Introduction of [2,2'-Bipyridine]-1,1'-Diium Perchlorate as a Novel and Highly Efficient Dicationic Bronsted Acidic Organic Salt for the Synthesis of 3-Methyl-4-Arylmethylene Isoxazole-5(4H)-One Derivatives in Water

In this work, a novel pyridinium-based dicationic organic salt, [H-2-BiPyr][ClO4](2), was easily prepared and characterized by FT-IR and NMR spectroscopy. After characterization, it was used as the catalyst in a one-pot multi-component reaction of aromatic aldehydes, ethyl acetoacetate and hydroxylamine hydrochloride under aqueous conditions at reflux temperature leading to the formation of 3-methyl-4-arylmethylene isoxazole-5(4H)-one derivatives. Easy and low-cost preparation of the catalyst, high yields, short reaction times and acceptable reusability of the catalyst are the most important advantages of this method.

Automated summary

A novel dicationic organic salt catalyst was successfully utilized in promoting the metal-free multi-component reaction of pyridine with aromatic aldehydes under aqueous conditions, resulting in the formation of the desired products. The method offers advantages such as easy preparation of the catalyst, high reaction efficiency, short reaction time, and reusability of the catalyst.