Synthesis and Structural Characterization of Phenylcarbamate Derivatives of Chitin and Chitosan

Phenylcarbamate derivatives of chitin and chitosan with different degrees of substitution were synthesized via addition reactions of phenyl isocyanate onto polysaccharides under various conditions. The molecular structure of the phenylcarbamate derivatives was characterized mainly through (1)H NMR measurements A two-dimensional (1)H NMR technique, double quantum filtered correlation spectroscopy, and a long-range selective proton decoupling (13)C NMR were also applied for precise spectral assignments On the basis of the spectral data, equations were proposed to determine the degree of substitution (DS), molar substitution (MS), and degree of polymerization in the side chains (DPs). These molecular characterizations indicated that phenyl isocyanate reacted not only with the hydroxyl and amino groups of the chitinous polymers but also with the phenylcarbamoyl groups previously Introduced, so that urethane, urea, allophanate and biuret could be formed in the finally obtained derivatives.