Benzo quinone quinols

It will be recalled that when para-di-hydroxy benzene, hydro-quinol, and also other para di-substitution products of benzene are oxidized there is obtained the compound known as quinone or benzo-quinone (p. 636). In a similar way para di-suhstituied naphthalenesy especially hydroxyl and amino compounds, and in fact naphthalene itself when oxidized with chromic acid, yield a quinone analogous to benzoquinone and which is known as alpha-naphthoquinone. 

Chemistry. A new method has been described for the regio- and stereo-controlled polyprenylation of quinones by means of trimethyltin derivatives. The polyprenyl trimethylstannanes (200) were prepared from the polyprenyl halides (201) and trimethylstannyl-lithium, and were then coupled with the required benzo-quinone (202) or naphthoquinone (203) in the presence of BFs-ether to give a quinol which was reduced with Ag20 to the ubiquinone (204) or vitamin K... 

Benzo[a]pyrene-3,6-quinol and other quinols are involved in toxic quinone/quinol redox cycles (Lo-RENTZEN and Ts o 1977, Loeentzen etal. 1979). Quinols are formed from the corresponding qui-nones by several reductases. They are rapidly auto-xidizes while superoxide anions are formed. Benzo[fl]pyrene-3,6-quinone has been shown to be mutagenic in the Ames test, using tester strain TA 104 (Chesis et al. 1984) or TA 102, strains which are particularly sensitive to reactive oxygen species. In male Sprague-Dawley rats, a rapid increase of unmetabolised benzo[fl]pyrene was observed in sera 3h after benzo [a] pyrene treatment followed by a sharp decrease (Kim et al. 2000). The time-dependent pattern of serum lipid peroxidation and the level of erythrocyte antioxidant enzymes were shown to be related to the concentrations of the formation of benzo[ ]pyrene-quinones, oxidatively altered lipids and antioxidant enzymes in the blood. 

Quinols from quinones. Benzopinacol added during several min. under Ng to a refluxing suspension of p-benzo-quinone in decalin hydroquinone. Y 87%. 

Anhydrous HCl rapidly bubbled through a soln. of 3-bromo-2,5-di-/ r/-butyl-1,4-benzoquinone in glacial acetic acid during 1 hr., and the intermediate quinol oxidized with N2O4 in chloroform -> 2-diloro-3-bromo-5-tert-butyl-l,4-benzo-quinone. Y 75%. F. e. s. H. W. Moore et al., J. Org. Chem. 57, 1984 (1972). 

Dihydroxybenzene is prepared industrially by the alkali fusion of benzene-1,3-disulfonic acid. 1,4-Dihydroxybenzene is prepared in large quantities for use as a photographic developer, one process being by the oxidation of aniline with manganese dioxide [manganese(IV) oxide] in sulfuric acid to give benzo-l,4-quinone, which is then reduced to 1,4-dihydroxybenzene (hydroquinone, quinol). 

Hydrogen chloride Benzo[l,2-d 4,5-d]diimidazoles Quinols from quinones... 

---