Tetramethylguanidine-[bmim][BF4].: An efficient and recyclahle catalytic system for one-pot synthesis of 4H-pyrans

A clean and efficient method for the synthesis of 4H-pyran derivatives through the one-pot condensation of aromatic aldehydes, malononitriles, and beta-dicarbonyl compounds, using guanidine base tetramethylguanidine in [bmim][BF4] ionic liquid as a recyclable catalytic system, was described.