Comparison of the effectiveness of two piperazine based nano-catalysts in the synthesis of benzoxazoles and benzimidazoles and use of the powerful one in the N-Boc protection of amines.

Abstract

In this work, a comparison between the catalytic activity of two piperazine based ionic liquids immobilized on ZnO NPs and SiO2 NPs is presented in the synthesis of benzoxazoles and benzimidazoles. These reactions are performed under solvent free conditions during appropriate reaction times with high yields. The catalyst obtained from ZnO-NPs (PINZS), as the more efficient one, is used for the efficient promotion of the N-Boc protection of amines. High chemoselectivity, no by-products, facile separation of the catalyst, short reaction times and no need for volatile organic solvents are the best features of the proposed methods.