Coupling reactions of activated oligo(epsilon-caprolactone)s

Oligo(epsilon-caprolactone)s functionalised with acid groups were prepared by reacting hydroxyl terminated oligo(epsilon-caprolactone)s with succinic anhydride, maleic anhydride or glutaric anhydride. Quantitative conversion of the hydroxyl functionality was achieved in the melt at 130 degrees C. Th e resulting acid terminated oligo(epsilon-caprolactone)s were characterised by H-1 and C-13 NMR spectroscopy. The reactivity of these oligomers was en hanced by conversion of the acid functionality in an acid chloride function ality using thionyl chloride or an anhydride functionality using acetic anh ydride. It was shown that these activated oligo(epsilon-caprolactone)s can be used for coupling reactions with compounds containing alcohol- or amino functionalities.