Benzyl phenyl ethers, oxidation

Fission of aryl ethers can also be effected by metallic sodium or potassium. For instance, diphenyl ether, which is one of the most resistant ethers, is decomposed by liquid potassium-sodium alloy at room temperature.38 Weber and Sowa have cleaved 4,4 -disubstituted diphenyl ethers into benzene and phenol derivatives by sodium in liquid ammonia.39 Diallyl ether is converted by sodium dust at 35° into allylsodium and sodium allyl oxide, which provides a suitable method for preparation of allylsodium.3 7a Anisole, phenetole, benzyl phenyl ether, and diphenyl ether give the phenols in 90% yield, without by-products, when boiled with sodium or potassium in pyridine.40... 

Hydrogenolysis. Benzyl phenyl ethers and benzyl benzoates are stable to Pd/C-cyclohexene in refluxing benzene. This is a limitation as well as an exploitable selectivity. 1-Alkene oxides undergo C-0 bond scission to give secondary alcohols by treatment with Pd/C and HCOONH in ethanol at room temperature. 

A number of different types of benzyl substrates, diethyl benzylphosphonate, benzyl methyl sulfide, benzyl phenyl sulfide, benzyl benzoate, benzyl phenyl ether, and benzyloxytrimethylsilane were also reacted with Mn. Unfortunately, according to TLC and/or gas chromatography analyses, no oxidative addition occurred with these substrates. 

Peroxides. These are formed by aerial oxidation or by autoxidation of a wide range of organic compounds, including diethyl ether, allyl ethyl ether, allyl phenyl ether, dibenzyl ether, benzyl butyl ether, n-butyl ether, iso-butyl ether, r-butyl ether, dioxane, tetrahydrofuran, olefins, and aromatic and saturated aliphatic hydrocarbons. They accumulate during distillation and can detonate violently on evaporation or distillation when their concentration becomes high. If peroxides are likely to be present materials should be tested for peroxides before distillation (for tests see entry under "Ethers", in Chapter 2). Also, distillation should be discontinued when at least one quarter of the residue is left in the distilling flask. 

Geraniol Citronellol beta Damascone Rose oxide Geranium Citronellyl acetate Phenyl ethyl alcohol Orthomethoxy benzyl ethyl ether... 

Aliphatic alcohols and benzyl alcohol are oxidized by Ph3Bi(OOtBu)2 to the corresponding carbonyl compounds (Equation (141)).233 It has been suggested that the oxidation occurs via dehydrogenation of alcohols by phenyl or tert-butoxy radical. When treated with diethyl ether, Ph3Bi(OOtBu)2 oxidizes the methyl group to afford ethoxyacetic... 

Flavone (2-phenylchromone) (68) is more labile to hydrogenolysis at the ether linkage than are 2-alkylchromones because it may be considered to be a benzyl-phenyl-type ether. Hydrogenation of flavone over copper-chromium oxide at 140-150°C gave 4-flavanol in a maximum yield of 65% in a very rapid reaction (8 min), while the flavanol was obtained in a yield of 85% in rapid hydrogenation of flavanone (69) at 135-145°C or in a yield of 93% in the hydrogenation in a dilute ethanol solution at 120-135°C (eq. 12.123).233... 

Both of these compounds yield sulphides or thio-ethers. Thio-phenol by the diazo reaction yields di-phenyl sulphide, CeHs—S—Cell5, di-phenyl thio-ether and benzyl mercaptan yields di-benzyl sulphide, CeHs—CH2—S—CH2—CeHs, di-benzyl thio-ether. These sulphides on oxidation yield sulphones (p. 526). 

Praparativ interessante Benzaldehyd-Synthesen sind auch durch photoinduzierte oxidative Ether-Spaltungen bei UV-Bestrahlung von Benzyl-phenyl-ethern mit Licht oberhalb 330 nm in Gegenwart von Kupfer(II)-chlorid in Acetonitril/2n Salzsaure (9 1) moglich, bei denen in Ausbeuten von 85-100% bzw. 58-81%4-substituierte Phenoleund Benzaldehyde entstehen64 ... 

Biodegradable polyesters were synthesized via ring-opening copolymerizations of various oxiranes (glycidyl phenyl ether, benzyl glycidate, glycidyl methyl ether, styrene oxide) and various dicarboxylic anhydrides (succinic anhydride, phthalic... 

Scheme 4.26 Basic enzymatic polymerization of oxiranes (Glycidyl phenyl ether GPE benzyl glycidate BG glycidyl methyl ether GME styrene oxide SO) and dicarboxylic anhydrides (succinic anhydride SA maleic anhydride MA phthalic anhydride PA).

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