Supports polyethyleneglycol

Polyethyleneglycol oo-Monomethylether (MPEG)-Supported Solution-Phase Synthesis of Oligosaccharides... 

In a 100-ml round-bottomed flask place 16.1 g (O.lOmol) of 3-bromocyclo-hexene (Expt 5.68), 38.7 g of dried, redistilled quinoline and a magnetic stirrer follower. Attach to the flask a Claisen still-head fitted with a thermometer and a condenser set for downward distillation. Protect the apparatus from atmospheric moisture by a calcium chloride guard-tube attached to the side-arm of the receiver. Support the reaction flask in an oil bath which rests on a magnetic stirrer/hotplate, commence stirring rapidly and heat the oil bath to 160-170 °C. The cyclohexadiene steadily distils as colourless liquid, b.p. 80-82 °C, over a period of about 30 minutes, yield 5.4 g (68%). The product is 99 per cent pure by g.l.c. analysis use either a 2.7 m column of 10 per cent polyethyleneglycol adipate on Chromosorb W held at 60 °C with a flow rate of carrier gas of 40ml/minute, tR 2.4 minutes, or, a 1.5 m column of 10 per cent Silicone oil on Chromosorb W held at 6 °C with a flow rate of carrier gas of 40ml/minute, tR 1.5 minutes. 

The above drawbacks of the linear polyfunctional macromolecular supports are to a greater extent overcome by the use of appropriate polyethers as soluble supports for biopolymer synthesis. Absence of any steric effect, equivalence of functional groups and compatibility with the biopolymers being synthesized can be expected from polyethyleneglycols, which are linear polyethers with two hydroxy groups at the chain ends (21). 

However, because of the danger of racemization and other side reactions involved in the alkaline hydrolysis, the use of an aliphatic ester bond — direct attachment to PEG without the use of an anchoring group — is not desirable in many cases. Attempts to cleave this aliphatic ester bond under acidic reaction conditions were not successful. On the other hand, the peptide derivatives were cleaved from the polyethyleneglycol supports by transesterification, hydrazinolysis or aminolysis 174). 

Monofunctional polyethyleneglycol supports containing benzyloxycarbonylhydra-zide, p-benzyloxybenzyloxycarbonylhydrazide and t-butyloxycarbonylhydrazide anchoring groups, 22, 23 and 24 respectively have been developed recently for the liquid phase synthesis of protected peptide hydrazides 199). 

Solubilizing Effect of Polyethyleneglycol Supports and Conformational Analysis of Peptides... 

The foregoing typical results clearly illustrate another very important application of the polyethyleneglycol support method for the synthesis of peptides and protein sequences. The unique suitability of this linear, soluble macromolecular support with optimum hydrophilicity-hydrophobicity balance for the conformational analysis of the bound peptides originates from the peculiar conformational properties of the polymer chain. 

Wagner ML, Tamm LK (2000) Tethered polymer-supported planar lipid bilayers for reconstitution of integral membrane proteins Silane-polyethyleneglycol-lipid as a cushion and covalent linker. Biophys J 79 1400-1414... 

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