PEG monomethyl ether

Figure 2.3 SAM surface modification has been done using monothiol and dithiol compounds containing PEG linkers. Useful coatings typically contain mainly PEG-hydroxyl or PEG-monomethyl ether linkers that provide a biocompatible lawn, which prevents nonspecific binding of proteins to the metallic surface. About 10 percent of the surface modifications are done using a longer carboxylate-containing thiol-PEG linker that provides sites for attachment of affinity ligands.

Preparation of the donor 46 was started from 4,6-0-benzylidene protected thiomannoside 47 (Scheme 7.24). Alkylation with p-allyloxybenzyl chloride under phase transfer conditions78 was followed by 3-O-silylation and Pd(0)-mediated deallylation79 to give 48. The phenolic OH group was alkylated with ethyl 6-bromohexanoate and carboxylic acid, liberated by alkaline hydrolysis, was reacted with PEG monomethyl ether (MW -5000) under Mitsunobu conditions to afford 46. 

A novel route to DHBC is outlined in Scheme 11. Reaction of TEMPO-ter-minated poly(VBC) with PEG-monomethyl ether results in reactive block copolymers 47, which can be converted readily to polymers 48 and 49 containing a cationic or a betainic block besides a PEG block [84]. 

Preparation of the reagent [70] A solution of PEG monomethyl ether 89 (MW = 750 5.88 g, 7.8 mmol) in benzene (20 mL) was dried azeotropically for 24 h in an apparatus fitted with a Dean-Stark trap and subsequently added dropwise to a solution of chlorosulfonyl isocyanate (88) (1.10 g, 7.8 mmol) in dry benzene (20 mL). The mixture was stirred at room temperature for 1 h, then concentrated to dryness. A solution of this residue in benzene (35 mL) was added dropwise to a solution of triethylamine (2.5 mL, 17.3 mmol) in benzene (15 mL). The mixture was stirred for 30 min at room temperature, then filtered, and the solid was dried to yield polymer-supported Burgess reagent 91 (6.2 g, 82%). 

It is reported that the covalent attachment of PEG or other polymers to enzymes allows them to be soluble in polar organic solvents (e.g., dioxane, carbon tetrachloride, and benzene), which in turn enhances their catalytic rates. ° The methodology involves tedious bioconjugation chemistry steps to attach activated forms of polymers (e.g., PEG monomethyl ether) to the free amino (lysine) groups of enzymes. In addition, isolation of the modified protein from the bioconjugate chemical reaction mixtnre is required. Proteins can also be modified using fatty acid chlorides, to create hydrophobic derivatives for cell membrane insertion. Modification is not recommended by the author for most situations due to the modest... 

Figure 37 SEM images of 200-nm PRINT particles made from the copolymer of trimethylolpropane ethoxylate friactylafe, PEG monomethyl ether monomethacrylate, and para-hydroxystyrene. Reproduced with permission from Kelly, J. Y. DeSimone, J. M. J. Am. Chem. Soc. 2008,130, 5438-5439. ...

Up to early 1990s, it was assumed that oxyethylation can occur only when the hydrophobic reagent had a labile hydrogen [1-3,5]. Thus, fatty acid methyl esters (FAME) were not considered as a raw material for the direct synthesis of nonionic surfactants with a polyoxyethylene chain. However, esters of fatty acids and PEG monomethyl ethers were known and their properties were described [6]. They were synthesized in a two-step process. Methanol was oxyethylated to PEG monomethyl ether that was then converted into the final product by transesterification with FAME or by esterification with fatty acids, carried out in the presence of an alkaline B or an acid catalyst, respectively. Esters of typical nonionics were synthesized in similar ways and their properties were described [7-9]. 

PEG -monomethyl-ether CR polymerization degree 2-76 Water / methanol 20/80 vol. Silica gd Spherisorb ODS 2,5 pm, 25x0.46cm 0.5 ml/min 50 pi Rl, density detector... 

For the synthesis of HA oligosaccharides, model glycosylations were carried out in solution and on PEG support. A glucosamine acceptor coupled with hydrojyl-terminated PEG monomethyl ether 11 was efficiently glycosylated with trichloroacetimidate donor 10 afford an orthogonally protected disaccharide 12 which can be used for the synthesis of HA sequences, see Scheme 3. 

Diblock copolymer consisting of poly(ethylene glycol) (PEG) monomethyl ether and polyamide was prepared by the reaction of PEG monomethyl ether with the polyamide, prepared by CGCP of 14a, in the presence of NaH (Scheme 24). An excess of PEG was used in this polymer reaction, but unreacted PEG could be washed out with water to isolate the block copolymer [39]. Similar reaction of PEG with a polyamide obtained by the CGCP of 14a with phenyl terephthalate as a bifunctional initiator gave a triblock copolymer PEG-aromatic polyamide-PEG [56]. 

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