A pH-dependent cyanate reactivity model: application to preparative N-carbamoylation of amino acids

Taillades, J.; Boiteau, Laurent; Beuzelin, Isabelle; Lagrille, Olivier; Biron, Jean‐Philippe; Vayaboury, Willy; Vandenabeele-Trambouze, O.; Giani, Olivia; Commeyras, A.

doi:10.1039/b005856o

Cited by 43 publications

(36 citation statements)

References 14 publications

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“…[32] DMF was distilled over 4 Å molecular sieves in vacuo before the polymerization. After the synthesis of N a -carbamoyl-N e -trifluoroacetyl-L-lysine (Lys NCAA) by reaction between N e -trifluoroacetyl-L-lysine and potassium cyanate in aqueous medium, [33] Lys NCA was prepared by nitrosation of Lys NCAA using an NO/O 2 gas mixture. [34,35] In a Schlenk flask fitted with a stir bar and a silicon septum, 2.144 g of Lys NCA was dissolved under nitrogen in 50 mL of distilled DMF.…”

Section: Polymerization Under Standard Conditionsmentioning

confidence: 99%

Living Polymerization of α‐Amino Acid N‐Carboxyanhydrides (NCA) upon Decreasing the Reaction Temperature

Vayaboury¹,

Giani²,

Cottet³

et al. 2004

Macromol. Rapid Commun.

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168

133

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Summary: The n‐hexylamine‐initiated polymerization of Nε‐trifluoroacetyl‐L‐lysine N‐carboxyanhydride in N,N‐dimethyformamide was studied by nonaqueous capillary electrophoresis. A polypeptide with a broad molecular weight distribution was obtained and side reactions were clearly identified for polymerization at room temperature. The possibility of living polymerization at 0 °C was demonstrated.Synthesis of living polypeptides by primary amine initiated polymerization of NCA at low temperatures.imageSynthesis of living polypeptides by primary amine initiated polymerization of NCA at low temperatures.

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Section: Polymerization Under Standard Conditionsmentioning

confidence: 99%

Living Polymerization of α‐Amino Acid N‐Carboxyanhydrides (NCA) upon Decreasing the Reaction Temperature

Vayaboury¹,

Giani²,

Cottet³

et al. 2004

Macromol. Rapid Commun.

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168

133

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“…[29] NO + O 2 -promoted nitrosation [28] of C-LysA C H T U N G T R E N N U N G (Tfa) in acetonitrile gave monomer LysA C H T U N G T R E N N U N G (Tfa)-NCA, which was then reacted in aqueous sodium hydrogen carbonate (pH 6.5) to give N e -protected oligoA C H T U N G T R E N N U N G (l-lysine) G1P. An important feature of this reaction sequence is that both nitrosation and polycondensation steps were carried out in one pot without isolating the NCA intermediate.…”

Section: Resultsmentioning

confidence: 97%

“…Synthesis: The synthesis of the first generation of polyA C H T U N G T R E N N U N G (llysine) was carried out by a three-step sequence (Scheme 2) by implementing the knowledge from our research group [17,28,29] and by starting from N-carbamoyl derivative CLysA C H T U N G T R E N N U N G (Tfa), which was prepared by a straightforward NcarbamA C H T U N G T R E N N U N G oylation of N e -trifluoroacetyl-l-lysine. [29] NO + O 2 -promoted nitrosation [28] of C-LysA C H T U N G T R E N N U N G (Tfa) in acetonitrile gave monomer LysA C H T U N G T R E N N U N G (Tfa)-NCA, which was then reacted in aqueous sodium hydrogen carbonate (pH 6.5) to give N e -protected oligoA C H T U N G T R E N N U N G (l-lysine) G1P.…”

Section: Resultsmentioning

confidence: 99%

“…), as illustrated by, for example, a recent investigation on interactive transport properties of DGL (either native or chemically modified) through liposomal and cellular membranes. [39] Experimental Section Materials: N a -Carbamoyl,N e -trifluoroacetyl-l-lysine, C-LysA C H T U N G T R E N N U N G (Tfa), was prepared and purified according to Taillades et al [29] from N e -trifluoroacetyll-lysine LysA C H T U N G T R E N N U N G (Tfa), which was generously supplied by Degussa (purity 99 % by HPLC), and used without further purification. Acetonitrile (MeCN; Baeckeroot Labo, Jacou, France) was stored over 4 molecular sieves.…”

Section: Discussionmentioning

confidence: 99%

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An Expeditious Multigram‐Scale Synthesis of Lysine Dendrigraft (DGL) Polymers by Aqueous N‐Carboxyanhydride Polycondensation

Collet

Souaïd

Cottet

et al. 2010

Chemistry A European J

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104

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The synthesis and characterisation of new arborescent architectures of poly(L-lysine), called lysine dendrigraft (DGL) polymers, are described. DGL polymers were prepared through a multiple-generation scheme (up to generation 5) in a weakly acidic aqueous medium by polycondensing N(epsilon)-trifluoroacetyl-L-lysine-N-carboxyanhydride (Lys(Tfa)-NCA) onto the previous generation G(n-1) of DGL, which was used as a macroinitiator. The first generation employed spontaneous NCA polycondensation in water without a macroinitiator; this afforded low-molecular-weight, linear poly(L-lysine) G1 with a polymerisation degree of 8 and a polydispersity index of 1.2. The spontaneous precipitation of the growing N(epsilon)-Tfa-protected polymer (GnP) ensures moderate control of the molecular weight (with unimodal distribution) and easy work-up. The subsequent alkaline removal of Tfa protecting groups afforded generation Gn of DGL as a free form (with 35-60% overall yield from NCA precursor, depending on the DGL generation) that was either used directly in the synthesis of the next generation (G(n+1)) or collected for other uses. Unprotected forms of DGL G1-G5 were characterised by size-exclusion chromatography, capillary electrophoresis and (1)H NMR spectroscopy. The latter technique allowed us to assess the branching density of DGL, the degree of which (ca. 25%) turned out to be intermediate between previously described dendritic graft poly(L-lysines) and lysine dendrimers. An optimised monomer (NCA) versus macroinitiator (DGL G(n-1)) ratio allowed us to obtain unimodal molecular weight distributions with polydispersity indexes ranging from 1.3 to 1.5. Together with the possibility of reaching high molecular weights (with a polymerisation degree of ca. 1000 for G5) within a few synthetic steps, this synthetic route to DGL provides an easy, cost-efficient, multigram-scale access to dendritic polylysines with various potential applications in biology and in other domains.

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“…Succinctly, DMF was distilled on a 4 Å molecular sieve under vacuum before the polymerization. After the synthesis of N a -carbamoyl-N e -trifluoroacetyl-Llysine (Lys NCAA) with potassium cyanate in aqueous media [48], the Lys NCA was prepared by nitrosation of Lys NCAA using the NO/O 2 gas mixture [49]. In a Schlenk flask fitted with a stir bar and a silicon septum, 2 144 g Lys NCA was dissolved under nitrogen in 50 mL distilled DMF.…”

Section: Polymersmentioning

confidence: 99%

Noncovalent coatings for the separation of synthetic polypeptides by nonaqueous capillary electrophoresis

et al. 2005

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Recently, we demonstrated the possibility to extend the range of capillary electrophoresis (CE) applications to the separation of non-water-soluble synthetic polymers. This work focuses on the control of the electro-osmotic flow (EOF) and on the limitation of the solute adsorption in nonaqueous electrolytes. For these purposes, different strategies were investigated. For the initial, a viscous additive (ethylene glycol or glycerol) was used in the electrolyte in order to decrease the EOF magnitude and, possibly, to compete with solute adsorption. A second strategy was to modify, before separation, the fused-silica capillary wall by the adsorption of poly(ethylene oxide) (PEO) via hydrogen bonding. The influence of the molecular mass of the adsorbed PEO on the EOF magnitude and direction was studied in electrolytes based on methanol/acetonitrile mixtures containing ammonium ions. For PEO molecular masses above 1000 g/mol, reversed (anodic) EOF were reported in accordance with previous results obtained with PEO covalently bonded capillaries. The influence of the nature and the concentration of the background electrolyte cation on the EOF magnitude and direction were also investigated. A third strategy consisted in modifying the capillary wall by the adsorption of a cationic polyelectrolyte layer. Advantageously, this polyelectrolyte layer suppressed the adsorption of the polymer solutes onto the capillary wall. The results obtained in this work confirm the high potential and the versatility of CE for the characterization of ionizable organic polymers in nonaqueous media.

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A pH-dependent cyanate reactivity model: application to preparative N-carbamoylation of amino acids

Cited by 43 publications

References 14 publications

Living Polymerization of α‐Amino Acid N‐Carboxyanhydrides (NCA) upon Decreasing the Reaction Temperature

Living Polymerization of α‐Amino Acid N‐Carboxyanhydrides (NCA) upon Decreasing the Reaction Temperature

An Expeditious Multigram‐Scale Synthesis of Lysine Dendrigraft (DGL) Polymers by Aqueous N‐Carboxyanhydride Polycondensation

Noncovalent coatings for the separation of synthetic polypeptides by nonaqueous capillary electrophoresis

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