1-Ethoxyethyl ether

In a reaction sequence202 protected a-hydroxy sulphones were alkylated, after which acid hydrolysis followed by mild basic hydrolysis gave ketones. The protecting group used was the 1-ethoxyethyl ether, and overall yields for the sequence were generally modest (equation 89). 

Ethyl vinyl ether is also useful for hydroxy group protection. The resulting derivative (1-ethoxyethyl ether) is abbreviated as the EE group.156 As with the THP group, the EE group introduces an additional stereogenic center. 

As an alternative to protection as ethers, alcohols can also be protected as acetals, the most common being tetrahydropyranyl ethers (THP-OR) and 1-ethoxyethyl ethers (EE-OR) (Table 7.7). Support-bound secondary aliphatic alcohols have been... 

Trifluoromethyl-P-lactam 63 was prepared in racemic form via a ketene-imine [2 + 2] cycloaddition, following previously published methods81 with modifications.46 The subsequent oxidative cleavage of PMP, acylation of NH with (f-Boc)20, hydrogenolysis over Pd/C, and protection as 1-ethoxyethyl ether gave N-f-Boc-P-lactam 63 in good overall yield (Scheme 13). 

As a similar protecting function the 1-ethoxyethyl ether, formed by reaction of the alcohol with ethyl vinyl ether, was introduced (Scheme 28). It displayed advantageous properties for the construction of oligonucleotides since it could be cleaved with 5% acetic acid without affecting the intemucleotide bond. ... 

The ethoxyethyl ether was selectively introduced on a primary alcohol in the presence of a secondary alcohol. ... 

N HCl, THE, 0°, 100% yield. The ethoxyethyl ether is more readily cleaved by acidic hydrolysis than the THP ether, but it is more stable than the 1-methyl-1-methoxyethyl ether. 

The ethoxyethyl ether is prepared by acid catalysis from a phenol and ethyl vinyl ether and is cleaved by acid-catalyzed methanolysis. ... 

Among the tasks remaining is the replacement of the C-16 hydroxyl group in 16 with a saturated butyl side chain. A partial hydrogenation of the alkyne in 16 with 5% Pd-BaS04 in the presence of quinoline, in methanol, followed sequentially by selective tosylation of the primary hydroxyl group and protection of the secondary hydroxyl group as an ethoxyethyl ether, affords intermediate 17 in 79% overall yield from 16. Key intermediate 6 is formed in 67 % yield upon treatment of 17 with lithium di-n-butylcuprate. 

The synthetic preparation of 2,8-dichlorodibenzo-p-dioxin was facilitated in that the chemical precursor, 2,4,4 -trichloro-2 -hydroxydiphenyl ether, was available as a pure material. Condensation was induced by heating the potassium salt at 200 °C for 15 hours in bis (2-ethoxyethyl) ether. Product analysis by GLC and mass spectrometry revealed an unexpected dichlorophenol and a monochlorodibenzo-p-dioxin. Further, the product initially isolated by crystallization from the reaction mixture was 2,7-dichlorodibenzo-p-dioxin, rather than the expected 2,8-isomer. Cooling of the mother liquor yielded crystalline plates which were shown to be 2,8-dichlorodibenzo-p-dioxin by x-ray diffraction (Reaction 2). 

The preparation of 2,3,7,8-tetrachlorodibenzo-p-dioxin by chlorination of 2,7-dichlorodibenzo-p-dioxin yields a product containing significant quantities of trichloro- and pentachlorodibenzo-p-dioxins (11). Such mixtures are not amenable to separation on a preparative scale. Although 2,3,7,8-tetrachlorodibenzo-p-dioxin has been prepared by the pyrolytic condensation of sodium 2,4,5-trichlorophenate, this method is undesirable for preparation of 2,3,7,8-tetrachlorodibenzo-p-dioxin on the gram scale (2, 12). The pyrolytic reaction is difficult to control and the potential danger is enhanced by the product s toxicity. The salt was dissolved in bEEE [bis(2-ethoxyethyl) ether, bp 189°-190°C] and refluxed for 15 hours with the Ullmann catalyst. The desired product was obtained in 39% yield by condensation of potassium 2,4,5-trichlorophenate (Reaction 3). 

Tetraphenyltellurophene A solution of 1,4-diiodotetraphenyl-l,3-butadiene (2.0 g, 3.3 mmol), finely powdered lithium telluride (1.5 g, 11 mmol), in 125 mL of 2-ethoxyethyl ether is heated at reflux, under stirring and flushing with N2, for 8 h. The mixture is then poured in 1000 mL of water, the organic phase is separated and submitted to usual workup. After evaporation, the residue is recrystallized from dicloromethane/ethanol, giving the product 1.3 g (82%), m.p. 239°C. 

Since the first report in 1960 of the observation that sodium methoxide induced carbenoid decomposition of cyclobutanone tosylhydrazone (1) at 180 °C in either bis(2-ethoxyethyl) ether or /V-methylpyrrolidone results in an intriguing ring contraction to produce methylenecyclopropane (3),1 many experimental results have been presented invoking cyclobutylidene (2) as a key intermediate in this rearrangement. 

Bis-(2-ethoxyethyl) ether see diethylene glycol diethyl ether. 

Ethoxyethyl ether [6is-(2-ethoxyethyl) ether] [112-36-7] M 162.2, b 76°/32mm, d 0.910, n 1.412.. Refluxed with LiAlH4 for several hours, distd under reduced pressure and stored with CaH2 under nitrogen. Also passed through (alkaline) alumina. 

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