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Synthesis of Pyrazolo[3,4‐ d ]pyrimidin‐4‐ones Catalyzed by Br?nsted‐acidic Ionic Liquids as Highly Efficient and Reusable Catalysts
Author(s) -
TavakoliHoseini Niloofar,
Moloudi Raheleh,
Davoodnia Abolghasem,
Shaker Mohammad
Publication year - 2011
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.201180411
Subject(s) - chemistry , ionic liquid , hydrogen sulfate , catalysis , sulfonic acid , solvent , brønsted–lowry acid–base theory , homogeneous , organic chemistry , hydrogen , medicinal chemistry , physics , thermodynamics
Abstract A convenient and efficient method for the synthesis of pyrazolo[3,4‐ d ]pyrimidin‐4‐ones via heterocyclization reaction of 5‐amino‐1 H ‐pyrazole‐4‐carboxamides with triethyl orthoesters using two Br?nsted‐acidic ionic liquids, 3‐methyl‐1‐(4‐sulfonic acid)butylimidazolium hydrogen sulfate [MIM + (CH 2 ) 4 SO 3 H][HSO 4 − ] or N ‐(4‐sulfonic acid)butyl triethylammonium hydrogen sulfate [Et 3 N + (CH 2 ) 4 SO 3 H][HSO 4 − ], as efficient homogeneous catalysts under solvent‐free conditions is described.