Formation of substituted dioxanes in the oxidation of gum arabic with periodate
Harmke S. Siebe, Andy S. Sardjan, Sarina C. Maßmann, Jitte Flapper, Keimpe J. van den Berg, Niek N. H. M. Eisink, Arno P. M. Kentgens, Ben L. Feringa, Akshay Kumar, Wesley R. Browne
Abstract
1,2-diols in the rhamnopyranoside monosaccharides present as terminal groups in the biopolymer. While formally oxidation of vicinal diols results in the formation of two aldehyde groups, only traces of aldehydes are observed in solution, with the main final products obtained being substituted dioxanes, both in solution and in the solid state. The substituted dioxanes form most likely by the intramolecular reaction of one aldehyde with a nearby hydroxyl group, followed by hydration of the remaining aldehyde to form a geminal diol. The absence of significant amounts of aldehyde functional groups in the modified polymer impacts crosslinking strategies currently attempted in the preparation of renewable polysaccharide-based materials.