Organocatalyzed Ring-Opening Polymerization of (S)-3-Benzylmorpholine-2,5-Dione.

A 3-benzylmorpholine-2,5-dione monomer was synthesized from the natural amino acid l-phenylalanine and characterized by means of nuclear magnetic resonance and infrared spectroscopy, electro-spray ionization mass spectrometry and elemental analysis. Subsequent to preliminary polymerization studies, a well-defined poly(ester amide) homopolymer was synthesized via ring-opening polymerization using a binary catalyst system comprising diazabicyclo[5.4.0]undec-7-ene (DBU) and a 1-(3,5-bis(trifluoromethyl)-phenyl-3-cyclohexyl-2-thiourea) (TU) co-catalyst with a feed ratio of M/I/DBU/TU = 100/1/1/10. Kinetic studies revealed high controllability of the dispersities and molar masses up to conversions of almost 80%. Analysis by mass spectrometry hinted towards excellent end group fidelity at these conditions. In consequence, utilization of hydroxyl-functionalized poly(ethylene glycol) and poly(2-ethyl-2-oxazoline) as macroinitiators resulted in amphiphilic block copolymers. Bulk miscibility of the building blocks was indicated by differential scanning calorimetry investigations. As more and more promising new drugs are based on hydrophobic molecules featuring aromatic moieties, the novel polyesteramides seem highly promising materials to be used as potential drug delivery vehicles. This article is protected by copyright. All rights reserved.