Journal of Atoms and Molecules

J. Atoms and Molecules / 3(2); 2013 / 478–491

Hamdy Khamees et al

Research Article

Journal of Atoms and Molecules An International Online Journal ISSN – 2277 – 1247

SYNTHESIS, CHARACTERIZATION, ANTICANCER, ANALGESIC, AND ANTIINFLAMMATORY ACTIVITIES OF HITHERTO UNKNOWN THIAZOLO[3,2-A] PYRIDINE AND THIAZOLO [3,2-A] 1,8-NAPHTHYRIDINE DERIVATIVES Hamdy Khamees1, Gehad A.Abdel Jaleel3, Mahmed.E.Azab2, Gameel.A.M. Mohamed 1*, Tarek.A.Abd-elaziz1, Hassan.A.Eyada1 1 Al-AZhar University, Faculty of Science(boys), Chemistry department, 11284, Nasr City, Cairo. 2 Ain Shams University, Faculty of Science, Chemistry department, Cairo, Egypt 3 Pharmacology Department, National Research Center, El-Bohoth St., Dokki, Cairo, Egypt. Received on: 31-01-2013

Revised on: 24-02-2013

Accepted on: 18–03–2013

ABSTRACT: Ethyl-5-(arylmethylene)-4-oxothiazolidin-2-ylidene)acetate (2)was synthesized by refluxing of 2,4dichlorobenzaldehyde with 4- thiazolidinone derivative (1) which further underwent cyclization with different α-substituted cinnamonitriles to afford thiazolo [3,2-a] pyridines (3,4,5)a-e , respectively. Reaction of 3a with Ac2O gave the corresponding N-acetyl amino thiazolo[3,2a]pyridine (6), together with 1,8-naphthyridine derivative (7) depending on the time of the reflux . Also ,treatment of 3a with HCO2H and/or p-chlorobenzoyl chloride gave the corresponding 1,8naphthyridine derivatives (8,9),respectively. Thi-azolo[3,2a] pyridine (3a), reacted with chloroacetonitrile to give amidine derivative (10) , while upon treatment with malononitrile undergoes concerted addition to give the corresponding thiazolo [3,2-a] 1,8-naphthyridine derivative (11), Also, 3a reacted with ethylisothiocyanate to afford the corresponding thiourea derivative (12).Finally;Where 3a refluxed with hydrazines (as binucleophile) in ethanol and gave pyrazolo [3',4'‫׃‬4,5] thiazolo [3,2-a] pyridine derivatives (13a-c), through cyclocondensation and oxidation reactions with α-β unsaturated carbonyl system KEY WORDS: Anticancer, analgesic, anti-inflammatory ,thiazolo [3,2-a] pyridines, thiazolo[3,2-a] [1,8] nap-hthyridines. INTRODUCTION:

* Corresponding author Gameel.A.M. Mohamed, Email: [email protected] Tel: 002-1117150693

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4- Thiazolidinones and their derivatives are an import class of compounds in organic and medicinal chemistry. The 4-thiazolidinone ring system is a core structure in various synthetic pharmaceutical agents, displaying a broad spectrum of biological activities such as, anti-tubercular [1], anti bacterial [2], antiHIV [3], anti-inflammatory [4], antimycobacterial [5], anti convulsant [6], anti histaminic [7], anti cancer [8], anti protocol www.jamonline.in 478

J. Atoms and Molecules / 3(2); 2013 / 478–491 [9] and analgesic [10]. On the above findings ,the authors reported the synthesis of some new thiazolo [3,2-a] pyridine and thiazolo[3,2-a] 1,8- naphthyridine derivatives via the reaction of 1 with some electrophilic and nucleophiliic reagents [11-19] . EXPERIMENTAL: All melting points are uncorrected. IR spectra (KBr) were measured on Shimadzu 440 spectrometer, 1H NMR spectra were obtained in DMSO on a Varian Gemini 200 MHz spectrometer using TMS as internal standard; Chemical shifts are reported as (ppm). Mass spectra were obtained on GCMS\QP 1000 Ex mass spectrometer at 70 eV. Elemental analyses were carried out at the Microanalytical Center, Faculty of Science (Cairo University, Egypt). Biological evaluation was carried out at Pharmacology Department, National Research Center, ElBohoth St., Dokki,Cairo.Egypt Ethyl-5-(2,4-dichlorophenylmethylidine)4-oxothiazolidin-2-ylidene)acetate(2) A mixture of compound 1 (0.01 mol), and 2,4-dichlorobenzaldehyde(0.01 mol) in dioxane (30 mL) containing few drops of piperidine was refluxed for 3h, the solid product so formed on heating was collected and recrystallised from suitable solvent to give 2 . 70% yield; yellow crystals (acetic acid), m.p. 138-40°C. IR (KBr): ν = 3214, (NH ) and 1710 cm−1 (C=O thiazolidinone and ester). 1H NMR (DMSO-d6): δ = 0.94(t,3H,CH3), 4.13 (q,2H, CH2) , 5.07 (s,1H,methine-H), 7.128.05(m,4H,Ar-H + methine-H) , 10.27 (s,1H, NH). MS: m/z = (343; 7.51%), . Anal. Calcd for C14H11Cl2NO3S (343): C, 48.97; H, 3.20; N, 4.08. Found: C, 49.02; H, 2.92; N, 3.85%.


Hamdy Khamees et al Ethyl-5-amino-6-cyano-2(arylmethylidine)-7-aryl-3-oxo-3,7dihydro-2H-thiazolo [3,2-a]pyridine-8carboxylate(3a-e). A mixture of compound 2 (0.01 mol), and αcyanocinnamonitriles (0.01 mol) in ethanol (30 mL) containing few drops of piperidine was refluxed for 3h, the solid product so formed on heating was collected and recrystallised from suitable solvent to give 3ae. 3a‫ ׃‬81% yield; yellow powder (EtOH), m.p. 176-78 °C. IR (KBr): ν = 3396,3294 (NH2 ) 2188 (C≡N) and1694 cm−1 (C=O thiazolidinone and ester).1H NMR (DMSOd6): δ = 0.95(t,3H,CH3), 4.00(q,2H,CH2) , 5.07(s,1H,pyridine-H), 7.38-7.89(m, 9H,Ar-H + met-hine-H + NH2). Anal. Calcd for C24H15Cl4N3O3S (565): C, 50.97; H, 2.65; N, 7.43. Found: C, 50.52; H, 2.82; N, 7.81%. 3b‫ ׃‬72% yield; yellow powder (EtOH), m.p. 180-82 °C. IR (KBr): ν = 3389,3289 (NH2 ) 2190 (C≡N)and 1699 cm−1 (C=O thiazolidinone and ester),. MS: m/z = 499 (M32(S); 11.20%) . Anal. Calcd for C24H16Cl3N3O3S (531): C, 54.23; H, 3.01; N, 7.90. Found: C, 54.52; H, 2.82; N, 8.20%. 3c‫ ׃‬77% yield; yellow powder (EtOH), m.p. 184-86°C. IR (KBr): ν = 3392,3293 (NH2 ) 2191 (C≡N) and1697 cm−1 (C=O 1 thiazolidinone and ester). H NMR (DMSOd6): δ = 0.95(t,3H,CH3), 2.27 (s,3H,CH3),4.01(q,2H,CH2) , 5.08 (s,1H,pyridine-H), 7.38-7.80 (m, 10 ,Ar-H + methine-H + NH2). Anal. Calcd for C25H19 Cl2N3O3S (511): C, 58.70; H, 3.71; N,8.21. Found: C, 59.00; H, 3.62; N, 8.73%. 3d‫ ׃‬73% yield; yellow powder (EtOH), m.p. 178-80 °C. IR (KBr): ν = 3392,3293 (NH2 ) 2191 (C≡N) and1697 cm−1 (C=O 1 thiazolidinone and ester). H NMR (DMSOd6): δ = 0.95 (t,3H,CH3), 3.10 (s,6H,N(CH3)2),4.03(q,2H,CH2) , 5.07 www.jamonline.in 479

J. Atoms and Molecules / 3(2); 2013 / 478–491 (s,1H,pyridine-H), 6.84-8.03 (m, 10 ,Ar-H + methine-H + NH2) .13C NMR (DMSO-d6):δ 13.48, 40.37, 60.96, 63.97, 66.66,111.72,115.44,116.18,118.70,120.80,12 4.84,126.26,,130.01,130.07,130.20,132.83, 133.26,133.51,147.94,154.94,154.26,158.75,a nd 165.48. Anal. Calcd for C26H22 Cl2N4O3 S (540): C, 57.77; H, 4.07; N,10.37. Found: C, 57..01; H, 4.42; N, 9.91%. 3e‫ ׃‬73% yield; yellow powder (EtOH), m.p. 182-84 °C. IR (KBr): ν = 3392,3293 (NH2 ) 2191 (C≡N) and 1697 cm−1 (C=O thiazolidinone and ester). 1H NMR (DMSOd6): δ = 0.94 (t,3H,CH3), 3.97(q,2H,CH2), 5.07(s,1H,pyridine-H), 6.84-8.03(m,11 ,Ar-H + methine -H + NH2) .MS: m/z = 465 (M32(S)); 8.20%) . Anal. Calcd for C24H17Cl2N3O3S (497): C, 57.94; H, 3.42; N,8.45. Found: C, 57..51; H, 3.10; N, 8.32% Ethyl-5-amino-2-(arylmethylidine)-6carbamoyl-7-aryl-3-oxo-3,7-dihydro-2Hthiazolo[3,2-a]pyridine-8-carboxylate(4a-e). A mixture of compound 2 (0.01 mol), and αcarboxamidocinnamonitriles (0.01 mol) in ethanol (30 mL) containing few drops of piperidine was refluxed for 3h, the solid product so formed on heating was collected and recrystallised from suitable solvent to give 4a-e.

Hamdy Khamees et al ester and amide)1H NMR (DMSO-d6): δ = 0.84(t,3H,CH3), 4.04 (q,2H,CH2) , 5.17(s,1H,pyridine-H), 6.55(s,2H,CONH2) 7.31-8.33 (m,10H, H,Ar-H +methineH+NH2). Anal. Calcd for C24H18 Cl3N3O4S (549): C, 52. 45; H, 3.27; N, 7.65. Found: C, 52.34; H, 3.01; N, 7.92%. 4c‫ ׃‬73% yield; yellow powder (EtOH), m.p. 190-92 °C. IR (KBr): ν = 3343,3190 (NH2 and1687,1657cm−1 (C=O thiazolidinone, ester and amide).1H NMR (DMSO-d6): δ = 0.97 (t ,3H,CH3),2.20 (s,3H,CH3) 4.16 (q,2H,CH2) , 5.68(s,1H,pyridine-H), 6.70 (s,2H, CO NH2),7.16-7.96 (m,10H ,Ar-H+ methineH+NH2 ).MS: m/z = 528 (M-1); 2.46%), Anal. Calcd for C25H21Cl2N3O4S (529): C, 56.71; H, 3.96; N, 7.93. Found: C, 56.20; H, 4.20; N, 7.61%. 4d‫ ׃‬85% yield; yellow powder (EtOH), m.p. 182-84 °C. IR (KBr): ν = 3422,3262 (NH2 and1713, 1659cm−1 (C=O thiazolidinone,ester and amide).1H NMR (DMSO-d6): δ = 0.84 (t,3H,CH3),2.94 (s,6H,N(CH3)2) 4.16 (q,2H,CH2) , 5.59(s,1H,pyridine-H), 6.70 (s,2H, CONH2), 7.09-8.20 (m,10H ,Ar-H+ methine-H+NH2 ).MS: m/z = 558 ; 0.57%), Anal. Calcd for C26H24 Cl2N4O4S (558): C, 55.91; H, 4.30; N, 10.03. Found: C, 55.22; H, 4.20; N, 10.25%.

4a‫ ׃‬81% yield; yellow powder (EtOH), m.p. 180-82 °C. IR (KBr): ν = 3477,3390 (NH2 and 1701,1655 cm−1 (C=O thiazolidinone, ester and amide).1H NMR (DMSO-d6): δ = 1.10(t,3H,CH3), 4.12 (q,2H,CH2) , 5.17 (s,1H,pyridine-H), 6.54(s,2H,CONH2), 7.317.85(m,8H,Ar-H+NH2 ),8.85(s,1H, methineH) .MS: m/z = 551 (M-32(S)); 8.20%), Anal. Calcd for C24H17 Cl4N3O4S (583): C, 49.39; H, 2.91; N, 7.20. Found: C,49.91; H, 2.82; N, 7.81%.

4e‫׃‬84% yield; yellow powder (EtOH), m.p. 186-88 °C. IR (KBr): ν = 3381,3190 (NH2 and1696,1658cm−1 (C=O thiazolidinone, ester and amide).1H NMR (DMSO-d6): δ = 0.84 (t, 4.16 (q,2H,CH2) , 3H ,CH3), 5.67(s,1H,pyridine-H), 6.69 (s,2H, CONH2), 7.14-8.87 (m,11H ,Ar-H+ methine-H+NH2 ).MS: m/z = 483 (M-32(S)); 0.57%), Anal. Calcd for C24H19Cl2N3O4S (515): C, 55.92; H, 3.68; N, 8.15. Found: C, 56.23; H, 4.21; N, 7.82%.

4b‫ ׃‬72% yield; yellow powder (EtOH), m.p. 184-86 °C. IR (KBr): ν = 3468,3385 (NH2 ) and 1697,1579 cm−1 (C=O thiazolidinone,

4.4.Diethyl-5-amino-2-arylmethylidine-3oxo-7-aryl-3,7-dihydro-2H-thiazolo[3,2-a] pyridine -6,8-dicarboxylate(5a-e).


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J. Atoms and Molecules / 3(2); 2013 / 478–491 A mixture of compound 2 (0.01 mol), and αethoxycarbonylcinnamonitriles(0.01 mol) in ethanol (30 mL) containing few drops of piperidine was refluxed for 3h, the solid product so formed on heating was collected and recrystallised from suitable solvent to give 5a-e. 5a‫ ׃‬66% yield; brown powder (EtOH), m.p. 176-78 °C. IR (KBr): ν = 3388,3252 (NH2 and1701 cm−1 (C=O thiazolidinone, and ester).1H NMR (DMSO-d6): δ =1.10, 1.21 (2t 3.84,3.85 (2q,4H,2CH2) , ,3H,CH3), 5.16(s,1H,pyridine-H), 7.18-8.14(m,7H,ArH+ m ethine-H ), 11.48(s,2H,NH2). .Anal. Calcd for C26H20 Cl4N2O5S (612): C, 50.98; H, 3.26; N, 4.57. Found: C, 50.45; H, 3.66; N, 5.07%. 5b‫ ׃‬62% yield; yellow powder (EtOH), m.p. 182-84 °C. IR (KBr): ν = 3396,3263 (NH2 and1710cm−1 (C=O thiazolidinone and ester)1H NMR (DMSO-d6): δ = 1.03 ,1.04 (2t, 6H ,2CH3), 3.09,4.01 (2q,4H,2CH2) , 5.20(s,1H,pyridine-H), 7.14-7.86 (m, 8H,ArH+ methine-H ), 8.70(s,2H,NH2) . MS: m/z = 546 (M-32(S)) Anal. Calcd for C26H21 Cl3 N2 O5S (578): C, 53.97; H, 3.63; N, 4.84. Found: C, 54.34; H, 4.01; N, 5.01%. 5c‫ ׃‬64% yield; yellow powder (EtOH), m.p. 186-88 °C. IR (KBr): ν = 3395,3263 (NH2 and1711, cm−1 (C=O thiazolidinone, and ester).1H NMR (DMSO-d6): δ =1.03, 1.05 (2t,6H,2CH3), 2.20(s,3H,CH3),3.97,4.00 (2q,4H,2CH2) , 5.16(s,1H,pyridine-H), 7.207.84 (m, 8H,Ar-H+methine-H ), 13 8.72(s,2H,NH2). C NMR (DMSO-d6) : δ =13.48, 14.16, 22 .68,59.11,60.10,66.66,116.18,118.70,120.84,1 20.91,124.84,126.26,128.32,129.97, 130.09, 132.83, 133.16, 133.26, 135.10,136.12,145.07,147.94, 154. 94, 158.75,and 168 .09. Anal. Calcd for C27H24 Cl2 N2 O5S (558): C, 58.06; H, 4.30; N, 5.01. Found: C, 58.31; H, 4.11; N, 5.61%.


Hamdy Khamees et al 5d‫ ׃‬73% yield; yellow powder (EtOH), m.p. 190-92 °C. IR (KBr): ν = 3422,3262 (NH2 and 1659cm−1 (C=O thiazolidinone and ester).1H NMR (DMSO-d6) =1.03 ,1.08 (2t,6H,2CH3), 2.05(s,6H,N(CH3)2),3.97,4.00 (2q,4H,2CH2) , 5.17(s, 1H, pyridine -H), 7.23-7.79 (m, 8H,Ar-H+methine-H ), 8.67(s,2H,NH2).MS: m/z = 556 (M-32); 0.44%), Anal. Calcd for C28H27 Cl2N3O5S (587): C, 57.24; H, 4.59; N, 7.15. Found: C, 56.20; H, 4.12; N, 7.63%. 5e‫׃‬87% yield; yellow powder (EtOH), m.p. 184-86 °C. IR (KBr): ν = 3398,3270 (NH2 and1711cm−1 (C=O thiazolidinone, and ester).1H NMR (DMSO-d6): 1.05 ,1.08 (2t , 6H , 2CH3), 3.97,4.07 (2q,4H,2CH2) , 4.79(s, 1H, pyridine -H), 7.12-7.85 (m, 9H,ArH+methine-H ), 8.54(s,2H,NH2). Anal. Calcd for C26H22Cl2N2O5S (544): C, 57.35; H, 4.04; N,5.14. Found: C, 56.23; H, 4.21; N, 5.43%. Ethyl5-N-acetylamino-2-(2,4dichlorophenylmethylidine)-6-cyano-3-oxo7-(2,4-di -chlorophenyl)-3,7 -dihydro-2Hthiazolo[3,2-a]pyridine-8-carboxylate(6) A mixture of compound 3a (0.01 mol) in enough amount of acetic anhydride was refluxed for 3h, the solid product so formed on heating was collected and recrystallised from suitable solvent to give 6. 6‫ ׃‬72% yield; yellow powder (EtOH), m.p. >300°C. IR (KBr): ν = 3295, (NH ), 2190 (C≡N) and 1697,1642 cm−1 (C=O 1 thiazolidinone,ester and amide) H NMR (DMSO-d6): δ = 0.92(t,3H,CH3), 3.96 (q,2H,CH2) ,2.05 (s,3H,CH3), 5.03 (s,1H,pyridine-H),7.48-7.82 (m, 8H,Ar-H + methine-H+NH) . Anal. Calcd for C26 H17 Cl4N3O4S (607): C, 51.40; H, 2.80; N, 6.91. Found: C, 51.56; H, 3.11; N, 6.31%.


J. Atoms and Molecules / 3(2); 2013 / 478–491 Ethyl-2-(2,4-dichlorophenylmethylidine)3,8-dioxo-9H-thiazolo[3,2-a]3-aza-[1,8] naphthyridine-10-carbrboxylate (8)and 6(methyl and / or 4-chlorophenyl) derivatives (7,9) respectively. A mixture of compound 3a (0.01 mol), and acid or acid derivative(0.01 mol) was refluxed for 6h, the solid product so formed on heating was collected and recrystallised from suitable solvent to give 8,7and 9 respectively. 7‫ ׃‬52% yield; brown powder (EtOH), m.p. 280-82 °C. IR (KBr): ν = 3259 (NH) and1693cm−1 (C=O thiazolidinone, ester and amide).1H NMR (DMSO-d6): δ = 0.98 (t, 3H,CH3),2.12 (s,3H,CH3) 4.03 (q,2H,CH2) , 5.58(s,1H,pyridine-H), 7.48-7.87 (m,8H ,ArH+ methine-H+NH).Anal. Calcd for C26H17Cl4N3O4S (607): C, 51.40; H, 2.80; N, 6.91. Found: C, 51.30; H, 3.21; N, 6.45%. 8‫ ׃‬73% yield; yellow powder (EtOH), m.p. 260-62 °C. IR (KBr): ν = 3421,3236 (NH2 and1689 cm−1 (C=O thiazolidinone, ester).1H NMR (DMSO-d6): δ = 0.95(t,3H,CH3), 4.03 (q,2H,CH2) , 5.08(s,1H,pyridine-H), 6.54(s,1H,NH), 7.36-7.86(m,7H,Ar-H+ pyrimi-dine-H ),8.85(s,1H, methine-H). Anal. Calcd for C25 H15Cl4N3O4S (593): C, 50.59; H, 2.52; N,7.08. Found: C, 60.22; H, 2.21; N, 7.71%. 9‫ ׃‬73% yield; yellow powder (EtOH), m.p. 272-74 °C. IR (KBr): ν = 3116 (NH) and 1658, cm−1 (C=O thiazolidinone, and ester).1H NMR (DMSO-d6): δ = 0.97 (t,3H,CH3), 4.00 (q,2H,CH2) , 5.59(s,1H,pyridine-H), 7.54-7.59 (m,11H,ArH+ methine-H), 8.41 (s,1H,NH). Anal. Calcd for C31H18 Cl5N3O4S (703): C, 52.91; H, 2.56; N, 5.97. Found: C, 52.22; H, 3.02; N, 5.51%. Ethyl-5-(2-N-(chloroethylimino)amino)-6cyano-2-(2,4-dichlorobenzylidene)-7-(2, 4 dichlorophenyl )-3-oxo-3,7-dihydro-2Hthiazolo[3,2-a]pyridine-8-carboxylate(10)


Hamdy Khamees et al A mixture of compound 3a (0.01 mol), chloroacetonitrile(0.01 mol) in ethanol (30 mL) catalyzed with piperidine was refluxed for 6h, the solid product so formed on heating was collected and recrystallised from suitable solvent to give 10. 10 ‫ ׃‬77% yield; brown powder (EtOH), m.p. 290-92 °C. IR (KBr): ν = 3124 (NH) , and 1701 cm−1 (C=O 2202(C≡N) thiazolidinone and ester) .MS: m/z = 641 (M+1); 0.40%), Anal. Calcd for C26H17Cl5N4O3S (640): C, 48.75; H, 2.65; N,8.75. Found: C, 48.35; H, 2.11; N, 8.32%. 4.8.Ethyl-6,8-diamino-7-cyano-2-(2,4dichlorophenylmethylidine)-9-(2,4dichlorop hen yl )-3-oxo-2,3,9-trihydrothiazolo[3,2-a][1,8]naphthyridine-10carboxylate(11) A mixture of compound 3a (0.01 mol), malononitrile (0.01 mol) in ethanol (30 mL) catalyzed with piperidine was refluxed for 6h, the solid product so formed on heating was collected and recrystallised from suitable solvent to give 11. 11‫ ׃‬68% yield; brown powder (EtOH), m.p. >300°C. IR (KBr): ν = 3332,3231 (NH2 ) 2187 (C≡N) and1698 cm−1 (C=O 1 thiazolidinone and ester). H NMR (DMSOd6): δ = 1.60 (t, 3H,CH3), 4.11 (q,2H,CH2) ,3.07(s,2H,NH2) 5.40(s,1H,pyridine-H), 7.427.95 (m, 9H,,Ar-H +methine-H+NH2). Anal. Calcd for C27 H17 Cl4N5O3S (631): C, 51.34; H, 2.69; N, 11.09. Found: C, 51.77; H, 3.02; N, 11.39%. Ethyl-6-cyano-2-(2,4dichlorophenylmethylidine)-7-(3,4dichlorophenyl)-5-(3-ethyl-thioureido)-3oxo-3,7-dihydro-2H-thiazolo[3,2a]pyridine-8-carboxylate(12) A mixture of compound 3a (0.01 mol),ethyl isothiocyanate (0.01 mol) in DMF (30 mL) containing 1gm of NaOH was stirred for 2h, www.jamonline.in 482

J. Atoms and Molecules / 3(2); 2013 / 478–491 the solid product so formed on heating was collected and recrystallised from suitable solvent to give 12. 12‫ ׃‬84% yield; brown powder (EtOH), m.p. 246-48°C. IR (KBr): ν =3217, (NH) 2202(C≡N) and 1670cm−1 (C=O 1 thiazolidinone and ester). H NMR (DMSOd6): δ = 0.95 ,1.02 (2t,6H,2CH3), 3.98,4.00 (2q,4H,2CH2) , 5.08(s,1H,pyridine-H),7.357.87 (m,9H ,Ar-H+ methine-H+2NH ). Anal. Calcd for C27H20Cl4N4O3S2 (652): C, 49.69; H, 3.06; N, 8.58. Found: C, 50.10; H, 3.13; N, 8.10%. Ethyl-3-(2,4-Ddchlorophenyl)-7-amino-8cyano-9-hydro-pyrazolo[3',4'-4,5] thiazolo [3, 2-a]pyridine-10-carboxylate (13a-c) A mixture of compound 3a (0.01 mol),hydrazine derivatives(0.01 mol) in ethanol (30 mL) was refluxed for 3h, the solid product so formed on heating was collected and recrystallised from suitable solvent to give 13a-c. 13a‫ ׃‬84% yield; yellow powder (EtOH), m.p. 248-286 °C. IR (KBr): ν =3412,3252, (NH2), 2204(C≡N) and1693cm−1 (C=O ester).1H NMR (DMSO-d6): δ = 0.84 (t,3H, CH3),4.00 (q,2H,CH2) , 4.81(s,1H,pyridine-H),), 3.92(br,1H,NH)7.29-8.16 (m,6H ,Ar-H). 8.26(s,2H,NH2). MS: m/z = (577 ; 0.52%) Anal. Calcd for C24 H15 Cl4 N5 O2 S (577) : C, 49.91; H, 2.59; N, 12.13. Found: C, 49.12; H, 3.13; N, 12.10%. 13b‫ ׃‬84% yield; brown powder (EtOH), m.p. 286-288 °C. IR (KBr): ν =3316,3127, (NH2), 2220 (C≡N) and 1716cm−1 (C=O ester).1H NMR (DMSO-d6): δ = 0.93 (t,3H,CH3),3.96 (q,2H,CH2) , 5.05(s,1H,pyridine-H),), 7.337.84 (m,13H ,Ar-H+ NH2 ). MS: m/z = (653; 0.64%) Anal. Calcd for C30H19Cl4N5O2S (653): C, 55.13; H, 2.90; N, 10.71. Found: C, 55.54; H, 3.16; N, 10.20%. 13c‫ ׃‬84% yield; brown powder (EtOH), m.p. 288-290 °C. IR (KBr): ν =3398,3290, (NH2), All rights reserved© 2011

Hamdy Khamees et al 2204(C≡N) and 1693cm−1 (C=O 1 thiazolidinone and ester ). HNMR (DMSOd6): δ = 0.95(t,3H, CH3),4.00 (q,2H,CH2) , 5.05(s,1H,pyridine-H),), 7.33-7.84 (m,12H ,Ar-H+ NH2).Anal. Calcd for C30H18Cl4N6O4S (698): C, 51.57; H, 2.57; N, 12.03. Found: C, 51.23; H, 2.51; N, 12.31%. RESULTS & DISCUSSION: Chemistry: The starting material 2-ethoxy carbonylethylene-4-thiazolidinone (1) was synthesized via cyclocondensation of thioglycollic acid with ethylcyanoacetate in refluxing ethanol in the presence of ammonium acetate [20]; Scheme 1. It was noted that compound 1 includes two active methylene groups, the first group is endocyclic and adjacent to the carbonyl group, while the second group is emanating at position-2 and adjacent to the endocyclic amino group. Thus, the reactivity of 1 towards some electrophiles was investigated. Thus, treatment of 1 with 2,4-dichlorobenzaldehyde in dioxane catalyzed with piperidine at reflux temperature yielded the ethyl-5(arylmethylene)-4-oxothi-azolidin-2-ylidene) acetate derivative (2). The infrared spectrum of 2 was characterized by appearance of NH stretching band at 3214 cm-1, in addition to stretching band at 1710 cm-1 attributed to the 4-thiazolidinone, its 1H NMR spectrum in DMSO-d6 revealed the presence of triplet signal at δ 0.94 ppm and quartet signal at δ 4.13 ppm corresponding to ethoxy carbonyl protons , a singlet signal for methine-H at δ 5.07 ppm, in addition to the presence of aromatic and NH protons. Cyclocondensation of ethyl-5-(arylmethylene)-4-oxothiazolidin2-ylidene) acetate derivative (2) with appropriate α-substituted cinnamonitriles at reflux temperature in ethanol having catalytic amounts of piperidine afforded the corresponding thiazolo[3,2-a] pyridines(3,4,5) a-e , respectively ; Scheme 1. www.jamonline.in 483


Hamdy Khamees et al

O C N

SH H 2C

C HO

O

CH 2 C

OC2H 5

Ethanol/ Am m.acetate

EtO 2C N

S

EtO2C

H

EtO2C

S

N

S

-H 2O OH

-H

, +H

NH O

O

O

(1)

H Dioxane/ Pip.

X

Ar 1 X

EtO2C S

3, X=CN 4, X=CONH2 5, X=CO2 Et

NH2

Ar 1

C H

C

CN

(3,4,5)

EtO2 C

a

NH

S

O

Ar a;Ar=C6 H3C l2-2,4,Ar 1=C6 H3C l2-2,4, b;Ar=C6 H3C l2-2,4,Ar 1=C6 H4C l-2, c;Ar=C 6H 3Cl 2-2,4,Ar 1=C 6H 4-C H3-4, d;Ar=C6 H3C l2-2,4,Ar 1=C6 H4N (CH3) 2-4 e;Ar=C6 H3C l2-2,4,Ar 1=C6 H5,

N

ArCHO

reflux 3hrs.

-H2O

O

Ar (2)

a-e Ar=C6H3Cl2-2,4

Scheme 1.Synthesis of thiaazolo[3,2-a] pyridines derivatives. (a) EtOH , Pip, reflux 3hrs. The composition and structure of the obtained compounds (3,4,5)a-e was proved by elemental analysis and from their infrared , 1H NMR, 13C NMR, and mass spectra. The infrared spectra of compounds (3 a-e) showed stretching bands for the( C≡N), group at ν 2184-2202 cm-1, in addition to NH2 and carbonyl stretching bands. 1H NMR spectrum (DMSO-d6) which exhibited the presence of triplet and quartet signals at at δ 0.95 , 4.00 ppm and singlet signal at δ 5.07 ppm corresponding to ethoxy carbonyl and 1 pyridine -4H fragments of 3a. Also, H NMR spectrum of compound 4c in DMSO-d6 revealed the presence of methyl and pyridine– 4H moieties besides aromatic and NH2, its mass spectrum exhibited a molecular ion peak at m/z 528(M-1; 2.46%) corresponding to the molecular formula C25H21N3 Cl2O4S, and a base peak was found in the spectrum at m/z 62. 13C NMR spectrum of 3d (DMSO-d6) revealed signals at δ 13.48, 40.37 , 60.96 , ,115.44,158.75 and 165.48 ppm attributed to ethoxy carbonyl ,two N- methyl , cyano and carbonyl carbon atoms. Also,13C NMR of 5c (DMSO-d6) revealed signals at δ13.48, 14.16, 22.68 , 59.11, 60.10 ,158.75 and 168.09 ppm attributed to methyl, two ethoxy-carbonyl, All rights reserved© 2011

and carbonyl carbon atoms. Reaction of 3a with acetic anhydride gave the corresponding N-acetyl amino thiazolo [3,2-a] pyridine (6) together with 1,8-napht-hyridine derivative (7) depending on the time of reflux. Elemental analyses and spectral data were in a complete agreement with the assigned structures. IR spectrum of 6 revealed the presence of absorption band at 2190 cm-1 due to C≡N group, where as IR spectrum of 7 showed disappearance of nitrile stretching absorption band.. Also, treatment of 3a with HCO2H and / or p-chlorobenzoyl chloride gave the corresponding naphthyridine derivatives (8,9) . IR spectrum of 8 showed disappearance of absorption band in the region 2000-2200 cm-1 for C≡N group. Its1H NMR spectrum showed signals at δ 0.95, 4.03, and 5.08 ppm due to ethyl and pyridine4H protons , respectively, in addition to aromatic and pyrimidine protons in the region 7.36-7.81 ppm .Also, 1H NMR data for 9, in DMSO-d6 exhibited a strong significant signals, three protons triplet and two protons quartet at δ 0.97, 4.00 ppm for ethyl protons, one proton singlet for pyridine-4H at δ 5.59 ppm, in addition to aromatic , methine and NH protons ;Scheme 2. www.jamonline.in 484


Hamdy Khamees et al

Ar1

O

N

N

EtO 2C

NH

S

O

Ar (8)

Ar1 CN O

EtO 2C

Ref flux 3 hrs.

reflux 6hr

a

EtO2 C

N

S

(3a)

CH3

NH2

N

N Cl

O

Ar

O

Ar

Refflux 3 hrs.

NH N

N

S

b

Ar 1 O

NH

CN

EtO2 C

(6)

S

Ar 1 O EtO2C

Ar 1

O

Ar

HCOOH

CH 3

N H

N

S

(9)

Ar=Ar 1=C6 H 3Cl2 -2,4

O

Ar (7)

Scheme 2.Synthesis of thiazolo[3,2-a] pyridine(6) and thiazolo[3,2-a] 1,8- naphthyridine (79)derivatives. (a) Acetic anhydride ;(b) p-chloro benzoyl chloride , benzene ,reflux 6hrs. concerted cyclic addition takes place to furnish thiazolo[3,2-a]-1,8-naphthyridine (11)derivative ;Scheme 3. IR Spectrum of 10 revealed presence of stretching absorption band at ν 2202 cm-1 for C≡N Also, the mass spectra revealed in each case a molecular ion peak which is consistent with the assigned structure ;Scheme 3.

The present work was extended to investigate the behavior of chloroacetonitrile and / or malononitrile towards 3a in presence of refluxing ethanol piperidine solution, Thus, in case of chloroacetonitrile the product was proved as amidine derivatives (10) through the addition of of NH2 group of 3a to the nitrile moiety , but in case of malononitrile Cl

Cl

Cl

Cl

S

NH

Cl C N

EtO2 C N O

Cl

NH 2

CN H

EtO2C

H 2C CN C N

S

a

N

N H

NH

O

Cl

(3a) Cl proton shif t

Cl b

Cl

EtOH/Pip.

Cl CN Ref lux 6hrs.

EtO 2C

NH2

Cl S

N

N C CH2Cl H NH

O

Cl Cl

(10)

CN

EtO2C S

N

N

NH2

O

Cl Cl

(11)

Scheme 3.Reaction of thiazolo[3,2-a] pyridine 3a with malononitrile and or chloro acetonitrile. (a) EtOH, Pip, reflux 6hrs; (b)ClCH2CN, EtOH, Pip, reflux 6hrs All rights reserved© 2011



Hamdy Khamees et al

Stirring of 3a with ethyl isothiocyanate , at room temperature in presence of DMF/ NaOH mixture gave the corresponding thiourea derivative ( 12); Scheme 4. Structure of 12 was based on its analytical and spectral data. IR spectrum of 12 showed presence of absorption band at ν 2202 cm-1 corresponding to C≡N, its 1H NMR spectrum showed two signals triplet at δ = 0.95,1.35 , and two signals quartet at δ = 3.98,4.00 ppm

for two ethyl groups and pyridine –4H singlet signal at δ = 5.08 ppm beside the other expected signals. Treatment of 3a with hydrazines (binucleophile) in absolute ethanol under reflux afforded the corresponding [3,4: 4,5] thiazolo [3,2-a] pyridine derivatives (13a-c) ;Scheme 4.Elemental and spectral data are in good agreement with assigned structure.

Cl

Cl CN

EtO 2C

a

O

Cl

Cl

Cl

(12) Cl

Cl CN

EtO 2C

NH 2

N

S

N C NHC 2H5 H S

N

S

Cl CN

EtO2C

O

Cl

NH 2

N

S

(3a)

b

Cl

N

Cl

y

N Cl

a ,Y=H b ,Y=ph c ,Y=C6H4NO2-4

(13 a-c)

Scheme 4. Reaction of 3a with ethylisothiocynate and hydrazine derivatives. (a) C2H5NCS , DMF, NaOH, Stirring 2hrs ; (b) NH2NH Y,EtOH, reflux 3hrs

The mechanism of this reaction started by intramolecular cyclocondensation with α,β- unsaturated carbonyl system of 3a followed by oxidation to give 13a-c.

Cl

Cl

Cl X

EtO 2C S

N

Y

O Cl H2N


NHY

Cl CN

EtO 2C proton shift

S H

Cl

Cl

EtO 2C NH2

N OH N Y

Cl

N H H Cl

Cl CN

1 2

-H2O -H2

N

S

NH2

N Y

Cl

N Cl (13a-c)


J. Atoms and Molecules / 3(2); 2013 / 478–491 IR spectrum of compounds 13a-c indicated that appearance of stretching absorption bands of NH2 and C≡N functional groups. The molecular ion peak of 13a was found in the mass spectrum at m/z (577 ,0.52 %) corresponding to the molecular formula C24H15Cl4N5O2S. .1H NMR spectrum DMSOd6 which exhibited the presence of three signals at δ 0.95,4.00 and 5.05 ppm corresponding to the ethoxycarbonyl and pyridine fragments, respectively for 13c .

Hamdy Khamees et al Table1: Cytotoxicity Assay in Vitro for the synthesized compounds. Compounds

IC50(μmol/L)

Compound 2

0.0408

Compound 3a

7.528

Compound 3d

1.3474

Compound 4a

7.3631

Compound 4d

0.1362

1.Cytotoxicity assay in vitro:

Compound 5a

0.2695

The cytotoxicity of the drugs will be tested against human liver cancer cell line (HepG2) by SRB assay as described by Skehan et al [21]. Exponentially growing cells will be collected using 0.25% Trypsin-EDTA and plated in 96-well plates at 1000-2000 cells/well. Cells will be exposed to the drugs for 72 hrs and subsequently fixed with TCA (10%) for 1 h at 4 ºC. After several washings, cells will be exposed to 0.4% SRB solution for 10 min in dark place and subsequently washed with 1% glacial acetic acid. After drying overnight, Tris-HCl will be used to dissolve the SRB-stained cells and color intensity will be measured at 492 nm and 630 nm (for the reference wavelength) with the enzymelinked immunosorbent assay (ELISA) reader. All of the target synthesized compounds were tested twice in each of the cell lines. The results expressed as IC50 (inhibitory concentration of 50%) were the averages of two determinations and were calculated by using igmoidal concentration– response curve fitting models (SigmaPlot software). Table1.

Compound 5d

12.294

Compound 8

0.6081

Compound 9

5.7345

Compound 12

3.1256

Biological evaluation :


This study revealed that ethyl-5(arylmethylene)-4-oxothiazolidin-2-ylidene) acetate (2) derivative is the most potent( IC50(μmol/L) 0.0408 ). Thiazolo[3,2-a] pyridines ( 3a,3d,4a, 5d and 12) were found to possess moderate activity IC50(μmol/L 1.374-12.2941 while 5a and 4d with ethoxycarbonyl and amide groups having high IC50(μmol/L) 0.2695 and 0.1362 ,respectively. The synthesized compound 5d, is the least potent one with (IC50(μmol/L) 12.2941) . Thaizolo[3,2-a][1,8] naphthyridine (8) showed high anticancer activity IC50(μmol/L) 0.6081and 6-(4-chlorophenyl) derivative ( 9) showed moderate activity IC50(μmol/L) 5.7345 2.Tail-flick test Antinociceptive responses were determined using the tail-flick test (D’Amour and Smith, 1941)[22]. To measure the latency of the tailflick response, rats were gently held with the tail put on the apparatus (Ugo Basile, USA) for radiant heat stimuli. The tail flick response www.jamonline.in 487

J. Atoms and Molecules / 3(2); 2013 / 478–491 was elicited by applying radiant heat to the dorsal surface of the rat-tail. The time in seconds, from initial heat source activation until tail withdrawal was recorded. The mean

Hamdy Khamees et al of two measures was used for each experimental animal as the tail withdrawal latency. In order to avoid excessive suffering of animals, a cut-off was set at 30 s. Table 2.

Table2.Analgesic effect; Tail withdrawal latency (seconds) Time

0 min

30 min

60 min

90 min

Control

3.640±0.444

3.760± 0.280

4.320±0.505

Indomethacin

3.720±0.773

7.760± 0.625*

9.420±0.879* 10.88±0.924*

Compound 2

4.200±0.374

7.180± 1.181*

9.240±0.778* 10.90±0.689*

Compound 3a

4.200±0.522

4.450± 0.259

5.875±0.398

6.925±0.349

Compound 3d

3.725±0.359

5.150± 0.533

6.450±0.263

7.750±1.109

Compound 4a

3.800±0.374

6.000± 0.316

9.460±0.657* 11.00±1.140*

Compound 4d

4.375±0.898

5.200± 0.200

8.960±0.470* 11.25±0.853*

Compound 5a

3.250±0.629

4.643± 0.152

6.000±1.291

Compound 5d

4.080±0.699

7.480± 0.214*

8.800±1.056* 10.90±2.052*

Compound 8

2.800±0.871

4.375± 0.154

5.625±0.325

Compound 9

3.750±0.478

7.720± 0.455*

8.500±0.673* 9.750±0.365*

Compound 12

4.400±0.955

4.200± 0.705

5.280±0.568

5.340±0.847

5.925±0.123

5.600±1.065

7.280±0.865

- Values are expressed as means ± SEM (n = 6). * Significantly different from control group at P < 0.05. Statistical analysis was done using one way ANOVA followed Tukey for multiple comparison test. Tail withdrawal latency (seconds)

Most of the synthesized compounds 4thiazolidinone and thiazolo[3,2-a] pyridine derivatives2, 3a 3d, ,4a, 4d , 5a ,5d, and 12 showed high analgesic activity , except thiazolo[3,2-a] naphthyridine (8 ) derivative showed the lowest activity . Analgesic activity of this compound can be increased by introduction of p-chlorophenyl moiety at 6position in naphthyridine ring , thereby leading to the highly active compound 9 All rights reserved© 2011

3. Carrageenan- induced rat paw edema The method developed by Winter et al. 1962[23], was employed. Albino wistar rats of either sex (130- 150 g) were divided into various groups of six animals each. Animals were deprived of food for 12 h prior to experiment and only water was given adlibitum. First group was used as a control group and received 1 ml of 20% v/v DMSO www.jamonline.in 488

J. Atoms and Molecules / 3(2); 2013 / 478–491 solution; The second group received indomethacin orally (10 mg/kg) dissolved in 20% v/v DMSO solution. Other groups received DMSO solution of test compounds at a dose of 100 mg/kg orally. One hour after the administration of the tested compounds, carrageenan suspension (0.1 ml of 1% w/v suspension in 0.9% saline solution) was injected into the sub planter region of left hind paw of animals. Immediately, the paw volume was measured initial paw volume using plethysmometer (UGO Basile 21025 Comerio, Italy) before carrageenan injection. Thereafter, the paw volume was measured after 1, 2, 3 and 4 h after carrageenan administration. The difference between initial

Hamdy Khamees et al and subsequent readings gave the change in edema volume for the corresponding time table 3. Edema volume of control (Vc) and volume of treated (Vt) were used to calculate percentage (%) inhibition and (%) edema volume by using following formula: % Inhibition = [1- (Vt/Vc)] × 100 % Edema volume = 100 × (Edema volume after drug treatment/Initial volume) Statistical analysis: Values were expressed as means ± S.E. Comparisons between means were carried out using one way ANOVA followed by Tukey multiple comparisons test.

Table 3.Carragenan induced rat paw edema % Time(h)

1st

2nd

3rd

4th

Control

117 ± 9

137 ± 12

152 ± 12

132 ± 14

Indomethacin

49 ± 4

36.8 ± 4

19.5 ± 2.9

7.2 ±0 .1

Compound 2

52 ± 10

67 ± 11

46 ± 14

32±13

Compound 3a

52± 9

40 ± 5

23 ± 6

16± 4

Compound 3d

61 ± 6

70 ± 7

50 ± 7

39 ± 5

Compound 4a

38.7 ± 3.9

47.9 ± 2.7

29.1 ± 3.0

18.1 ± 1.8

Compound 4d

38 ± 3.6

30 ± 1.6

23 ± 1.5

19± 1.9

Compound 5a

64± 5

45± 4

20 ± 2

11 ± 1

Compound 5d

48 ± 12

44 ± 7

31 ± 6

15 ± 4

Compound 8

40 ± 10

47 ± 12

34 ± 9

15 ± 7

Compound 9

44±4

34±4

19±3

10±4

Compound 12

64±4

50±4

34±4

12±2

- Values are expressed as means ± SEM (n = 6). * Significantly different from control group at P < 0.05. ª Significantly different from indomethacin group at P < 0.05. Statistical analysis was done using one way ANOVA followed Tukey for multiple comparisons respectively. All rights reserved© 2011


J. Atoms and Molecules / 3(2); 2013 / 478–491 Paw edema was induced by sub plantar injection of 100 µl of 1% sterile carrageenan in saline into the right hind paw of the rats. One hour before induction of edema. Saline was administrated in one group of animals orally and the group served as control. Indomethacin (10 mg/kg) was administrated in second group of animals and served as reference drug. All tested compounds (2, 3a ,3d, ,4a, 4d 5a 5d, 8, 9 and12) were administrated orally in others groups in dose of 100 mg /kg . The right hind paw volume was measured immediately before carrageenan injection and at selected times (1, 2, 3 and 4 hours) thereafter by water displacement plethysmometer. All the drugs were administrated one hour before carrageenan injection. Carrageenin-induced edema is a nonspecific inflammation resulting from a complex of diverse mediators (Shen, 1981)[24]. Since edemas of this type are highly sensitive to non steroidal anti-inflammatory drugs (NSAIDs), carrageenin has been accepted as a useful agent for studying new anti-inflammatory drugs (Winter et al. 1962). This model reliably predicts anti-inflammatory efficacy of the NSAIDs, and during the second phase it detects compounds which are antiinflammatory agents as a result of inhibition of prostaglandin amplification. Most of the tested compounds were more potent than indomethacin . Thiazolo[3,2-a] pyridine (3d ) derivatives the most potent compound, the second more potent is 4-thiazolidinone (2). Thiazolo[3,2-a][1,8] naphthyridines(8,and 9) are more potent than the others thiazaolo[3,2-a] pyridines 3a,4a,5d,4d,and 5a .


Hamdy Khamees et al CONCLUSION The research study reports the successful synthesis and biological evaluation of new thiazolo[3,2-a] pyridine and thiazolo[3,2-a] [1,8] naphthyridine derivatives. The biological evaluation study revealed that all the tested compounds showed moderate to good activity towards anticancer, analgesic , and anti-inflammatory . REFERENCES: 1)

Naeem .M , Chaudhary .M.N , Baloch .F.H , Amjad .R, J.chem.soc.pak, (2009), 31(4) ,633. 2) Sharma .M.C, Shahu .N.K , Kohli .D.V, Chaturvedi .S.C , Sharma .S .Osar ,Digest journal of Nanomaterials and Bio structures, (2009),4( 1),223. 3) Patel .R.B, Desai .P.S, Desai .K.R , Chikhalia .K.H ., Indian journal of chemistry, (2006),45B ,773. 4) Turgut .Z , Yolacan .C, Aydogan .F, Bagdatli . E , Ocal N. Molecules, (2007) ,12 2151. 5) Bouzroura S , Bentarzi . Y, Kaoua . R , Kolli. B. N , Martini S.P. E, Org. Commun ,(2010),3(1) 8. 6) Mistry .K.M, Desai. K.R , E-journal of chemistry, (2004),(4), 189. 7) Shah .N , Pant .P.C , Joshi .P.C, Asian J. chem., (1993), 95,83. 8) Ramalakshmi .N, Aruloly .L , Arunkumar .S , Ilango .K, Puratchikody .A. Malaysian journal of science, (2009),28(2)197. 9) Patel .N.B , Patel .V.N, Iranian journal of pharmaceutical research, (2007),6(4), 251. 10) Vigorita .M.G, Ottana .R, Monforte .F, Trovato. R .M, Monforte. M.T, Taviang .M.F , Biorg Med.Chem.Lett, (2001), 11,2791. 11) El-HagAli .G.A.M. Part 3, Phosphorus, Sulfur and Silicon (2003),178 (4),711720. www.jamonline.in 490

J. Atoms and Molecules / 3(2); 2013 / 478–491 12) El-HagAli .G.A.M, Khalil .A, Ahmed .A.H.A, El-Gaby .M.S.A., Acta. Chim. Slov, (2002),49 ,365. 13) Azab.M.E, El-HagAli .G.A.M, Abd ElWahab. A.H.F. ,Acta. Pharm.( 2003),53 ,213. 14) A.A. El-Maghraby, G.A.M. El-Hag Ali, A.H.A. Ahmed, M.S.A. El-Gaby. ,Phosphorus, Sulfur and Silicon (2002),177 (2), 293. 15) M.S.A. El-Gaby, M.M. Khafagy, G.A.M. El-Hag Ali, H.A. Eyada, A.A. El-Maghraby, M.H. Helal, Phosphorus, Sulfur and Silicon,(2003), 178 (8), 1681. 16) A.Khalil1, S.I. Mohamed, H.A.Eyada, T.A. abdel Alaziz and G. A. M. El-Hag, Journal of Materials Science and Engineering A 1, (2011) , 228. 17) M. S.A. El-Gaby , G. A.M. El-Hag Ali ,A. A. El-Maghraby , M.T. Abd ElRahman , M.H.M. Helal. European Journal of Medicinal Chemistry,(2009),44 4148.


Hamdy Khamees et al 18) A.A. Farag1, A..Khalil, Sh. Ibrahim Mohamed, A. A. El-Henaway, G. Ahamed Mohamed El-Hag Ali and Y.A Ammar, Journal of Materials Science and Engineering A, (2012),2 (2), 220. 19) G.A.M. El-Hag Ali, M.T. Abd ElRahman, M.H.M. Helal, M.S.A. ElGaby,Phosphorus, Sulfur and Silicon, . (2008), 183, 3023. 20) K.U. Sadek, E.A. Hafez, A.E. Mourad, M.H. Elnagdy., Z. Naturforsch, (1984) ,39B, 824. 21) Skehan .P , Storeng .R , Scudiero .D , Monks. A, Mahon .M.C, Vistica .D , Warren .J.T , Bokesch .H, Kenney .S , Boydjn. M. R., J Natl Cancer Inst, (1990) ,82 ( 13),1107. 22) Amour D. F.E, Smith. D.L, J. Pharmacol. Exp. Ther, (1941),72,74. 23) Winter .C .A , Risely .E.A , Nuss .G. W., Proc. Soc. Expt. Bio. Med, (1962), 1,544 24) T. J .Shen, John Willey & Sons, New York, NY, USA, 4th edition,(1981),1205.
