Chemoenzymatic Synthesis of Fluorescent and Colored Polyesters

A simple chemoenzymatic strategy for the synthesis of colored and fluorescent poly(epsilon-caprolactone) esters has been developed. The procedure involves first the reaction of a functionalized primary amine with epsilon-caprolactone, to give an amide with a terminal primary hydroxy group, followed by an enzymatic ring-opening polymerization catalyzed by Novozym 435. The proposed method is easy to handle and is suitable for the incorporation of different amines, as it shown for the yellow compound N-deacetylthiocolchicine and the fluorescent amines 4-(2-aminoethylamino)-7-(N,N-dimethylsulfamoyl) benzofurazan and dansylcadaverine. A similar strategy is considered for the synthesis of poly(epsilon-caprolactone) esters, employing alcohols as initiators of the reaction. In this case, an intermediate ester carrying a terminal primary hydroxy group cannot be isolated and the reaction forms directly the desired polymers.