Sodium bromate, oxidation with

Catalytic Ce(IV) reagent combined with an additional oxidant such as sodium bromate oxidizes hydroquinones, catechols, and their derivatives to quinones in aqueous acetonitrile (e.g., Eq. 7.18).43... 

In MeCN and in combination with a Lewis acid (e.g., AlClj), sodium bromate oxidizes aromatic aldehydes to carboxylic acids. 

Related oxidants that have been exploited to similar ends include l-(rm-butoxy)-13-benzoiodoxol-3(l//)-one 2 and sodium bromate. Oxidation of benzyl ethers by l-(/err-butoxy)-13 benzoiodoxol-3(l//)-one followed by easy basic hydrolysis of the resultant benzoate ester provides a convenient alternative to the usual reductive deprotection. The reaction is carried out in the presence of alkali metal carbonates and the conditions are mild enough to be compatible with other hydroxyl protecting groups such as methoxymethyl, tetrahydropyranyk TBS and acetate. 

Recently it was pointed out [6] that potassium and sodium bromate oxidize arenes in good yields in a 3 2 dioxane-water solution by using cerium ammonium nitrate (CAN) as catalyst. Toluene derivatives are oxidized to ca. 1 1 mixture of benzaldehydes and benzoic acids, while ethylbenzenes are converted to acetophenones. According to the proposed mechanistic scheme, water either influences the polarity of the reaction medium or acts as the reagent, reacting with the intermediate benzylic carbonium ion to give a hydroxy derivative, which is oxidized from either Ce or BrOa ions. 

Neutralizing Lotion. The principal active ingredient of cold wave neutralizers is usually an oxidizing agent. The most popular is hydrogen peroxide [7722-84-1J, employed at a concentration of 1—2% it continues to find widespread use. Aqueous solutions of sodium bromate [7789-38-0] at a concentration of 10—20% occasionally are used and are technically preferred over the peroxide formulations because of excellent stabiUty and absence of hair bleaching. Neutralizing powders appear to be on the decline but formulations stiU in use consist of sodium perborate [7632-04-4] combined with hexametaphosphates to improve solubiUty in hard water. 

Oxidation. Oxidation of the -amyl alcohols produces aldehydes, which after continued oxidation can yield acids. This route to aldehydes has httle merit. However, oxidative esterifications with alkah metal hypohaUtes (eg, calcium chlorite, Ca(OCl)2) (49), bromates (eg, sodium bromate, NaBrO )... 

When large amounts of copper deposits in boiler mbes cannot be removed with hydrochloric acid due to the relative insolubility of copper, ammonia-based oxidizing compounds have been effective. Used in a single separate stage, the ammonia sodium bromate step includes the introduction into the boiler system of solutions containing ammonium bromate to rapidly oxidize and dissolve the copper. 

Oxidative cleavage of alkyl and silyl ethers.4 CAN catalyzes the oxidative ikiivngo of alkyl and silyl ethers to carbonyl compounds with sodium bromate in yield s usually of 75 95% (equation 1). 

Although NaI04 or KI04 are the secondary oxidants used in the vast majority of cases in which alcohols are oxidized with catalytic Ru04, the employment of sodium hypochlorite (NaOCl),31 sodium bromate (NaBrOj )32 or Cl+, electrolytic-ally generated by oxidation of chloride ion,33 have also been reported. 

Cerium (TV) ammonium nitrate (CAN)37 and a cerium (TV) impregnated resin38 are able to catalyze the selective oxidation of secondary alcohols with sodium bromate (NaBrOi). Stoichiometric cerium bromate— CelBrCb h, prepared in situ from barium bromate and cerium (III) sulfate, is also able to perform selective oxidations of secondary alcohols.39... 

Perbromates are obtained by oxidation of bromates in aqueous solution. Electrolytic oxidation, the best method of preparing perchlorates and periodates, is not very satisfactory in the case of perbromates. The most practical synthesis involves oxidation with elemental fluorine in sodium hydroxide solution. The procedure is somewhat hazardous, and the experimenter should familiarize himself with the precautions necessary for safely handling fluorine before undertaking the synthesis.1... 

After the oxidation, the sodium, fluoride, and excess bromate must be removed to obtain a pure product. The bulk of the bromate and fluoride are precipitated with barium, and the sodium is removed with cation exchange resin. After concen-... 

Ammonium cerium(IV) nitrate or cerium(IV) sulfate will catalyze the selective oxidation of secondaiy alcohols with sodium bromate as cooxidant, in this case remote C—C double bonds interfere, but 1,2-diols are not cleaved. It has been found that sodium bromite in aqueous acetic acid will act as a selective oxidant for secondary mary diols without the need for other catalysts (Scheme 21). ... 

A similar rearrangement occurs when a-epoxyketones are refluxed with 30% aqueous sodium hydroxide. Best directions ate those for benzilic acid (90%) from benzoin, sodium bromate, and sodium hydroxide. Oxidation of the benzoin to benzil and rearrangement of benzil to benzilic acid are accomplished in one step. a-Ketoaldehydes and potential a-ketoalde-hydes undergo a similar internal oxidation-reduction reaction in excellent yields, viz.,... 

Ceric ammonium nitrate in water or in 50% acetic acid oxidizes ben-zylic alcohols at 90 °C in very good yields [420]. Only catalytic amounts of the reagent and sodium bromate as a reoxidant are needed to convert benzyl alcohol into benzaldehyde in 90% yield on heating in acetonitrile at 80 °C [421]. A similar result is obtained on treatment of benzyl alcohol with lead tetraacetate in pyridine at room temperature for a few hours (yield 85%) [442]. 

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