Polyethylene Glycol Aldehydes

Monofunctional methoxypolypropylene glycol aldehydes were prepared in a five-step synthetic route. These materials are useful as protein conjugates, and they induce very mild immunogenic responses. 

Methoxypolyethylene glycol and potassium t-butoxide were dissolved in t-butyl alcohol, stirred at 60°C, and then next treated with ethyl bromoacetate. The mixture was next stirred an additional 15 hours at between 80°C and 85°C, filtered, and 

The Step 1 product was dissolved in 1M sodium hydroxide and stirred for 15 hours at ambient temperature. The reaction mixture pH was then adjusted to 2 using 1M hydrochloric acid and extracted twice with CH2CI2. The mixture was worked up as described in Step 1, and the product was isolated as a white powder. 

The Step 3 product was dissolved in CH2CI2, treated with l-amino-3,3-diethoxypro-pane dissolved in CH2CI2, and stirred 2 hours at ambient temperature. Precipitation was then induced by the addition of diethyl ether. The mixture was filtered, recrystallized using EtOAc, and dried the product was isolated as a white powder. 

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Polyethylene glycol Aldehydes, peroxides, organic acids... 

Polyethylene glycol [25322-68-3] various, from -200 to -35,000. May be contaminated with aldehydes and peroxides. Methods are available for removing interfering species. [Ray and Purathingal Anal Biochem 146 307 7955.]... 

Polyethylene glycol 400 cysteine adducts of a-, -unsaturated aldehydes as dansyl hydrazones stabilization and enhancement dipping solution, 25% in chloroform [268]... 

In a similar manner to the [4+2] cycloaddition, Benagha has shown that a polyethylene glycol supported imidazolidinone leads to similar levels of enantioselec-tivity in the [3+2] cycloaddition of nitrones with a,P-unsaturated aldehydes when compared to a non-supported catalyst, however, significantly lower chemical yields were obtained, which deteriorated upon catalyst recycling [65]. 

Bromo substituents in the 6- and 6 -positions of 2,2 -bipyridines are particularly reactive, being readily converted to amino,cyano, ° al-koxyl, hydrazino, chloro, and hydrogen groups and by way of the corresponding lithio derivatives to carboxyl, methyl, aldehyde or alkylcarbonyl, and other groupings. 6,6 -Dibromo-2,2 -bi-pyridine also reacts with the disodium derivatives of polyethylene glycols to give crown ethers akin to 100, and 6,6 -bis(chloromethyl)-2,2 -bi-pyridine " and the derived 6,6 -bis(mercaptomethyl)-2,2 -bipyridine... 

Polyethylene glycol. May be contaminated with aldehydes and peroxides, removing interfering species. [Ray and Purathingal AB 146 307 1985]. 

Formaldehyde, along with other short-chain aldehydes such as acetaldehyde, is a low molecular weight, volatile, reactive contaminant that can be present at low levels from a variety of sources (e.g., excipients such as polyethylene oxide, polyethylene glycol (64,65), or from carbohydrate degradation (66), solvent contamination (51), packaging materials (52), etc.). Formaldehyde is known to react with amines (Fig. 33) to form a reactive N-hydroxymethyl compound (a hemiaminal) that can further react with other nucleophiles. Reaction of formaldehyde with amino acids (67) can cause... 

Aldehydes and ketones are polar compounds that can be separated on a polar or an intermediate polar column. Polyethylene glycol (PEG)-type phase, such as Carbowax 20 M, Supelcowax 10, VOCOL, DBWax, or equivalent are suitable for the purpose. Compounds may also be separated according to their boiling points on a nonpolar column. A 60 m long, 0.53 mm ID and 1 pm film or other appropriate dimension methyl silicone capillary columns, such as SPB-1, DB-1, or DB-5. 

Glycol ether (molecular mass 134) for aldehydes, ketones Polyethylene glycol average molecular mass <380... 

Wong and co-workers [22] also applied the methodology in the preparation of a library of neomycin B mimetics (Fig. 6). Two libraries were prepared by a multiple-component condensation of neamine derived aldehyde, f-butyl isocyanide or isocyanoacetic acid methyl ester, CBZ-N amino acids (xl3) and a glycine conjugated polyethylene glycol methyl ether. The products of the reaction were isolated by precipitation. 

Park WKC, Auer M, Jaksche H, Wong CH, Rapid combinatorial synthesis of aminoglycoside antibiotic mimetics use of a polyethylene glycol-linked amine and a neamine-derived aldehyde in multiple component condensation as a strategy for the discovery of new inhibitors of the HIV RNA Rev responsive elements, J. Am. Chem. Soc., 118 10150-10155, 1996. 

The one-pot three-component reaction of polyethylene glycol-supported acrylate 623 with aldehydes 621 and hydrazines 622 in the presence of chloramine-T followed by methanolysis afforded pyrazolines 624 in good yields and high purities (Scheme 77) <2003SL1467>. 1,3-Dipolar cycloaddition of resin-supported acrylic acid 625 with the nitrilimines generated in situ by oxidation of the aldehyde phenylhydrazones with (diacetoxy)iodobenzene under microwave irradiation gave 626, which was converted into l-phenyl-3-substituted-2-pyrazolinyl-5-carboxylates 627 (Scheme 78) <2004SC3521>. 

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