Base catalyzed oxidations

TABLE 13. Base catalyzed oxidation of nitro compounds by BTSP... 

The oxidation by molecular oxygen or the base-catalyzed oxidative decarboxylation of saturated 5(4//)-oxazolones 278 yields diacylamines and provides an efficient procedure to prepare imides 279 from Al-acylamino acids (Scheme 7.90). 

The effects of heteroatoms on autoxidation reactions are reviewed and discussed in terms of six phenomena (1) the effect on reactivity of a-hydrogens in the hydroperoxide chain mechanism in terms of electron supply and withdrawal (2) the effect on a-hydrogen acidity in base-catalyzed oxidation (3) the effect on radical ion stability in base-catalyzed redox chains (4) the possibility of heteroatom hydrogen bond attack and subsequent reactions of the resulting heteroradical (5) the possibility of radical attack on higher row elements via valence expansion (6) the possibility of radical addition to electron-deficient II and III group... 

Table VIII indicates a small effect of solvent upon the rate of the base-catalyzed oxidation. The effect of the concentration of excess base on the rate of oxidation is also small. The small variations in rate illustrated in Table VIII are not considered necessarily definitive since the...

Selective formation of ketones may be achieved through base-catalyzed oxidations.848 Transformation of 9,10-dihydroanthracene catalyzed by benzyltrimethy-lammonium hydroxide (Triton B)855 starts with proton abstraction ... 

Clague MJ, Keder NL, Butler A (1993) Biomimics of Vanadium Bromoperoxidase Vanadium(V)-Schiff Base Catalyzed Oxidation of Bromide by Hydrogen Peroxide. Inorg Chem 32 4754... 

Superoxide ion is a strong base and can be used for initiation of the autoxida-tion of certain aromatic hydrocarbons. Thus, electrolysis of fluorene at -0.8 V (SCE) in DMF-tetrabutylammonium perchlorate solution continuously flushed with oxygen produces fluorenone with a current efficiency of about 5000 %. The reaction was demonstrated to be a base-catalyzed oxidation, in which superoxide ion acts as a base 16 6a ... 

Base-catalyzed hydrolysis of PET can be used to obtain TPA and oxalic acid [19], PET is completely hydrolyzed to TPA and EG at 250°C in concentrated aqueous NaOH solution. Then EG is converted to oxalic acid and CO2 by the introduction of oxygen. Since the sodium terephthalate formed is stable to oxidation, the yield of TPA reaches 100%. EG is converted to oxalic acid by base-catalyzed oxidation with a maximum yield of 61% ... 

Oxiranes can be converted to dialdehydes with hydrogen peroxide in the presence of a boric acid ester or phosphoric acid ester.The base-catalyzed oxidation of oxirane and alkyl-substituted oxiranes with fcA-r-butylhydroperoxide has been reported. With increased substitution the molecule undergoes fragmentation. With DMSO in the presence of terf-butylhydroperoxide and strong acids, a-ketols are formed via a sulfonium salt (Eq. 156). ... 

Deshpande, A., Bassi, A., and Prakash, A. Ultrasound-assisted, base-catalyzed oxidation of 4,6-dimethyldibenzothiophene in a biphasic diesel-acetonitrile system. Energy Fuels, 2005, 19, 28. 

Scheme 14.31 CuCl/ TEMPO/base-catalyzed oxidation of alcohols with O,...

F. 10 Co-Schiff base catalyzed oxidation of para-substituted phenolics... 

Catalytic oxidative cleavage of catechols 6.3.1. Base catalyzed oxidations... 

The first synthetic reports on cycloalkynes involved a base-catalyzed oxidative decomposition of bis-hydrazones, readily prepared from the respective precursor 1,2-cycloalkadiones by condensation with hydrazine (Fig. 1, top). As oxidant, mercury oxide is most typically applied, however Ag20 or Pb(OAc)4 are also suitable. An analogous procedure (Fig. 1, bottom) employs the tosylate (Ts) derivative of hydrazine, which upon condensation with the diketone under reflux conditions forms the tosylated aminotriazole intermediate. Acidic removal of the tosyl group, followed by lead-mediated oxidation, also forms the desired cycloalkyne ring. 

Base-Catalyzed Oxidation-Reduction of Aldehydes by the Cannizzaro Reaction... 

Unfortunately, relatively high loadings of these additives were required to realize significant improvement in fire retardant performance, and the loss o f mechanical properties precluded application of this system. Finally, it should be noted that Weil et al. have proposed that K2CO3 acts as a flame retardant for acrylonitrile-butadiene-styrene by base catalyzed oxidative crosslinking of the butadiene block of the terpolymer [232]. This mechanism may be important for PVA and cellulose, since they decompose to give olefinic products. 

The two isomeric saturated diones shown in Scheme 4 both gave the same semidione upon base-catalyzed oxidation. Perhaps again valence isomerization at the dianion stage has occurred although in this case a base-catalyzed stepwise eplmerlzation of the bridgehead hydrogen atoms in the semidione may be responsible for the isomerization assumed to occur for the... 

Base catalyzed oxidation of octa-1 5-diene-5 8-dlone produced semidione 9 and a new species assigned structure (equatTon ) ... 

The oxidative addition of HX (X = G1, Br, I) to H20s3(GO)io affords four new clusters with the general formula Os3H(/x-H)2(GO)io(X), which differ only in the positions occupied by the terminal hydride ligand. The base-catalyzed oxidative addition in the presence of NH3 is also discussed. " ... 

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