Polyethylene glycol graft resin

Cleavage of bis-amide 492 from polyethylene glycol grafted polystyrene resin with 20% MeS03H afforded 2-acyl-l, 3,4,6,7,11 fc-hexahydro-2H-pyrazino[2,1 -a isoquinolin-4-ones 493 (06TL1287). 

Amphiphilic resin-supported ruthenium(II) complexes similar to those shown in Structure 3 (cf. also Section 7.5) were employed as recyclable catalysts for dime-thylformamide production from supercritical C02 itself [24], Tertiary phosphines were attached to crosslinked polystyrene-polyethylene glycol) graft copolymers (PS-PEG resin) with an amino groups to form an immobilized chelating phosphine. Catalytic activity declined with each subsequent recycling step, probably due to oxidation of the phosphines and to metal leaching. 

Within the context of chiral secondary amine-catalyzed conjugate reduction, the polyethylene glycol grafted polystyrene resin-supported peptide 18 was developed as an effective catalyst for the 1,6-selective transfer hydrogenation of 3-methyl-2,4-dienals with Hantzsch ester, followed by enantioselective 1,4-reduction (Scheme 14) [26]. The combination of the five terminal residues of the catalyst. 

Park, B.-D., Lee, H.-L, Ryoo, S.-J. and Lee, Y.-S., Convenient method for preparing polystyrene having -hydroxy group Its application to the synthesis of polyethylene glycol-grafted polystyrene resin. Tetrahedron Lett., 38 (1997) 591-594. 

Highly enantioselective reductions in aqueous media were realized using peptide catalysts covalently attached to polyethylene glycol grafted on polystyrene resin. Catalyst 8 gave the best results among various oligopeptides screened for the... 

S Zalpsky, JL Chang, F Albericio, G Barany. Preparation and applications of polyethylene glycol-polystyrene graft resin supports for solid-phase peptide synthesis. Reactive Polymers 22, 243, 1994. 

M. Gr0tH, . H. Gotfredsen, J. Rademann, J. Buchardt, A. J. Clark, J. O. Duus and M. Meldal, Physical properties of polyethylene glycol) (PEG)-based resins for combinatorial solid phase organic chemistry A comparison of PEG-cross-linked and PEG-grafted resins, J. Comb. Chem., 2000, 2, 108 119. 

Polyethylene glycol-polystyrene graft resin (PEG-PS) (Applied Biosystems). 

The oxidation-reduction method, developed initially by Mukaiyama et al. [133] and related to the previously described organophosphorus methods, has permitted a variety of important solid-phase applications. The mechanism of the activation is complex and involves the oxidation of the triaryl/ alkyl-phosphine to the oxide as well as reduction of the disulfide to the mercapto derivative. However, different active species, such as 81 (Fig. 11), the 2-pyridyl thioester, or even the symmetrical anhydride, have been postulated to form. For the intermediate 81, the peptide bond formation may proceed through a (cyclic transition state. The method has been used for conventional stepwise synthesis [134], acylation of the first protected amino acid to a hydroxymethyl resin, and to achieve segment condensation on a solid support in the opposite direction (N C) [135,136]. Lastly, it has been used for efficient grafting of a polyethylene glycol (molecular weight 2000) derivative to an aminomethyl resin to prepare PEG-PS resins [137]. 

The solid support should be well solvated to facilitate reactions to take place involving the two phases. The original supports were based on polystyrene but have generally been superseded by polyamide resins, which have an advantage in that they have a similar polarity to the peptide backbone. More recently, resins based on polyethylene glycol (PEG) grafted onto low... 

Polystyrene resin, frequently used resin material for solid-phase peptide synthesis (SPPS). The polymeric support for SPPS must be chemically inert, mechanically stable, completely insoluble in the solvents used, and easily separated by filtration. For many applications a copolymer of polystyrene with 1% of divinyl benzene as crosslinker is used. The dry resin beads are able to swell up to the five-or sixfold volume in the different organic solvents mainly used for peptide synthesis (e.g., dichloromethane or dimethylfor-mamide). For SPPS the resin material must be chemically functionalized in order to allow for attachment of a handle/liker (e.g. Wang resin), or the first amino acid (—> Merrifield resin). Hydrophilic tentacle polymers gels (TentaGel) are obtained by grafting polyethylene glycol (PEG) chains with an arbitrary degree of polymerization onto porous polystyrene beads. 

Preparation and applications of polyethylene glycol-polystyrene graft resin supports for solid-phase peptide synthesis ... 

The present report details our initial experiences with a novel class of supports for peptide synthesis, polyethylene glycol-polystyrene (PEG-PS) graft resins (Fig. 1). Our PEG-PS supports contain approximately equal weight amounts of the two polymer... 

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