Perbenzoic acid, from oxidation

By means of perbenzoic acid oxidation, a bicyclic oxazirane (233,234) (152) is formed from 5,5-dimethyl-4-phenyl-/l -pyrroline (151). 

The rate constants k and ku for la calculated from the data in Fig. 14 of ca. 3.5 x 103 and 1.5 x 104M 1s 1 (pH 11, 25°C), respectively, illustrate a very high activity of Fe-TAML activators particularly in terms of k. For example, Oakes and Gratton reported the value of 0.08M s1 for the oxidation of Orange II by p-sulfonated perbenzoic acid under the same conditions (57). 

D,L-Ketopinic acid has been prepared by oxidation of bornyl chloride with nitric acid at 20° or with perbenzoic acid in acetic acid from 10,10-dinitrocamphan-2-on or apocamphan-2-ol-l-carboxylic acid with alkaline permanganate and from the oxidation of 10-camphorchlorosulfoxide, obtained from 10-camphorsulfonyl chloride by the action of pyridine, with potassium permanganate. The present procedure represents a simplification of the latter and gives as high an overall yield. ... 

Current studies43,44 show that a range of isatogens can now be prepared in good yield by the oxidation of 2-substituted 1-hydroxyindoles and 2-substituted indolines with perbenzoic acids. Until this work, 2-phenylisatogen was reported as only a minor product from a number of reactions of 2-phenylindole derivatives with a variety of oxidizing agents. 

When treated with perbenzoic acid, l-methyl-l,2,3,4,5-pentaphenylsilole yields a mixture of products, resulting from the oxidation of the diene system, various cleavages and rearrangements163. 

Perbenzoic acid reacts with organic disilanes by oxidation to the corresponding disiloxanes488) in a second-order reaction. A substitution on the phenyl group of the phenylpentamethyl-disilanes increases the nucleophilic reaction rate of the Si-Si oxidation and increases pw— d conjugation from the phenyl-group to the silicon. 

Addition of halogens produces dihalides, of which, for example, a dibromide crystallizes easily but is very unstable.7 Perbenzoic acid oxidizes L-rhamnal to L-rhamnose.7 The primary oxidation product, probably an epoxide, upon treatment with anhydrous methanol gives methyl diacetyl-a-L-rhamnoside.38 Crystalline 2-desoxy-L-rhamnose was prepared from L-rhamnal.18-3 ... 

The sulfide-based linker 1.32 (89), obtained from commercial thio-PEG-PS resin and chloropyrimidine, is activated to nucleophilic substitution via oxidation with perbenzoic acid after multistep SP transformations treatment with amines then releases pure 2-aminopyrimidines in solution. Other nucleophiles should be suitable for the modular release of this and other heterocyclic S-supported nuclei. 

A curious result was obtained by Kuhn and Kainer69 on oxidation of tetraphenylpyrrole with perbenzoic acid in chloroform. The only product isolated in appreciable quantity was tetraphenylpyrazine (71), from which the starting pyrrole may be regenerated by reaction with metal and acids. 

Many other peroxy acids, such as trifluoroperacetic acid (equation 26), peroxydodecanoic acid (equation 27) and various perbenzoic acids " are also useful oxidants to give a high yield of sulfones from sulfoxides or directly from sulfides under suitable conditions. 

Halopyridazines were likewise successfully iV -oxidized. 3-Chloro-pyridazine gives the corresponding 1-oxide with perbenzoic acid, whereas the isomeric 2-oxide is prepared indirectly by adding powdered copper to a diazotized solution of 3-aminopyridazine 2-oxide in hydrochloric acid-. " After earlier reported - failures to prepare 3,6-dichloropyridazine A-oxide from 3,6-dichloropyrid-azine and hydrogen peroxide in acetic acid [6-chloro-3(2/ )-p3nrid-azinone was isolated due to hydrolysis], the desired A-oxide was later obtained in low yield. " The yield of 3,6-dichloropyridazine A-oxide can be improved when using monoperphthalic acid in ethereal solution or perbenzoic acid in chloroform. ... 

Purine with perbenzoic acid slowly (two weeks) afforded the 1-oxide (155) (62JOC567), whereas peracetic acid was used to convert adenine or adenosine (58JA2755) into their 1-oxides, these reactions taking a few days. Similar compounds are produced from other nucleosides (67JMC130) and from adenosine mono-, di- and tri-phosphates <58AG57i). Hypoxanthine, however, did not readily yield the 1-oxide (58JA2755) which is best obtained from the adenine derivative by deamination. 

Examples of all the four purine iV-oxides are known. Purine 1-oxide may be prepared from purine and perbenzoic acid over two weeks (62JOC567), and adenine 1-oxide is similarly prepared from adenine over 2 days (58JA2759). On the other hand hypoxanthine 1-oxide is best obtained by deamination of adenine 1-oxide (66JOC966). Reaction of 5-amino-4-hydroxyformamidinoimidazole with carbon disulfide may be used to make 2-thioadenine 1-oxide which with alkaline peroxide provides a useful route to isoguanine 1-oxide (67JOC1151). 

A similar intermediate is proposed to explain the retentive oxidation of Si-H bonds with perbenzoic acid. In this reaction, Br is replaced with OH and Cl is replaced with C6H5C02. Cleavage of alkyl groups from silicon can be accomplished with strongly electrophilic reagents, such as hydrogen halides in the presence of aluminum halides ... 

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