A Facile Synthesis of Some New Thiazolo[3, 2]pyridines Containing Pyrazolyl Moiety and Their Antimicrobial Activity

Abstract

Abstract Condensation of 2-cyanomethyl-4-thiazolinone 1 with 1,3-diphenyl-pyrazole-4-carboxaldehyde 2 in ethanol containing a few drops of piperidine yielded the novel methylene derivative 3 . Compound 3 was refluxed with malononitrile to give the corresponding thiazolo[ [3] Elneairy, M. A. A., Abdel-Rahman, M. and Hammad, A. M. 1998. J. Chem. Research (S), 684 [Google Scholar], [2] hamid, A. O. Abdel and Al-Sherif, S. M. 1997. J. Chem. Research (S), 240 [Google Scholar]]pyridine derivative 5 . Also, treatment of compound 3 with benzylidenemalononitriles gave the thiazolo[ [3] Elneairy, M. A. A., Abdel-Rahman, M. and Hammad, A. M. 1998. J. Chem. Research (S), 684 [Google Scholar], [2] hamid, A. O. Abdel and Al-Sherif, S. M. 1997. J. Chem. Research (S), 240 [Google Scholar]]pyridine derivatives 6a–e . Refluxing of compound 6d with triethyl orthoformate furnished the ethoxymethylideneamino derivative 7 . Formic acid and malononitrile were reacted with compound 6d to produce thiazolo[ [3] Elneairy, M. A. A., Abdel-Rahman, M. and Hammad, A. M. 1998. J. Chem. Research (S), 684 [Google Scholar], [2] hamid, A. O. Abdel and Al-Sherif, S. M. 1997. J. Chem. Research (S), 240 [Google Scholar]][ [1] Liu, H. N., Li, Z. C. and Anthosen, T. 2000. Molecules, 5: 1055[Crossref], [Web of Science ®] , [Google Scholar], [8] El-Gaby, M. S. A., Atalla, A. A., Gaber, A. M. and Abd Al-Wahab, K. A. 2000. IL Farmaco, 55(9–10): 596 [PUBMED][INFOTRIEVE][Crossref] , [Google Scholar]]naphthyridine derivative 8 and 11 , respectively. Condensation of 2 with cyanoacetohydrazide in ethanol containing piperidine as catalyst gave the hydrazone derivative 12 which, on treatment with salicyaldehyde and 2-cyano-3-(4-fluorophenyl)acrylic acid ethyl ester, yielded the novel chromene 13 and pyridinone 14 , respectively. Structures of the synthesized compounds have been established by elemental analysis and spectral data. Compounds 3 , 5 , 6a–d , 8 , 11 , 13 , and 14 have been screened for antimicrobial activities.