Ketones to oximes

By 1990, most of the catalytic reactions of TS-1 had been discovered. The wide scope of these reactions is shown in Fig. 6.1.35 Conversions include olefins and diolefins to epoxides,6,7 12 16 19 21 24 34 36 38 13 aromatic compounds to phenols,7,9 19 25 27 36 ketones to oximes,11 20 34 46 primary alcohols to aldehydes and then to acids, secondary alcohols to ketones,34-36 42 47-30 and alkanes to secondary and tertiary alcohols and ketones.6 34 43 31 52... 

In the absence of alcohol solvents, hydrogen peroxide is thought to coordinate with Ti by displacing an Si-O bond as shown in Fig. 6.11. This sets the stage for ammonia interaction to form hydroxylamine and subsequent ammoximation of ketones to oximes.20,56 57... 

Hydroxylamine condenses with the carbonyl group of an aldehyde or ketone to form an oxime ... 

Since hydroxylamine is usually available only in the form of its salts, e.g., the hydrochloride or sulphate, the aqueous solution of these salts is treated with sodium acetate or hydroxide to liberate the base before treatment with the aldehyde or ketone. Most oximes are weakly amphoteric in character, and may dissolve in aqueous sodium hydroxide as the sodium salt, from which they can be liberated by the addition of a weak acid, e.g., acetic acid. 

Hypochlorous acid adds to oximes of cyclic ketones forming intermediate a-chloronitroso compounds that can be converted to nitro compounds (108). 

Conversion of a ketone to a highly substituted imine interestingly leads to a compound which shows analgesic activity, anidoxime (197). Phenyl 2-di-ethylaminoethyl ketone is converted to its oxime (196) in the usual way, and this is converted to... 

One of the exciting results to come out of heterogeneous catalysis research since the early 1980s is the discovery and development of catalysts that employ hydrogen peroxide to selectively oxidize organic compounds at low temperatures in the liquid phase. These catalysts are based on titanium, and the important discovery was a way to isolate titanium in framework locations of the inner cavities of zeolites (molecular sieves). Thus, mild oxidations may be run in water or water-soluble solvents. Practicing organic chemists now have a way to catalytically oxidize benzene to phenols alkanes to alcohols and ketones primary alcohols to aldehydes, acids, esters, and acetals secondary alcohols to ketones primary amines to oximes secondary amines to hydroxyl-amines and tertiary amines to amine oxides. 

The oxidation of NH3 to NH2OH forms the basis of a process for the ammoximation of cyclohexanone to the oxime because the NH2OH formed in solution readily reacts with the ketone (non-catalytically) to give the oxime (231). Table XXX (165) illustrates the conversions and selectivites obtained for a few typical ketones and aldehydes. The ammoximation of aldehydes is faster than that of ketones. The oxime selectivity is also higher. The ammoximation of cyclohexanone by this method offers a more eco-friendly alternative route to the cyclohexanone oxime intermediate for the production of Nylon-6. The current route coproduces large quantities of ammonium sulfate and involves the use of hazardous chemicals such as oleum, halides, and oxides of nitrogen. 

Asymmetric catalytic reduction reactions represent one of the most efficient and convenient methods to prepare a wide range of enantiomerically pure compounds (i.e. a-amino acids can be prepared from a-enamides, alcohols from ketones and amines from oximes or imines). The chirality transfer can be accomplished by different types of chiral catalysts metallic catalysts are very efficient for the hydrogenation of olefins, some ketones and oximes, while nonmetallic catalysts provide a complementary method for ketone and oxime hydrogenation. 

Reductions with aluminum are carried out almost exclusively with aluminum amalgam. This is prepared by immersing strips of a thin aluminum foil in a 2% aqueous solution of mercuric chloride for 15-60 seconds, decanting the solution, rinsing the strips with absolute ethanol, then with ether, and cutting them with scissors into pieces of approximately 1 cm [141,142]. In aqueous and non-polar solvents aluminum amalgam reduces cumulative double bonds [143], ketones to pinacols [144], halogen compounds [145], nitro compounds [146, 147], azo compounds [148], azides [149], oximes [150] and quinones [151], and cleaves sulfones [141, 152, 153] and phenylhydrazones [154] (Procedure 30, p. 212). 

Primary amines add to aldehydes and ketones to form imines, R-N=CR2-Secondciry cimines react to form enamines, R 2C=CR(NR2). Hydroxylamine reacts to form an oxime, R2C=NOH. Hydrazine reacts to form a hydrazone,... 

A small number of examples is available for the synthesis of E and Z isomers of oximes. In many cases, E isomers were obtained either from the Z forms (by the hydrochloride method) or isolated by column chromatography. Often, the reagents that have been used for oximation of aldehydes and ketones also catalyze the interconversion of Z and E isomers. The rate of equilibration of a mixture of Z and E isomers and the position of the equilibrium is temperature-dependent ". In 2001, Sharghi and Sarvani reported a convenient method for controlling the stereochemistry of the reaction of hydroxylamine hydrochloride with aldehydes or ketones in the solid state. The highly stereoselective conversion of aldehydes and ketones to their corresponding oximes... 

On the other hand, since oxime ethers were electrochemically more inert than ketones under the electroreduction conditions, the electroreductive intra- and inter-molecular coupling of ketones with oxime ethers proceeded via anion radicals in good yields (equations 5 and 6) °4i. Moreover, cobaloxime-mediated intramolecular radical addition onto oxime functions in the electrolysis media proceeded to afford the cyclized aminoethers (equation 7). ... 

Most applications of this compound are similar to those of the hydrochloride. It is primarily used as a reducing agent for organic synthesis and chemical analysis. Other uses are to purify aldehydes and ketones to inhibit oxidation of fatty acids in dehairing hides in synthesis of oximes for paints and varnishes in photographic developer solutions in rust proofing and as a catalyst. 

Treatment of aliphatic active methylene compounds with such reagents normally leads to oxime formation. An exception is the nitrosation of compounds with active tertiary carbon atoms such as ethyl isopropyl ketone which are convertible into C-nitroso compounds. 

Conversion of oximes derived from cyclobutyl ketones to amides represents the classic Beckmann rearrangement. One example of this reaction is the formation of optically active 7,7-dimethyl-2-azabicyclo[4.1.1]octan-3-one (1) from 6,6-dimethylbicyclo[3.1.1]heptan-2-one oxime, which is readily derived from /3-pinene.40... 

Reaction with alcohols is general for diazo compounds, but it is most often performed with diazomethane to produce methyl ethers or with diazo ketones to produce a-keto ethers, since these kinds of diazo compounds are most readily available. With diazomethane593 the method is expensive and requires great caution. It is used chiefly to methylate alcohols and phenols that are expensive or available in small amounts, since the conditions are mild and high yields are obtained. Hydroxy compounds react better as their acidity increases ordinary alcohols do not react at all unless a catalyst such as HBF4594 or silica gel595 is present. The more acidic phenols react very well in the absence of a catalyst. Oximes, and ketones that... 

In another type of process, oximes can be obtained by passing a mixture of ketone vapor, NH3, and 02 over a silica-gel catalyst.213 Ketones can also be converted to oximes by treatment with other oximes, in a transoximation reaction.214... 

Cleavage of enol estersEnol esters arc converted to oximes of the corresponding ketone by reaction with excess hydroxylamine in THF or pyridine. 

When the hydroxyliminoenamines (797) were treated with hydrazine, 2,3-dihydro-l,2,4-triazine 4-oxides (799) were obtained. The intermediates are the a-hydrazono oximes (798) which as indicated above (c/. 635 ->637, Section 2.19.4.2.1) can also be cyclized with ketones to afford the 2,3-dihydro derivatives (800 Scheme 31) (75S794,76GEP2527490). 

It turned out that the acetylene-assisted pyrrolization of ketoximes could be successfully extended to oximes of condensed aromatic ketones, such as 1- and 2-acetylnaphthalenes (Scheme 10) (82KGS1351). 

Extention of the reaction of ketoximes with acetylene to oximes of hydroxyalkyl ketones can lead to the synthesis of inaccessible, functionally substituted pyrroles and A-vinyl derivatives. However, the methyl a- and /3-hydroxyalkyl ketoximes used by Trofimov et al. (80ZOR410) appeared to react with acetylene in the KOH/DMSO system in an abnormal way. 

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