LAUSR

Polyesters are known biodegradable materials that are frequently used for biomedical applications that require biocompatibility. Their synthesis usually requires transition metal catalysts, which may become a source of contamination. In addition, using such compounds translates to extensive purification procedures, which do not agree with green chemistry principles. In addition to being renewable, enzymes such as lipases are milder for biological systems, and were studied for both ring-closure and ring-opening reactions. Here, Candida antarctica lipase B was used in ring-closure, reducing a two-step synthesis to a single step with 58% yield. The bile acid-containing macrocycles were subsequently polymerized with the same enzyme; relatively high molar masses (40 000 g/mol) were obtained. The conditions for the enzymatic ring-closure and ring-opening reactions were established through the reaction of thapsic acid with 1,10-decanediol. The di- and tetralactones afforded semicrystalline polymers with relative...