Hydrolysis oximes

Peroxyacids are powerful oxidants and so side reactions are to be expected. Ketones are known to undergo Baeyer-Villiger " oxidation to the carboxylic acid ester on treatment with peroxyacids and so these by-products can be observed if oxime hydrolysis occurs during the oxidation. Paquette and co-workers " " observed such a by-product (61) during the oxidation of the dioxime (59) to the dinitro compound (60) with m-CPBA in hot acetonitrile. 

The furan oxime 320 was boiled with hydrochloric acid and a mixture of the Beckmann rearranged heterocycle 321 and 2-acetylfuran derivative 322 (resulting from the oxime hydrolysis) was obtained (equation 117). 

NOH and the oxime hydrolysis product HNC5H4CHO. The displacement in aqueous perchloric acid was found to follow the rate equation... 

Similarly, on-column methylation has been applied to carbamate pesticides containing an active N-H group. Wien and Tanaka (41) showed that N-aryl carbamates are methylated on-column with tri-methylanilinium hydroxide-methanol to give the intact N-methyl and N-aryl derivatives. On the other hand N-methyl, 0-aryl carbamates such as carbaryl or carbofuran yielded only the methyl ethers of their respective phenols. This work has now been extended to sulfur-containing carbamates such as methomyl, methio-carb, aldicarb, etc. (42-43). Here the oxime hydrolysis products of these carbamates are chromatographed as the 0-methyl oximes. 

Imine (and therefore oxime) hydrolysis was discussed in Chapter 14, p. 000. 

Oxime hydrolysis. Aldoximes and ketoximes are readily cleaved by stirring with activated MnO, in hexane at room temperature. 

The nitroso functional group, -N=0, may be new to you, but you met oximes in Chapter 11. Imine (and therefore oxime) hydrolysis was also discussed in Chapter 11. 

Q -chloroketones. Hydrolysis presumably proceeds via the oxime tautomer of the monomeric nitroso compound. Levulinic acid is used to react with the hydrox-ylamine formed in the oxime hydrolysis. The stereochemistry of nitrosyl chloride addition has not been investigated for a wide variety of olefins. Both syn and anti addition have been reported in systems studied to date. 

Hydrolysis of Acetoxime. Place about i g. of the recrystallised oxime in a small distilling-flask (50 ml.), add 10 ml. of dilute HjSO, and heat gently until about half the solution has distilled over. Test [a] the aqueous distillate for acetone by the iodoform reaction (p.346), b) the residual solution in the distilling-flask for hydroxylamine by... 

The imides, primaiy and secondary nitro compounds, oximes and sulphon amides of Solubility Group III are weakly acidic nitrogen compounds they cannot be titrated satisfactorily with a standard alkaU nor do they exhibit the reactions characteristic of phenols. The neutral nitrogen compounds of Solubility Group VII include tertiary nitro compounds amides (simple and substituted) derivatives of aldehydes and ketones (hydrazones, semlcarb-azones, ete.) nitriles nitroso, azo, hydrazo and other Intermediate reduction products of aromatic nitro compounds. All the above nitrogen compounds, and also the sulphonamides of Solubility Group VII, respond, with few exceptions, to the same classification reactions (reduction and hydrolysis) and hence will be considered together. 

Oximes, hydrazines and semicarbazones. The hydrolysis products of these compounds, t.e., aldehydes and ketones, may be sensitive to alkali (this is particularly so for aldehydes) it is best, therefore, to conduct the hydrolysis with strong mineral acid. After hydrolysis the aldehyde or ketone may be isolated by distillation with steam, extraction with ether or, if a solid, by filtration, and then identified. The acid solution may be examined for hydroxylamine or hydrazine or semicarbazide substituted hydrazines of the aromatic series are precipitated as oils or solids upon the addition of alkali. 

Biacetyl is produced by the dehydrogenation of 2,3-butanediol with a copper catalyst (290,291). Prior to the availabiUty of 2,3-butanediol, biacetyl was prepared by the nitrosation of methyl ethyl ketone and the hydrolysis of the resultant oxime. Other commercial routes include passing vinylacetylene into a solution of mercuric sulfate in sulfuric acid and decomposing the insoluble product with dilute hydrochloric acid (292), by the reaction of acetal with formaldehyde (293), by the acid-cataly2ed condensation of 1-hydroxyacetone with formaldehyde (294), and by fermentation of lactic acid bacterium (295—297). Acetoin [513-86-0] (3-hydroxy-2-butanone) is also coproduced in lactic acid fermentation. 

An alternative route to 5-nitro-2-furancarboxaldehyde requires nitration of 2-furancarboxaldehyde oxime [1121 -47-7] with mixed acid to give the nitrated oxime [555-15-7] and concomitant hydrolysis (22). Furthermore, 2-furan-carboxaldehyde derivatives with the R-substituent in place have been nitrated to the desired product (23). 

Diels-Alder reaction of 2-bromoacrolein and 5-[(ben2yloxy)meth5i]cyclopentadiene in the presence of 5 mol % of the catalyst (35) afforded the adduct (36) in 83—85% yield, 95 5 exo/endo ratio, and greater than 96 4 enantioselectivity. Treatment of the aldehyde (36) with aqueous hydroxylamine, led to oxime formation and bromide solvolysis. Tosylation and elimination to the cyanohydrin followed by basic hydrolysis gave (24). 

Alloxan forms an oxime (1007) which is the same compound, violuric acid, as that formed by nitrosation of barbituric acid likewise, a hydrazone and semicarbazone. Reduction of alloxan gives first alloxantin, usually formulated as (1008), and then dialuric acid (1004 R = OH) the steps are reversible on oxidation. Vigorous oxidation with nitric acid and alkaline hydrolysis both give imidazole derivatives (parabanic acid and alloxanic acid, respectively) and thence aliphatic products. Alloxan and o-phenylenediamine give the benzopteridine, alloxazine (1009) (61MI21300). 

The reaction of the dilithio salt (597) with methyl benzoate and subsequent acid hydrolysis yielded 3-phenyl-4,5,6,7-tetrahydro-2,1-benzisoxazole (598) (76JPS1408). The oxime (599) was converted into (600) by treatment with ethanolic HCl (75JCS(P1)1959>. 

Oximes are cleaved by oxidation, reduction, or hydrolysis in the presence of another carbonyl compound. Some synthetically useful methods are shown below. 

This method is an adaptation of that of Dengel. -Methoxy-phenylacetonitrile can also be prepared by the metathetical reaction of anisyl chloride with alkali cyanides in a variety of aqueous solvent mixtures by the nitration of phenylaceto-nitrile, followed by reduction, diazotization, hydrolysis, and methylation 1 by the reduction of ct-benzoxy- -methoxy-phenylacetonitrile (prepared from anisaldehyde, sodium cyanide, and benzoyl chloride) and by the reaction of acetic anhydride with the oxime of -methoxyphenylpyruvic acid. ... 

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