Monomethyl ether, solubility

Pyridine, and its monomethyl and 3,5-dimethyl derivatives " combine exothermically with dimethyl acetylenedicarboxylate in ether yielding some ether soluble materials, including trimethyl pyrrocoline-1,2,3-tricarboxylate (Section III,F,3) and deep red ether-insoluble gums. A number of crystalline compounds have been isolated from these gums by fractional crystallizations and will now be considered in detail. In the case of pyridine, Diels et al. ° isolated a red labile 1 2 molar adduct, which they formulated as (75), which isomerized rapidly on standing to a yellow stable adduct (76). These formulations are no longer accepted. Diels and Alder also suggested that the acetylenic ester first dimerized to the diradical (74) which then combined with the pyridine. 

A synthesis of comblike organoboron polymer/boron stabilized imidoanion hybrids was examined via reactions of poly(organoboron halides) with 1-hexylamine and oligo(ethylene oxide) monomethyl ether and subsequent neutralization with lithium hydride (scheme 8). The obtained polymers (10) were amorphous soft solids soluble in common organic solvents such as methanol, THF, and chloroform. In the nB-NMR spectra (Fig. 11), neutralization of the iminoborane unit with lithium hydride... 

These researchers also described [93] the design and synthesis of iron(II) porphyrin dendrimers with triethylene glycol monomethyl, ether surface groups (e.g., 31) which render them soluble in a wide range of organic solvents and water. The potential difference between the first (1 FeCl) and second generation (2 FeCl) Fe-porphryin dendrimers was found to increase more in water than in dichloromethane (0.42 vs 0.08 V). This remarkable potential difference between 2 FeCl and 1 FeCl in water was comparable with that found between cytochrome c and a similarly ligated, more solvent-exposed cytochrome c heme model compound. 

Turanose Phenylosazone. A mixture of 4 g. of turanose, 2 ec. of water, and 1 co. of phenylhydrazine was warmed on the steam-bath until solution was complete. To the cooled solution was added 3.5 cc. of phenylhydrazine and 4 cc. of glacial acetic acid, and the mixture returned to the steam-bath for one hour. At the expiration of this time, 40 cc. of warm 60% alcohol was added and, upon cooling, a rapid crystallization of the osazone occurred. The osazone was recovered by filtration and washed with absolute alcohol followed by ether to yield 4.2 g. (69%) of lemon-yellow needles. The osazone is soluble in hot water and separates on cooling as jelly-like particles, but water is not a satisfactory solvent for its purification. It was recrystallized from 15 parts of 95% alcohol with good recovery, as needles which melted with decomposition at 200-205° and rotated [ ]d +24.5° - +33.0° (24 hours, constant value c, 0.82) in a mixture of 4 parts of pyridine, by volume, and 6 parts of absolute ethyl alcohol. In methyl cellosolve (ethylene glycol monomethyl ether) solution it rotated C< 3d" + 44.3°— + 48.5° (24 hours, constant value c, 0.80). 

Janda, Bolm and Zhang generated soluble polymer-bound catalysts for the asymmetric dihydroxylation by attaching cinchona alkaloid derivatives to polyethylene glycol monomethyl ether (MeO-PEG) [84—87]. Since these polymeric catalysts like (24) are soluble in many common solvents they are often as effective as their small homogenous counterparts. Janda et al. prepared catalyst (24) in which two dihydroquinidine (DHQD) units were linked together by phthalazine and finally were attached to MeO-PEG via one of the bicyclic ring system moieties (Scheme... 

In 1998 the commercially available polymer PVP (Mw 20,000) was introduced as a dielectric layer for organic TFTs by the Philips group [19]. It is soluble in common organic solvents (e.g. acetone, n-butanol, propylene glycol monomethyl ether ace-... 

Polymer-supported liquid-phase synthesis was introduced for the preparation of oligosaccharides by Douglas, Whitheld and Krepinsky [99]. In their procedure, the carbohydrate is attached to the soluble polymer, poly(ethylene glycol)monomethyl ether (PEG), and all the chemical... 

B) Ethers of Glycol. Determine the solubility of the monomethyl ether (cellosolve) and dioxane in water, alcohol, and ether. Determine the solubility of cellulose acetate in these two ethers. Use 0.1 g in 2 ml of the ether. 

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... 

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