Immobilized galactose oxidase in alginate gel (GO-Bead): a versatile and efficient biocatalyst for the regioselective synthesis of 1,4-disubstitued-1,2,3-triazoles: click reaction

Abstract

Galactose oxidase (E.C. 1.1.3.9) is an extracellular oxidoreductase enzyme containing Cu(I) which is produced by some fungi like Fusarium species. The enzyme catalyzes the selective oxidation of primary alcohols like galactose. In this study, a heterogeneous enzymatic system for click reaction was prepared. The most important advantage of the heterogeneous catalyst is the ease of separation and their possible reusability. Therefore, galactose oxidase was immobilized by entrapment; for this purpose, alginate polysaccharide beads with different diameters were synthesized and galactose oxidase was immobilized into them to obtain galactose oxidase-bead (GO-Bead). Next, the catalytic activity of galactose oxidase-beads was examined in the one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles via click reaction comprising diversely benzyl halides, sodium azide and different alkynes in aqueous medium which need Cu(I) for their performance. The catalyst was conventionally recovered and effectively reused in several runs with no appreciable decrease in its catalytic activity.