe le10 [18] In the present studies the title compounds havelog P value varied from 273 to 472 (lt5) MW varied from203 to 375 (lt500) number of hydrogen bond acceptors variedfrom 4 to 6 (le10) number of hydrogen bond donors variedfrom 1 to 2 (le5) and number of rotatable bond varied from 3to 5 (le10)

2 Materials and Methods

21 Chemistry All chemicals were procured from E MerckCDH Drug laboratory and SD Fine Chemicals Meltingpoints were determined by open tube capillary method andwere uncorrected Purity of the compounds was checkedby elemental analysis and the progress of reactions wasmonitored by TLC plates (silica gel G) using mobile phasechloroform methanol (9 1) and acetone n-hexane (8 2)and the spots were identified by iodine vapours or UV lightIR spectra were recorded on a Shimadzu 8201 PC FT-IRspectrometer (KBr pellets) NMR spectra were recorded ona Bruker AC 300MHz spectrometer using TMS as internalstandard in DMSO d6 Mass spectra were recorded on aBruker Esquire LCMS using ESI and elemental analyses wereperformed on Perkin-Elmer 2400 Elemental Analyzer

22 General Method for the Synthesis of Substituted PhenylUrea Analogues (2andashd) Aromatic anilines (01mol) weredissolved in 20mL of glacial acetic acid and 10mL of hotwater and sodium cyanate (65 g 01mol) in 80mL of hotwater was added with stirring It was allowed to stand for 30min then cooled in ice bath filtered with suction dried andrecrystallized from boiling water to obtain substituted phenylurea (2andashd) [20ndash22]

23 General Method for the Synthesis of Semicarbazide Ana-logues (3andashd) Equimolar quantities (005mol) of substitutedphenyl urea (2andashd) and hydrazine hydrate (AR 99-100)(25mL 005mol) in ethanol were refluxed for 48 h withstirring The two-thirds volume of alcohol was distilled byvacuum distillation and then poured into the crushed iceThe resultant precipitate was filtered washed with water anddried The solid mass was recrystallized from 50mL absoluteethanol to obtain semicarbazide analogues (3andashd) [20ndash22]

24 General Method for the Synthesis of 5-Substituted-N-aryl-134-oxadiazol-2-amine Analogues (4andashx) Substitutedphenyl semicarbazide (0005mol) (3andashd) and aromatic alde-hydes (0005mol) were refluxed for 10ndash12 h using 20molNaHSO

3and ethanol-water system (1 2 vv) solvent [23]

After completion of reaction the excess solvent was removedand the concentrate was poured into crushed ice filterwashed with water dried and recrystallized with absoluteethanol to obtain the final product (4andashx) The reaction wasmonitored throughout by thin layer chromatography (TLC)using chloroform methanol (9 1) and acetone n-hexane(8 2) as mobile phase

241 N-(4-Methylphenyl)-5-(4-methoxyphenyl)-134-oxadia-zol-2-amine (4a) Yield 72Mp 178ndash180∘C IR (KBr) cmminus13219 (NH) 1523 (C=N) 1173 (CndashOndashC) 1H NMR (300MHzDMSO-119889

6) 120575 225 (3H s CH

3) 379 (3H s OCH

3) 695ndash

698 (2H d J = 78Hz ArH) 707ndash709 (2H d J = 72HzArH) 750ndash752 (2H d J = 75Hz ArH) 773ndash776 (2H d J =78Hz ArH) 867 (1H s NH) 13C NMR (75Hz DMSO-119889

6)

120575 2431 5592 11482 11621 11855 12812 12852 1299214009 15212 16071 16455 mz = 281 (M+) 282 (M+1)+CalAna [C (6822) 6831H (545) 537N (1482) 1494]

242 N-(4-Methylphenyl)-5-(4-chlorophenyl)-134-oxadia-zol-2-amine (4b) Yield 68Mp 214ndash216∘C IR (KBr) cmminus13191 (NH) 1531 (C=N) 1203 (CndashOndashC) 694 (CndashCl) 1HNMR(300MHz DMSO-119889

6) 120575 203 (3H s CH

3) 682ndash685 (2H d

J = 84Hz ArH) 708ndash712 (2H d J = 81Hz ArH) 721ndash724(2H d J = 81Hz ArH) 731ndash734 (2H d J = 84Hz ArH)844 (1H s NH) mz = 285 (M+) 287 (M+2)+ CalAna [C(6301) 6305H (419) 423N (1473) 1471]

243 N-(4-Methylphenyl)-5-(4-hydroxyphenyl)-134-oxadia-zol-2-amine (4c) Yield 74 Mp 182ndash185∘C IR (KBr) cmminus13402 (OH) 3199 (NH) 1511 (C=N) 1119 (CndashOndashC) 766 (CndashCl) 1H NMR (300MHz DMSO-119889

6) 120575 224 (3H s CH

3)

678ndash681 (2H d J =63HzArH) 706ndash708 (2H d J = 54Hz



NH O

N NR

NH NHO

N N

O

R

4e 4k 4r 4x

O

N NR

4f 4l

R1





6) 120575 224 (3H s CH

3) 379 (6H s



6) 120575

2432 5621 11231 11581 11623 11951 12082 12842 1299914019 14211 14981 15031 16451 mz = 311 (M+) CalAna[C (6541) 6558H (546) 555N (1376) 1350]


DMSO-1198896) 120575 223 (3H s CH

3) 686ndash689 (2H d J = 61Hz



6)


3) 262




6) 120575 379 (3H s OCH

3) 677ndash680 (2H








6) 120575 671ndash673 (2H d J



6) 120575 673ndash675 (2H d J



6) 120575 379 (6H s OCH

3) 679ndash681


6) 120575 5612 11233 11311

11583 11851 11912 12082 13253 14211 14908 14951 1620216459mz = 375 (M+) 377 (M++2) CalAna [C (5111) 5108H (372) 375N (1116) 1117]


6) 120575 680ndash682 (2H d J = 62Hz ArH)



6) 120575 134 (3H s CH

3) 259 (2H m CH

2) 733ndash735



6) 120575 383 (3H s OCH

3)



6) 120575 721ndash724 (2H d J



6) 120575 727ndash729 (2H d J = 61Hz





6) 120575 723ndash725 (2H d



6) 120575 378 (6H s OCH

3) 120575 729ndash


6) 120575 5629 11231 11508

11771 11951 12081 12433 12982 14121 14981 15033 1620216459mz = 331 (M+) 333 (M++2) CalAna [C (5798) 5793H (422) 425N (1256) 1267]


6) 120575 727ndash729 (2H d J = 60Hz ArH)



6) 120575 221 (6H s CH

3) 378 (3H s



6) 120575

1588 2463 5623 11232 11581 11611 11853 12082 1269312832 12892 13179 13911 14981 15032 16271 16455 mz= 295 (M+) CalAna [C (6912) 6914H (585) 580N (1419)1423]


6) 120575 223 (6H s CH

3) 697-692



6) 120575 249 (6H s CH

3) 639ndash741



6) 120575 222 (6H s CH

3)



6) 120575 223 (6H s CH

3) 379 (6H



6) 120575 1583 2467 5623 11231 11589 11616

11859 12081 12699 12830 12892 13170 13919 1498315032 16271 16455 mz = 325 (M+) CalAna [C (6641)6645H (586) 589N (1286) 1291]


6) 120575 223 (6H s CH

3) 691ndash693 (2H t J = 75Hz













7288804483988588


8459864692109237

4c 777952 9855 7667 to 11771SR (leukemia)


7667810582028385



8346866389428992




8087831087928813

4f 777951 9850 6575 to 11026SR (leukemia)



6575825887208820



6045674280028297




7533818885638868



SNB-75 (CNS cancer)

7506763179428173



7329822183758414



SR (leukemia)

7662779679518294



7980807880818112


5921828484218627


Table 3 Continued





1543182234273977




682248041034474



8097874489019055

RNaCNO

AcOH

N

O

H

RN N

O

H H

REtOH

EtOH

N O

N N

Ar

H

R

NH2

NH2NH2

NaHSO3

NH2NH2 middot H2O

ArCHOR998400CHO


4andashx










4 Conclusion




Acknowledgments


References

































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of



NH O

N NR

NH NHO

N N

O

R

4e 4k 4r 4x

O

N NR

4f 4l

R1





6) 120575 224 (3H s CH

3) 379 (6H s



6) 120575

2432 5621 11231 11581 11623 11951 12082 12842 1299914019 14211 14981 15031 16451 mz = 311 (M+) CalAna[C (6541) 6558H (546) 555N (1376) 1350]


DMSO-1198896) 120575 223 (3H s CH

3) 686ndash689 (2H d J = 61Hz



6)


3) 262




6) 120575 379 (3H s OCH

3) 677ndash680 (2H








6) 120575 671ndash673 (2H d J



6) 120575 673ndash675 (2H d J



6) 120575 379 (6H s OCH

3) 679ndash681


6) 120575 5612 11233 11311

11583 11851 11912 12082 13253 14211 14908 14951 1620216459mz = 375 (M+) 377 (M++2) CalAna [C (5111) 5108H (372) 375N (1116) 1117]


6) 120575 680ndash682 (2H d J = 62Hz ArH)



6) 120575 134 (3H s CH

3) 259 (2H m CH

2) 733ndash735



6) 120575 383 (3H s OCH

3)



6) 120575 721ndash724 (2H d J



6) 120575 727ndash729 (2H d J = 61Hz





6) 120575 723ndash725 (2H d



6) 120575 378 (6H s OCH

3) 120575 729ndash


6) 120575 5629 11231 11508

11771 11951 12081 12433 12982 14121 14981 15033 1620216459mz = 331 (M+) 333 (M++2) CalAna [C (5798) 5793H (422) 425N (1256) 1267]


6) 120575 727ndash729 (2H d J = 60Hz ArH)



6) 120575 221 (6H s CH

3) 378 (3H s



6) 120575

1588 2463 5623 11232 11581 11611 11853 12082 1269312832 12892 13179 13911 14981 15032 16271 16455 mz= 295 (M+) CalAna [C (6912) 6914H (585) 580N (1419)1423]


6) 120575 223 (6H s CH

3) 697-692



6) 120575 249 (6H s CH

3) 639ndash741



6) 120575 222 (6H s CH

3)



6) 120575 223 (6H s CH

3) 379 (6H



6) 120575 1583 2467 5623 11231 11589 11616

11859 12081 12699 12830 12892 13170 13919 1498315032 16271 16455 mz = 325 (M+) CalAna [C (6641)6645H (586) 589N (1286) 1291]


6) 120575 223 (6H s CH

3) 691ndash693 (2H t J = 75Hz













7288804483988588


8459864692109237

4c 777952 9855 7667 to 11771SR (leukemia)


7667810582028385



8346866389428992




8087831087928813

4f 777951 9850 6575 to 11026SR (leukemia)



6575825887208820



6045674280028297




7533818885638868



SNB-75 (CNS cancer)

7506763179428173



7329822183758414



SR (leukemia)

7662779679518294



7980807880818112


5921828484218627


Table 3 Continued





1543182234273977




682248041034474



8097874489019055

RNaCNO

AcOH

N

O

H

RN N

O

H H

REtOH

EtOH

N O

N N

Ar

H

R

NH2

NH2NH2

NaHSO3

NH2NH2 middot H2O

ArCHOR998400CHO


4andashx










4 Conclusion




Acknowledgments


References

































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of








6) 120575 671ndash673 (2H d J



6) 120575 673ndash675 (2H d J



6) 120575 379 (6H s OCH

3) 679ndash681


6) 120575 5612 11233 11311

11583 11851 11912 12082 13253 14211 14908 14951 1620216459mz = 375 (M+) 377 (M++2) CalAna [C (5111) 5108H (372) 375N (1116) 1117]


6) 120575 680ndash682 (2H d J = 62Hz ArH)



6) 120575 134 (3H s CH

3) 259 (2H m CH

2) 733ndash735



6) 120575 383 (3H s OCH

3)



6) 120575 721ndash724 (2H d J



6) 120575 727ndash729 (2H d J = 61Hz





6) 120575 723ndash725 (2H d



6) 120575 378 (6H s OCH

3) 120575 729ndash


6) 120575 5629 11231 11508

11771 11951 12081 12433 12982 14121 14981 15033 1620216459mz = 331 (M+) 333 (M++2) CalAna [C (5798) 5793H (422) 425N (1256) 1267]


6) 120575 727ndash729 (2H d J = 60Hz ArH)



6) 120575 221 (6H s CH

3) 378 (3H s



6) 120575

1588 2463 5623 11232 11581 11611 11853 12082 1269312832 12892 13179 13911 14981 15032 16271 16455 mz= 295 (M+) CalAna [C (6912) 6914H (585) 580N (1419)1423]


6) 120575 223 (6H s CH

3) 697-692



6) 120575 249 (6H s CH

3) 639ndash741



6) 120575 222 (6H s CH

3)



6) 120575 223 (6H s CH

3) 379 (6H



6) 120575 1583 2467 5623 11231 11589 11616

11859 12081 12699 12830 12892 13170 13919 1498315032 16271 16455 mz = 325 (M+) CalAna [C (6641)6645H (586) 589N (1286) 1291]


6) 120575 223 (6H s CH

3) 691ndash693 (2H t J = 75Hz













7288804483988588


8459864692109237

4c 777952 9855 7667 to 11771SR (leukemia)


7667810582028385



8346866389428992




8087831087928813

4f 777951 9850 6575 to 11026SR (leukemia)



6575825887208820



6045674280028297




7533818885638868



SNB-75 (CNS cancer)

7506763179428173



7329822183758414



SR (leukemia)

7662779679518294



7980807880818112


5921828484218627


Table 3 Continued





1543182234273977




682248041034474



8097874489019055

RNaCNO

AcOH

N

O

H

RN N

O

H H

REtOH

EtOH

N O

N N

Ar

H

R

NH2

NH2NH2

NaHSO3

NH2NH2 middot H2O

ArCHOR998400CHO


4andashx










4 Conclusion




Acknowledgments


References

































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of




6) 120575 723ndash725 (2H d



6) 120575 378 (6H s OCH

3) 120575 729ndash


6) 120575 5629 11231 11508

11771 11951 12081 12433 12982 14121 14981 15033 1620216459mz = 331 (M+) 333 (M++2) CalAna [C (5798) 5793H (422) 425N (1256) 1267]


6) 120575 727ndash729 (2H d J = 60Hz ArH)



6) 120575 221 (6H s CH

3) 378 (3H s



6) 120575

1588 2463 5623 11232 11581 11611 11853 12082 1269312832 12892 13179 13911 14981 15032 16271 16455 mz= 295 (M+) CalAna [C (6912) 6914H (585) 580N (1419)1423]


6) 120575 223 (6H s CH

3) 697-692



6) 120575 249 (6H s CH

3) 639ndash741



6) 120575 222 (6H s CH

3)



6) 120575 223 (6H s CH

3) 379 (6H



6) 120575 1583 2467 5623 11231 11589 11616

11859 12081 12699 12830 12892 13170 13919 1498315032 16271 16455 mz = 325 (M+) CalAna [C (6641)6645H (586) 589N (1286) 1291]


6) 120575 223 (6H s CH

3) 691ndash693 (2H t J = 75Hz













7288804483988588


8459864692109237

4c 777952 9855 7667 to 11771SR (leukemia)


7667810582028385



8346866389428992




8087831087928813

4f 777951 9850 6575 to 11026SR (leukemia)



6575825887208820



6045674280028297




7533818885638868



SNB-75 (CNS cancer)

7506763179428173



7329822183758414



SR (leukemia)

7662779679518294



7980807880818112


5921828484218627


Table 3 Continued





1543182234273977




682248041034474



8097874489019055

RNaCNO

AcOH

N

O

H

RN N

O

H H

REtOH

EtOH

N O

N N

Ar

H

R

NH2

NH2NH2

NaHSO3

NH2NH2 middot H2O

ArCHOR998400CHO


4andashx










4 Conclusion




Acknowledgments


References

































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of







7288804483988588


8459864692109237

4c 777952 9855 7667 to 11771SR (leukemia)


7667810582028385



8346866389428992




8087831087928813

4f 777951 9850 6575 to 11026SR (leukemia)



6575825887208820



6045674280028297




7533818885638868



SNB-75 (CNS cancer)

7506763179428173



7329822183758414



SR (leukemia)

7662779679518294



7980807880818112


5921828484218627


Table 3 Continued





1543182234273977




682248041034474



8097874489019055

RNaCNO

AcOH

N

O

H

RN N

O

H H

REtOH

EtOH

N O

N N

Ar

H

R

NH2

NH2NH2

NaHSO3

NH2NH2 middot H2O

ArCHOR998400CHO


4andashx










4 Conclusion




Acknowledgments


References

































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of


Table 3 Continued





1543182234273977




682248041034474



8097874489019055

RNaCNO

AcOH

N

O

H

RN N

O

H H

REtOH

EtOH

N O

N N

Ar

H

R

NH2

NH2NH2

NaHSO3

NH2NH2 middot H2O

ArCHOR998400CHO


4andashx










4 Conclusion




Acknowledgments


References

































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of



4 Conclusion




Acknowledgments


References

































Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of

















Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of





Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of

Documents

Research Article Synthesis and Anticancer Activity of N