Synthesis of Phosphorus-Containing Chitosan Derivatives

Three new phosphorus-containing chitosan derivatives were prepared in good yield under mild conditions from 6-O-triphenylmethyl-chitosan and native chitosan. The three reactions used are thioacylation by a phosphonodithioester, alkylation by a halogeno-phosphonate, and Michael addition using a tetraethyl vinylidenebisphosphonate. The modified chitosan derivatives were fully characterized; their solubilities and thermal properties were evaluated.