22954-01-4

Upstream product

• 615-93-0 2,5-Dichloro-1,4-benzoquinone 
• 150-76-5 4-methoxy-phenol 
• 695-99-8 2-Chloro-1,4-benzoquinone 
• 697-91-6 2,6-dichloro-1,4-benzoquinone 
• 106-51-4 p-benzoquinone 
• 17332-11-5 2-bromo-4-methoxyphenol 
• 118-75-2 chloranil 

Relevant academic research and scientific papers

Aerobic oxidation of phenols and related compounds using carbon nanotube-gold nanohybrid catalysts

Gold nanoparticles supported on carbon nanotubes were investigated as catalysts in the aerobic oxidation of various substrates (phenols, hydroquinones, catechols, aminophenols, and thiols). The nanohybrid system compares favorably with other supported noble metal catalysts in terms of overall efficacy as it operates at room temperature, under air atmosphere (no external oxidant needed), and can readily be recycled. Coming up for air: Gold nanoparticles supported on carbon nanotubes were investigated as efficient catalysts in the catalytic aerobic oxidation of phenol-type compounds.

Aryloxy Radicals from Diaryloxydiazirines: α-Cleavage of Diaryloxycarbenes or Excited Diazirines?

(Equation presented) The synthesis of diaryloxydiazirines, precursors to diaryloxycarbenes, is described. Thermolyses of the diazirines afford anticipated carbene products, but photolyses afford both carbenes and aryloxy radicals by α-scission. UV spectra of the carbenes and radicals are observed.

Solid-state oxidation of phenols by tetrabenzopentacene endoperoxide

Solid state oxidation of phenols with TBPA-O2 were examined. Depending on the electron-releasing ability of p-substituents of phenols, different products were obtained. In the case of p-alkylphenols, successive proton transfers occur from the phenols to TBPA-O2 to give phenolate anions and a π-delocalized cation. They are coupled to give 6,15-diaryloxy TBPA. On the other hand, in the case of phenols with electron-releasing substituents (e.g. p-SCH3, p-OCH3), there occurs an electron transfer from a phenolate anion to a π-delocalized cation which are formed through proton transfer from the phenol to TBPA-O2. The resulted phenoxy radicals are coupled to afford dimeric products of them. Replacing process of included solvent in the crystal of TBPA-O2 with the substrate was monitored by a powder X-ray diffraction method.

A novel copper-catalyzed oxidation of 4-methoxyphenol. A mechanistic study

Dioxygen and cuprous chloride react in acetonitrile and provide an oxidizing μ-oxo dicupric complex which unexpectedly transforms 4-methoxyphenol into the 2,6-disubstituted para-benzoquinone 8 via several oxidative steps.Each intermediate product has been

CIDNP STUDY ON PORPHYRIN-PHOTOSENSITIZED REACTIONS WITH PHENOL AND QUINONE; DIMERIZATION OF 4-METHOXYPHENOL AND CROSS COUPLING OF BENZOQUINONE TO PORPHYRINS COVALENTLY LINKED WITH PHENOL GROUP

Photoreactions of porphyrin (TPP) with phenol and/or quinone in non-polar benzene solution were studied mainly by the CIDNP technique.In the photoreaction of TPP with 4-methoxyphenol (1), CIDNP effects due to TPP.- and 1.+ were observed, while the generation of considerable amounts of free 4-methoxyphenoxyl radical was indicated by ESR and CIDNP in the three-component system involving TPP, 1, and p-benzoquinone (Q).Based on these results, two new photoreactions leading to permanent products were developed: (1) photosensitized dimerization of 1 and (2) photo-induced cross coupling of Q to porphyrins covalently linked with phenol group.The unique role of phenol in the photo-induced electron transfer reaction of TPP and Q in a non-polar solvent was discussed in terms of its dual function as both the proton and electron donor.

PHOTOSENSITIZED DIMERIZATION OF PHENOL IN PORPHYRIN-QUINONE-PHENOL SYSTEM

Photosensitized dimerization of 4-methoxyphenol was observed upon irradiation of porphyrin in the presence of quinone.Quantum yield for dimer was depended upon the concentration and reduction potential of quinones used.Free radical coupling mechanism was confirmed by means of ESR and CIDNP techniques.

ALLYLATION AND OXIDATION REACTIONS PROMOTED BY COBALT(ll) COMPLEXES.

Two examples of radical reactions involving cobalt complexes are described.The first one concerns the reactions of allylcobaloximes with 2-bromo 2-phenylacetonitriles leading to the corresponding monoallyl derivatives.It is shown that both the rate and regioselectivity of the reactions are affected by the nature of the substituents on the phenyl group : electron-withdrawing groups give higher rates and highly regiospecific reactions.The second type of radical reactions wich finds useful synthetic applications is the oxidation of phenols by O2 catalysed by Schiff base cobalt complexes.By choosing carefully the catalyst and the solvent, these oxidations can be highly selective, quinones being the major oxidation products in most cases.