Nickel peroxide oxidation

Compared to the anodic oxidation of Z-4-octene-l,8-diol (80%, Table 8) its oxidation with pyridinium dichromate in dimethyl formamide gave as the best chemical alternative only 65 % diacid Nickel peroxide oxidation under mild conditions (1.3 eq. peroxide, 25 °C, 1 M NaOH) led to 45% hydroxy acid 75, whereas under more vigorous conditions (3 eq. peroxide, 80 °C, 1 M NaOH) maleic acid was formed ... 

Nickel Peroxide Oxidation of Organic Compounds M. V. George and K. S. Balachandran, Chem. Rev., 1975, 75, 491-519. 

A suspension of the reagent oxidizes aniline at 80° to azobenzene in 80% yield and it oxidizes benzylamine at 60° to benzonitrile in 78% yield. Nickel peroxide oxidatively cleaves a-glycols and a-hydroxy acids in aprotic solvents (benzene, ether)." In an aqueous alkaline solution a-ketols and a-keto acids are cleaved to carboxylic acids. The reagent thus resembles lead tetraacetate. 

Oxidation of 2,4-diaryl-5(4//)-oxazolones (94) with molecular oxygen gives dimeric products (Equation (7)) <9iT568i>. The reaction rate is dependent on the solvent and oxygen concentration. The oxidation is faster in highly polar solvents, such as DMSO and DMF, that favor the mesoionic form. The dimers are also formed by nickel peroxide oxidation <85T234l>. 

Nickel peroxide oxidizes benzophenone hydrazone to diphenyldiazomethane in quantitative yield.9... 

A reinvestigation of lycoxanthin (19) and lycophyll (20) showed that the allylic hydroxy-group is on the terminal carbon atom. This result was confirmed by nickel peroxide oxidation to the corresponding aldehydes. 

Oxidations with nickel peroxide Oxidation of alcohols s. 17, 225... 

Labile and unstable acetylenes are conveniently coupled with halogeno-acetylenes as their copper(ir) salts. The terminal acetylenes required, e.j. (11), can be obtained by deformylation with base of the aldehydes obtained by nickel peroxide oxidation of the corresponding alcohols (12). lodo-... 

Review "Nickel-Peroxide Oxidation of Organic Compounds"... 

When heated in the presence of a carboxyHc acid, cinnamyl alcohol is converted to the corresponding ester. Oxidation to cinnamaldehyde is readily accompHshed under Oppenauer conditions with furfural as a hydrogen acceptor in the presence of aluminum isopropoxide (44). Cinnamic acid is produced directly with strong oxidants such as chromic acid and nickel peroxide. The use of t-butyl hydroperoxide with vanadium pentoxide catalysis offers a selective method for epoxidation of the olefinic double bond of cinnamyl alcohol (45). 

Nickel plating solutions may contain excess iron and unknown organic contaminants. Iron is removed by peroxide oxidation, precipitation at a pH of about 5, then filtered out. The more complex, less water-soluble organic contaminants along with some trace metals are removed with activated carbon treatments in separate treatment tanks. About 5 g/L of plating-grade activated carbon is mixed in the plating solution for at least 1—2 hours, usually at warmer temperatures. 

Pyridazine-3,6-diones (diazaquinones) are prepared from cyclic hydrazides by oxidation with lead tetraacetate or other oxidizing agents, such as r-butyl hypochlorite, chlorine or nickel peroxide. 

Oxidation ol alcohols to caitx>xyllc acids (or ketones) with nickel peroxide... 

Nickel peroxide is a solid, insoluble oxidant prepared by reaction of nickel (II) salts with hypochlorite or ozone in aqueous alkaline solution. This reagent when used in nonpolar medium is similar to, but more reactive than, activated manganese dioxide in selectively oxidizing allylic or acetylenic alcohols. It also reacts rapidly with amines, phenols, hydrazones and sulfides so that selective oxidation of allylic alcohols in the presence of these functionalities may not be possible. In basic media the oxidizing power of nickel peroxide is increased and saturated primary alcohols can be oxidized directly to carboxylic acids. In the presence of ammonia at —20°, primary allylic alcohols give amides while at elevated temperatures nitriles are formed. At elevated temperatures efficient cleavage of a-glycols, a-ketols... 

Isoxazolines 79, obtained from aromatic nitrile oxide cycloadditions to cyclohex-2-enone, reacted with nickel peroxide to give 3-aryl-6,7-dihydro[l] benzoisoxazol-4(5// )-ones 80. In contrast, the corresponding 2-bromocyclohex-2-enone underwent nitrile oxide cycloaddition, followed by dehydrobromination, to afford the regioisomeric 3-aryl-4,5-dihydro[l]benzoisoxazol-7(6//)-ones 81 (Scheme 1.23) (242). 

Cycloaddition of 5,6-dihydropyran-2-one with aromatic nitrile oxides leads to 3-aryl-3a,6,7,7a-tetrahydropyrano[3,4-d]isoxazol-4(47/)-ones 98. The latter react with nickel peroxide to give the corresponding dihydropyranoisoxazolones 99. Similar to 2-bromocyclohex-2-enone, 3-bromo-5,6-dihydropyran-2-one undergoes nitrile oxide cycloaddition, followed by dehydrobromination, to form regioi-someric 3-aryl-5,7-dihydropyrano 4,3-c/ isoxazol-7(4//)-ones 100 (Scheme 1.24) (242). 

The nickel hydroxide electrode resembles in its applications and selectivity the chemical oxidant nickel peroxide. The nickel hydroxide electrode is, however, cheaper, easy to use and in scale-up, and produces no second streams/ waste- and by-products [196], Nickelhydroxide electrode has been applied to the oxidation of primary alcohols to acids or aldehydes, of secondary alcohols to ketones, as well as in the selective oxidation of steroid alcohols, cleavage of vicinal diols, in the oxidation of y-ketocarboxylic acids, of primary amines to nitriles, of 2,6-di-tert-butylphenol to 2,2, 6,6 -tetra-rert-butyldiphenoquinone, of 2-(benzylideneamino)-phenols to 2-phenyloxazols, of 1,1-dialkylhydrazines to tetraalkyltetrazenes. For details the reader is referred to Ref. [195]. 

Methods for oxidative transformations continue to receive attention. Nickel peroxide on graphite oxidizes geraniol to citral in 89% yield. Three groups report " the oxidative rearrangement of tertiary vinyl carbinols. Linalool is con-... 

Treatment of carbazole with potassium permanganate in acetone (or nickel peroxide in ether ) gave mainly 9,9 -bicarbazole 9 (23%) together with the trimer 10 (8%). In the potassium permanganate oxidation,... 

Carbazole oxidized by nickel peroxide in the absence of light and in the presence of 2-methyl-2-nitrosopropane gave the radical 71, an observation taken as additional evidence for the intermediacy of radical cations, trapped in this case by the nitrosoalkane, in oxidative dimerization of carbazoles (see Section II,A,2). 

Some of the ring expansion reactions discussed in Section 2.03.3.3.1 can be extended to five-membered heterocycles containing two or more heteroatoms. Reaction of imidazoles and pyrazoles with dichlorocarbene, for example, gives chloropyrimidines together with small amounts of chloro-pyrazines or -pyridazines, and oxidative ring expansion of 1-aminopyrazole with nickel peroxide gives 1,2,3-triazine (this, in fact, constitutes the only known synthesis of the unsubstituted triazine). There are, however, a number of interesting and useful transformations which are unique to five-membered polyheteroatom systems. 

For reactive and short chain alcohols the nickel hydroxide electrode and nickel peroxide exhibit the same reactivity (Table 4).,The oxidation of long chain alcohols, which is possible in good yields at the electrode has not been reported for nickel peroxide. The close similarity in yield and products indicates that in both oxidations the same reagent is effective. 

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