ETHYL GLUCOSIDE AS A MULTIFUNCTIONAL INITIATOR FOR ENZYME-CATALYZED REGIOSELECTIVE LACTONE RING-OPENING POLYMERIZATION

The one-pot biocatalytic synthesis of novel amphiphilic products consi sting of an ethyl glucopyranoside (EGP) headgroup and a hydrophobic ch ain is described. The porcine pancreatic Lipase (PPL) catalyzed ring-o pening polymerization of epsilon-caprolactone (epsilon-CL) by the mult ifunctional initiator EGP was carried out at 70 degrees C in bulk. Pro ducts of variable oligo(epsilon-CL) chain length (M-n = 450, 2200) wer e formed by variation of the epsilon-CL/EGP ratio. Extension of this a pproach using Candida antarctica lipase (Novozym-435) and EGP as the i nitiator for trimethylene carbonate (TMC) ring-opening polymerization also resulted in the formation of an EGP-oligo(TMC) conjugate (M-n = 7 200). Structural analysis by H-1, C-13, and COSY (C-13-C-13) NMR exper iments showed that the reaction was highly regiospecific; i.e., the ol igo(epsilon-CL)/oligo(TMC) chains formed were attached by an ester/car bonate link exclusively to the primary hydroxyl moiety of EGP.