A rapid, easy, and efficient method for synthesis of 4,4'-(arylmethylene)-bis-(1H-pyrazol-5-ols), catalyzed by boehmite nanoparticles

An efficient and eco-friendly method is introduced for the synthesis of 4,4'-(arylmethylene)-bis-(1H-pyrazol-5-ols) by the condensation reaction of two equivalents of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one with various aromatic aldehydes, catalyzed by the boehmite nanoparticles (BNPs). This heterogeneous catalyst was recycled and used in four runs for the reaction between benzaldehyde and 3-methyl-l-phenyl-5-pyrazolone without any loss of its catalytic activity.