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Synlett 2007(10): 1600-1604
DOI: 10.1055/s-2007-982545
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
Further Information
Received
22 March 2007
Publication Date:
06 June 2007 (online)
Publication History
Publication Date:
06 June 2007 (online)
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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
-
1a
Zificsak CA.Hlasta DJ. Tetrahedron 2004, 60: 8991 -
1b
Haino T.Tanaka M.Ikeda K.Kubo K.Mori A.Fukazawa Y. Tetrahedron Lett. 2004, 45: 2277 -
1c
Török M.Abid M.Mhadgut SC.Török B. Biochemistry 2006, 45: 5377 -
1d
Török B.Abid M.London G.Esquibel J.Török M.Mhadgut SC.Yan P.Prakash GKS. Angew. Chem. Int. Ed. 2005, 44: 3086 -
2a
Xiao L.Lu XY.Ruden DM. Mini-Rev. Med Chem. 2006, 6: 1137 -
2b
McDonald E.Jones K.Brough PA.Drysdale MJ.Workman P. Curr. Top. Med. Chem. 2006, 6: 1193 -
2c
Barsoum FF.Hosni HM.Girgis AS. Bioorg. Med. Chem. 2006, 14: 3929 -
2d
Stauffer SR.Coletta CJ.Tedesco R.Nishiguchi G.Carlson K.Sun J.Katzenellenbogen BS.Katzenellenbogen JA. J. Med. Chem. 2000, 43: 4934 -
2e
Prasanna S.Manivannan E.Chaturvedi SC. J. Enzyme Inhib. Med. Chem. 2005, 20: 455 -
3a
Elguero J. In Comprehensive Heterocyclic Chemistry II Vol. 3:Katritzky AR.Rees CW.Scriven EFV. Pergamon Press; Oxford: 1996. p.1 -
3b
Lautens M.Roy A. Org. Lett. 2000, 2: 555 -
3c
Wang X.Tan J.Grozinger K. Tetrahedron Lett. 2000, 41: 4713 -
4a
Huang YR.Katzenellenbogen JA. Org. Lett. 2000, 2: 2833 -
4b
Katritzky AR.Wang M.Zhang S.Voronkov MV. J. Org. Chem. 2001, 66: 6787 -
4c
Kovelesky AC.Shine HJ. J. Org. Chem. 1988, 53: 1973 -
4d
Bishop BC.Brands KMJ.Gibbs AD.Kennedy DJ. Synthesis 2004, 43 -
4e
Mishriky N.Asaad FM.Ibrahim YA.Girgis AS. Indian J. Chem., Sect. B: Org. Chem. Incl. Med. Chem. 1996, 35: 935 - 5
Szöllösi G.Török B.Baranyi L.Bartók M. J. Catal. 1998, 179: 619 - 6
Török B.London G.Bartók M. Synlett 2000, 631 -
7a
Balogh M.Laszlo P. Organic Chemistry Using Clays Springer; Berlin / Heidelberg: 1993. -
7b
Abid M.Török B.Spaeth A. Adv. Synth. Catal. 2006, 348: 2191 -
7c
Abid M.Landge SM.Török B. Org. Prep. Proced. Int. 2006, 35: 495 -
7d
Abid M.Török B. Adv. Synth. Catal. 2005, 347: 1797 -
8a
Augustine RL. Heterogeneous Catalysis for the Synthetic Chemist Marcel Dekker; New York: 1996. -
8b
Bartók M.Molnár . In Chemistry of Functional Groups Suppl. A3:Patai S. Wiley; Chichester: 1997. Chap. 16. p.843 -
8c
Smith GV.Notheisz F. Heterogeneous Catalysis in Organic Chemistry Academic Press; San Diego: 1999. -
8d Review:
Blaser H.-U.Studer M. Adv. Synth. Catal. 2003, 345: 103 -
9a
Varma RS.Dahiya R.Kumar S. Tetrahedron Lett. 1997, 38: 2039 -
9b
Walla P.Kappe CO. Chem. Commun. 2004, 5: 594 -
9c
Loupy A. Microwaves in Organic Synthesis 2nd ed.: Wiley-VCH; Weinheim: 2006. -
9d
Kappe CO.Stadler A. Microwaves in Organic and Medicinal Chemistry Wiley-VCH; Weinheim: 2005. -
9e
Kappe CO.Dallinger D. Nature Rev. 2006, 5: 51