Synlett, Inhaltsverzeichnis Synlett 2013; 24(14): 1825-1829DOI: 10.1055/s-0033-1339333 letter © Georg Thieme Verlag Stuttgart · New York A Simple One-Pot Procedure for the Synthesis of 1,2,4-Triazolo[1,5-a]pyrid-ines via Pseudo Five-Component Reactions Catalyzed by Molecular Iodine Abdolali Alizadeh* Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran Fax: +98(21)88006544 eMail: abdol_alizad@yahoo.com eMail: aalizadeh@modares.ac.ir , Vahid Saberi Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran Fax: +98(21)88006544 eMail: abdol_alizad@yahoo.com eMail: aalizadeh@modares.ac.ir , Javad Mokhtari Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran Fax: +98(21)88006544 eMail: abdol_alizad@yahoo.com eMail: aalizadeh@modares.ac.ir › Institutsangaben Artikel empfehlen Abstract Artikel einzeln kaufen Alle Artikel dieser Rubrik Abstract In this paper we report the synthesis of the 1,2,4-triazolo[1,5-a]pyridine ring system. The reaction between benzylidenehydrazines, dialkyl acetylenedicarboxylates, benzaldehydes, and malononitrile proceeds in EtOH at reflux in the presence of molecular iodine as catalyst in good to excellent yields. Key words Key wordsbenzylidenehydrazine - dialkyl acetylenedicarboxylate - benzaldehyde - malononitrile - 1,2,4-triazolo[1,5-a]pyridine - catalyst - iodine - multicomponent reaction Volltext Referenzen References and Notes 1a Nettekoven M, Pullmann B, Schmitt S. Synthesis 2003; 1649 1b Dugan BJ, Gingrich DE, Mesaros EF, Milkiewicz KL, Curry MA, Zulli AL, Dobrzanski P, Serdikoff C, Jan M, Angeles TS, Albom MS, Mason JL, Aimone LD, Meyer SL, Huang Z, Wells-Knecht KJ, Ator MA, Ruggeri BA, Dorsey BD. J. Med. Chem. 2012; 55: 5243 2 Utsumi Y. JP 81,100,783, 1981 ; Chem. Abstr. 1982, 96, 6735x. 3 Kubo K, Ito N, Souzo I, Isomura Y, Homma H, Murakai M. GB 1588166, 1981 ; Chem. Abstr. 1982, 96, 68987q. 4 Koeckritz P, Liebscher J, Huebler D. Ger. (East) DD280110, 1990 ; Chem. Abstr. 1991, 114, 81850z. 5a Huntsman E, Balsells J. Eur. J. Org. Chem. 2005; 3761 5b Al-Masoudi IA, Al-Soud YA, Al-Salihi NJ, Al-Masoudi NA. Chem. Heterocycl. Compd. (N.Y.) 2006; 42: 1377 6a Larsen SD, DiPaolo BA. Org. Lett. 2001; 3: 3341 6b Balsells J, DiMichele L, Liu J, Kubryk M, Hansen K, Armstrong JD. III. Org. Lett. 2005; 7: 1039 6c Stocks MJ, Cheshire DR, Reynold R. Org. Lett. 2004; 6: 2969 7a Potts KT, Burton HR, Bhattacharyya J. J. Org. 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Then a solution of DMAD (0.142 g, 1 mmol) was added, and the mixture was stirred for 3 min. At this point, the condensation product of 4-chlorobenz-aldehyde (0.140 g, 1 mmol) and malononitrile (6a, 0.066 g, 1 mmol) was added, and the reaction mixture was stirred for 3 h under reflux and progress was followed by TLC. After completion, the reaction mixture was cooled to r.t., I2 (0.1 mmol) was added, and the mixture was stirred for a further 2 h. The progress of the reaction was again followed by TLC and, after completion, the solvent was removed under reduced pressure, and the residue was purified by column chromatography (n-hexane–EtOAc, 5:1). All products gave satisfactory spectroscopic data in accordance with the assigned structures.Representative Spectroscopic DataDimethyl 7-(4-Chlorophenyl)-8-cyano-2-phenyl-[1,2,4]triazolo[1,5-a]pyridine-5,6-dicarboxylate (4a)White powder; yield: 0.26 g (59%); mp 263–265 °C. IR (KBr): 2358 (CN), 1748 (CO2Me), 1538 and 1443 (Ar), 1251 (C–O of ester) cm–1. 1H NMR (500.13 MHz, CDCl3): δ = 3.65 (3 H, s, OCH3), 4.17 (3 H, s, OCH3), 7.38 (2 H, d, 3 J HH = 8.0 Hz, 2 CH of Ar), 7.52–7.54 (5 H, m, 5 CH of Ar), 8.37 (2 H, d, 3 J HH = 8.0 Hz, 2 CH of Ar) ppm. 13C NMR (125.75 MHz, CDCl3): δ = 53.4 (OCH3), 54.3 (OCH3), 102.4 (C8), 112.6 (C5), 118.6 (CN), 128.3 (2 CH meta of Ph), 128.8 (2 CH of Ar), 128.9 (C6), 129.2 (2 CH of Ar), 129.7 (2 CH ortho of Ph), 131.5 (CH para of Ph), 132.8 (C ipso of Ph), 135.3 (C–Cl), 136.5 (C ipso of Ar), 147.6 (C8a), 150.77 (C7), 159.9 (C2),163.6 (C=O), 167.8 (C=O) ppm. MS (EI, 70 eV): m/z (%) = 446 (22) [M+], 367 (35), 298 (31), 224 (22), 190 (36), 167 (22), 149 (57), 111 (28), 97 (46), 81 (57), 69 (100), 57 (65). Anal. Calcd (%) for C23H15ClN4O4 (446.85): C, 61.82; H, 3.38; N, 12.54. Found: C, 61.79; H, 3.39; N, 12.55.Dimethyl 2,7-Bis(4-chlorophenyl)-8-cyano-[1,2,4]triazolo[1,5-a]pyridine-5,6-dicarboxylate (4f)White powder; yield: 0.24 g (51%); mp 281–283 °C. IR (KBr): 2357 (CN), 1746 (CO2Me), 1440 (Ar), 1259 (C–O of ester) cm–1. 1H NMR (400.13 MHz, CDCl3): δ = 3.66 (3 H, OCH3), 4.17 (3 H, OCH3), 7.38 (2 H, d, 3 J HH = 8.0 Hz, 2 CH of Ar), 7.50 (2 H, d, 3 J HH = 8.0 Hz, 2 CH of Ar), 7.54 (2 H, d, 3 J HH = 8.0 Hz, 2 CH of Ar), 8.32 (2 H, d, 3 J HH = 8.0 Hz, 2 CH of Ar) ppm. 13C NMR (100.61 MHz, CDCl3): δ = 53.4 (OCH3), 54.40 (OCH3), 102.4 (C8), 112.5 (C5), 118.8 (CN), 127.3 (C6), 129.1 (2 CH of Ar), 129.2 (2 CH of Ar), 129.5 (2 CH of Ar), 129.6 (2 CH of Ar), 132.6 (C ipso of Ar), 135.2 (C–Cl), 136.7 (C ipso of Ar), 137.7 (C–Cl) 147.7 (C8a), 150.7 (C7), 159.7 (C2), 163.5 (C=O), 166.7 (C=O) ppm. MS (EI, 70 eV): m/z (%) = 481 (31) [M+], 480 (100) [M+ – 1], 449 (22), 364 (51), 190 (22), 163 (22), 138 (72), 102 (30), 75 (53), 59 (33). Anal. Calcd (%) for C23H14Cl2N4O4 (481.30): C, 57.40; H, 2.93; N, 11.64. Found: C, 57.42; H, 2.92; N, 11.65.Dimethyl 7-(3-Bromophenyl)-8-cyano-2-p-tolyl-[1,2,4]triazolo[1,5-a]pyridine-5,6-dicarboxylate (4h)White powder; yield: 0.25 g (55%); mp 287–289 °C. IR (KBr): 2359 (CN), 1742 (CO2Me), 1441 (Ar), 1264 (C–O of ester) cm–1. 1H NMR (400.13 MHz, CDCl3): δ = 2.45 (3 H, s, Me), 3.66 (3 H, OCH3), 4.17 (3 H, OCH3), 7.33 (2 H, d, 3 J HH = 8.0 Hz, 2 CH of Ar), 7.38 (2 H, d, 3 J HH = 8.0 Hz, 2 CH of Ar), 7.54 (2 H, d, 3 J HH = 8.0 Hz, 2 CH of Ar), 8.27 (2 H, d, 3 J HH = 8.0 Hz, 2 CH of Ar) ppm. 13C NMR (100.61 MHz, CDCl3): δ = 29.7 (Me), 53.3 (OCH3), 54.3 (OCH3), 100.2 (C8), 112.7 (C5), 118.3 (CN), 126.0 (C6), 128.2 (2 CH of Ar), 129.2 (2 CH of Ar), 129.5 (2 CH of Ar), 129.6 (2 CH of Ar), 132.4 (C ipso of Ar), 135.6 (C–Cl), 136.5 (C ipso of Ar), 140.6 (C–Me), 142.0 (C8a), 151.8 (C7), 155.0 (C2), 164.6 (C=O), 166.0 (C=O) ppm. MS (EI, 70 eV): m/z (%) = 460 (53) [M+], 422 (38), 391 (27), 364 (89), 199 (43), 163 (43), 138 (100), 111 (49), 75 (46), 59 (58) (32). Anal. Calcd (%) for C24H17ClN4O4 (460.87): C, 62.55; H, 3.72; N, 12.16. Found: C, 62.53; H, 3.73; N, 12.14.