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Naphtho pyran-5,10-quinone

In an effort to elucidate the mechanism of oxidative phosphorylation, 6-hydroxy-2,2,5-trimethyl-2H-naphtho[l,2-6]pyran (183) was treated with silver(II) oxide. The product (184) was a stable quinone hemiketal (71JOC4045). [Pg.671]

The oxidative cyclization of the alcohol (214) with ceric ammonium nitrate gave a mixture of the two naphthopyrans (215) and (216) in a ratio of 3 1 (81CC534). The reaction is of interest because of the natural occurrence of quinones containing the naphtho[2,3-c]pyran ring system. [Pg.770]

Several dibenzo[6,tf ]pyran-6-ones (360) have been prepared by the reaction of substituted phenols with 2-methoxycarbonyl-l,4-benzoquinone in the presence of trifluoroacetic acid (79HCA2833). Treatment with silver oxide converts the products into the related quinones which may be elaborated to benzo[6]naphtho[[Pg.800]

Phenols (e.g., phenol itself [CeHs-OH or Ar-OH], Table 6.10, item 2) and their esters (e.g., the trifluoroacetate ester of phenol [C6H5-O2CCF3 or Ar02CCH3], Table 6.10, item 3) have been oxidized with air and oxygen (O2), in neutral and alkaUne solutions, with and without ionic and/or radical catalysts and/or irradiation and in a variety of solvents. Enzymes (this chapter and Chapter 12) from a wide variety of sources have also been used. Frequently, oxidation of aromatic systems to phenols cannot be stopped before quinones and products of ring fragmentation occur and numerous, sometimes ill-defined, products result. Thus, as shown in Equation 6.80, oxidation of the polynuclear hydrocarbon chrysene with anunonium cerium(IV) sulfate [ceric ammonium sulfate, Ce(NH,)4(S04)4] is reported to produce 6H-benzo[d]naphtho[l,2-/>]pyran-6-one (8% yield) and a quinone (23% yield). The remainder of the product(s) (69%) was unidentified. [Pg.417]


See other pages where Naphtho pyran-5,10-quinone is mentioned: [Pg.102]    [Pg.106]    [Pg.44]    [Pg.102]    [Pg.106]   


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Quinones naphtho

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