Find in Library

In this study, new Cu(II)/chitosan-based systems were designed via (i) the treatment of chitosan with sodium sulfate (<b>1a</b>) or sodium acetate (<b>1b</b>); (ii) the coating of <b>1a</b> or <b>2a</b> with a sodium hyaluronate layer (<b>2a</b> and <b>2b</b>, correspondingly); (iii) the treatment of a cholesterol–chitosan conjugate with sodium sulfate (<b>3a</b>) or sodium acetate (<b>3b</b>); and (iv) the succination of <b>1a</b> and <b>1b</b> to afford <b>4a</b> and <b>4b</b> or the succination of <b>2a</b> and <b>2b</b> to yield <b>5a</b> and <b>5b</b>. The catalytic properties of the elaborated systems in various organic transformations were evaluated. The use of copper sulfate as the source of Cu²⁺ ions results in the formation of nanoparticles, while the use of copper acetate leads to the generation of conventional coarse-grained powder. Cholesterol-containing systems have proven to be highly efficient catalysts for the cross-coupling reactions of different types (e.g., Sonogashira, Buchwald–Hartwig, and Chan–Lam types); succinated systems coated with a layer of hyaluronic acid are promising catalysts for the aldol reaction; systems containing inorganic copper(II) salt nanoparticles are capable of catalyzing the nitrile-oxide-to-nitrile 1,3-dipolar cycloaddition. The elaborated catalytic systems efficiently catalyze the aforementioned reactions in the greenest solvent available, i.e., water, and the processes could be conducted in air. The studied catalytic reactions proceed selectively, and the isolation of the product does not require column chromatography. The product is separated from the catalyst by simple filtration or centrifugation.