Controlled Synthesis of Polylatides using Biogenic Creatinine Carboxylate Initiators

摘要

@@1.Introduction In recent years the design and tailoring of biocompatible and biodegradable polymers have attracted considerable attention due to the increasingly demand of the pharmaeeutics and the biomedical science for bioresorbable materials. Polylactides (PLAs), homo-or eopolymers derived from lactides (LA) and glycolide, have found significant biomedical applications as resorhable sutures, drug-delivery carriers, artificial materials for tissue reconstruction and so forth. PLAs are prepared predominantly through ring-opening polymerization (ROP) of the corresponding cyclic esters. Stannous octoate Sn(Oct)2 is a widely and commercially used catalyst. The tin(Ⅱ) catalyst shows high catalytic efficiency in general, however its cytotoxicity has recently aroused increasingly deep concern about the biosafety of materials synthesized with it and use for man-purpose. Seeking tin-free catalysts of highly biosafety is a new challenge in this field. The design of metal-free organic initiators to realize the controlled synthesis of biodegradable polymers have recently attracted considerable interest and attention. Biodegradable polymers used for man-purse should be free of metals. Our work has focused on the design of guanidine-based initiators for the controlled synthesis of biodegradable polymers[1,2]. Guanidine is non-toxic organic base. Creatinine (CR) is a guanidine derivative participates in the human metabolism. Recently we synthesized two ereatinine carboxylates, I.e. Creatinine acetate (CRA) and ereatinine glycolate (CRG), and found that the two biogenic organic compounds effectively initiate the living ROP of lactides (Scheme 1).