Peroxycarboxylic acid

Mixtures of products are frequentiy observed. Oxidation by peroxycarboxylic acids usually give similar products (22). Several chemical oxidants give good yields of specific oxidation products. Dimethyl sulfoxide in aqueous acid gives oxindoles (23). In methanol, MoO HMPA (hexamethylphosphoramide) gives 3-hydroxy-2-methoxyindolines (24). 

Functional groups that stabilize radicals would be expected to increase susceptibility to autoxidation. This is illustrated by two cases that have been relatively well studied. Aldehydes, in which abstraction of the aldehyde hydrogen is fecile, are easily autoxidized. The autoxidation initially forms a peroxycarboxylic acid, but usually the corresponding carboxylic acid is isolated because the peroxy acid oxidizes additional aldehyde in a... 

In a similar system, the reaction of the ferric(edta) complex with peroxycarboxylic acids was probed by adding 2,4,6-tri-fe/r-butyl phenol, ArOH.2 This experiment gave rise to the aryloxyl radical, ArO, which persisted for hours and was detected by its characteristic spectrum. It was indeed formed in the reaction mentioned, at a rate that was independent of [ArOH], It was proposed that ArO results from a reactive oxo-iron intermediate, tentatively (edta)FevO. 

Another consequence of application of organic solvents as a reaction medium is associated with the mechanism of enzyme-catalyzed transformations. According to the commonly accepted mechanism, the first product of the interaction of a hydrolytic (serine) enzyme with an ester is an O-acylenzyme (Scheme 5.4). When the reaction is performed in an aqueous solution, water acts as a nucleophile in the next step, to give acid B. If more nucleophilic hydrogen peroxide is present in the reaction mixture, peroxycarboxylic acids C are formed. However, in organic solvents the O-acylenzyme also reacts readily with other nucleophiles, such as... 

The selenides prepared by any of these methods can be converted to selenoxides by such oxidants as hydrogen peroxide, sodium metaperiodate, peroxycarboxylic acids, 1-butyl hydroperoxide, or ozone. 

The stereoselectivity of epoxidation with peroxycarboxylic acids has been well studied. Addition of oxygen occurs preferentially from the less hindered side of the molecule. Norbornene, for example, gives a 96 4 exo endo ratio.76 In molecules where two potential modes of approach are not very different, a mixture of products is formed. 

Similarly to peroxycarboxylic acids, DMDO is subject to cis or syn stereoselectivity by hydroxy and other hydrogen-bonding functional groups.93 However a study of several substituted cyclohexenes in CH3CN —H20 suggested a dominance by steric effects. In particular, the hydroxy groups in cyclohex-2-enol and... 

For the mechanism of azolide hydrolysis under specific conditions like, for example, in micelles,[24] in the presence of cycloamyloses,[25] or transition metals,[26] see the references noted and the literature cited therein. Thorough investigation of the hydrolysis of azolides is certainly important for studying the reactivity of those compounds in chemical and biochemical systems.[27] On the other hand, from the point of view of synthetic chemistry, interest is centred instead on die potential for chemical transformations e.g., alcoholysis to esters, aminolysis to amides or peptides, acylation of carboxylic acids to anhydrides and of peroxides to peroxycarboxylic acids, as well as certain C-acylations and a variety of other preparative applications. 

Peroxycamphoric acid (l,2,2-Trimethyl-l-carboxycyclopentane-3-peroxycarboxylic acid)... 

In studies of the asymmetric epoxidation of olefins, chiral peroxycarboxylic acid induced epoxidation seldom gives enantiomeric excess over 20%.1 Presumably, this is due to the fact that the controlling stereocenters in peroxycarboxylic acids are too remote from the reaction site. An enantiomeric excess of over 90% has been reported for the poly-(Y)-alanine-catalyzcd epoxidation of chalcone.2 The most successful nonmetallic reagents for asymmetric epoxidation have been the chiral TV-sulfonyloxaziridincs3 until asymmetric epoxidation reactions mediated by chiral ketones were reported. Today, the... 

Aliphatic iodine derivatives, 14 376 Aliphatic ketones, 14 563, 571, 581-585 reactions of, 16 331-332 Aliphatic monothiopolyesters, 23 739 Aliphatic nitration, 12 187 Aliphatic peroxyacids, 13 464 Aliphatic peroxycarboxylic acids, 18 463 Aliphatic phosphines, 19 60 Aliphatic polyamides (PA), 10 207-210 19 713, 739. See also Aromatic polyamides PA entries producers of, 10 210 properties of, 10 208, 209t Aliphatic polycarbonates, 24 703 preparation of, 19 798 Aliphatic polyketones (PK), 10 197 costs of, 10 222 properties of, 10 198t Aliphatic poly(monosulfide)s, 23 702-704 Aliphatic polyphosphonate dyes, 9 480 Aliphatic poly(polysulfide)s, 23 711 Aliphatic polysulfides, 23 734 Aliphatic polysulfoxides, 23 733 miscibility of, 23 735 Aliphatic polyurea preparation, carbonyl sulfide in, 23 625... 

Choose peroxycarboxylic acids or peracids over peroxygen for applications at low or ambient temperatures and neutral pH. 

Scheme 12.3 Chemoenzymatic generation of the peroxycarboxylic acid and subsequent epoxidation of the fatty material.

Table 4.2 Oxidation of arylamines with peroxycarboxylic acids ...

The stereoselectivity of epoxidation with peroxycarboxylic acids has been well studied. Addition of oxygen occurs preferentially from the less hindered side of the... 

Although none of these reagent combinations have been as generally usefirl as the peroxycarboxylic acids, they serve to illustrate that epoxidizing activity is not unique to the peroxy acids. 

Selective Paraffin Hydroxylations with Activated Peroxycarboxylic Acids 7aH-cis-3a-Hydroxy Tetrahydroindene... 

Formation of polymeric peroxycarboxylic acids of variously grafted celluloses, such as 228 and 229, where the thick line represents the main cellulose strand, and assessment of their thermal stability by following their decomposition at various temperatures is based on iodometric determination of the peracids . 

CZE-ELD, with a Au microelectrode at —0.6 V vs. SCSE and a Pt wire as auxiliary electrode, using sodium borate buffer and dodecyltrimethylammonium bromide for dynamic coating of the capillary internal surface, can be applied for separation and determination of peroxycarboxylic acids to ultra-trace amounts. Thus, the first four homologous... 

A UVV spectrophotometric method for the specific detection of peroxycarboxylic acids in the presence of H2O2 is based on direct oxidation of ABTS (103) by the analyte in an acidic medium. The spectrum of the resulting green free radical presents five absorption maxima where measurements can be made 406, 415 (the most intense), 649, 732 and 815 nm. Full color development may be accelerated by traces of iodide. The LOD is 1 p,M of AcOOH, with linearity in the 2.5 to 100 p,M range. Note that reaction of 103 with H2O2 in Section in.B.2.a requires peroxidase catalysis. 

The RP-HPLC method based on the CL reaction of luminol (124) catalyzed by Co(II) (Section in.B.2.c) can be applied for determination of peroxycarboxylic acids, esters and diacyl peroxides (see examples of LOD in equation 67, Section V.B.2.c) . The biosensor prepared according to equation 70, that is effective in the determination of hydroperoxides (Section V.B.6.b), becomes deactivated after three days of operation when trying to determine t-butyl peracetate. ... 

Enthalpies of formation, (continued) peroxycarboxylic acids and derivatives, 158-63... 

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