Novel Functional Polycarbonate by Lipase-Catalyzed Ring-Opening Polymerization of 5-Methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one
TL;DR: In this article, an enzyme-catalyzed ring-opening polymerization of a novel carbonate monomer, 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one, was reported.
Abstract: Water-soluble polycarbonate having pendent carboxyl groups on the main-chain carbons is reported for the first time. This paper describes synthesis and enzyme-catalyzed ring-opening polymerization of a novel carbonate monomer, 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one (1). Various commercially available lipases were screened for their ability to polymerize 1 in bulk at 80 °C. Monomer conversion and molecular weight of the polymer were significantly influenced by the source of the enzyme. For example, of the seven lipases screened, lipase AK (from Pseudomonas fluorescens) gave the highest monomer conversion (97%) and molecular weight (Mn = 6100). In reactions carried out under identical experimental conditions, no polymerization was observed when thermally deactivated lipase AK was used. Debenzylation of 2 by catalytic hydrogenation led to the corresponding linear polycarbonate, 3, with pendent carboxyl groups. Presence of pendent carboxyl groups is expected to enhance the biodegradability of the polyc...
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TL;DR: This review presents a comprehensive introduction to various types of synthetic biodegradable polymers with reactive groups and bioactive groups, and further describes their structure, preparation procedures and properties.
1,088 citations
TL;DR: In this article, the ring-opening polymerization of cyclic monomers is used as a representative polymerization process to illustrate some of the features of organic catalysts and initiators and compare them to metal-based approaches.
Abstract: Organocatalysis offers a number of opportunities in polymer synthesis and was among the earliest methods of catalyzing the synthesis of polyesters. In the following Perspective we attempt to highlight the opportunities and challenges in the use of organic molecules as catalysts or initiators for polymerization reactions. The ring-opening polymerization of cyclic monomers is used as a representative polymerization process to illustrate some of the features of organic catalysts and initiators and to compare them to metal-based approaches. The convergence of convenience, functional group tolerance, fast rates, and selectivities will continue to drive innovations in polymerization catalysis, and it is our perspective that organocatalysis will continue to play an important role in these developments.
749 citations
TL;DR: Microbial polymers are synthesized from renewable low-cost feedstocks, and the polymerizations operate under mild process conditions with minimal environmental impact, providing products that, when disposed, can degrade to nontoxic products.
Abstract: In nature, living organisms are constantly producing different macromolecules for their metabolic needs. These macromolecules, such as polysaccharides, polynucleotides, proteins, or polyesters, are essential to organism survival. Their synthesis generally involves in vivo enzyme-catalyzed chaingrowth polymerization reactions of activated monomers, which are generally formed within the cells by complex metabolic processes. Because of their diversity and renewability, microbial polymers such as polysaccharides, bacterial polyhydroxyalkanoates (1) and polyanions such as poly(γ-glutamic acid) (2) have received increasing attention as candidates for industrial applications. In many cases, microorganisms carry out polymer syntheses that are impractical or impossible to accomplish with conventional chemistry. Thus, microbial catalysts enable the production of materials that might otherwise be unavailable. Microbial polymers are synthesized from renewable low-cost feedstocks, and the polymerizations operate under mild process conditions with minimal environmental impact. In addition, microbial polymers provide products that, when disposed, can degrade to nontoxic products.
640 citations
TL;DR: This review presents the recent trends in the synthesis of functional aliphatic polyesters and their application for protein delivery and tissue engineering.
366 citations
TL;DR: The present review outlines the development up to date concerning the design and biomedical application of functional aliphatic polycarbonates, with an emphasis on their ring-opening (co)polymerization preparation.
300 citations
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TL;DR: In this article, a review brings together the literature on various aspects of the bioerosion of polymers containing ester groups, with particular emphasis on release and degradation studies that might form a basis for the design and selection of controlled macromolecular release systems.
484 citations
331 citations
TL;DR: The fourth generation tridendron dendrimer based on 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) with 48 hydroxyl groups was synthesized in high yields using N,N‘-dicyclohexylcarbodiimide (DCC) for the coupling steps as discussed by the authors.
Abstract: The fourth generation tridendron dendrimer based on 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) with 48 hydroxyl groups was synthesized in high yields using N,N‘-dicyclohexylcarbodiimide (DCC) for the coupling steps A double-stage convergent approach reduced the number of synthetic and liquid chromatographic steps required in the synthesis and purification of the final dendrimers The hydroxyl functional dendrimer was subjected to a variety of surface modifications by reaction with different acid chlorides The acetonide, hydroxy, acetate, n-octanoate, n-palmitoate, and benzoate end-functionalized dendrimers showed large differences in thermal and solution behavior depending on the nature of their end groups The glass transition temperature varied from −4 °C for the acetate-terminated dendrimer to +57 °C for the hydroxyl-functionalized dendrimer Dendrimers terminated with long alkyl chains were highly soluble in hexane and dichloromethane and poorly soluble in water and methanol whereas the hydroxy-
297 citations
TL;DR: Comparison of % conversion vs time for bulk PDL polymerizations at 70 °C catalyzed by NI- and I-PS-30 showed that for short reaction times, the immobilized catalyst gave % conversions that were more than 10 times greater.
Abstract: Lipase-catalyzed ring-opening bulk polymerizations of ω-pentadecalactone (PDL) were investigated. Screening of selected commercial lipases as catalysts for PDL polymerization at 80 °C was carried out. The results of this work showed that polymerizations catalyzed by lipases PS-30, AK, Lipozyme-IM and Novozym-435 gave % PDL conversions ranging from 80 to 100% for 24 h reactions (Mn = 15 000−34 400). Lipase PS-30 both physically immobilized onto Celite-521 (I-PS-30) and in the crude powder or nonimmobilized form (NI-PS-30) was selected for further study. Comparison of % conversion vs time for bulk PDL polymerizations at 70 °C catalyzed by NI- and I-PS-30 showed that for short reaction times, the immobilized catalyst gave % conversions that were more than 10 times greater. In fact, the % monomer conversion to poly(PDL) was nearly quantitative (>98%) for 8 h polymerizations catalyzed by I-PS-30. Furthermore, for reactions conducted at 70 °C with careful removal of water, substantially greater poly(PDL) molecu...
174 citations
TL;DR: In this paper, a copolymere alterne forme d'unites acide glycolique et α-(S)-malate de benzyle is presented, which is a forme de benzyl acid.
Abstract: Obtention d'un copolymere alterne forme d'unites acide glycolique et α-(S)-malate de benzyle
161 citations