P-Diphenols

Another hydroxylation reaction is the Elbs reaction In this method, phenols can be oxidized to p-diphenols with K2S20g in alkaline solution. Primary, secondary, or tertiary aromatic amines give predominant or exclusive ortho substitution unless both ortho positions are blocked, in which case para substitution is found. The reaction with amines is called the Boyland-Sims oxidation. Yields are low with either phenols or amines, generally under 50%. The mechanisms are not clear, but for the Boyland-Sims oxidation there is evidence that the S20 ion attacks at the ipso position, and then a migration follows. ... 

Laccase (EC 1.10.3.2), arising from fungal contamination by B. cinerea, which is the agent of gray and noble rot, also catalyzes reaction 2 and accepts a wider range of substrates, including, in particular, glycosylated flavonoids such as anthocyanins and also p-diphenols (oxidized to p-quinones). ... 

Hydroquinone (Quinol, hydroquinol, p-diphenol, dihydroxybenzene, 1,4-benzenediol)... 

SYNS BISFEROL A (GERMAN) 2,2-BIS-4 -HYDROXYFENYLPROPAN (CZECH) BIS(4-HYDROXYPHENYL) DIMETHYLMETHANE BIS(4-HYDROXYPHENYL)PROPANE 2,2-BIS(p-HYDROXYPHENYL)PROPANE 2,2-BIS(4-HYDROXYPHENYL)PROPANE DIAN p,p -DIHYDROXYDIPHENYLDIMETHYLMETHANE 4,4 -DIHYDROXYDIPHENYLDIMETHYLMETHANE p,p -DIHYDROXYDIPHENYLPROPANE 2,2-(4,4 -DIHYDROXYDIPHENYL)PROPANE 4,4 -DIHYDROXYDIPHENYLPROPANE 4,4 -DIHYDROXYDIPHENYL-2,2-PROPANE 4,4 -DIHYDROXY-2.2-DIPHENYLPROPANE 3-DI-p-HYDROXYPHENYLPROPANE 2,2-DI(4-HYDROXYPHENYL)PROPANE DIMETHYL BIS(p-HYDROXYPHENYL)METHANE DIMETHYLMETHYL-ENE-p,p -DIPHENOL 2,2-DI(4-PHENYLOL)PROPANE p,p -ISOPROPYLIDENE-BISPHENOL 4,4 -ISOPROPYLIDENEBISPHENOL p,p -ISOPROPYLIDENEDIPHENOL NCI-C50635... 

METHYLENEBICYCLO(3,l.l)HEPTANE see POH750 DIMETHYLMETHYLENE-p,p -DIPHENOL see BLD500... 

Laccases (EC 1.10.3.2) are copper containing blue oxidases, which couple four one-electron oxidation processes of p-diphenols and catechols to the... 

Bis(4-hydroxyphenylpropane 4,4 -Bis-phenol a p,p -Dihydroxydiphenylpropane 2,2-(4,4-di-hydroxydiphenyl)propane 4,4 -Dihydroxdiphe-nylpropane 4,4 -Dihydroxydiphenyl-2,2-propane 4,4 -Dihydroxy-2,2-diphenylpropane Dimethyl-methylene-/ ,p -diphenol )S-di-/7-Hydroxyphenyl-propane Dimethyl bis(/ -hydroxyphenyl)methane Diphenylolpropane 2,2-di(4-Phenylol)propane /7,p -Isopropylidenebisphenol 4,4 -Dimethyl-methylenediphenol Phenol, 4,4 -( 1-methylethyli-dene) bis- 2,2-Bis(4,4 -hydroxyphenyl)propane Chemical/Pharmaceutical/Other Class Phenolic Chemical Structure ... 

Elbs persulfate oxidation. Hydroxylation of phenols to p-diphenols by potassium persulfate in alkaline solution. 

Laccases (p-diphenol O2 oxidoreductase EC 1.10.3.2) catalyze the oxidation of p-diphenols with the concurrent reduction of dioxygen to water. However, the actual substrate specificities of laccases are often quite broad and vary with the source of the enzyme [116,117]. Laccases are members of the blue copper oxidase enzyme family. Members of this family have four cupric (Cu +) ions where each of the known magnetic species (type 1, type 2, and type 3) is associated with a single polypeptide chain. In the blue copper oxidases the Cu + domain is highly conserved and, for some time, the crystallographic structure of ascorbate oxidase, another member of this class of enzymes, has provided a good model for the structure of the laccase active site [124,125]. The crystal structure of the Type-2 Cu depleted laccase from Coprinus cinereus at 2.2. A resolution has also been elucidated [126]. 

To differentiate between the enzyme activities of laccase and other phenoloxi-dases is not a trivial matter. The reason is that laccases, unlike most enzymes, are relatively nonspecific in terms of their substrates. Not only p-diphenols, but also... 

The synthesis of Amaryllidaceae alkaloids siculine, oxocrinine and peicrinine was reported using a key phenyliodine(III) bis(trifluoroacetate)-mediated intramolecular p-p diphenol coupling reaction of norbelladine derivatives followed by an intramolecular Michael addition <04T4901>. An alternative approach to isoquinoline derivatives was reported by Chang and coworkers. In this report the benzene nucleus is installed via an intramolecular electrophilic cyclization of 3,4-disubstituted lactams 87 to provide 3,4-dihydrobenzo[g]isoquinoline-l(27/)-one 88 and 3,4-dihydroisoquinoline-l(2/7)-one 89 derivatives in good yields <04TL10637>. 

Beilstein Handbook Reference) A13-04009 Biphenol A Bis(4hydroxyphenyl) dimethyl-methane Bis(4-hydroxyphenyljpropane Bisferol A Bis-phenol Bisphenol A BRN 1107700 CCRIS 95 DIAN Diano Dimethyl bis p-hydroxyphenyl)methane Di-methylmethylene-p,p -diphenol ... 

Laccases are enzymes which catalyze the oxidation of p-diphenols according to the reaction... 

CAS 80-05-7 EINECS/ELINCS 201-245-8 Synonyms Bis (4-hydroxyphenyl) dimethylmethane 2,2 -Bis (4,4-hydroxyphenyl) propane 2,2-Bis (p-hydroxyphenyl) propane Bis (4-hydroxyphenyl) propane 4,4-Bisphenol A BPA DIAN 4,4-Dihydrot dihenylpropane p,p -Dihydroxydiphenyldimethylmethane 2,2-(4,4-Dihydroxydiphenyl) propane p,p -Dihydroxydiphenylpropane P-Di-p-hydroxyphenylpropane Dimethyl bis (p-hydroxyphenyl) methane Dimethylmethylene-p,p -diphenol Diphenylolpropane 2,2-Di (4-phenylol) propane DPP 4,4 -Isopropylidenebisphenol p,p-Isopropylidenebisphenol 4,4 -Isopropylidenediphenol (INCI) p,p-Iso-propylidenediphenol 4,4 -(1 -Methylethylidene) bisphenol Phenol, 4,4 -isopropylidenedi- Phenol, 4,4 (l-methylethjrtidene) bis-Classificatbn Bisphenol Empirical CisH Oj Frnnula (CH,)2C(CeH,OH)2... 

Fungal laccase is a copper-containing oxidase which catalyses the oxidation of p-diphenols and related substances (notably aryl amines) by molecular oxygen. It seems that laccase contains two electron-accepting sites other than Type 1 (blue) and Type 2 (non-blue) copper(ii), and a mechanism involving the co-operation of several electron-accepting sites has been proposed which is consistent with recent kinetic results. 

The catalytic properties of laccase differ from tyrosinase in that laccase catalyses the oxidation of diphenols in discrete one-electron steps, whereas a single two-electron step occurs with tyrosinase (5,6). Unlike tyrosinase, laccase has no monophenol o-hydroxylating activity. Both o- and p-diphenols are oxidized by laccase, but tyrosinase oxidizes only the former compounds. Methylhydroquinone is a p-diphenol that is often used to... 

Dimethyl-6-methylenecyclohexenyl)-3-buten-2-one. See y-lonone Dimethylmethylene-p,p -diphenol. See Bisphenol A... 

In addition to the classical extradiol cleaving dioxygenases, the dioxygenases which cleave o-amino phenols (44) and p-diphenols (45) (Scheme 22) also appear to share the same catalytic properties. 

The production of p-diphenols (quinols) commonly occurs and is associated with the appearance of the corresponding quinones after oxidation in the medium (Packter, 1%6, 1969a Packter and Steward, 1967). Their formation can be restricted if the medium is rapidly extracted with solvent after exposure to the atmosphere and may generally be considered artifacts of the isolation procedures. 

Oxidases use oxygen as electron acceptor and transfer two or four electrons. Those which transfer two electrons form H2O2. They include Glucose oxidase (see), the iron- and molybdenum-containing Xanthine oxidases (see), and the n-amino acid oxidases (containing FMN or FAD). The latter catalyse the irreversible formation of the corresponding a-ke-toacid. Oxidases which transfer four electrons contain copper they oxidize the substrate and form water, e.g. laccase, ascorbate oxidase and p-diphenol oxidase. 

Synonyms 2,2-bis(4-hydroxyphenyl)propane p,p -isopropylidenediphenol bis(4-hydroxyphenyl) dimethylmethane bis(4-hydroxy-phenyi)propane 4,4 -bisphenol A DIAN p,p -dihydroxydiphenyldimethylmethane p,p -dihydroxydiphenylpropane 2,2-(4,4-dihy-droxydiphenyl)propane 4,4 -dihydroxydiphenylpropane 4,4 -dihydroxydiphenyl-2,2-propane 4,4 -dihydroxy-2,2-diphenylpropane dimethylmethylene-p,p -diphenol P-di-p-hydroxyphenylpropane dimethyl bis(p-hydroxyphenyl)methane diphenylolpropane ... 

Laccases do not possess hydroxylating properties. They oxidize o-diphenols and p-diphenols by a radicalic mechanism. Enzymes of this type were first obtained from the Japanese lack tree Rhus vernicifera. Laccases contain 4 atoms of copper 2 Cu+ ions and 2 Cu + ions. One of the latter is responsible for the blue color of the enzymes. This Cu + ion is reduced by the substrate to Cu+, i.e., it has the properties of an electron carrier (as is the case with iron in dioxygenases and some monooxygenases, C 2.5 and C 2.6). Hence laccases are capable of producing radicals from phenols according to the following equation ... 

Other phenol derivatives such as catechol (o-diphenol), hydroquinone (p-diphenol), or pyrogallol (1 3-triphenol) have also been polymerized by peroxidase in phosphate buffer giving polymeric compounds whidi are insoluUe in an aqueous HCl solution [110]. 

The yield of the polymer from pyrogallol was 20%, however, that from o- or p-diphenol was less than 5% (Table 1). After further purification of the polymer by dialysis (molecular weight exdusion 12000X the yield of the remaining polymer was very low, less than 1 %. Resorcinol (m-diphenol) or phloroglucinol (l,3,S-triphenol) did not polymerize under the same reaction conditions. 

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