Enzyme-catalyzed ring-opening polymerization of 3(S)-isopropylmorpholine-2,5-dione

The enzymatic ring-opening polymerization of a 6-membered cyclic depsipeptide, 3(S)-isopropylmorpholine-2,5-dione in the bulk, was investigated by using lipases as catalysts at 100 and 130°C. Unchanged monomer was recovered in the absence of the enzyme or using an inactivated enzyme, indicating that the present polymerization proceeds through enzymatic catalysis. Poly(3-isopropylmorpholine-2,5-dione) has a carboxylic acid group at one end and a hydroxy group at the other end.