Copper(II) acetate-catalyzed one-pot conversion of aldehydes into primary amides through a Beckmann-type rearrangement

Copper(II) acetate is a versatile catalyst for the direct transformation of any type of aldehydes into primary amides by stoichiometric reaction with hydroxylamine in water. The catalyst could be recovered 10 times without losing its activity, just by a simple organic layer extraction of the product. The catalyst and the protocol avoid the use of any type of expensive and difficult to handle organic ligand, as well as bases, showing excellent yields, under mild reaction conditions. The great purity of the crude product permits its purification by a simple recrystallization process. The whole protocol fulfils the principle of green chemistry and sustainability, minimizing the use of organic solvents and any type of wastes.