Aryl derivatives phenols

Pseudo-saccharin ethers. When pseudo-saccharin chloride is heated with an excess of a phenol, 0-aryl derivatives of saccharin are produced (compare Section 111,27, 7). 

Heating arylamines with carbon dioxide at 200 C (8500 atm) gives good yields of 3-aryl derivatives of 2,4-dihydroxyquinazoline ° (see 5e). The method is unsatisfactory when riitro, halo, and phenolic anilines and a- or p-naphthylamines are used. 

Organophosphate Ester Hydraulic Fluids. Organophosphate esters are made by condensing an alcohol (aryl or alkyl) with phosphorus oxychloride in the presence of a metal catalyst (Muir 1984) to produce trialkyl, tri(alkyl/aryl), or triaryl phosphates. For the aryl phosphates, phenol or mixtures of alkylated phenols (e.g., isobutylated phenol, a mixture of several /-butylphenols) are used as the starting alcohols to produce potentially very complex mixtures of organophosphate esters. Some phosphate esters (e.g., tricresyl and trixylyl phosphates) are made from phenolic mixtures such as cresylic acid, which is a complex mixture of many phenolic compounds. The composition of these phenols varies with the source of the cresylic acid, as does the resultant phosphate ester. The phosphate esters manufactured from alkylated phenylated phenols are expected to have less batch-to-batch variations than the cresylic acid derived phosphate esters. The differences in physical properties between different manufacturers of the same phosphate ester are expected to be larger than batch-to-batch variations within one manufacturer. 

This adds to other reports of intra- and intermolecular arylations of phenolic derivatives (Equations (145)-( 147)). 124,124a 124c... 

Method A The glucopyranosyl bromide (1 mmol) in CH2C12 (10 ml) and HzO (10 ml) is added to the phenol (3 mmol) and TEBA-C1 or Adogen (0.2 mmol) in aqueous KOH or NaOH (25 mmol) and the mixture is stirred at room temperature for 8-60 h. The organic phase is separated, washed with H20, dried (MgS04), and evaporated to yield the O-aryl derivative (68% from phenol 60% from 2-cresol 53% from 3-chlorophenoI, 54% from 4-methoxyphenol 56% from 4-nitrophenol 57% from 1-naphthol 44% from thio-phenol 36% from 8-hydroxyquinoline). 

Protonated phenols and phenol ethers formed in superacids can be trapped by aromatics (benzene, naphthalene, tetrahydroquinoline). The products are either cyclohexenone derivatives301 [Eq. (5.112)] or aryl-substituted phenols. In the reaction of phloroglucinol with benzene, the diphenyl-substituted derivative is the main product [Eq. (5.113)], whereas 1,3,5-trimethoxybenzene gives selectively the monophenyl derivative (80% yield). Protonated dicationic species, such as 76, detected by Olah and Mo302 using NMR, were suggested to be intermediates in these processes. 

There has been a summary of the use of insertion reactions of arynes into a-bonds to prepare nrt/io-disubs tituted arenes. A key to the success of these processes is the ability to generate benzyne under mild conditions by the reaction of readily available o-(trimethylsilyl)phenyl triflate with fluoride ions.61 Reaction of amines and their derivatives with benzynes generated in this way has been shown to be an efficient method for the production of N-arylated derivatives, as illustrated in Scheme 8. The method also works well in the O-arylation reactions of phenols and carboxylic acids 62... 

Similarly, on-column methylation has been applied to carbamate pesticides containing an active N-H group. Wien and Tanaka (41) showed that N-aryl carbamates are methylated on-column with tri-methylanilinium hydroxide-methanol to give the intact N-methyl and N-aryl derivatives. On the other hand N-methyl, 0-aryl carbamates such as carbaryl or carbofuran yielded only the methyl ethers of their respective phenols. This work has now been extended to sulfur-containing carbamates such as methomyl, methio-carb, aldicarb, etc. (42-43). Here the oxime hydrolysis products of these carbamates are chromatographed as the 0-methyl oximes. 

In spite of the immense quantity of literature available on alkyl-substituted phenols including their syntheses, chemical and physical properties, their great importance as intermediates in the synthesis of natural products, as well as their many applications in science or industry, much less is known about aryl-substituted phenols and their derivatives. Even in recent comprehensive reviews on phenols1,2) no chapter specifically concerning arylated phenols has been included. What may be the reasons for this strange gap ... 

Contrary to the easy synthesis of alkylated phenols, e.g. via the electrophilic alkylations of phenols using alkyl halides, alkenes or other alkyl derivatives, there is no universal method for the preparation of arylated phenols. Radical or other arylation procedures usually lead to a mixture of difficult to separate isomers. Aryl-substituted phenols have, therefore, to be prepared by special routes. 

Whereas the alkyl phenols can, in most cases, be easily characterized using chemical or physical methods, aryl substituted phenols are often more difficult to characterize. When 2,4,6-triphenylphenol is substituted by only one new substituent, e.g. by a bromine atom, seven isomeric monobromo derivatives have to be considered. Two bromo atoms in the same aryl-substituted phenol can give rise to forty isomeric dibromo derivatives. When the less symmetrical 2,3,5-triphenylphenol is substituted, the number is even greater (11 mono- and 65 dibromo isomers). It is sometimes rather difficult to establish the constitution of such a reaction product. 

Similar syntheses of arylated 1,3-dioxo-cyclohexanone derivatives also lead to arylated phenols. The enolic methoxyl group of the enolketone is removed using lithiumaluminiumhydride. Acetone cyanhydrin transforms the enolic methoxyl group into a cyano group. Arylated cyano phenols are also available109) by this route ... 

Pyrolysis of 4-ethylguaiacol yielded 4-ethylphenoI by cleavage of the O-C (alkyl) and O-C (aryl) bonds . Similarly, methyl-, dimethyl- and vinylphenols originated from guaiacol intermediates. It has also been reported that phenol is a secondary pyrolysis product of guaiacol and derivatives. Phenol, cresol, ethylphenol, dimethylphenol, propytphenol and methylcatechol were the main components of the oil fraction in the fourth step. Traces of hydrocarbons such as toluene and styrene were produced by the dehydroxylation of phenols in this fraction. 

Aryl halide - phenol. In a novel route from an aryl halide to a phenol, /-butyl hydroperoxide is treated with I equivalent of ethylmagnesium bromide to form the MgBr derivative, and 1 equivalent of phenylmagnetium bromide ti added hydrolysis of the reaction mixture alfordi phenol In good yield. 

Three types of pentavalent arylbismuth derivatives can be used for the arylation of phenols. They derive from the triaryl, the tetraaryl and the pentaaryl series. The C-arylation of phenolic compounds can be performed by triarylbismuth carbonate, the presence of a base being not mandatory. It can also be realized by a variety of pentavalent triarylbismuth compounds and tetraarylbismuthonium salts, both in the presence of a base, in various solvents (methylene chloride, benzene, toluene or... 

In a series of outstanding papers, Pinhey et al have shown that aryllead tricarboxylates react with soft nucleophiles to afford C-arylation products. These aryllead derivatives behave as aryl cation equivalents in reactions which involve a ligand coupling mechanism (see section 7.5).9 2 ju most cases, the reactions proceed in chloroform at 40-60 C in the presence of pyridine as a base with a ratio of substrate to organolead derivative to pyridine of 1 1 3. The substrates which easily undergo C-arylation include phenols, p-dicarbonyl compounds and their vinylogues, a-cyanoesters, a-hetero-substituted ketones, enamines and nitroalkanes. A very limited number of non-carbon nucleophiles has also been reported to react. 

These reports on copper-mediated coupling reactions set the stage for pioneering reports by UUmarm and Irma Goldberg (his later wife) on the use of catalytic amounts of copper for coupling reactions of haloarenes. Thus, the arylation of phenol (16) and its derivatives with low catalyst loadings of copper enabled the selective syntheses of diarylethers (Scheme 1.5) [29]. 

Polyhydric alcohols—glycols, glycerol, sorbitol, and so on Aryl alcohols—phenols and alkyl derivatives of phenols Aldehydes—formaldehyde, acetaldehyde, and so on Ethers—diethyl ether Ketones— acetone... 

Chelation-assisted ortho arylation of aromatic imines with aryl halides was reported by Oi and Inoue [10b] and Ackermann [14b] (Scheme 17.5). In 2003, Bedford [15a,b] demonstrated the C-H arylation of phenol derivatives at their ortho position using various aryl halides in the presence of a rhodium catalyst. Subsequently, Oi [15c] also reported a similar rhodium-catalyzed C-H arylation of phenols. In 2008, Bedford [15d] reported conditions for the C-H/C-X couphng of simple phenol derivatives. 

Figure 4.15 A cross-section of results for the Cu(ll)-catalyzed direct para-selective arylation of phenol and aniline derivatives as described by Gaunt and coworkers [34].

Subsequent to Wandless s AAA approach to ustiloxin D being published, Joullie reported a second-generation synthesis. JouUie s second-generation route employed Wandless s method to prepare the p-hydroxydopa residue 30, which as explained earher, is close to perfect. To generate the crucial aUcyl-aryl ether, JouUie developed a novel Cu-promoted coupling of the dopa-derived phenol 31 with a o-serine derived aziridine 32. This reaction proceeds with excellent stereocontrol to generate just one diastereomer of the alkyl-aryl ether adduct 33 (Scheme 6). 

Christensen LP, Brandt K (2006) Bioactive polyacetylenes in food plants of the Apiaceae family occurrence, bioactivity and analysis. J Pharm Biomed Anal 41 683-693 Chung JG (1998) Inhibitory actions of ellagic acid on growth and aryl amine N-acetyltransferase activity in strains of Helicobacter pylori from peptic ulcer patients. Microbios 93 115-127 Clifford MN (2004) Diet-derived phenols in plasma and tissues and their imphcation for health. Planta Med 70 1103-1114... 

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