Synthesis of highly branched block copolymers of enantiomerically pure amino acids

Birchall, Andrew C.

doi:10.1039/a802158i

Cited by 12 publications

(12 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, although not shown in the present contribution, the repetitive grafting strategy is very versatile with respect to tailoring, e.g., the branching density and chemical composition of the dendritic−graft polypeptides. The molecular weights of the reported dendritic−graft polypeptides are much higher than those of topologically related branched block copolypeptides, which have been reported before, and are also not restricted by solubility problems. The reported dendritic−graft polypeptides are of potential interest as carriers for gene delivery and for the development of synthetic vaccines.…”

Section: Discussionmentioning

confidence: 58%

“…Their synthetic strategy involved quenching the NCA ring-opening polymerization by addition of N α , N ε -di(benzyloxycarbonyl)- l -lysine-( p -nitrophenyl ester), which after hydrogenation affords two new terminal amino groups that can act as initiator for a successive NCA ring-opening polymerization step. The highly branched block copolymers prepared in this way, however, were exclusively composed of water-insoluble α-amino acids and, presumably due to solubility problems, were only of moderate molecular weight (<∼9 kDa) …”

Section: Resultsmentioning

confidence: 99%

“…Branched polypeptide block copolymers topologically related to the dendritic-graft polypeptides shown in Scheme 1 have been reported previously by Birchall and North. 16 Their synthetic strategy involved quenching the NCA ring-opening polymerization by addition of N R ,N -di(benzyloxycarbonyl)-L-lysine-(p-nitrophenyl ester), which after hydrogenation affords two new terminal amino groups that can act as initiator for a succes- a Isolated yields. Determined gravimetrically after precipitation, filtration, and freeze-drying of the dendritic-graft poly(Z-Llysine)s. b Gel permeation chromatography (GPC) in DMF relative to poly(ethylene oxide).…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Dendritic−Graft Polypeptides

Klok

Rodriguez-Hernández

2002

Macromolecules

View full text Add to dashboard Cite

A new synthetic strategy for the preparation of highly branched, or dendritic−graft, polypeptides is presented. The synthetic strategy is based on a repetitive sequence of ring-opening copolymerization and deprotection steps. Comonomers for the ring-opening polymerization are a set of orthogonally protected l-lysine N-carboxyanhydride derivatives. After each polymerization step, selective removal of the ε-NH2 protecting groups of one of the monomers generates a number of new initiator sites that allow grafting of a successive generation of polypeptide branches. Following this strategy, dendritic−graft polypeptides containing up to ∼160 α-amino acids, corresponding to a number-average molecular weight of ∼40 kDa, could be obtained after only four ring-opening polymerization−deprotection cycles. In contrast to perfect dendrimers, the dendritic−graft polypeptides are neither structurally uniform nor monodisperse. Dendritic−graft polypeptides, however, are conveniently prepared in multigram quantities and do not require laborious purification procedures.

show abstract

Section: Discussionmentioning

confidence: 58%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Dendritic−Graft Polypeptides

Klok

Rodriguez-Hernández

2002

Macromolecules

View full text Add to dashboard Cite

show abstract

“…Few authors describe the preparation of hyperbranched or dendritic polypeptides using ROP of the α ‐amino acid NCAs 46–50. Using the lysine‐based dendrimer LD4 (Scheme ) as an NCA polymerization initiator [M]:[I] = 52 ($\overline {DP} $ = 13 per polypeptide arm) we prepared four‐arm, star‐like PBA‐LD4 and PBG‐LD4 with fairly narrow monomodal MMDs ( Đ M s < 1.3) (Table 4, Figure 9).…”

Section: Resultsmentioning

confidence: 99%

Homo and Block Copolymers of Poly(β‐benzyl‐L‐aspartate)s and Poly(γ‐benzyl‐L‐glutamate)s of Different Architectures

Brulc

Žagar

Gadzinowski

et al. 2011

Macro Chemistry & Physics

View full text Add to dashboard Cite

Homopolypeptides of linear and star‐like architectures were prepared by polymerizing benzylic‐protected L‐glutamic acid and L‐aspartic acid N‐carboxyanhydrides (Glu NCA, Asp NCA) in DMF. The polymerization rate of the Glu NCA is faster than that of Asp NCA. Using a simple monoamino initiator, its hydrochloride, di‐, tri‐, and tetraamino functional initiators, homopolypeptides with well‐defined structures and molar masses were obtained. The molar‐mass averages of the poly(γ‐benzyl‐L‐glutamate)s lie very close to calculated values, according to the initial [M]:[I] ratios, while those of the linear poly(β‐benzyl‐L‐aspartate)s were lower than the predicted ones. PBAs had somewhat broader molar‐mass distributions than PBGs. magnified image

show abstract

“…The development of controlled ring-opening polymerization (ROP) of amino acid N -carboxyanhydrides (NCAs) allows for the synthesis of polypeptides with controlled molecular weights (MWs) and narrow molecular weight distributions (MWDs). − Unlike many other synthetic polymers that form flexible, coil-like structures, synthetic polypeptides can adopt rigid rod-like, α-helical structures with large persistence lengths (Figure A). − These predetermined secondary structural components, when incorporated into different macromolecular architectures (e.g., block copolymers, multiarms or brush-like polymers), may allow for the construction of large and complex, yet structurally well-defined, macromolecules. − Polypeptide-containing brush polymers are particularly interesting as their conformations, assembly behaviors and physical properties are largely controlled by the backbone architecture and the interactions among the grafted polymeric chains. ,,− New applications are expected to arise from the unique, highly dense macromolecular architectures and the controllable chain interactions from the grafted polypeptides in these brush polymers.…”

Section: Introductionmentioning

confidence: 99%

Interrupted Helical Structure of Grafted Polypeptides in Brush-Like Macromolecules

Wang

Ren

et al. 2011

Macromolecules

View full text Add to dashboard Cite

Brush-like polymers are a type of graft polymers with densely and regularly spaced side chains. Their unique topologies and large sizes afforded a number of potential applications in nanotechnology. Incorporating helical polypeptides as grafted chains in brush polymers may allow for the construction of large macromolecules with structurally well-defined, rod-like domains. However, due to a congested local environment in brush polymers, the conformational structure of grafted polypeptides can deviate from the “rigid-rod” α-helical structure observed in homopolypeptides. Because of synthetic challenges, the effect of macromolecular environments on the conformational structures of grafted polypeptides has not been systematically studied in brush polymers. Here we synthesized a small library of polynorbornene-g-poly(γ-benzyl-l-glutamate) (PN-g-PBLG) with variable PN, PBLG lengths and grafting densities, and we studied solvent induced helix–coil transition of grafted PBLGs in these brush polymers to explore their specific conformational structures. Instead of forming rigid-rod α-helices in helicogenic solvents, the grafted PBLGs in PN-g-PBLG, especially those with high grafting density and high molecular weights (MWs), adopt interrupted helical structures that can be represented by a “broken rod” model, which was also confirmed by the nuclear overhauser enhancement spectroscopy (NOESY) experiments. The behavior also exists in other types of grafted polypeptides in brush polymers, e.g., PN-g-poly(ε-benzyloxycarbonyl- l -lysine) (PN-g-PZLL). These findings and the structural analysis methods we developed in this study provide the guidance to the rational design and characterization of polypeptide-containing macromolecules with complex architectures.

show abstract

Synthesis of highly branched block copolymers of enantiomerically pure amino acids

Cited by 12 publications

References 7 publications

Dendritic−Graft Polypeptides

Dendritic−Graft Polypeptides

Homo and Block Copolymers of Poly(β‐benzyl‐L‐aspartate)s and Poly(γ‐benzyl‐L‐glutamate)s of Different Architectures

Interrupted Helical Structure of Grafted Polypeptides in Brush-Like Macromolecules

Contact Info

Product

Resources

About