Download PDF
Synlett 2007(10): 1600-1604  
DOI: 10.1055/s-2007-982545
LETTER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of Pyrazoles by a One-Pot Tandem Cyclization-Dehydrogenation Approach on Pd/C/K-10 Catalyst

Shainaz M. Landge, Allison Schmidt, Verona Outerbridge, Béla Török*
Department of Chemistry, University of Massachusetts Boston, 100 Morrissey Blvd., Boston, MA 02125, USA
Fax: +1(617)2876030; e-Mail: bela.torok@umb.edu;
Further Information

Publication History

Received 22 March 2007
Publication Date:
06 June 2007 (online)

    Permissions and Reprints All articles of this category

Abstract

A novel one-pot synthesis of substituted pyrazoles from chalcones and hydrazines via a tandem cyclization-dehydro­genation approach is described. This process is based on the use of a bifunctional noble-metal/solid-acid catalyst, Pd/C/K-10 montmorillonite and microwave irradiation under solvent-free conditions. The cyclization of chalcones with hydrazines readily takes place on the strong solid acid while the presence of the metal ensures the ­formation of the aromatic product through dehydrogenation. The ­reactions are complete in 30 minutes providing good yields and high selectivities.

Key words

chalcones - hydrazines - bifunctional catalysis - microwave heating - pyrazoles

    References

  • 1a Zificsak CA. Hlasta DJ. Tetrahedron  2004,  60:  8991 
    Google Scholar
  • 1b Haino T. Tanaka M. Ikeda K. Kubo K. Mori A. Fukazawa Y. Tetrahedron Lett.  2004,  45:  2277 
    Google Scholar
  • 1c Török M. Abid M. Mhadgut SC. Török B. Biochemistry  2006,  45:  5377 
    Google Scholar
  • 1d Török B. Abid M. London G. Esquibel J. Török M. Mhadgut SC. Yan P. Prakash GKS. Angew. Chem. Int. Ed.  2005,  44:  3086 
    Google Scholar
  • 2a Xiao L. Lu XY. Ruden DM. Mini-Rev. Med Chem.  2006,  6:  1137 
    Google Scholar
  • 2b McDonald E. Jones K. Brough PA. Drysdale MJ. Workman P. Curr. Top. Med. Chem.  2006,  6:  1193 
    Google Scholar
  • 2c Barsoum FF. Hosni HM. Girgis AS. Bioorg. Med. Chem.  2006,  14:  3929 
    Google Scholar
  • 2d Stauffer SR. Coletta CJ. Tedesco R. Nishiguchi G. Carlson K. Sun J. Katzenellenbogen BS. Katzenellenbogen JA. J. Med. Chem.  2000,  43:  4934 
    Google Scholar
  • 2e Prasanna S. Manivannan E. Chaturvedi SC. J. Enzyme Inhib. Med. Chem.  2005,  20:  455 
    Google Scholar
  • 3a Elguero J. In Comprehensive Heterocyclic Chemistry II   Vol. 3:  Katritzky AR. Rees CW. Scriven EFV. Pergamon Press; Oxford: 1996.  p.1 
    Google Scholar
  • 3b Lautens M. Roy A. Org. Lett.  2000,  2:  555 
    Google Scholar
  • 3c Wang X. Tan J. Grozinger K. Tetrahedron Lett.  2000,  41:  4713 
    Google Scholar
  • 4a Huang YR. Katzenellenbogen JA. Org. Lett.  2000,  2:  2833 
    Google Scholar
  • 4b Katritzky AR. Wang M. Zhang S. Voronkov MV. J. Org. Chem.  2001,  66:  6787 
    Google Scholar
  • 4c Kovelesky AC. Shine HJ. J. Org. Chem.  1988,  53:  1973 
    Google Scholar
  • 4d Bishop BC. Brands KMJ. Gibbs AD. Kennedy DJ. Synthesis  2004,  43 
    Google Scholar
  • 4e Mishriky N. Asaad FM. Ibrahim YA. Girgis AS. Indian J. Chem., Sect. B: Org. Chem. Incl. Med. Chem.  1996,  35:  935 
    Google Scholar
  • 5 Szöllösi G. Török B. Baranyi L. Bartók M. J. Catal.  1998,  179:  619 
    Google Scholar
  • 6 Török B. London G. Bartók M. Synlett  2000,  631 
    Google Scholar
  • 7a Balogh M. Laszlo P. Organic Chemistry Using Clays   Springer; Berlin / Heidelberg: 1993. 
    Google Scholar
  • 7b Abid M. Török B. Spaeth A. Adv. Synth. Catal.  2006,  348:  2191 
    Google Scholar
  • 7c Abid M. Landge SM. Török B. Org. Prep. Proced. Int.  2006,  35:  495 
    Google Scholar
  • 7d Abid M. Török B. Adv. Synth. Catal.  2005,  347:  1797 
    Google Scholar
  • 8a Augustine RL. Heterogeneous Catalysis for the Synthetic Chemist   Marcel Dekker; New York: 1996. 
    Google Scholar
  • 8b Bartók M. Molnár . In Chemistry of Functional Groups   Suppl. A3:  Patai S. Wiley; Chichester: 1997.  Chap. 16. p.843 
    Google Scholar
  • 8c Smith GV. Notheisz F. Heterogeneous Catalysis in Organic Chemistry   Academic Press; San Diego: 1999. 
    Google Scholar
  • 8d Review: Blaser H.-U. Studer M. Adv. Synth. Catal.  2003,  345:  103 
    Google Scholar
  • 9a Varma RS. Dahiya R. Kumar S. Tetrahedron Lett.  1997,  38:  2039 
    Google Scholar
  • 9b Walla P. Kappe CO. Chem. Commun.  2004,  5:  594 
    Google Scholar
  • 9c Loupy A. Microwaves in Organic Synthesis   2nd ed.:  Wiley-VCH; Weinheim: 2006. 
    Google Scholar
  • 9d Kappe CO. Stadler A. Microwaves in Organic and Medicinal Chemistry   Wiley-VCH; Weinheim: 2005. 
    Google Scholar
  • 9e Kappe CO. Dallinger D. Nature Rev.  2006,  5:  51 
    Google Scholar