PREPARATION AND BIODEGRADABILITY OF CHITIN DERIVATIVES HAVING MERCAPTO GROUPS

Two kinds of chitin derivatives having mercapto groups have been prepared, and the properties, including solubility and susceptibility to lysozyme, are discussed. Chitosan was first modified by N-acylation with S-protected mercaptoacetic acid, followed by selective acetylation of the remaining amino groups and deprotection to give derivatives having mercaptoacetyl groups at the C-2 amino groups. In an alternative preparation of mercapto-chitins, tosyl-chitin was treated with potassium thioacetate and then with alkali to afford derivatives having mercapto groups at the C-6 positions. The derivatives showed much enhanced swelling and solubility in organic solvents. Biodegradability of the mercapto derivatives was evaluated with lysozyme, and they turned out to be more susceptible to enzyme hydrolysis than the original chitin.