Synthesis of Potential Antimicrobial/Antitubercular s-triazine Scaffolds Endowed with Quinoline and Quinazoline Heterocycles

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1 Rahul V. Patel et al : Synthesis of Potential Antimicrobial/Antitubercular s-triazine Scaffolds Endowed with Quinoline and 733 International Journal of Drug Design and Discovery Volume 3 Issue 1 January March Synthesis of Potential Antimicrobial/Antitubercular s-triazine Scaffolds Endowed with Quinoline and Quinazoline Heterocycles Rahul V. Patel a, Premlata kumari 1, Dhanji P. Rajani 2, Kishor H. Chikhalia 3* 1 Applied Chemistry Department, S.V. ational Institute of Technology, Surat , India. 2 Microcare Laboratory, Surat , India. 3 School of Science, Department of Chemistry, Gujarat University, Ahmedabad , India. ABSTRACT: Two series of 2 (4 cyanophenyl amino) 4 quinoline (quinazoline) 4 yloxy 6 piperazinyl (piperidinyl) 1,3,5 triazines were synthesized so as to investigate their antimicrobial and antitubercular action. ewer analogues were characterized by IR, 1 H MR spectroscopy and elemental analyses. Pharmacological screening against eight bacteria (S. aureus, B. cereus, E. coli, P. aeruginosa, K. pneumoniae, S. typhi, P. vulgaris, S. flexneria), four fungi (A. niger, A. fumigatus, A. clavatus, C. albicans) and Mycobacterium tuberculosis H37Rv was examined and the effects of various substituents on biological profiles (MIC, µg/ml) of final analogues were investigated. Some of the final analogues displayed good antimycobacterial activity (MIC, 12.5 µg/ml). KEYWORDS: s-triazine; quinoline, quinazoline; antimicrobial activity; antituberculosis activity. Introduction Since last 10 years it has been observed that the evolution and spread of multidrug resistant microorganisms is of grave concern to global health care. These organisms possessed the ability to withstand attack by antimicrobial drugs currently available, and the uncontrolled rise in resistant pathogens threatens lives. Such infections most commonly affect immunocompromised individuals, patients with malignancies and transplant recipients 1. A potential approach to overcome the resistance problem is to design innovative agents with a different mode of action so that no cross-resistance with the present therapeuticals can occur. According to the World Health Organization (WHO), there were 9.4 million new TB cases (including 3.3 million women) in Moreover, the development of drug-resistant strains of mycobacterium species, has contributed to the inefficiency of the conventional antituberculosis therapy, thus, it is still necessary to search for new antimycobacterial agents. When a patient develops bacterial resistant to the first-line drugs: isoniazid, rifampicin, ethambutol and pyrazinamide 3, problems in the chemotherapy of tuberculosis arise, which seriously threatens the progress in antituberculosis medical care. * For correspondence: Kishor H. Chikhalia, Tel: chikhalia_kh@yahoo.com Consequently, identifying and developing novel drug entities is apparent in light of the significant problems associated with current drugs. The design of inhibitors that can accommodate potency to multiple biological targets remains an intriguing scientific endeavour. 1,3,5-Triazine nucleus have attracted a great deal of attention among chemists due to its diverse biological activities such as antimicrobial 4,5, antiprotozoal 6, anticancer 7, antimalarial 8 and antiviral 9 activity. Profound medicinal applications associated with piperazine heterocycle render them as useful structural units in drug research while the piperazine-quinoline combination is found in the structure of many well known antimicrobial drugs like ciprofloxacin, norfloxacin, ofloxacin, pefloxacin, rufloxacin, enrofloxacin etc. In our previous study, we have introduced various piperazine and piperidine derivatives to the s-triazine core and indentified the compounds with good antibacterial activity, in an order to expand the structure activity relationship we carried out this research work aiming to the discovery of the similar type of scaffolds with selective piperazine bases, that were activity in the previous research work 15,16. Prompted by these observations it was contemplated to envisage the combination of above mentioned biolabile components of significant activities in a compact system to identify new candidates that may be value in designing new biologically active agents. 739

2 740 International Journal of Drug Design and Discovery Volume 3 Issue 1 January March 2012 Results and Discussion Chemistry The triazines described were synthesized starting from cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) and different nucleophiles (Scheme 1). The nucleophiles can selectively displace the different chlorines by control of the reaction temperature 17. In general, the first chlorine can be displaced when the temperature is maintained at 0 C, the second between 25 o C-50 C, and the third substitution at above 60 C and due to reactivity the temperature can exceed 80 C. Another important factor that has to be considered for the preparation of the different derivatives is the nature of the reactive group and the order of entry of the group. ext, different amino/phenoxy groups were introduced, a compound with strong nucleophile (OH) was introduced after the substitution of compound with weak nucleophile (-H 2 ) at the first chlorine atom. In addition, a wide range of cyclic amines were introduced to the third reactive chlorine atom because of the ease of reaction condition carried at reflux temperature. C THF, Et 3 H H 2 O-5 C C 2,4,6-Trichloro-1,3,5-triazine 4-Amino-benzonitrile 4-(4,6-dichloro-1,3,5-triazin-2-ylamino)benzonitrile 1 1 OH X THF, ah R.T - 50 C X O H C X=H: 4-Hydroxyquinoline (2a) X=: 4-Hydroxyquinazoline (2b) X=H: 4-Hydroxyquinoline (3a) X=: 4-Hydroxyquinazoline (3b) 3a, 3b 4a-j 1,4-Dioxane K 2 CO 3 Reflux X O R H X=H: 4-Hydroxyquinoline (5a-j) C X=: 4-Hydroxyquinazoline (6a-j) R=

3 Rahul V. Patel et al : Synthesis of Potential Antimicrobial/Antitubercular s-triazine Scaffolds Endowed with Quinoline and 741 CH 3 4a H 4d H 4g H F CH 3 CF 3 4h H 4b H 4e H CH H 3 CO OCH 3 4i H CH 2 OCH 3 4c H C O CH 3 4f H F 4j H OCH 3 Scheme 1 Synthesis of target compounds. Hence, in the present study the first step comprises formation of intermediate 1 in very good yield by the nucleophilic displacement of one chlorine atom of s- triazine ring by 4-amino-benzonitrile. Compound 1 displayed an absorption band at 2223 cm -1 confirming the presence of a C group, and a strong band near 3288 cm -1 further confirmed the presence of an -H group. The synthesis of disubstituted s-triazine intermediates (3a, 3b) was achieved in 80-85% of yield by the reaction between (1) and 4-hydroxyquinoline (2a) or 4-Hydroxy quinazoline (2b) in the presence of 60% ah at C. A characteristic band appeared at 1251 cm -1 and 1256 cm -1 corresponded to the C-O-C linkage in the FT-IR spectra of compound 3. Subsequent coupling of the so formed compound 3 with the desired cyclic amines under basic conditions in 1,4-dioxane solvent at C formed the corresponding 5a-j and 6a-j 18 and this reaction proceeded in good yields. The correct synthesis of 5a-j and 6a-j was confirmed on the basis of IR and 1 H MR spectral analysis, and the purity was ascertained by elemental analysis. Biological activity Investigation on antimicrobial screening data (Table 1 and 2) showed some of the compounds showed excellent activity against all the mentioned microorganisms. From the bioassay it can be stated that the final analogues with the substitutions of 4-hydroxyquinazoline demonstrated improved efficacy as compared to analogues bearing 4- hydroxyquinoline. Both the type of scaffolds displayed inhibitory efficacy in a good range of MIC as well as inhibition zones. All the newer analogues showed µg/ml of MIC against bacteria, µg/ml against fungi 12.5 µg/ml of lowest MIC against mycobcatria. From these results, it was also possible to make a number of correlations regarding the relationship between the structure of the newer scaffolds and their antimicrobial activities as: (i) Analogues with 4-hydroxyquinoline substituent and cyclic amines bearing electron withdrawing halogen atom(s) were effective against K. pneuminiae and S. flexneria, with electron donating alkoxy functionality showed inhibition towards A. niger, where as analogues with methyl substituent displayed activity against E. coli. (ii) Analogues with 4-hydroxyquinazoline substituent and cyclic amines bearing electron withdrawing halogen atom(s) demonstrated activity against S. typhi bacteria and A. fumigatus fungi, with electron donating alkoxy functionality displayed inhibitory action against S. aureus, P. vulgaris bacteria and C. albicans fungi, while analogues with methyl substituent were effective against P. aeruginosa. (iii) ewer analogues with both the type of, 4- hydroxyquinoline and 4-hydroxyquinazoline moieties were mixdly active against B. cereus bacteria, A. clavatus fungi as well as against mytcobacteria H37Rv.

4 742 International Journal of Drug Design and Discovery Volume 3 Issue 1 January March 2012 Compound Table 1 In vitro antibacterial activity of compounds 5a-6j. Zone of inhibition [mm (MIC in µg/ml)] Gram (+) Gram (-) S.a B.c E.c P.a K.p S.t P.v S.f 5a 16 (100) 17 (100) <10 (100) 13 (100) 23 (25) 15 (100) 13 (100) 14 (100) 5b 18 (100) 18 (100) 16 (100) 14 (100) 19 (100) 18 (100) 14 (100) 15 (100) 5c 17 (100) 19 (50) 24 (25) 20 (50) 15 (100) 13 (100) 19 (100) 14 (100) 5d 21 (25) 22 (12.5) 20 (100) 22 (25) 15 (100) 17 (100) 16 (100) 13 (100) 5e 17 (100) 17 (100) 17 (100) 15 (100) 22 (50) 22 (50) 15 (100) 11 (100) 5f 19 (50) 19 (100) 16 (100) 13 (100) 23 (25) 20 (100) 15 (100) 18 (100) 5g 15 (100) 22 (12.5) 17 (100) 16 (100) 21 (50) 23 (50) 15 (100) 17 (100) 5h 22 (25) 21 (25) 20 (50) 17 (100) 19 (100) 20 (100) 16 (100) 24 (25) 5i 25 (12.5) 20 (50) 21 (50) 20 (50) 15 (100) 14 (100) 22 (50) 14 (100) 5j 20 (50) 18 (100) 21 (50) 17 (100) 13 (100) 15 (100) 20 (100) 17 (100) 6a 14 (100) 16 (100) 12 (100) 14 (100) 22 (50) 14 (100) 11 (100) 13 (100) 6b 20 (50) 19 (50) 18 (100) 13 (100) 17 (100) 21 (50) 13 (100) 12 (100) 6c 16 (100) 20 (25) 23 (50) 21 (25) 17 (100) 17 (100) 20 (100) 16 (100) 6d 22 (25) 22 (12.5) 22 (50) 23 (12.5) 14 (100) 15 (100) 19 (100) 14 (100) 6e 19 (50) 18 (100) 19 (100) 14 (100) 21 (50) 24 (25) 17 (100) 14 (100) 6f 20 (50) 20 (50) 15 (100) 17 (100) 22 (50) 19 (100) 17 (100) 19 (100) 6g 17 (100) 21 (25) 18 (100) 15 (100) 20 (50) 24 (25) 15 (100) 19 (100) 6h 24 (12.5) 22 (12.5) 21 (50) 18 (100) 19 (100) 22 (50) 18 (100) 23 (50) 6i 25 (6.25) 20 (50) 22 (50) 21 (50) 16 (100) 16 (100) 23 (25) 16 (100) 6j 21 (25) 20 (50) 20 (100) 19 (100) 15 (100) 15 (100) 21 (50) 17 (100) Ciprofloxacin 30 (1.56) 31 (0.39) 32 (1.56) 33 (0.78) 33 (0.78) 30 (0.39) 31 (0.39) 32 (1.56) DMSO Table 2 In vitro antifungal and antitubercular activity of compounds 5a-6j. Compound Antifungal activity Zone of inhibition [mm (MIC in µg/ml)] Antituberculosis activity MIC (µg/ml) A.n A.f A.c C.a H37Rv % Inhibition 5a 13 (100) 17 (100) 16 (100) 12 (100) b 15 (100) 19 (100) 18 (100) 11 (100) c 18 (100) 13 (100) 12 (100) 18 (100) d 17 (100) 12 (100) 15 (100) 19 (50) e 16 (100) 16 (100) 22 (50) 15 (100) f 17 (100) 17 (100) 19 (100) 12 (100) g 17 (100) 18 (100) 20 (100) 14 (100) h 19 (100) 19 (100) 22 (50) 15 (100) i 22 (25) 13 (100) 20 (100) 20 (50) j 20 (100) 11 (100) 19 (100) 18 (50) a 15 (100) 17 (100) 16 (100) 14 (100) Table 2 Contd

5 Rahul V. Patel et al : Synthesis of Potential Antimicrobial/Antitubercular s-triazine Scaffolds Endowed with Quinoline and 743 Compound Antifungal activity Zone of inhibition [mm (MIC in µg/ml)] Antituberculosis activity MIC (µg/ml) % Inhibition 6b 15 (100) 21 (50) 17 (100) 15 (100) c 19 (100) 15 (100) 11 (100) 18 (100) d 18 (100) 14 (100) 22 (50) 20 (50) e 13 (100) 16 (100) 20 (100) 16 (100) f 16 (100) 18 (100) 18 (100) 14 (100) g 17 (100) 18 (100) 19 (100) 17 (100) h 19 (100) 21 (50) 22 (50) 18 (100) i 21 (50) 15 (100) 19 (100) 21 (25) j 19 (100) 16 (100) 22 (50) 20 (50) Kitaconazole 30 (1.56) 29 (0.78) 31 (0.78) 33 (1.56) - - Pyrazinamide DMSO Conclusions Two series of 4-hydroxyquinoline and 4- hydroxyquinazoline based s-triazinyl piperazines were synthesized and screened against wide range of pathogenic bacteria, fungi and mycobacteria. The bioassay results demonstrated that some analogues were potential active against all the microorganisms at MICs µg/ml. Analogues with 4-hydroxyquinazoline constituent displayed improved activity and can be highlighted as new active leads that provide a powerful incentive for further research in this area. Overall, The MIC values of these novel compounds evidenced that the presence of halogen atom(s) and alkyl or alkoxy substituent gave rise to a better pharmacological potency, whereas from the present bioassay the activity of the final analogues lies in the order antitubercular>antibacterial>antifungal. Moreover, we believe that findings of the present study will have a good impact on medicinal chemists to synthesize similar compounds which will probably indicate greater biological potency. Experimental Section Melting points were determined in open capillaries on a Veego electronic apparatus VMP D and are uncorrected. IR spectra of synthesized compounds were recorded on a Shimadzu 8400 S FT IR spectrophotometer using KBr pellets. Thin layer chromatography was performed on object glass slides (2 x 7.5 cm) coated with silica gel G and spots were visualized under UV irradiation. 1 H MR spectra were recorded on a Varian 400 MHz model spectrometer. Elemental analyses (C, H, ) were performed using a Heraeus Carlo Erba 1180 CH analyzer (Hanau, Germany). 4 [4,6 Dichloro 1,3,5 triazin 2 ylamino] benzonitrile (1) To a stirred solution of 2,4,6 trichloro 1,3,5 triazine (10 g, mole) in anhydrous THF (150 ml) 4 amino benzonitrile (6.41 g, mole) was drop wise added at 0 o C-5 C. The resulting reaction mixture was stirred at this temperature for 2 hours. Then triethyl amine (5.48 g, mole) was added and stirring was continued for another 2 hours. The reaction mixture was then treated with crushed ice, followed by neutralization with dilute H, and filtered, dried, and recrystallized from acetone to afford 1. Light Yellow solid, yield: 88%, melting point 248 o C-250 C (dec.); IR: 2223 (C ), 3288 ( H). 4 [4 Chloro 6 (quinoline 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (3a) and 4 [4 Chloro 6 (quinazolin 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (3b) To a stirred solution of 4 hydroxyquinoline or 4 hydroxyquinazoline (8 g, mole) in anhydrous THF (150 ml) 60% ah (1.32 g, mole) was added at room temperature during 1 h and 1 (14.63 g for 4- hydroxyquinoline and g for 4-hydroxyquinazoline, mole) was then added to the mixture. Stirring was continued for another 20 hours at 45 C. Progress of the reaction was monitored by TLC using toluene: acetone (95:5 v/v) as eluent. The mixture was treated with crushed ice, filtered and dried to afford 3a or 3b. (3a): Yellowish brown solids, yield: 84%, melting point 275 o C-277 C; IR: 2222 (C ), 1251 (C O C). (3b) Yellow Solid, Yield: 81%, melting point 249 o C- 251 C; IR: 2224 (C ), 1256 (C O C).

6 744 International Journal of Drug Design and Discovery Volume 3 Issue 1 January March 2012 General procedure for preparation of compounds 5a-j and 6a-j To a solution of 3a or 3b (0.01 mole) in 1,4 dioxane (30 ml), the respective substituted piperazine or piperidine derivative was added and the reaction mixture was refluxed for hours. Potassium carbonate (0.01 mole) was used for neutralization of the reaction mixture. Progress of the reaction was monitored by TLC using toluene: acetone (97:3 v/v) as eluent. The mixture was then treated with crushed ice and neutralized by dilute H. The precipitate thus obtained was filtered off, dried and recrystallized from THF to afford the desired compounds 5a-j and 6a-j. Characterization of compounds 5a-j and 6a-j 4 [4 (3 Chloro phenyl) piperazin 1 yl] 6 (quinoline 4 yloxy) 1,3,5 triazin 2 ylamino] benzonitrile (5a). Yield 80%, melting point 212 o C-214 C; IR: 3286 ( H), 2220 (C ), 1255 (C O C), 829 cm 1 (s triazine), 759 (C ); 1 H MR: δ 9.11 (s, 1H, H, C tri H ), 8.79 (d, J = 8.4 Hz, 1H), 8.67 (s, 1H), 8.43 (dd, J = 7.2, 1.2 Hz, 1H), 8.15 (dd, J = 8.1, 1.6 Hz, 1H), (m, 2H), (m, 7H, Ar H), 6.59 (dd, J = 7.4, 1.4 Hz, 1H, CH), 3.86 (br s, 4H pip ), 3.51 (br s, 4H pip ). Analysis: Calculated for C 29 H 23 8 O: C, 65.10; H, 4.33;, Found: C, 65.31; H, 4.22;, [4 [4 (2,3 Dichloro phenyl) piperazin 1 yl] 6 (quinoline 4 yloxy) 1,3,5 triazin 2 ylamino] benzonitrile (5b): Yield 79%, melting point 251 o C-254 C; IR: 3282 ( H), 2222 (C ), 1250 (C O C), 834 cm 1 (s triazine), 754 (C ); 1 H MR: δ 8.99 (1H, s, H, C tri H ), 8.70 (d, J = 8.0 Hz, 1H), 8.54 (s, 1H), 8.50 (dd, J = 7.4, 1.1 Hz, 1H), 8.07 (dd, J = 7.9, 1.3 Hz, 1H), (m, 2H), (m, 4H, Ar-H), 7.08 (dd, J = 7.7, 1.5 Hz, 1H, -CH), 6.91 (t, J = 7.2 Hz, 1H), 6.50 (dd, J = 7.0, 1.0 Hz, 1H, CH), 3.72 (br s, 4H pip ), 3.39 (br s, 4H pip ). Analysis: Calculated for C 29 H O: C, 61.17; H, 3.89;, Found: C, 61.24; H, 3.71;, [4 (4 Acetyl piperazin 1 yl) 6 (quinoline 4 yloxy) 1,3,5 triazin 2 ylamino] benzonitrile (5c): yield 75%, melting point 238 o C-239 C; IR: 3284 ( H), 2223 (C ), 1702 ( C=O), 1482 ( CH 3 ), 1254 (C O C), 837 cm 1 (s triazine); 1 H MR: δ 9.25 (1H, s, H, C tri H ), 8.82 (d, 1H, J = 8.1 Hz), 8.60 (s, 1H), 8.33 (dd, J = 7.1, 1.0 Hz, 1H), 8.16 (dd, J = 7.9, 1.6 Hz, 1H), (m, 2H), (m, 4H, Ar-H), 3.77 (br s, 4H pip ), 3.50 (br s, 4H pip ), 2.19 (s, 3H, COCH 3 ). Analysis: Calculated for C 25 H 22 8 O 2 : C, 64.37; H, 4.75;, Found: C, 64.15; H, 4.59;, [4 (3,5 Dimethyl piperidin 1 yl) 6 (quinoline 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (5d): Yield 81%, melting point 279 o C-281 C; IR: 3280 ( H), 2222 (C ), 1251 (C O C), 839 (s triazine); 1 H MR: δ 8.99 (1H, s, H, C tri H ), 8.65 (d, J = 7.1 Hz, 1H), 8.59 (s, 1H), 8.29 (dd, J = 7.3, 1.4 Hz, 1H), 7.93 (dd, J = 7.0, 1.2 Hz, 1H), (m, 2H), (m, 5H, Ar-H), 3.71 (dd, J = 12.1, 7.3 Hz, 2H pip ), 2.98 (dd, J = 12.4, 7.5 Hz, 2H pip ), (m, 3H pip ), 1.49 (d, J = 6.2 Hz, 6H, 2CH 3 ). Analysis: Calculated for C 26 H 25 7 O: C, 69.16; H, 5.58;, Found: C, 69.00; H, 5.77;, [4 {4 [(4 Chloro phenyl) phenyl methyl] piperazin 1 yl} 6 (quinoline 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (5e): Yield 78%, melting point 243 o C-245 C; IR: 3286 ( H), 2220 (C ), 1247 (C O C), 830 (s triazine); 1 H MR: δ 9.14 (s, 1H, H, C tri H ), 8.73 (d, J = 8.2 Hz, H 2, 1H), 8.64 (s, 1H), 8.39 (dd, J = 7.6, 1.6 Hz, 1H), 8.15 (dd, J = 7.9, 1.3 Hz, 1H), (m, 2H), (m, 13H, Ar-H), 3.90 (s, 1H, CH), 3.86 (br s, 4H pip ), 3.49 (br s, 4H pip ). Analysis: Calculated for C 36 H 29 8 O: C, 69.17; H, 4.68;, Found: C, 69.02; H, 4.79;, [4 [4 (2 Fluoro phenyl) piperazin 1 yl] 6 (quinoline 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (5f): Yield 86%, melting point 251 o C-253 C; IR: 3279 ( H), 2223 (C ), 1258 (C O C), 839 (s triazine); 1 H MR: δ 8.99 (s, 1H, H, C tri H ), 8.70 (d, J = 7.3 Hz, 1H), 8.57 (s, 1H), 8.30 (dd, J = 7.4, 1.5 Hz, 1H), 8.11 (dd, J = 7.4, 1.2 Hz, 1H), (m, 2H), (m, 10H, 10CH), 6.91 (dd, J = 12.5, 6.8 Hz, 2H), (1H, m), 6.49 (dd, J = 12.7, 6.5 Hz, 1H), 3.84 (br s, 4H pip ), 3.45 (br s, 4H pip ). Analysis: Calculated for C 29 H 23 F 8 O: C, 67.17; H, 4.47;, Found: C, 66.98; H, 4.31;, [4 [4 (4 Fluoro phenyl) piperazin 1 yl] 6 (quinoline 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (5g): Yield 82%, melting point 266 o C-267 C; IR: 3289 ( H), 2219 (C ), 1254 (C O C), 829 (s triazine); 1 H MR: δ 8.98 (s, 1H, H, C tri H ), 8.77 (d, J = 7.5 Hz, 1H), 8.64 (s, 1H), 8.43 (dd, J = 8.2, 1.9 Hz, 1H), 8.15 (dd, J = 7.4, 1.3 Hz, 1H), (m, 2H), (m, 10H, Ar-H), 7.12 (dd, J = 12.9, 7.3 Hz, 2H), (m, 1H), 6.50 (dd, J = 12.3, 6.1 Hz, 1H), 3.88 (br s, 4H pip ), 3.54 (br s, 4H pip ). Analysis: Calculated for C 29 H 23 F 8 O: C, 67.17; H, 4.47;, Found: C, 67.36; H, 4.22;, {4 (Quinoline 4 yloxy) 6 [4 (3 trifluoromethyl phenyl) piperazin 1 yl] 1,3,5 triazine 2 ylamino} benzonitrile (5h): Yield 72%, melting point 285 o C-286 C; IR: 3291 ( H), 2218 (C ), 1259 (C O C), 829 (s triazine); 1 H MR: δ 8.94 (s, 1H, H, C tri H ), 8.61 (d, J = 6.9 Hz, 1H), 8.50 (s, 1H), 8.41 (dd, J = 7.7, 1.4 Hz, 1H), 8.01 (dd, J = 6.8, 1.0 Hz, 1H), (m, 2H), (m, 8H, Ar-H), 3.82 (br s, 4H pip ), 3.50 (br s,

7 Rahul V. Patel et al : Synthesis of Potential Antimicrobial/Antitubercular s-triazine Scaffolds Endowed with Quinoline and 745 4H pip ). Analysis: Calculated for C 30 H 23 F 3 8 O: C, 63.38; H, 4.08;, Found: C, 63.54; H, 3.91;, {4 (Quinoline 4 yloxy) 6 [4 (2,3,4 trimethoxy benzyl) piperazin 1 yl] 1,3,5 triazine 2 ylamino} benzonitrile (5i): Yield 75%, melting point 289 o C-291 C; IR: 3277 ( H), 2224 (C ), 1486 ( CH 2 ), 1255 (C O C), 834 (s triazine); 1 H MR: δ 9.17 (s, 1H, H, C tri H ), 8.78 (d, J = 8.8 Hz, 1H), 8.71 (s, 1H), 8.39 (dd, J = 7.8, 1.9 Hz, 1H), 8.01 (dd, J = 7.1, 1.0 Hz, 1H), (m, 2H), (m, 6H, Ar-H), 6.82 (d, J = 7.1 Hz, 1H), 6.61 (d, J = 7.5 Hz, 1H), 3.87 (br s, 4Hpip), 3.64 (s, 9H, 3OCH 3 ), 3.51 (br s, 4H pip ). Analysis: Calculated for C 33 H 32 8 O 4 : C, 65.55; H, 5.33;, Found: C, 65.31; H, 5.45;, [4 [4 (4 Methoxy phenyl) piperazin 1 yl] 6 (quinoline 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (5j): Yield 80%, melting point 242 o C-243 C; IR: 3285 ( H), 2222 (C ), 1249 (C O C), 835 (s triazine); 1 H MR: δ 8.97 (s, 1H, H, C tri H ), 8.77 (d, J = 7.5 Hz, 1H), 8.57 (s, 1H), 8.35 (dd, J = 8.0, 1.8 Hz, 1H), 8.11 (dd, J = 7.6, 1.3 Hz, 1H), (m, 2H), (m, 5H, Ar-H), 7.10 (d, J = 7.9 Hz, 1H), 6.69 (d, J = 7.1 Hz, 1H), 4.12 (s, 3H, OCH 3 ), 3.85 (br s, 4H pip ), 3.47 (br s, 4H pip ). Analysis: Calculated for C 30 H 26 8 O 2 : C, 67.91; H, 4.94;, Found: C, 67.70; H, 4.77;, [4 (3 Chloro phenyl) piperazin 1 yl] 6 (quinazolin 4 yloxy) 1,3,5 triazin 2 ylamino] benzonitrile (6a): Yield: 85%; melting point 252 o C-254 C; IR: 3281 (H), 2222 (C ), 1252 (C O C), 833 cm 1 (s triazine), 754 (C ); 1 H MR: δ 8.78 (s, 1H, C tri H ), 8.40 (s, 1H, CH qui ), 8.01 (dd, J = 11.1, 7.4 Hz, 2H), 7.75 (t, J = 7.4 Hz, 1H), (m, 6H, Ar H), 7.03 (dd, J = 7.5, 6.8 Hz, 1H), 6.77 (dd, J = 10.8, 4.1 Hz, 1H), 6.67 (d, J = 7.4 Hz, 1H), 3.86 (br s, 4H pip ), 3.47 (br s, 4H pip ). Analysis: Calculated for C 28 H 22 9 O: C, 62.74; H, 4.14;, Found: C, 62.92; H, 3.92;, [4 [4 (2,3 Dichloro phenyl) piperazin 1 yl] 6 (quinazolin 4 yloxy) 1,3,5 triazin 2 ylamino] benzonitrile (6b): Yield: 78%; melting point 261 o C-264 C; IR: 3277 (H), 2224 (C ), 1255 (C O C), 830 cm 1 (s triazine), 754 (C ); 1 H MR: δ 8.97 (s, 1H, H, C tri H ), 8.41 (s, 1H, CH qui ), 8.11 (dd, J = 10.8, 7.9 Hz, 2H), 7.70 (t, J = 6.9 Hz, 1H), (m, 3H, Ar H), 7.16 (d, J = 7.4 Hz, 2H), (m, 1H), 6.90 (t, J = 7.4 Hz, 1H), 6.51 (dd, J = 7.4, 0.8 Hz, 1H), 3.80 (br s, 4H pip ), 3.45 (br s, 4H pip ). Analysis: Calculated for C 28 H O: C, 58.96; H, 3.71;, Found: C, 58.83; H, 3.59;, [4 (4 Acetyl piperazin 1 yl) 6 (quinazolin 4 yloxy) 1,3,5 triazin 2 ylamino] benzonitrile (6c): Yield: 86%; melting point 228 o C-230 C; IR: 3280 (H), 2220 (C ), 1700 ( C=O), 1475 ( CH 3 ), 1257 (C O C), 839 cm 1 (s triazine). 1 H MR: δ 8.99 (s, 1H, C tri H ), 8.30 (s, 1H, CH qui ), 8.10 (dd, J = 10.3, 7.8 Hz, 2H), 7.81 (t, J = 7.2 Hz, 1H), (m, 5H, Ar H), 3.89 (br s, 4H pip ), 3.50 (br s, 4H pip ), 2.09 (s, 3H, COCH 3 ). Analysis: Calculated for C 24 H 21 9 O 2 : C, 61.66; H, 4.53;, Found: C, 61.82; H, 4.26;, [4 (3,5 Dimethyl piperidin 1 yl) 6 (quinazolin 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (6d): Yield: 83%; melting point 269 o C-271 C; IR: 3280 (H), 2221 (C ), 1256 (C O C), 838 (s triazine); 1 H MR: δ 8.90 (s, 1H, C tri H ), 8.42 (s, 1H, CH qui ), 8.13 (dd, J = 11.6, 5.5 Hz, 2H), 7.67 (t, J = 6.6 Hz, 1H), (m, 6H, Ar H), 3.66 (dd, J = 12.4, 7.6 Hz, 2H pip ), 3.08 (dd, J = 12.4, 7.6 Hz, 2H pip ), (m, 3H pip ), 1.45 (d, J = 6.4 Hz, 6H, 2CH 3 ). Analysis: Calculated for C 25 H 24 8 O: C, 66.36; H, 5.35;, Found: C, 66.21; H, 5.20;, [4 {4 [(4 Chloro phenyl) phenyl methyl] piperazin 1 yl} 6 (quinazolin 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (6e): Yield: 78%; melting point 258 o C-260 C; IR: 3284 (H), 2222 (C ), 1255 (C O C), 837 (s triazine); 1 H MR: δ 8.82 (s, 1H, C tri H ), 8.41 (s, 1H, CH qui ), 8.20 (dd, J = 11.3, 5.6 Hz, 2H), 7.70 (t, J = 7.1 Hz, 1H), (m, 14H, Ar H), 3.90 (s, 1H, CH), 3.77 (br s, 4H pip ), 3.43 (br s, 4H pip ). Analysis: Calculated for C 35 H 28 9 O: C, 67.14; H, 4.51;, Found: C, 66.97; H, 4.40;, [4 [4 (2 Fluoro phenyl) piperazin 1 yl] 6 (quinazolin 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (6f): Yield: 81%; melting point 265 o C-266 C; IR: 3272 (H), 2220 (C ), 1260 (C O C), 834 (s triazine); 1 H MR: δ 8.95 (s, 1H, C tri H ), 8.32 (s, 1H, CH qui ), 7.98 (dd, J = 10.9, 7.0 Hz, 2H), 7.76 (t, J = 7.2 Hz, 1H), (m, 5H, Ar H), 6.92 (dd, J = 12.6, 6.7 Hz, 2H), (m, 1H), 6.51 (dd, J = 12.6, 6.3 Hz, 1H), 3.82 (br s, 4H pip ), 3.55 (br s, 4H pip ). Analysis: Calculated for C 28 H 22 F 9 O: C, 64.73; H, 4.27;, Found: C, 64.88; H, 4.16;, [4 [4 (4 Fluoro phenyl) piperazin 1 yl] 6 (quinazolin 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (6g): Yield: 70%; melting point 282 o C-284 C; IR: 3284 (H), 2218 (C ), 1258 (C O C), 829 (s triazine); 1 H MR: δ 8.96 (s, 1H, C tri H ), 8.44 (s, 1H, CH qui ), 8.18 (dd, J = 11.1, 7.5 Hz, 2H), 7.83 (t, J = 7.9 Hz, 1H), (m, 5H, Ar H), 7.02 (dd, J = 12.8, 6.9 Hz, 2H), (m, 1H), 6.49 (dd, J = 12.1, 6.0 Hz, 1H), 3.44 (br s, 4H pip ), 3.85 (br s, 4H pip ). Analysis:

8 746 International Journal of Drug Design and Discovery Volume 3 Issue 1 January March 2012 Calculated for C 28 H 22 F 9 O: C, 64.73; H, 4.27;, Found: C, 64.66; H, 4.42;, {4 (Quinazolin 4 yloxy) 6 [4 (3 trifluoromethyl phenyl) piperazin 1 yl] 1,3,5 triazine 2 ylamino} benzonitrile (6h): Yield: 77%; melting point >300 C; IR: 3294 (H), 2223 (C ), 1187, 1134, 1109 (C F), 1251 (C O C), 839 (s triazine); 1 H MR: δ 8.91 (s, 1H, C tri H ), 8.51 (s, 1H, CH qui ), 8.24 (dd, J = 10.3, 7.2 Hz, 2H), 7.71 (t, J = 7.1 Hz, 1H), (m, 9H, Ar H), 3.48 (br s, 4H pip ), 3.83 (br s, 4H pip ). Analysis: Calculated for C 29 H 22 F 3 9 O: C, 61.16; H, 3.89;, Found: C, 60.98; H, 3.79;, {4 (Quinazolin 4 yloxy) 6 [4 (2,3,4 trimethoxy benzyl) piperazin 1 yl] 1,3,5 triazine 2 ylamino} benzonitrile (6i): Yield: 81%; melting point 265 o C-267 C; IR: 3289 (H), 2219 (C ), 1482 ( CH 2 ), 1258 (C O C), 830 (s triazine); 1 H MR: δ 8.82 (s, 1H, C tri H ), 8.49 (s, 1H, CH qui ), 8.17 (dd, J = 10.1, 6.9 Hz, 2H), 8.07 (t, J = 7.6 Hz, 1H), (m, 27H, Ar H), 6.89 (d, J = 7.4 Hz, 1H), 6.71 (d, J = 7.6 Hz, 1H), 3.71 (s, 9H, 3OCH 3 ), 3.78 (br s, 4H pip ), 3.41 (br s, 4H pip ). Analysis: Calculated for C 32 H 31 9 O 4 : C, 63.46; H, 5.16;, Found: C, 63.60; H, 5.00;, [4 [4 (4 Methoxy phenyl) piperazin 1 yl] 6 (quinazolin 4 yloxy) 1,3,5 triazine 2 ylamino] benzonitrile (6j): Yield: 84%; melting point 260 o C-261 C; IR: 3281 (H), 2222 (C ), 1249 (C O C), 835 (s triazine); 1 H MR: δ 8.88 (s, 1H, C tri H ), 8.41 (s, 1H, CH qui ), 8.09 (dd, J = 9.9, 6.1 Hz, 2H), 8.11 (t, J = 7.8 Hz, 1H), (m, 7H, Ar H), 7.03 (d, J = 7.7 Hz, 1H), 6.66 (d, J = 7.1 Hz, 1H), 4.02 (s, 3H, OCH 3 ), 3.85 (br s, 4H pip ), 3.47 (br s, 4H pip ). Analysis: Calculated for C 29 H 25 9 O 2 : C, 65.53; H, 4.74;, Found: C, 65.37; H, 4.87;, Antimicrobial activity The synthesized derivatives (6a k, 7a k) were examined for antimicrobial activity against several bacteria (Staphylococcus aureus MTCC 96, Bacillus cereus MTCC 619, Escherichia coli MTCC 739, Pseudomonas aeruginosa MTCC 741, Klebsiella pneumoniae MTCC 109, Salmonella typhi MTCC 733, Proteus vulgaris MTCC 1771, Shigella Flexneria MTCC 1457) and fungi (Aspergillus niger MTCC 282, Aspergillus fumigatus MTCC 343, Aspergillus clavatus MTCC 1323, Candida albicans MTCC 183) species using paper disc diffusion technique 19 and MIC of the compound was determined by agar streak dilution method 20 as described earlier 21. Antituberculosis screening for test compounds was performed against M. tuberculosis H37Rv using L. J. (Lowenstein and Jensen) MIC method 22 for the measurement of MIC. The MIC values were evaluated at concentration range of µg/ml and each value presented in Table 1 and 2 is the mean of three independent experiments. Acknowledgements The authors are thankful to Applied Chemistry Department of S. V. ational Institute of Technology, Surat for the scholarship, encouragement and facilities. The authors wish to offer their deep gratitude to Microcare Laboratory, Surat, India for carrying out the biological screenings. We are also thankful to Centre of Excellence, Vapi, India for carrying out FT IR and 1 H MR analysis. References [1] athan, C. ature 2004, 431, 899. [2] WHO report 2010: Global tuberculosis control. Available at: [3] Sriram, D.; Yogeeswari, P.; Madhu, K. Bioorg. Med. Chem. Lett. 2005, 15, [4] Zhou, C.; Min, J.; Zhigang, L.; Anne, Y.; Heather, D.; Tian, G.; Young-Tae, C.; eville, R.K. Biorg. Med. Chem. Lett. 2008, 18, [5] Srinivas, K.; Srinivas, U.; Bhanuprakash, K.; Harakishore, K.; Murthy, U.S..; Jayathirtha, Eur. J. Med. Chem. 2006, 41, [6] Alessandro, B.; Gorka, J.B.; Mhairi, L.S.; Vanessa, Y.; Reto, B.; Michael, P.B.; Ian, H.G. J. Med. Chem. 2005, 48, [7] Rita, M.; Simona, S.; Giovanni, S.; Francesca, V.; Lisa, D.V. J. Med. Chem. 2004, 47, [8] Sergio, M.; Davide, P.; Paolo, C.; icoletta, B.; Diego, M. ChemMedChem 2008, 3, 873. [9] Yuan-Zhen, X.; Fen-Er, C.; Jan, B.; Erik, D.C.; Christophe, P. Eur. J. Med. Chem. 2008, 43, [10] Kerns, R. J.; Rybak, M. J.; Kaatz, G. W.; Vaka, F.; Cha, R.; Grucz, R. G. Bioorg. Med. Chem. Lett. 2003, 13, [11] Upadhayaya, R.S.; Sinha,.; Jain, S.; Kishore,.; Chandra, R.; Arora, S.K. Bioorg. Med. Chem. 2004, 12, [12] Upadhayaya, R.S.; Vandavasi, J.K.; Kardile, R. A.; Lahore, S.V.; Dixit, S.S.; Deokar, H.S.; Shinde, P.D.; Sarmah, M.P.; Chattopadhyay, J. Eur. J. Med. Chem. 2010, 45, [13] Singh, K.K.; Joshi, S.C.; Mathela, C.S. Ind. J. Chem. 2001, 50, 196.

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