Highly efficient and green chemical synthesis of imidazolyl alcohols and N-imidazolyl functionalized β-amino compounds using nanocrystalline ZSM-5 catalysts

Abstract

A solvent free protocol is developed for the synthesis of imidazolyl alcohols and N-imidazolyl functionalized β-amino compounds. Imidazolyl alcohols were synthesized by the ring opening of epoxides with imidazoles and N-imidazolyl functionalized β-amino compounds were synthesized by the hydroamination reaction of imidazoles and activated olefins. These reactions were catalyzed by a variety of crystalline heterogeneous catalysts such as Al/Zr substituted nanocrystalline ZSM-5 (M-Nano-ZSM-5), conventional M-ZSM-5 (where M = Zr, Al), and Zr substituted amorphous mesoporous catalysts (Zr-SBA-15 and Zr-KIT-6). Among these catalysts, nanocrystalline Zr-Nano-ZSM-5 exhibited the highest activity and regioselectivity. Structure activity relationship is explained based on the catalytic activity, acidity measurements, reactivity of reactants (imidazoles/epoxides/methyl acrylate), competitive adsorption, nature, and type of catalysts. Zr-Nano-ZSM-5 exhibited exceptionally high catalytic activity compared to the catalysts reported in the literature for the synthesis of imidazolyl alcohols and other imidazole derivatives.