Ionic liquid-catalyzed one-pot synthesis of 1 H-pyrano[2,3-d[pyrimidin-2(8a H)-one derivatives via three-component reaction under solvent-free conditions

摘要

A series of 1H-pyrano[2,3-d]pyrimidin-2(8aH)-one derivatives were synthesized via one-pot, three-component reaction of aromatic aldehydes, urea or thiourea, and 3,4-dihydro-2H-pyran using the green and inexpensive Brnsted acidic ionic liquid 1-methyl-2-pyrrolidinone hydrosulfate ([Hnmp]HSO _4) as catalyst under solvent-free conditions. The method has several advantages such as mild conditions, shorter reaction time, good yields, and environmentally benign procedure. Moreover, the catalyst could be recovered conveniently and reused at least four times without evident loss of activity.