Glycols, synthesis with

Another synthesis, described in detail in Scheme 12, was devised specifically for the introduction of deuterium at both ends of l-deoxy-D-t/ireo-pentulose.21,22 Stannylene methodology was used twice, first for glycol splitting with phenyliodonium diacetate, under strictly neutral conditions (necessary to preserve the benzylidene acetal), and secondly to convert the sequence -CHOH-CD3 to CO-CD3 by brominolysis. The final, labeled pentulose was l-deo y-D-threo-(1-2H3, 5-2H)pentulose. 

Lipase CA catalyzed the polymerization of cyclic dicarbonates, cyclobis (hexamethylene carbonate) and cyclobis(diethylene glycol carbonate) to give the corresponding polycarbonates [105]. The enzymatic copolymerization of cyclobis(diethylene glycol carbonate) with DDL produced a random ester-carbonate copolymer. As to enzymatic synthesis of polycarbonates, reported were polycondensations of 1,3-propanediol divinyl dicarbonate with 1,3-propanediol [110], and of diphenyl carbonate with bisphenol-A [111]. 

Suitable thermomorphic solvent systems were appUed to the telomeriza-tion of butadiene with ethylene glycol or with carbon dioxide, to the isomer-izing hydroformylation of trans-4-octene and to the hydroaminomethylation of 1-octene with morpholine. Further investigations for the carboxytelomer-ization and for the synthesis of 4-nitrodiphenylamine were also carried out. In addition to common Ugands, PEG-modified ligands and fiuorous Ugands were used for the telomerization and the carboxytelomerization. 

Takeoka S, Mori K, Ohkawa H, Sou K, Tsuchida E. Synthesis and assembly of poly(ethylene glycol)-Upids with mono-, di-, and tetraacyl chains and a poly(ethylene glycol) chain of various molecular weights. J Am Chem Soc 2000 122 7927-7935. 

The asymmetric a-alkylation of carbonyl compounds is a fundamental reaction. Under PTC conditions, acidic substrates such as phenylketone derivatives can be used to create chiral stereogenic centers. Andrus demonstrated asymmetric glycolate alkylation with up to 90% ee using various electrophiles and its application to the synthesis of (-)-ragaglitazar in six steps (Scheme 3.16) [37-39]. 

Grinstaff succeeded in growing bio-dendrimers via divergent synthesis with branched AB2 monomers, which could be of future use in the clinical sector. Adducts of glycolic acid and lactic acid or derivatives of adipic acid are examples of the monomers used [72 a]. 

A. E, Mat, G. Sel vesen, R P. Schnebli, and V. Kzzo. Evaluation of the rapid plasma elimination of recombinant alpha 1-proteinase inhibitor synthesis of polyethylene glycol conjugates with improved therapeutic potential. /. Lab. din. Med. 116 58 (1990). 

Figure 10.1 Temperature dependence of the H T2 relaxation time of well-defined end-linked (PPO) networks with narrow molecular mass distributions between chemical crosslinks [44], The molecular mass of network chains (in g/mol) is shown in this figure. The temperature dependence of a linear, high-molecular-mass polypropylene oxide) prepared from a polypropylene glycol precursor (with a molecular mass of 4000 g/mol) using a chain extender with a chemical structure similar to that of the crosslinker is shown for comparison. The synthesis of the model networks has been...

DegussaAG Butyl glycols Butanol, ethylene oxide Continuous synthesis with dissolved catalyst followed by distillation NA NA... 

Esters of carboxylic acids are, in general, not suitable starting materials for the synthesis of fluorides because the ester group cannot be substituted by fluorine. However, ft- and y-fluoro alcohols 1 and 2 can be obtained by treatment of the cyclic carbonates of 1.2- and 1,3-glycols, respectively, with anhydrous potassium fluoride. 

The polyol method could be applied to synthesis LaP04 Ce,Tb and other rare earth orthophosphate NCs. The so-called polyol method is the precipitation of a solid while heating sufficient precursors in multivalent and high-boiling alcohol like diethylene glycol (DEG) with a boiling point of 246 °C. Therefore, spherical NPs of 20-300 nm in size, usually metal... 

Synthesis from polyethylene glycol dibromides. Treatment of a poly (ethylene glycol) dibromide with Ba(OH)2 8H2O as a source of OH" and Ba followed by pyrolysis results in a crown ether. The Ba ion acts as a template. The present method requires only one building block (with one less oxygen than the crown ether formed). Highest yields (50%) are obtained with 18-crown-6. ... 

Knifton reported that the combination of ruthenium complex/phosphonium salt, such as Ru02/Bu4PBr and Ru(acac)3/Bu4PBr, is a good catalyst for the synthesis of ethylene glycol together with methanol and ethanol [12]. 

Fu J, Krauland E, Har-el Y, Hanes J. Biodegradable cationic poly(aspartic anhydride-co-ethylene glycol) Synthesis, characterization, and self-assembly with plasmid DNA, submitted to Macromolecules. 

Very recently the synthesis of a covalently bound chlorophyll-a-dimer analogue has been reported703). It was shown that bis-(chlorophyllide-a)ethylene glycol diester with porphyrin rings held together via nucleophilic hydrogen bridging closely resembles in its spectral properties, photochemical activity and redox potential to Chl-aj and therefore can serve as an in vitro model for the native Chl-ai-dimer-protein complex. 

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