Ionic Liquid Promoted Facile One-Pot Synthesis of 1-Pyridylimidazo[1,5-a]pyridines from Dipyridylketone and Aryl Aldehydes

Abstract

A highly efficient one-pot methodology has been developed to synthesize a class of substituted 1-pyridylimidazo[1,5-a]pyridines, using Bronsted acidic ionic liquid 1-butylimidazolium tetrafluoroborate, [Hbim]BF₄ in excellent isolated yields in the absence of any catalyst. The methodology is characterized by simple work-up procedures along with efficient recovery and recycling of the ionic liquid, which acts as a reaction medium as well as a promoter.

Key words

imidazo[1,5-a]pyridines - aldehyde - heterocycles - ionic liquids - ammonium acetate

References

• 1 Biachi G. Rodriguez A. Yakurshigiu K. J. Org. Chem.  1989,  54:  4497 
• 2 Bolger L. Brittain RJ. Jack D. Jackson MR. Martin LE. Mills J. Poynter D. Tyers MB. Nature (London)  1972,  238:  354 
• 3 Zito SW. Martlnez M. J. Biol. Chem.  1980,  255:  8645 
• 4 Jansonius JN. Eichele G. Ford GC. Picot D. Thaller C. Vicent MG. In Transaminases   Christen P. Metzler DE. Wiley; New York: 1985.  p.110 
• 5 Arbilla S. Allen J. Wick A. Langer S. Eur. J. Pharmacol.  1986,  130:  257 
• 6 Ford NF. Browne LJ. Campbell T. Gemenden C. Goldstein R. Gude C. Wasley JNF. J. Med. Chem.  1985,  28:  164 
• 7 Ligtenbarg AJ. Spek AL. Hage R. Feringa BL. J. Chem. Soc., Dalton Trans.  1999,  659 
• 8 Bluhm ME. Ciesielski M. Gorls H. Walter O. Doring M. Inorg. Chem.  2003,  42:  8878 
• 9a Bower JD. Ramage GR. J. Chem. Soc.  1955,  2834 
• 9b Winterfeld K. Franzke H. Angew. Chem., Int. Ed. Engl.  1963,  75:  1101 
• 10a Bourdais J. Omar A.-ME. J. Heterocycl. Chem.  1980,  17:  555 
• 10b El Khadem HS. Kawai J. Swartz DL. Heterocycles  1989,  28:  239 
• 11 Sasaki K. Tsurumori A. Hirota T. J. Chem. Soc., Perkin Trans. 1  1998,  3851 
• 12 Palacios F. Alonso C. Rubiales G. Tetrahedron  1995,  51:  3683 
• 13 Katritzky AR. Qiu G. J. Org. Chem.  2001,  66:  2862 
• 14a Krapcho AP. Powell JR. Tetrahedron Lett.  1986,  27:  3713 
• 14b Grigg R. Kennewell P. Savic V. Sridharan V. Tetrahedron  1992,  48:  10423 
• 15 Wang J. Dyers L. Mason R. Amoyaw P. Bu XR. J. Org. Chem.  2005,  70:  2353 
• 16 Bluhm ME. Ciesielski M. Gorls H. Walter O. Doring M. Angew. Chem. Int. Ed.  2002,  41:  2962 
• 17a Welton T. Chem. Rev.  1999,  99:  2071 
• 17b Wasserscheid P. Keim W. Angew. Chem. Int. Ed.  2000,  39:  3772 
• 18a Deshmukh RR. Rajagopal R. Srinivasan KV. Chem. Commun.  2001,  1544 
• 18b Rajagopal R. Jarikote DV. Srinivasan KV. Chem. Commun.  2002,  616 
• 19a Palimkar SS. Siddiqui SA. Thomas D. Lahoti RJ. Srinivasan KV. J. Org. Chem.  2003,  68:  9371 
• 19b Siddiqui SA. Synlett  2006,  155 
• 20 Perrin DD. Ionization Constant of Inorganic Acids and Bases in Aqueous Solution   2nd ed.:  Pergamon; Elmsford, New York: 1982. 
• 21 Fletcher KA. Storey IA. Hendricks AE. Pandey S. Pandey S. Green Chem.  2001,  3:  210