Optimization of enzymatic ring-opening copolymerizations involving -gluconolactone as monomer by experimental design

Enzymatic incorporation of carbohydrate-derived monomer units into hydrophobic polyester backbones represents a promising alternative to obtain new biodegradable oligomers and polymers. Immobilized lipases are efficient biocatalysts for copolymerization of β-butyrolactone and δ-gluconolactone, but only a systematic optimization study was able to highlight the influence of the main reaction parameters on the polymerization degree and on the relative copolymer content of the product. Therefore, experimental design was employed for determination of the optimal ring-opening copolymerization conditions in solventless reaction systems, at temperatures up to 80 °C. The obtained products, cyclic and linear polyesters, have been characterized by FT-IR, MALDI-TOF MS, NMR, and TG analysis, demonstrating the incorporation of gluconolactone unit(s) into the hydrophobic backbone of the polyester and the formation of new bio-based products

Allylic Amines as Key Building Blocks in the Synthesis of ( E

Nucleophilic imine additions with vinyl organometallics have developed into efficient, high-yielding, and robust methodologies to generate structurally diverse allylic amines. We have used the hydrozirconation/transmetalation/imine addition protocol in the synthesis of allylic amine intermediates for peptide bond isosteres, phosphatase inhibitors, and mitochondria-targeted peptide mimetics. The gramicidin S-derived XJB-5-131 and JP4-039 and their analogues have been prepared on up to 160-g scale for preclinical studies. These (E)-alkene peptide isosteres adopt type II β-turn secondary structures and display impressive biological properties including selective reactions with reactive oxygen species (ROS) and prevention of apoptosis. © 2012 American Chemical Society

Abstracts of the 6th FECS Conference 1998 Lectures

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