Phenols naphthols

In the absence of hydrogen fluoride catalysis, anisole. phenol, 2-naphthol, 1,2-dimethoxybenzene, 1,2-dihydroxybenzene and 1,3-dihydroxybcnzene react with xenon difluoride to give monosubstituted products in fair to good yield (Table 15). ... 

With the cupric chloride/oxygen system used for phenols, 2-naphthol in ethanol solution did not give a coupled product but only 4-ethoxy-1,2-naphthoquinone (65%) together with 1-chloro-2-naphthol (30%) was isolated. Finely powdered... 

Dyes. Sodium nitrite is a convenient source of nitrous acid in the nitrosation and diatozation of aromatic amines. When primary aromatic amines react with nitrous acid, the intermediate diamine salts are produced which, on coupling to amines, phenols, naphthols, and other compounds, form the important azo dyes (qv). The color center of the dye or pigment is the -N=N- group and attached groups modify the color. Many dyes and pigments (qv) have been manufactured with shades of the entire color spectmm. 

Condensation products of 4-nitiotoluene-2-sulfonic acid oi its detivatives together with phenols, naphthols, or aminophenols. An example here is Direct Yellow 19 (Cl 40030) (3) ... 

In mordant dyes, phenols, naphthols, and enolizable carbonyl compounds, such as pyrazolones, are generally the couplers. As a rule, 2 1 metal complexes are formed ia the afterchroming process. A typical example of a mordant dye is Eriochrome Black T (18b) which is made from the important dyestuff iatermediate nitro-l,2,4-acid, 4-amiQO-3-hydroxy-7-nitro-l-naphthalenesulfonic acid [6259-63-8]. Eriochrome Red B [3618-63-1] (49) (Cl Mordant Red 7 Cl 18760) (1, 2,4-acid — l-phenyl-3-methyl-5-pyrazolone) is another example. The equiUbrium of the two tautomeric forms depends on the nature of the solvent. 

Antioxidants that break chains by reactions with peroxyl radicals. These are reductive compounds with relatively weak O—H and N—H bonds (phenols, naphthols, hydro-quinones, aromatic amines, aminophenols, diamines), which readily react with peroxyl radicals forming intermediate radicals of low activity. 

With a phenol, naphthol or keto-enol coupling component the mechanism is given by Scheme 4.4, in which blocking of the p-position forces coupling at the o-position. In certain cases involving the use of feebly reactive diazonium salts, loss of the proton from the transition state (4-1) in Scheme 4.4 may be slow but may often be facilitated by the addition of a tertiary base, such as pyridine, to the coupling mixture [7,8]. 

Bieniek G, Wilczok T. 1986. Separation and determination of phenol, -naphthol, m- and />, o-cresols and 2,5-xylenol and catechol in the urine after mixed exposure to phenol, naphthalene, cresols and xylenols. Br J Ind Med 43 570-571. 

Phenol, naphthol Tetraphenylborate, tetraphe-nnylphosphonium ions HP-p, SBE-p p, DM-/8, y... 

Reaction LVIIL (a) Reduction of Phenols and Quinones by Distillation with Zinc Dust. (A., 140, 205.)—When certain aromatic oxygen compounds (phenols, naphthols, quinones, etc.), are heated with zinc dust, they are reduced to the corresponding hydrocarbons. Thus, phenol yields benzene, the naphthols naphthalene while anthracene can be obtained from anthraquinone or its hydroxy derivatives, alizarin, or quinizarin. In this way alizarin was first proved to be an anthracene derivative. (B., 1, 43.) For catalytic reduction of phenols, see C. r. 193, 1023. 

The phenomenon of azo—hydrazone tautomerism is firmly established75 in the benzeneazo-phenol, -naphthol, and -anthranol series, the azo form predominating in the first of these (65), the hydrazone form in the second (66), whilst the third exists exclusively in the hydrazone form (67). The situation is less clear in the analogous o-aminodiarylazo series. Thus, whilst it is known that o-aminoazobenzene (68) exists exclusively in the azo form, it has not been established whether... 

A variety of substituted aromatics have recently been found to be effective in alkylations. Phenols, naphthols, and their ethers,291,292 5-amino-l-naphthol,293 hydroxyquinolines294,295 and hydroxyisoquinolines295,296 [Eq. (5.110)] are activated... 

Several reports have suggested that carbo-carboxonium superelectrophiles may also be produced from phenols, naphthols, and related species, by diprotonation in superacidic media.34 For example, 1-naphthol is thought to form the distonic superelectrophile (93) with a variety of acids (excess AICI3, HF-SbFs, and HUSY zeolite).343 In the presence of benzene, the substituted tetralone, and with cyclohexane, 1-tetralone is produced (eq 34). 

Phenols, Naphthols (e.g., 39-47). Phenols mainly couple at the 4-position, or at the 2-position if the 4-position is occupied, p-Hydroxybenzoic acid couples with elimination of C02 resorcinol couples twice initially at the 4-position, and with a second equivalent of diazonium compound at the 2-position under acid conditions or at the 6-position under alkaline conditions. a-Naphthols mainly couple at the 4-position, in addition to which varying quantities of 2- and 2,4-coupling products are obtained, depending on the diazo component. p-Naphthol couples at the 1-position. Substituents in the 1-position, such as S03H, COOH, Cl, CH2OH, or... 

Direct dyes (see Section 3.3) that contain aromatic amino groups can be diazo-tized on the fiber after dyeing and then coupled with a developer (a phenol, naphthol, or aromatic amine). Wetfastness, in particular, is improved by such an enlargement of the molecule, and the shade also changes (see Section 2.2). Conversely, water-soluble, substantive azo dyes which bear amino or hydroxyl groups capable of coupling can also be used, followed by aftertreatment with a diazo-nium compound. The resulting polyazo dye shows excellent wetfastness (see also Section 4.8). 

Transbromination of ketones and activated aromatic compounds (phenols, naphthols, indole) by 4-(tribromomethyl)quinazoline is catalyzed by TFA245. Alkanes are brominat-ed by complexes of bromoform with aluminum tribromide (equation 33)246. 

Other important hydroxylation reactions are shown in Fig. 13.70. Here it can be seen that the Bucherer reaction is reversible, that the fusion reaction works for sulfonated benzene compounds, and that diazonium compounds undergo hydrolysis to produce phenols/naphthols. 

Carboxylation. The introduction of carboxyl groups into the structures of phenols and naph-thols produces some important dye intermediates, including salicylic acid and (3-oxynaphthoic acid (BON acid). This process is conducted under pressure at elevated temperatures using the sodium salts of phenols/naphthols and in the case of (3-naphthol, the carboxyl group enters... 

Sulfotransferases (SULTs) are cytosolic phase II detoxification enzymes involved in sulfonation of various xenobiotics and endobiotics. There are also membrane-bound SULTs that are not involved in phase II metabolism but are involved in the sulfonation of proteins and polysaccharides. Substrates of cytosolic SULTs include alcohols (ethanol, 2-butanol, cholesterol, bile acids), phenols (phenol, naphthol, acetaminophen), aromatic amines and hydroxyamines (2-naphthylamine, A-hydroxy 2-naphthylamine). SULTs transfer sulfonate (S03) to a hydroxy or amino group of a substrates from the cofactor 3 -phosphoadenosine-5 -phosphosulfate (PAPS), generating highly water-soluble metabolites for elimination through the kidney and liver. 

The alkyl ethers of phenols, naphthols and hydroxyanthraquinones can be prepared, in many cases, by treatment of the halogen compounds with alcoholates at high temperature under pressure (e.g., anisole, page 97). Of course, the phenols themselves can be etherified (cf., page 148), and the cheaper method is used in each case. The dialkyl sulfates serve as active alkylating reagents in certain instances, as in the preparation of Caledon jade green (dimethoxydibenzanthrone). 

The investi tions summarized earlier do not eliminate the possibility that other equilibrium forms than the diazonium ion as well as the conjugate bases of phenols, naphthols and enols also react. Until now no evidence is available for the reactivity of the cis- and tra s-diazohydroxides and the respective diazotates. 

The investigations of acid-base pre-equilibria of active methylene compounds (C-acids) as coupling components began in 1968 i.e. about two to three decades later than those on phenols (naphthols) and aromatic amines. The most extensive and comprehensive paper on pre-equilibria in azo coupling of active methylene compounds was published by Hashida s group in 1971. They investigated no fewer... 

Chem. Sect. 76, 1007-10 (1955). IR Avt, possible double minimum potential, phenols, naphthols, cresols in dioxane, acetone, meth-lyacetate, nitromethane, acetonitrile. 

Nitrogen rings and nitrogt nous compounds of unknown constitution A nes, phenols, naphthols, aminophenols, aminonaphthols Distillation of tar, extraction of wood vinegar, etc. 

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