A 4-trehalosamine-derived acrylamide monomer: Synthesis and preparation of composition-tunable water-soluble polyacrylamides.

4-Trehalosamine is a trehalase-resistant trehalose analog with a chemically differentiated amino group at the C4 position. Herein, we report the synthesis of a 4-trehalosamine-derived acrylamide monomer and its homo- and copolymerization with acrylamide (AAm). The monomer was prepared by the acylation of 4-trehalosamine with 6-bromohexanoyl chloride, azide substitution, per-O-acetylation, deacetylation, azide reduction, and acryloylation. The conversion of the terminal bromide to an azide before per-O-acetylation facilitated the chromatographic isolation of the protected intermediate. Aqueous redox polymerization using ammonium persulfate (APS) and N, N, N', N'-tetramethylethylenediamine (TEMED) afforded a water-soluble homopolymer and a series of copolymers with AAm. 1H NMR spectroscopy showed that the pendant trehalosamine content could be varied by changing the monomer feed ratio, although the copolymers became increasingly AAm-rich relative to the feed at higher AAm concentrations. Aqueous size-exclusion chromatography yielded apparent weight-average molecular weights of 215-305 kDa and dispersities of 1.24-2.26. These results establish the differentiated C4 amino group of 4-trehalosamine as a practical entry point for constructing an acrylamide glycomonomer and composition-tunable polyacrylamides bearing pendant trehalosamine units.