Hydrophobically modified polysaccharides that contain carboxyl groups possess exceptional features for drug delivery and other applications. Carboxyl groups were introduced at C-6 in the pullulan backbone by applying the well-established oxidation with TEMPO and NaOCl/NaBr. The oxidized product, 6-carboxypullulan, is even more water-soluble than pullulan. Consequently, further chemical modifications have been mainly restricted to reactions that can be performed in water or under heterogeneous conditions. We found that the TBA salt of 6-carboxypullulan is soluble in a range of organic solvents and can be reacted homogeneously with various alkyl halides in DMSO and sodium hydroxide at 40 �C to yield 6-carboxypullulan ethers. A full DS of 7 (per trisaccharide repeat unit) was achieved upon reaction with iodoethane, while reaction with longer chain alkyl halides led to products with DS up to about 3.   The amphiphilic products have impressive surfactant properties.

Synthesis of amphiphilic 6-carboxypullulan ethers

245th National Meeting (2013)

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