Aromatics oxygenation

Behaviour with halogenated solvents, bases, oxidizing acids, amines and aromatic oxygenated solvents can be limited. 

Aczel, T. Lumpkin, H.E. Correlation of Mass Spectra With Structure in Aromatic Oxygenated Compounds. Aromatic Alcohols and Phenols. Anal. Chem. 1960, 32, 1819-1822. 

The pyrylium cation is isoelectronic with pyridine it has the same number of electrons and, therefore, we also have aromaticity. Oxygen is normally divalent and carries two lone pairs. If we insert oxygen into the benzene ring structure, then it follows that, by having one electron in a p orbital contributing to the aromatic sextet, there is a lone pair in an sp orbital,... 

Methyl benzoate, anisole, and diphenyl ether each give sandwich compounds with chromium vapor, although in rather low yield (32, 55, 110). Chromium appears to attack alkyl ethers and this deoxygenation probably competes with complexation with the aromatic oxygen compounds. No simple product has been isolated from chromium atoms and aniline, but bis(7V,7V-dimethylaniline)chromium has been prepared (32). The behavior of molybdenum and tungsten vapors closely resembles that of chromium in reactions with oxygen- and nitrogen-substituted arenes (113). 

Reaction LVIIL (a) Reduction of Phenols and Quinones by Distillation with Zinc Dust. (A., 140, 205.)—When certain aromatic oxygen compounds (phenols, naphthols, quinones, etc.), are heated with zinc dust, they are reduced to the corresponding hydrocarbons. Thus, phenol yields benzene, the naphthols naphthalene while anthracene can be obtained from anthraquinone or its hydroxy derivatives, alizarin, or quinizarin. In this way alizarin was first proved to be an anthracene derivative. (B., 1, 43.) For catalytic reduction of phenols, see C. r. 193, 1023. 

The oxidation effect is concluded from the increase of the aromatic oxygen-containing ion at +149, the aliphatic ions at + 67 amu, and also from the increase of the ions at -16 and -17 amu. 

Barbiturates are absorbed orally and distributed widely throughout the body. They are metabolized in the liver by aliphatic oxygenation, aromatic oxygenation, and A-dealkylation. 

Clivojuline (195) (10) represents an unusual structural type since it lacks the 9,10-aromatic oxygenation pattern, which is ubiquitious among the other lactone alkaloids. The structure of the related alkaloid cliviahaksine (196) was assigned on the basis of spectral comparisons with 195 although its stereochemistry was not specifically indicated (15). Since cliviaaline (197) was isolated in only very small amounts, its structure was deduced principally from its IR spectrum and its mass spectral fragmentation pattern however, the possibility that it was an artifact was not rigorously excluded (14). 

The < a/o-peroxides of aromatic oxygen-containing five-membered heterocycles such as furan and oxazole are actually ozonides (1,2,4-trioxolanes), and by a reverse dipolar [3+2] cycloaddition they can be a source of carbonyl oxides. 

These four alkaloids have the same aromatic oxygenation pattern as decodine (6) and nesodine (5). The methoxylation pattern of verticillatine was established in the same way as described for decodine. Enantiomerism of the dimethyl ethers of dihydroverticillatine (25) and decodine at C-5 was demonstrated by a parallel series of degradations to. V-nitroso derivatives... 

An attractive example is the pigment of red roses, which is an interesting aromatic oxygen heterocycle (an anthocyanidin). Two of the phenolic OH groups are present as (5-glycosides. 

Figure 6 Six-membered aromatic oxygen and sulfur heterocycles.

Mulder, P.P., Devanesan, P., van Alem, K., Lodder, G., Rogan, E.G., Cavalieri, E.L. (2003). Fluorobenzo(a)pyrenes as probes of the mechanism of cytochrome P450-catalyzed oxygen transfer in aromatic oxygenations. Free Radio. Biol. Med. 34 734-45. 

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