Coupling of polysaccharides activated by means of chloroacetaldehyde dimethyl acetal to amines or proteins by reductive amination

Abstract A novel method has been developed for the coupling of modified polysaccharides to proteins or other amines. Chloroacetaldehyde dimethyl acetal has been used for the introduction of O -(2,2-dimethoxyethyl) groups into amylose, dextran, and a linear (1→3)-β- d -glucan. In amylose and the (1→3)-β- d -glucan, these groups were attached preponderantly at O-6 and in dextran at O-2. Mild treatment with acid then gave polysaccharide derivatives substituted with aldehyde groups which were coupled in good yields to proteins and other amines by reductive amination with sodium cyanoborohydride in aqueous solution at pH 7. An aminated (1→3)-β- d -glucan derivative that induced antitumor activity in mouse macrophages in vitro is reported.