P2W18O62.24H2O as efficient and recyclable catalyst for the ecofriendly preparation of beta-aminocrotonates

Abstract

H6P2W18O62·24H2O bulk- and silica-supported catalysts were found to be efficient and recyclable catalysts for the synthesis of a series of -aminocrotonates using toluene as the solvent or under no solvent reaction conditions. Several substituted -aminocrotonates can be prepared in very good yields and purity by direct reaction of amines and 1,3-dicarbonyl compounds in the presence of a catalytic amount of bulk- and silica-gel-supported H6P2W18O62·24H2O. The title compounds were prepared in very good yields using both methodologies, and no secondary products were detected. The procedure using no reaction solvent resulted in a clean and useful alternative, which has the advantages of a greener methodology with operative simplicity, the use of a reusable and noncorrosive solid catalyst, soft reaction conditions, low reaction times, and good yields.