Organic peroxy acids

Peroxyfomiic acid (perfomiic acid), HCO3H, is always prepared in situ from 25-30% hydrogen peroxide and 88 or 98-100% formic acid. At 26.5 C, the conversion of formic acid into peroxyformic acid requires approximately 1 h (as proven by analysis of peroxyformic acid and hydrogen peroxide contents [239]). The preparation of peroxyformic acid is carried out in the presence of the compounds to be oxidized, most often alkenes and double-bond-containing carboxylic acids. After an induction period of 

Sometimes the formyl ester of the diol is directly converted into a ketone [245, 246] (equation 14). 

A much rarer application of performic acid is the transformation of 2- or 4-dialkylaminoperhalopyridines into either amine oxides or N,N-dialkylhydroxylamines [247, 248] (equation 15). 

Peroxyacetic acid (peracetic acid), CHaCOaH, can be formed in situ from 30 or 90% hydrogen peroxide, usually in the presence of catalytic amounts of sulfuric or perchloric acid and sometimes also in the presence of acetic anhydride. The reaction of hydrogen peroxide with acetic acid to form peroxyacetic acid is reversible. The presence of substrate to be oxidized drives the oxidation to completion at moderate temperatures (25-70 °C), External cooling is frequently necessary, because the reaction is strongly exothermic. 

Peroxyacetic acid is commercially available as 40-45% solutions in acetic acid. Such a reagent is prepared by adding 1 mol of 90% hydrogen peroxide to a cooled mixture of 1.5 mol of glacial acetic acid and 1% of 

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Alkenes can also be epoxidized directly with a variety of organic peroxy acids or related reagents such as peroxy carboximidic acid, RC(NH)OOH, which is readily available through an in situ reaction of... 

The most widely used method for synthesizing epoxides is the reaction of an alkene with an organic peroxy acid (peracid). 

R0)2P-S—S—P(0R)2. A number of these products and others from reactions of dithiophosphoric acids with oxidants are listed in Table 2 since they are some of the impurities to be anticipated. Thiophosphoryl (P=S) compounds are rapidly, quantitatively, and stereospecifically converted to phosphoryl (P=0) compounds by organic peroxy acids under mild conditions. The reactions of peroxy acids and dithiophosphoric acids and salts have apparently not been characterized. 

Hydrogen peroxide undergoes substitution reactions with alkyl hahdes forming an organic peroxy acid or peroxide, depending on reaction conditions and molar ratios of reactants. The mechanism of such reactions are very complex. These reactions may be represented in the following equations ... 

Photooxidation finds occasional use in synthesis. Compounds such as XXX are formed by the oxidation of sterically hindered bis (sec-alkyl)-, and bis(pyridine solution of thiourea236 in the presence of photosensitizer and oxygen under the influence of ultraviolet light. 

Epoxides (oxiranes) are three-membered cyclic ethers. The simplest and commercially most important example is ethylene oxide, manufactured from ethylene, air, and a silver catalyst. In the laboratory, epoxides are most commonly prepared from alkenes and organic peroxy acids. 

Know the meaning of epoxide, oxirane, organic peroxy acid, nucleophilic addition to epoxides, diethylene glycol. 

Commonly, a-pinene is epoxidized to its oxide using organic peroxy acids such as m-chloroperbenzoic acid (m-CPBA). The main drawbacks of this method are the production of vast amounts of waste and the incompatibility with acid-sensitive epoxides, yielding the corresponding diol, sobrerol [47]. 

Alkenes conjugated with are electron-deficient and hence do not react readily with organic peroxy acids. The observation that the stereochemistry of the pyrazolinone (109) is not retained in the epoxidadon product (110) is interesting (equation 38). The epoxide (110) is not fomaed directly fiom (109). Since the double brad in (109) is electron-deficient its peroxy acid epoxidadon to furnish (111) is a slow process. The isomerizadon the (Z)-pyrazolinfast process. MCPBA epoxidadon of the ( )-isomer derived from (109) Amishes (110). 

A convenient and inexpensive method to transform electron rich aromatic aldehydes to phenols," or a,p-unsaturated aldehydes to vinyl formates, utilizes 30% hydrogen peroxide catdyzed by bis(n-nitro-phenyl) diselenide. A two-step formylation/MCPBA oxidation procedure (Scheme 25) was utilized by Kishi and coworkers in the 100 g scale conversion of 2,6-dimethoxytoluene to the mitomycin precursor (76). An organic peroxy acid was not required for the conversion of 9-formyl-6-methylellipticine (77) to... 

By organic oxides, hydrogen peroxide and organic peroxy acids... 

A variety of organic peroxy acids such as perbenzoic acid, MCPBA. monoperoxyphthalic acid, peracetic acid and trifiuoroperacetic acid are much stronger oxidants dian H2O2, and oxidize sulfides to sulfoxides under very mild conditions. Usually 1 equiv. of peroxy acid to sulfide is employed, otherwise overoxidation easily occurs to give sulfones. Among these, MCPBA has die advantage of being convenient to use and Ae oxidation is normally carried out at 0 C or lower temperatures, in di-chloromethane. The preparations of the base-sensitive sulfoxide (15), a new dienophile alkynyl sulfoxide (16), " and thiiraneradialene S-oxide (17) are typical examples. Selective oxidation of the sulfur atom of penicillins by polymer-supported peroxy acids in DMF or acetone is also known (equation 17). ... 

EPOXIDATIONS WITH ORGANIC PEROXY ACIDS 3.1 2,1 General Survey of Reactivity... 

The most popular derivatives of hydrogen peroxide used for epoxi-dation are organic peroxy acids (equation 56) peroxyacetic [250, 251], pcroxytrifluoroacetic [283, 287], peroxybenzoic [295, 296, 297, 300], m-chloroperoxybenzoic [315, 316], p-nitroperoxybenzoic [328], peroxy-phthalic [330], peroxymaleic [338], and peroxylauric [174]. 

Organic peroxy acids oxidize phenols and ort/io-dihydroxy aromatic compounds with the concomitant opening of the rings to dicarboxylic acids (equations 322 and 323) 249, 273, 274. The reaction is very exothermic and requires external cooling. 

The oxidation of ketones to esters is known as the Baeyer-Villiger reaction and is effected mainly by hydrogen peroxide and peroxy acids, especially the organic peroxy acids. 

Oxidants suitable for the partial oxidation of amines to nitroso compounds are peroxy acids Caro acid, which is prepared in situ from potassium persulfate and sulfuric acid [195, 199 potassium peroxysulfate (Oxone) [295] peroxyacetic acid [i53], and peroxybenzoic add [1186], 3-Nitro-o-toluidine [195] and 5-nitro-o-toluidine [199] in aqueous-alcoholic solutions, when treated with a mixture of potassium persulfate and concentrated sulfuric acid, give 3-nitro-2-nitrosotoluene and 5-nitro-2-nitrosotoluene in respective yields of 60 and 55-66%. Organic peroxy acids convert 2,6-dihaloanilines into 2,6-dihalonitrosobenzenes (equation 497) [753, 1186]. p-Phenylenediamine (1,4-diaminobenzene) is oxidized by Oxone (2KHS05 KHS04 K2S04) in an aqueous suspension at room temperature to p-dinitrosobenzene in a quantitative yield [205]. 

Organic peroxy acids, especially at low temperatures, oxidize sulfides to sulfoxides 163, S24], whereas tetrabutylammonium persulfate 209] at room temperature and hydrogen peroxide at higher temperatures yield sulfones 163, 324], However, hydrogen peroxide in acetic anhydride at room temperature yields sulfoxides 166], Under these conditions, double bonds resist epoxidation 163, 166, 324] (equation 553). 

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