Ethers benzyl phenolic

Lithium diphenyphosphide (THF, 25°, 2 h HCl, H2O, 87% yield) selectively cleaves an aryl methyl ether in the presence of an ethyl ether.It also cleaves a phenyl benzyl ether and a phenyl allyl ether to phenol in 88% and 78% yield, respectively. ... 

Benzyl ethers of phenols can also be prepared by reaction with phenyldi-azomethane. 

Tarbell and Petropoulos159 measured the rate of formation of phenol from benzyl phenyl ether catalysed by aluminium bromide and found it to be a first-order process. Moreover, the rate coefficient was the same as that for the formation of phenol from ortho benzyl phenol. Since the ratio of products (phenol ortho benzyl phenol) was unaffected by a large change in the temperature it was argued... 

As seen in the retro-synthetic Scheme 5.3, intermediate 15 is useful for both routes. The choice of benzyl protection group was made based on the robust stability of benzyl phenol ethers toward most reactions and several possible avenues to remove it, although it was reported from Medicinal Chemistry that benzyl group removal via hydrogenolysis posed challenges in this compound. The choice of iodide substitution was born out of the known high reactivity of iodides in the Ullmann-type coupling reaction with alcohols and the robust stability of aryl iodides in many other common reactions. 

Phenyl benzyl ether 320 30 31.4 PhCH3 55, PhOH 50, Benzyl phenol 40... 

Phenyl benzyl ether was mostly converted to toluene and phenol, but partly isomerized to benzyl phenol. 

As shown in Table IV, all phenols tested were confirmed to accelerate the conversion of phenyl benzyl ether. In this thermolysis, benzyl phenyl ether was decomposed to toluene and phenol (ca. 60%) and also isomerized to benzyl phenol (ca. 40%). 

Phenyl benzyl ether 400 30 100 PhCH3 61, PhOH 66, PhCH2Ph 6, Benzyl phenol 27, Benzyltetralin 2... 

Hydroxy aldehydes are reduced to hydroxy alcohols without complications. In benzyl ethers of phenol aldehydes the benzyl group was hydrogenolyzed in preference to the reduction of the carbonyl by catalytic hydrogenation over 10% palladium on charcoal at room temperature and 2 atm to give phenol aldehyde [791]. 

Fhiorination of aromatics. The reagent reacts with toluene to form benzyl fluoride as the major product ( 65% yield). It is also useful for fluorination of phenols- and of alkyl ethers of phenols the or/Ao-isomcr is formed as the major product. Reactions with this reagent thus differ from those with xenon difluoride, which generally favors formation of paro-isomers. 

With phenols either the phenolic nr nuclear hydrogens can react lo give benzylaryl ether or benzylated phenols. Reaction with NaCN gives benzyl cyanide (phenylacelonitrile) with aliphatic primary amines the product is (he N-alkylbenzylamine. and with aromatic primary amines N-benzylaniline is formed. Benzyl chloride is converted 10 butyl benzyl phlhalatc plasticizer and other chemicals. 

Protection of phenols.1 This highly O-selective reagent is preferred to benzyl chloride for preparation of benzyl ethers of phenols containing substituents prone to C-alkylation. Thus 2 is converted into the dibenzyl ether 3 in high yield using 1, whereas the yield of the ether is only 18% when benzyl chloride is used. 

Phenolic substrates are not readily reduced to benzene derivatives, and this fact can be used to effect the transformation of methyl or benzyl ethers of phenols to their silyl ethers with elimination of CH4 or toluene as the only by-products. These studies include detailed mechanistic studies that support and corroborate our experiments and support the silane activation mechanism. The reaction is clean and high yielding enough to be applied towards the functionalization of the periphery of carbosilane dendrimers with perfluoroaryl borane moieties (Scheme 25).196... 

You have seen (Chapters 17 and 23) the useofHBr, BBr3 and Me3SiClto deprotect methyl and benzyl ethers of phenols. 

Utilization of this principle for the synthesis of the target tree-like (dendritic) macromolecule is shown in Scheme 4.31. The basic reaction chosen was again very simple, namely the formation of benzyl ethers from phenols and benzylic halides. It was found that the coupling of benzylic bromide 91 with 2 equivalents of 3,5-dihydroxybenzyl alcohol 92 could be carried out without affecting the... 

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). 

A similar process has been used to prepare benzyl ethers of phenols, a strongly basic exchanger being washed with a solution of the phenol in water and in dilute alkali and then with alcohol. The modified resin is then stirred with a solution of a benzyl halide until reaction is complete. 

MetHoxym0thyl ethers of phenols. These ethers are readily prepared by reaction of chloromethyl methyl ether with a suspension of the dry sodium salt of a phenol in benzene or toluene. They are useful as protective groups because they are stable to alkali, to potassium cyanide, to Grignard reagents, and to n-butyllithium, but can be hydrolyzed when desired by very gentle treatment with acid. They are cleaved more easily than the corresponding benzyl ethers. Examples of synthetic uses are as follows. 

The photochemistry of benzylic ethers of phenols has also been examined, Eqs. (23) (the numbers in brackets are quantum yields of formation) [96] and... 

Isopropyl 2-iodoxybenzoate is a useful reagent for the clean, selective oxidation of organic sulfides to sulfoxides [1127]. This reaction proceeds without overoxidation to sulfones and is compatible with the presence of the hydroxy group, double bond, phenol ether, benzylic carbon and various substituted phenyl rings in the molecule of organic sulfide. Duschek and Kirsch have reported that isopropyl 2-iodoxybenzoate in the presence of trifiuoroacetic anhydride can be used for the a-hydroxylation of p-keto esters at room temperature in THF [1128]. 

BF3 is most easily handled as its complex with diethyl ether, written BF3 OEt2 or BF3 OEt3, in which the ether lone pair donates into the boron s empty p orbital. In related reactions FIBr, BBrj, or MejSiCI are used to activate methyl and benzyl ethers of phenols towards nucleophilic attack. See Chapters 15, p. 351 and 23, p. 551. 

The acid-catalysed rearrangement of benzyl phenolic ethers to diphenylmethane compounds and the rates of rearrangement of (Z)-aryUiydrazones of 5-amino-3-benzoyl-l,2,4-oxadiazole into (2-aryl-5-phenyl-2H-l,2,3-triazol-4-yl)ureas have been reported. ... 

Benzyl ethers of phenols are prepared by heating the latter in a reflux apparatus, during several hours, with the calculated quantities of sodium ethoxide and benzyl chloride in alcoholic solution the precipitated sodium chloride is removed by filtration from the hot... 

Synonyms Agerite alba monobenzone 4-(phenylmethoxy)phenol p-(benzyloxy)phenol hydroquinone benzyl ether p-hydroxy-phenyl benzyl ether benzyl hydroquinone monobenzyl hydroquinone Depigman Pigmex Benzoquin PBP Benoquin Uses antidegradant added to rubber products inhibitor in acrylic resins A... 

Potassium fluoride on basic alumina, combined with ultrasound, has been demonstrated to be an effective system for the deprotection of TBDMS ethers of phenols. When conducted in acetonitrile at 25-55°C, TBDMS ethers of benzyl alcohols are not affected. The following example is illustrative. 

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