Se estudió la ciclocondensación de chalconas con 3-amino-5-pirazolona, la cual lleva a la formación de 2-aril-4-fenil-5-oxopirazolo[4,5-b]piridinas. Las estructuras de los compuestos obtenidos se determinó con base en los análisis espectroscópicos (RMN 'H y "C y espectrometría de masas)

Aguirre, Alexandra

Insuasty O., Braulio

Marín, Martha

Meier, Herbert

Quiroga P., Jairo

Spanish

LAReferencia - Red Federada de Repositorios Institucionales de Publicaciones Científicas Latinoamericanas

REVISTA COLOMBIANA DE QUÍMICA, BOGOTÁ (COLOMBIA), VOLUMEN 21, Nos 1 -2DE 1992 SYNTHESIS OF AROMATIC DERIVATES OF THE 5-OXOPYRAZOLO[4,5-B]PYRIDINE. Jairo Quiroga P.'*, Braulio Insuasty O.^, Martha Marín', Alexandra Aguirre', Herbert Meier.'' 1* Departamento de Química, Universidad de los Andes, A.A. 4976, Santafé de Bogotá, Colombia. 2 Departamento de Química, Universidad del Valle, A.A. 25360, Cali, Colom-bia. 3 Departamento de Química, Universidad Distrital, Santafé de Bogotá, Colombia. 4 Instituí fur Organische Chemie, Mainz Universitat Mainz, Germany. Keywords: Chalcone, 3-ainino-5-pyrazolone, oxopyrazolopyridine. ABSTRACT Tile ciclocondensation of chalconas with 3-amino-5-pyrazolone in DMF was studied, which leads to the formation of2-aryl-2-phenyl-5-oxopyrazolo[4,5-b]pyridines. The structures of compounds obtained was determined based on spectroscopic analysis ('H and "C-nmr and mass spectrometry). RESUMEN Se estudió la ciclocondensación de chalconas con 3-amino-5-pirazolona, la cual lleva a la formación de 2-aril-4-fenil-5-oxopirazolo[4,5-b]piridinas. Las estructuras de los compues-tos obtenidos se determinó con base en los análisis espectroscópicos (RMN 'H y "C y espectrometría de masas). INTRODUCTION Continuing the study of reactions of pyrazol aminoderivatives with a,p-unsaturated aromatic ketones [1,2] we carried out experiments on the interaction of the 3-amino-5-pyrazolone [1] with chalcones [2a-e]. The interest of studying this aminopyrazole in its reaction with chalcones is due to the possibility of two cyclization routes. In the reactions of aminopyrazoles without substituent at the nitogen atom with carbonyl compounds, it is feasible to obtain derivatives ofpyrazolo[4,5-b] pyridines (3,4) or pyrazolo[ 1,5-a]pyrimidines (4-6) and even a mixture of these two prcxlucts (4,7). RESULTS AND DISCUSSION The interactior of 3-amino-5-pyrazolone [ 1] with chalcones [2] may, in principie, lead to the formation of two isomeric products: 29 REVISTA COLOMBIANA DE QUÍMICA, BOGOTÁ (COLOMBIA). VOLUMEN 21, Nos. 1 -2DE 1992 Jn our study heating equimolecular amounts of amine [1] and ketones [2a-e] in DMF we obtained compwunds 3a-e. Spectroscopic and cromatographic control showed that the syntethyzed compounds belong to a series of isomers. The products oflhe reaction "A" and "B" aredifferentiated inso far as in the first one there are two NH protons and one CH protón from the pyridine ring, while in the second product ["B"] there are only one protón from an HN group and two CH protons, one from the pyrimidinic cycle and one from the pyrazojic cycle. C6H5 O HN 1 +C6H5CH=CHCOC5H4R-4' ^ " ' HH2 2a-e H OCH3 Cl Br NO 9 • HN N-H B- HN "I 3 a - e „ - " C6H4R •4-C5H5 N I I N X5H4R-4-This explains why the problem concerning the tendency of the cyclization process is solved by nmr-spectroscopy. In the 'H-nmr spectra of the compounds 3a-e, measured in DMS0-d6, two singlets at low field (10.90-12.50 ppm) are clearly visible, these belong to two protons of NH group of the pyrazolic ring; additionally a signal was observed in the aromatic región (7.57-7.76 ppm) belonging to the aromatic protón of the pyridine ring (table 1). This serves as a confinnation of way "A" in the studied reaction. Table 1. 'H-nmr data or3a-e (5 valúes in DMSO-d6) O H N " ? . " N H ' ' * " i 3H 6H 7H aromatic H a b c d c 7.57 7.57 7.62 7.62 7.76 12.17 12.17 12.32 12.33 12.49 10.92 10.90 10.90 10.92 11.02 ?.17(2H),7.82(2H),7.50(6H) i. 16(2H),7.83(2H),7.49(2H),7.06(2H), 8.44(1H) 3.23(2H),7.83(2H),7.58(2H),7.51(3H) ?.16(2H),7.83(2H),7.70(2H),7.50(3H) B.34(2H),7.85(2H),7.52(2H),7.50(1H), 8.48(2H) 30 REVISTA COLOMBIANA DE QUÍMICA, BOGOTÁ (COLOMBL^), VOLUMEN 21. Nos. 1 - 2 DE 1992 The final elucidation of structure of compounds 3a-e was carried out by analysis of the "C-lunr spectra (spin-echo),in which the number of signáis belonging tó quaternary and tertiary carbón atoms compounds 3a-e could be determined (tabla 2). EXPERIMETAL PART Melting point were taken on a Buchi melting point apparatus. The 'H and "C- nmr spectra were run on a Bruker AM 400 in DMSO-d6. The mass spectra were recorded on a varían MAT711 and Finnigan M 95 of)erating at 70 eV. 2-aryl-4-phenyl-5-oxopyrazolo[4,5-b]pyridine [3a-e] General procedure (1),(2). A solution of 0,5 g (5.0 mmol) 3-amino-5-pyrazolone (1) and 5,0 mmol of chalcone (2a-e) in 2 mi DMF was refiuxed. The reaction can be controlled by TLC on silica gel. After the starting compounds have almost completely disapeared, the solution is cooled and the precipítate formed over night is filtered off. Table 2. "C-nmr data of 3a-e ( valúes in DMSO-d6) Pyrazolo[4,5-b]pyridine C aromatic 3 C-2,4,5 C-3 C-4a C-7a Ci Co,m Cp 156.6 112.8 100.4 145.9 138.8 129.6 129.3 154.3 136.5 128.7 128.8 154.0 128.0 127.3 156.3 112.2 98.8 145.8 136.5 129.6 160.4 154.3 131.15 114.1 128.8 154.1 128.1 128.7 155.1 112.6 100.4 146.0 137.6 129.6 134.1 154.0 136.3 129.0 128.8 153.7 129.3 128.0 155.1 112.6 100.4 146.0 137.9 128.1 123.0 154.1 136.4 129.7 128.9 153.7 129.3 131.7 154.0 113.4 100.9 146.2 136.1 128.0 147.8 153.7 144.8 123.8 129.0 153.5 128.4 129.7 31 REVISTA COLOMBIANA DE QUÍMICA. BOGOTÁ (COLOMBIA). VOLUMEN 21, Nos. 1 - 2 DE 1992 2,4-Dipheny 1-5-oxopyrazolo[4,5-b]pyridine [3a] The compound was obtained according to the general procedure as yellow crystals, mp 264-5 "C, yield (45%). The mass spectum a shows the following peaks: m/z (%)= 288(47.6), 287(100,M-), 286(15.5), 231(12.7),230(47.0), 228(10.0), 203(10.0),202(17.5), 143(15.9), 128(10.0), 127(12.1), 102(21.3), 101(12.2), 77(22.3). 2-(4-methoxyphenyl)-4-phenyl-5-oxopyrazolo[4,5-b]pyridine [3b]. The compound was obtained according to the general procedure as yellow crystal, mp 267-8 'C, yield (40%). The mass spectrum shows the following peaks: m/z(%)= 317(18.6M*), 217(11.7), 189(10.0), 128(10,2), 102(13.5), 101(10.0),91(10.1),9O(12.3),89(54.4),88(l 1.5), 78(20.7), 77(100). 2-(4-Chlorophenyl)-4-phenyl-5-oxopyrazolo[4,5-b]pyridine [3c]. The compound was obtained according to the general procedure as yellow crystals, mp 296-8 °C yield (65%). The mass spectrum shows the following peaks: m/z (%)= 323(36.8), 322(26.6),321(100,M*),264(18.7),230(10.6),227(10.1),202(10.8), 127(10.0), 101(10.5), 77(10.0). 2-(4-Bromophenyl)-4-phenyl-5-oxopyrazolo[4,5-b]pyridine [3d]. The compound was obtained according to the general procedure as yellow crystals, mp 278-80 "C, yield (70%). The mass spectrum shows the following peaks: m/z (%)= 368(19.7), 367(60.7), 366(22.9, M*), 365(59.5), 230(28.5), 229(26.9), 228(24.4), 227(20.0), 202(20.4), 166(21.1), 165(19.2), 129(16.3), 127(13.9), 112(40.5), 111(26.9), 105(15.1), 101(13.1), 77(25.0). 2-(4-Nitrophenyl)-4-phenyl-5-oxopyrazolo[4,5-b]pyridine [3e]. The compound was obtained according to the general procedure as yellow crystals, mp 304-5 °C, yield (76%). The mass spectrum shows the following peaks: m/z (%)= 333(20.1), 332(100, M*), 286(21.6), 230(20.1), 229(24.4), 228(29.5), 227(18.3), 202(18.8), 201(10.0), 189(10.0), 77(10.1). ACKNOWLEDGMENTS This work was supported by COLCIENCIAS. REFERENCES 1. Orlov, V. D.; Quiroga J.; Kolos, N. N., Khim Geterosiki Soed. 1987,2, 1247. 2. Orlov, V. D.; Quiroga, J, Kolos, N. N.; Desenko, S. M., Khim Geterosiki Soed. 1988, 2, 962. 3. Hall. T.; Vass. J. D., J. Soc. Chem. Commun. 1966, lü, 293. 4. Imbach, J. L.; Jacquier, R.; Vidal, J. L, Bull Soc. Chim. Fr. 1970,5, 1929. 5. Pecori, V. L.; Cecchi, L.; Costanzo, A.; Auzzi, G.; Bruni, F., Fármaco Ed. Sci. 1981, 2Ú, 344. 6. Ried, W.; Peuchert, K. P. Liebigs, Ann. Chem. 1962, MI , 104. 7. BaUcki, R.; Natka-Namirski, ?., Pol. J. Chem. 1980,54, 2175. 32 

Synthesis of aromatic derivates of the 5-oxopyrazolo[4,5-b]pyridine

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Synthesis of aromatic derivates of the 5-oxopyrazolo[4,5-b]pyridine

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