Quinols phenols

Clathration is the third sorption situation. Guests are incorporated during the growth of the host lattice. Their liberation occurs on heating or lowering the pressure with lattice breakdown. This situation is found for water, phenol, quinol, cresol, urea, and Dianin s compound. 

Hydroxybenzenes (phenols, quinols, catechols) (18) C-18 RP Aq. NaLS HPLC 105... 

In equation 7, ttimer radical (4) is produced when (3) dissociates. Whenever (4) couples with the other product of equation 7, ie, the 2,6-dimethylphenoxy radical, the tetramer is produced as described. These redistribution reactions of oligomers that proceed by ketal formation and subsequent dissociation ultimately generate terminal quinol ethers which enolize to the more stable terminal phenol (eq. 8). 

Plicnoh.— If it is a free phenol, ether will extiact it from its ac ueous solution. If it is present in alkaline solution, the solution should first be saturated with cat bon dioxide. (n.B.—The alkaline solutions of catecliol, quinol and pyrogallol daiken rapidly m the air.) The following tests should then be applied. 

Fe7-ric chloride reaclion.—Dissolve a drop of the free phenol in water and add a drop of ueutral ferric chloride. A green (catechol), blue (orcinol, pyiogallol) or purple (phenol, resorcinol) colouration is produced, which is often destroyed by acid or alkali. Quinol is o.xidised to quinone, and turns biown (p. 193). The naphthols give precipitates of dinaphthol (p. 220). 

Lead tetraacetate oxidation was applied to construct a benzo[c]-phenanthridine skeleton. The Hofmann degradation product 224 derived from the phenolic protoberberine 59a was oxidized with lead tetraacetate to afford the p-quinol acetate 225, which was cyclized to the benzo[c]-... 

Experiments.—To an ice-cooled solution of 2-3 g. of a phenol (phenol, cresol, /3-naphthol, salicylaldehyde, quinol) in a little ether, acetone, or methyl alcohol, the diazomethane solution prepared as described above is added in small portions until evolution of gas no longer takes place and the solution is coloured faintly yellow. 

Chemically, conversion into a vat consists in a 1 6-addition of hydrogen and recalls exactly the conversion of quinone into quinol. Like quinol, indigo white , also a dihydric phenol , is a weak add, the alkali salts of which are coloured intensely yellow. 

Synonyms AI3-00072 Arctuvin p-Benzenediol 1,4-Benzenediol Benzohydroquinone Benzoquinol Black and white bleaching cream BRN 0605970 CCRIS 714 Dihydroxybenzene jO-Dlhydroxybenzene 1,4-Dihydroxybenzene p-Dioxobenzene EINECS 204-617-8 Eldopaque Eldoquin HQ Hydroquinol Hydroquinole a-Hydroquinone p-Hydroquinone 4-Hydroxy-phenol p-Hydroxyphenol NC1-C55834 NSC 9247 Quinol p-Quinol Quinone Tecquinol Tenox HQ Tequinol UN 2662 USAF EK-356. 

Sheep that are given orcinol intravenously increase their energy expenditure by 5%. (Orcinol is a non-tannin phenolic that occurs in Ericaceae, including heather, Calluna vulgaris.) If orcinol and quinol are infused into the rumen. 

Lead tetraacetate in acetic acid oxidizes phenolic 1-benzylisoquinolines to p-quinol acetates which usually rearrange to aporphines in trifluoroacetic acid (25). However, Blasko et al. (24) recently reported that lead tetraacetate oxidized ( )-A -norlaudanosine (34) to dibenzopyrrocoline 35 in 16% yield. 

Aromatic hydroxylation. Aromatic hydroxylation such as that depicted in Figure 4.3 for the simplest aromatic system, benzene, is an extremely important bio transformation. The major products of aromatic hydroxylation are phenols, but catechols and quinols may also be formed, arising by further metabolism. One of the toxic effects of benzene is to cause aplastic... 

Other methods which have proved of value include the formation of substituted methides by the action of silver oxide on phenols (70JOC3666). It is postulated that upon oxidation of the phenol a phenoxy radical is formed which dimerizes to the quinol ether. Disproportionation to the methide and the original phenol follows. 

The oxidation of ds-2-hexene (II) catalyzed by palladium acetate proceeds after an induction period of 2-4 hrs shown in Figure 4. Using 0.00163M palladium acetate total inhibition of reaction was observed with 1.08 X 10 5M quinol. 2,4,6-tri (tert-Butyl) phenol (5.60 X 10 5M) only showed the reaction without total inhibition. The formation of the allylic complex IVb proceeds in a similar way to the reaction of I, and it is the major species in the catalyst solutions. The formation of unsatu-... 

Compounds from Pyrocatechol, Resorcinol and Quinol.—These three phenols yield compounds of the type (C6H5)4Cr.O.C6H4OH. C6H4(OH)2 the pyrocatechol derivative consists of orange columns, M.pt. 153 5° C., the resorcinol compound is a microcrystalline product, M.pt. 180° to 181° C., and the quinol compound forms yellow needles, decomposing at 206° C. 

Cobalt-Schifi base complexes catalyze the selective oxidation of phenols by dioxygen into quinols (equation 245561) or quinones (equations 246s62,563 and 247561) under mild conditions. 

Nishinaga and co-workers isolated a series of stable cobalt(III)-alkyl peroxide complexes such as (170) and (171) in high yields from the reaction of the pentacoordinated Co"-Schiff base complex with the corresponding phenol and 02 in CH2C12. Complex (170 R=Bu ) has been characterized by an X-ray structure. These alkyl peroxide complexes presumably result from the homolytic addition of the superoxo complex Co111—02 to the phenoxide radical obtained by hydrogen abstraction from the phenolic substrate by the CoUI-superoxo complex. The quinone product results from / -hydride elimination from the alkyl peroxide complex (172)561,56,565,566 The quinol (169) produced by equation (245) has been shown to result from the reduction of the CoIU-alkyl peroxide complex (170) by the solvent alcohol which is transformed into the corresponding carbonyl compound (equation 248).561... 

Under different reaction conditions, phenols can be oxidized to p-quinones (equations 272600-602 and 273603), but in the case of phenol itself, insufficient selectivity has prevented, as yet, the commercial application of this potentially important synthesis of p-benzoquinone and hydroquin-one. The selectivity of p-benzoquinone, or p-quinol formation can be increased at the expense of oxidative coupling products by using a large excess of the copper reagent [Cu4Cl402(MeCN)3 or CuCl + 02 in MeCN] with respect to the phenolic substrate.604 The suggested mechanism involves the oxidation of the phenoxide radical (189) by a copper(II)-hydroxo species to p-quinol (190) which can rearrange (for R2 = H) to hydroquinone (191 Scheme 14), which is readily oxidizable to p-quinone.6... 

In general, EC reactions are typically observed according to the following general rank order (by relative ease of oxidation) o,p-quinol and o,p-aminophenol > tertiary amine > m-quinol rv phenol rv arylamine > secondary amine thiol > thioether primary amines, aliphatic alcohols. (HDVs) each redox active metabolite are obtained from the response across adjacent EC-Array sensors. These data are a reflection of the kinetic and thermodynamic components of electron transfer reactions. Since chemical structure is a critical determinant of an analyte s redox behavior, the intrinsic generation of an HDV with EC-Array provides qualitative information for each species. 

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