Phenyl ethers compounds

They also synthesized and examined [24] a number of multiethyne discotic nema-togens with the hope of obtaining an N, phase. The pentakis [(4-pentylphenyl)ethy-nyl]phenyl ethers (compound 8), which are 5poo -shaped, do exhibit nematic phases and the transition temperatures together... 

Tables. Transition temperatures and enthalpies of pentakis [(4-pentylphenyl)ethynyl]phenyl ethers (compound 8) (firom [18]).

Perhaps, among all the observations made so far, those conoscopic investigations carried out on (1) nonyl pentakis[(4-pentylphenyl)ethynyl]phenyl ether (compound 8) R = H and (2) l,12-bis(penta-kis[(4-pentylphenyl)ethynyl]phenyloxy)do-decane (compound 9), n = 12 are the most... 

Ethers are compounds of the general formula Ar—O—Ar, Ar—O—R, and R—O—where Ar is an aryl group and R is an alkyl group. If the two R or Ar groups are identical, the compound is a symmetrical ether. Examples of symmetrical ethers are (di)methyl ether, CH OCH, and (di)phenyl ether,... 

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. 

In the context of their new synthetic route to arenediazo phenyl ethers (see Sec. 6.2), Tezuka et al. (1987 a, 1989) investigated the reaction products of phenyldi-azo 1-naphthyl ether (12.10) under various conditions. When an acetonitrile solution of the diazo ether 12.10 was kept standing at room temperature for one week in the dark, the 4- and 2-phenylazo-l-naphthol isomers (12.11 and 12.12) were formed in 48% (20%) and 9% (8%) yields respectively. In the presence of acid (aqueous HC1 or H2S04) or of various bases (aqueous NaOH, pyridine, aniline, or sodium acetate) the yields of the azo products are much lower, but higher proportions of biphenyl, 1-naphthol, and phenol are formed. The crosscoupling product l-phenylazo-2-naphthol was not detected when the reaction was carried out in the presence of 2-naphthol. As this mechanistic test reaction gave rather low yields of the two azo compounds 12.11 and 12.12 in the presence and absence of 2-naphthol,... 

Iodosobenzene diacetate is used as a reagent for the preparation of glycol diacetates from olefins,9 for the oxidation of aromatic amines to corresponding azo compounds,10 for the ring acetylation of N-arylacetamides,11 for oxidation of some phenols to phenyl ethers,12 and as a coupling agent in the preparation of iodonium salts.13 Its hydrolysis to iodosobenzene constitutes the best synthesis of that compound.14... 

The phenyl ether oxygen atoms allow the two borazaphenanthrene rings to pivot with respect to each other, therefore this dimeric boronic acid anhydride can potentially exist in two isomeric forms, either face-to-face or helical (Fig. 18). In the face-to-face form the boron atoms of the bis(borazaphe-nanthrene) moieties have syn-orientation, while they have approximate anti-orientation in the helical form. Compound 68 has been characterized by X-ray crystallography in the helical form [109]. The dimensions of the cavity can be described by the transannular C C contacts between the carbon atoms in 2-position of the phenyl ether units, which have values of 5.12 and 6.21 A. 

The 1,3,4-oxadiazole 113 is formed from the azo compound 112 by the action of triphenylphosphine <96SL652>. A general synthesis of 1,3.4-oxadiazolines consists in boiling an acylhydrazone with an acid anhydride (e.g., Scheme 18) <95JHC1647>. 2-Alkoxy-2-amino-l,3,4-oxadiazolines are sources of alkoxy(amino)carbenes the spiro compound 114, for instance, decomposes in boiling benzene to nitrogen, acetone and the carbene 115, which was trapped as the phenyl ether 116 in the presence of phenol <96JA4214>. 

These thermolysis reactions normally produce polymeric products, free of the cyclic analogs, in essentially quantitative yield and in sufficient purity to give satisfactory elemental analysis upon removal of the sHyl ether byproduct under vacuum. Final purification is generally achieved by precipitation of the polymer into a non-solvent such as hexane. With the exception of poly(diethylphosphazene) (2), which is insoluble in all common solvents (see below), the new polymers are readily soluble in CH CU and CHCU. In addition, the phenyl substituted compounds (3-6) are soluble in THF andvanous aromatic solvents. None of the polymers are water-soluble however, Me2PN]n (1) is soluble in a 50 50 water/THF mixture. 

In some model compound studies with the i-PrOH/KOH system we found that anthracene was converted to 9,10-dihydroanthracene in 64% yield. Benzyl phenyl ether was also studied and was converted to a polymeric material under the reaction conditions. There were no traces of phenol nor toluene, the expected reduction products. 

Note. In a recent paper, Miller and Stein have provided values for both C-C and C-0 bonds for a variety of coal model compounds, including bibenzyl and benzyl phenyl ether (11). Their rate constant for bibenzyl provides half-life values at 335°C and 400°C even larger than those discussed here, and it would seem on the basis of their data that at those low temperatures C-C scission in bibenzyl itself is too slow for thermal scission to be significant. 

The products of the reaction are the following /-butyl-phenyl-ether (TBPE), p-/-butyl-phenol (p-TBP), o-/-butyl-phenol (o-TBP) and 2,4-di-/-butyl-phenol (2,4-DTBP). Compounds adsorbed on the external surface were recovered in methylene chloride (CH2C12) by a soxhlet treatment for 24 hours of the deactivated zeolite sample. The content of the compounds inside the zeolite (coke) was determined after dissolution, in 40 % HF at room temperature, of the catalyst recoved after 5 min, 45 min, 5h and 7.5 h extraction by CH2C12 then followed. The composition of soluble coke was investigated by analysis GC-MS. The procedure is reported in detail elsewhere [10]. 

Acylation The reagent catalyses the arylation of activated aromatic compounds by reaction with carboxylic acids. Thus methyl phenyl ether can be acylated with acetic acid in presence of trifluoroacetic anhydride in good yields. 

The test (b) we carried out typically as follows but we have also used many variations of this procedure [18]. We used an assembly of connected reaction tubes attached to the vacuum line. In one tube we polymerised (I) by perchloric acid in methylene dichloride. Reaction was stopped by adding sodium phenate, and any phenol formed from secondary oxonium ions was neutralised with sodium hydride. The volatile compounds were distilled into a second tube where the same experiment was repeated. This technique is based on that of Saegusa and Matsumoto [19] phenol and phenyl ethers can be estimated separately by their UV spectra. 

A. The Basic Series.—In general, aromatic aldehydes condense with aromatic amines in the presence of zinc chloride to form triphenylmethane derivatives (0. Fischer) phenols and phenyl ethers behave similarly in the presence of concentrated sulphuric acid (Baeyer). The products formed are the leuco-compounds of well-known dyes. 

This aldehyde synthesis is applicable to compounds of the aromatic series having a labile hydrogen atom (phenyl ethers,1 naphthols,2 dialkylanilines,3-4 naphthostyril,2 anthrones 2) and to certain hydrocarbons of requisite reactivity (anthracene,5-6 7 1,2-benzanthracene,6 3,4-benzpyrene,3 7 pyrene,8 styrene,9 and a, a-diarylethylenes 9). With polynuclear hydrocarbons the best results are secured by the use of a solvent such as o-dichloro-benzene. 9-Anthraldehyde has also been prepared by the action of hydrogen cyanide and aluminum chloride on anthracene in chlorobenzene.10... 

For primary alkyl phenyl ethers 47, their hthiation under catalytic conditions (DTBB, 5%) in THF at room temperature gave the expected alkyUithiums, which by reaction with carbonyl compounds afforded, after hydrolysis, the expected alcohols 48 (Scheme 15) . In this case, only the O—Caiiyi bond cleavage was observed . On the other hand, the reaction shown in Scheme 15 failed for secondary (R = i-Pr) or tertiary (R = f-Bu) starting materials. 

For conversion of functionalized diorganozincs into tertiary amines, aromatic compounds which contain a directed metallation group, such as Af,Af-dialkylbenzamides, methoxymethyl phenyl ether, phenyl oxazolines and phenyl Af,Af-dialkylcarbamates, were ortho-lithiated, transmetallated and then aminated with 2a in good yields, but with a slower reaction rate (Scheme 19). 

The displacement of bromine from (5-1) with the phenoxide from meta-hydroxyphenylacetic acid (6-1) gives the phenyl ether (6-2). Saponification then leads to the dibasic acid (6-3). Ring closure of this compound with polyphosphoric acid gives the dibenzoxepinone. This product, isoxepac (6-4), not unexpectedly, displays NS AID activity [7]. 

Perhaps the best-known method of preparing aromatic azo compounds involves the coupling of diazonium salts with sufficiently reactive aromatic compounds such as phenols, aromatic amines, phenyl ethers, the related naphthalene compounds, and even sufficiently reactive aromatic hydrocarbons. Generally, the coupling must be carried out in media which are neutral or slightly basic or which are buffered in the appropriate pH range. The reaction may also be carried out in nonaqueous media. While some primary and secondary aromatic amines initially form an A-azoamine, which may rearrange to the more usual amino-C-azo compound, tertiary amines couple in a normal manner. 

Examples of the preparation of alkyl benzyl ethers by the Williamson synthesis are included in Section 5.6.2, p. 583. An example of an alkyl phenyl ether is provided by the synthesis of phenacetin (Expt 6.109) where p-aminophenol is first converted into its Af-acetyl derivative by reaction with slightly more than one equivalent of acetic anhydride. Treatment of the product with ethanolic sodium ethoxide solution followed by ethyl iodide then yields the ethyl ether of AT-acetyl-p-phenetidine (phenacetin). This compound is biologically active and has been widely employed for example as an antipyretic and analgesic however, owing to undesirable side reactions, its use is now restricted. 

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