Cellulose allylcarbamate with high content of reactive double bonds for thiol-ene reaction

Abstract

Polysaccharide phenylcarbonates react with amines to form carbamates with high efficiency and can be used to introduce reactive CC bonds into a biopolymer, which may be converted by thiol-ene click reactions. Thus, cellulose phenylcarbonates are allowed react with allylamine by nucleophilic reaction to yield cellulose allylcarbamate of very high degree of substitution (DS). The DS of allylcarbamate moieties could be controlled by the molar ratio of allylamine to phenylcarbonate groups. Pure products without remaining phenylcarbonate substituents were accessible. The allylcarbamate moieties are reactive regarding the radical thiol-ene reaction that was exemplified by the reaction of cellulose allylcarbamate with 2-(diethylamino)ethane-1-thiol hydrochloride (DEAET) in dimethyl sulfoxide using a photoinitiator under mild conditions. The phenylcarbonates- and allylcarbamates of cellulose as well as the DAEAET adduct were characterized by elemental analysis, NMR- and FTIR spectroscopy.