Proton transfer-controlled anionic polymerization of methyl-substituted ?-lactams with potassiumt-butoxide and subsequent coupling reaction with saccharides

Hashimoto, Kazuhiko; Yasuda, Jun; Kobayashi, Masaki

doi:10.1002/(sici)1099-0518(19990401)37:7<909::aid-pola7>3.0.co;2-j

Cited by 19 publications

(12 citation statements)

References 18 publications

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“…12; we note, however, that in the β-lactam imides of these small-molecule examples the exo-cyclic carbonyl is derived from a carbonic acid rather than a carboxylic acid). Indeed, there are limited reports of nylon-3 C-terminal modification with nucleophilic attack by amines or alcohols, 8, 9 but we found this approach to be capricious.…”

Section: Discussionmentioning

confidence: 91%

“…7 One might expect that this imide moiety would be broadly susceptible to reaction with nucleophiles, but we found it to be difficult or impossible to achieve efficient reaction of nylon-3 polymer end groups with amines or alcohols (unpublished), despite reports that the nylon-3 polymer shown in Figure 2 undergoes C-terminal reaction with benzylamine, 8 methyl α-D-glucoside or a polysaccharide. 9 To the best of our knowledge, there are no other reports describing C-terminal functionalization of nylon-3 polymers. Our failure to achieve efficient C-terminal functionalization with simple nucleophiles led us to explore specifically functionalized β-lactams for this purpose.…”

Section: Introductionmentioning

confidence: 99%

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C-Terminal Functionalization of Nylon-3 Polymers: Effects of C-Terminal Groups on Antibacterial and Hemolytic Activities

et al. 2011

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Nylon-3 polymers contain β-amino acid-derived subunits and can be viewed as higher homologues of poly(α-amino acids). This structural relationship raises the possibility that nylon-3 polymers offer a platform for development of new materials with a variety of biological activities, a prospect that has recently begun to receive experimental support. Nylon-3 homo- and copolymers can be prepared via anionic ring-opening polymerization of β-lactams, and use of an N-acyl-β-lactam as co-initiator in the polymerization reaction allows placement of a specific functional group, borne by the N-acyl-β-lactam, at the N-terminus of each polymer chain. Controlling the unit at the C-termini of nylon-3 polymer chains, however, has been problematic. Here we describe a strategy for specifying C-terminal functionality that is based on the polymerization mechanism. After the anionic ring-opening polymerization is complete we introduce a new β-lactam, approximately one equivalent relative to the expected number of polymer chains. Because the polymer chains bear a reactive imide group at their C-termini, this new β-lactam should become attached at this position. If the terminating β-lactam bears a distinctive functional group, that functionality should be affixed to most or all C-termini in the reaction mixture. We use the new technique to compare the impact of N- and C-terminal placement of a critical hydrophobic fragment on the biological activity profile of nylon-3 copolymers. The synthetic advance described here should prove to be generally useful for tailoring the properties of nylon-3 materials.

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Section: Discussionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

C-Terminal Functionalization of Nylon-3 Polymers: Effects of C-Terminal Groups on Antibacterial and Hemolytic Activities

et al. 2011

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“…In view of the current demand for functional and environmentally benign polymeric materials [25][26][27], the idea of obtaining polyesters and polyamides through direct carbonylative polymerization of heteroatom-containing monomers (COPH) deserves reassessment. Particularly, the carbonylative approach should serve as an alternative method for the synthesis of these advanced materials complementary to the relatively established methods of ring-opening polymerization of lactones and lactams [28][29][30][31][32][33][34]. In 1997, Sen [35,36] reported an oxidative carbonylative polymerization producing polysuccinates.…”

Section: Introductionmentioning

confidence: 99%

The role of phosphine in cobalt-catalyzed carbonylative polymerization of N-alkylaziridine

LeGall

et al. 2005

Journal of Organometallic Chemistry

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“… 15 Anionic ROP was selected for the polymerization strategy, as it can provide polymers of low dispersity and controlled length. 16 Polymerization of the monomer was performed for several degrees of polymerization (DP) from 20 to 50. Briefly, monomer and x mol % BocGly-OPFP, an activated ester initiator, were combined in freshly distilled THF and cooled to 0 °C, and 2.5 x mol % LiHMDS was added to begin the reaction.…”

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confidence: 99%

Carboxylated Glucuronic Poly-amido-saccharides as Protein Stabilizing Agents

et al. 2014

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The synthesis of novel carbohydrate-based polymers allows the structure to be tailored at the monomer level for a specific property and expands the range of available structures beyond those found in nature. Using a controlled anionic polymerization, a new type of carbohydrate polymer is synthesized in which glucose-derived monomers are joined by an α-1,2 amide linkage to give enantiopure poly-amido-saccharides (PASs). To investigate the effect of adding ionizable carboxylic acid groups, such as those found in natural polysaccharides containing glucuronic acid, the oxidation of the primary alcohol at the C6-position of the repeat unit to a carboxylic acid is reported. TEMPO-mediated oxidation provides control over the degree of oxidation in excellent yield. Based on circular dichroism, the oxidized polymers possess an ordered helical secondary structure in aqueous solution. Finally, oxidized PASs stabilize lysozyme toward dehydration and freezing stresses better than a current, widely used protein stabilizing agent, trehalose.

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Proton transfer-controlled anionic polymerization of methyl-substituted ?-lactams with potassiumt-butoxide and subsequent coupling reaction with saccharides

Cited by 19 publications

References 18 publications

C-Terminal Functionalization of Nylon-3 Polymers: Effects of C-Terminal Groups on Antibacterial and Hemolytic Activities

C-Terminal Functionalization of Nylon-3 Polymers: Effects of C-Terminal Groups on Antibacterial and Hemolytic Activities

The role of phosphine in cobalt-catalyzed carbonylative polymerization of N-alkylaziridine

Carboxylated Glucuronic Poly-amido-saccharides as Protein Stabilizing Agents

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