Highly convergent synthesis of dendrimerized chitosan-sialic acid hybrid

Surface bound chitosan-sialodendrimers with a high degree of substitution w ere successfully prepared using a doubly convergent approach. Poly(amidoami ne) (PAMAM) dendrimers (G = 1-5) having a 1,4-diaminobutane core were amida ted to N-carboxyethylchitosan methyl ester under conditions that prevented cross-linking. The extent of attachment (DS) to the polysaccharide backbone decreased from 0.53 to 0.11 with increasing dendrimer generation. Peracety lated p-formylphenyl alpha -sialoside was then successfully attached to the primary amine end groups of the dendrimerized chitosan hybrid with degree of substitution (DS) ranging from 0.7 to 1.4 using reductive amination. Wat er-soluble chitosan-sialodendrimer hybrids were finally obtained after prot ecting group hydrolysis and chitosan N-succinylation.