Hypobromite oxidation

Aliphatic nitroso compounds are obtained either by hypobromite oxidation of alkylhy-droxylamines made by oxaziridine hydrolysis, or directly from oxaziridines by action of a second mole of peracid (Section 5.08.3.1.3). 

Bei der Hypobromit-Oxidation von 2,4-Dinitro-anilin in Methanol erhalt man nicht 5-Nitro-benzofurazan-l-oxid in einer Folgereaktion entsteht daraus 5-Brom-4-methaxy-henzofurazan-1-uxid (48%)124... 

Nitrosation of mesityl oxide oxime leads to the dioxide 96, correctly formulated by Freeman.119 Earlier workers had formulated the product as a nitrimine128 and as a nitrosonitrone.118 Hypobromite oxidation of 97 leads to the same compound129 (Scheme 35), whereas the 4-bromo analog of 96 has been prepared by base elimination of HBr from a dibromopyrazoline N,N -dioxide precursor.119... 

Further illustration of the inadequacy of hypobromite oxidation for the conversion of glycosides to uronides is the work of Jackson and Hudson.79 Only a twelve percent yield of the brucine salt of methyl a-D-mannuronoside was obtained because of oxidative cleavage of the carbon chain of methyl a-D-mannopyranoside. 

An aqueous solution of sulfuric acid and a salt of periodic add, trisodium paraperiodate, or one of the potassium periodates, has been used frequently as a substitute for pure periodic add. When the product of the oxidation reaction is to be isolated, the effect of the presence of metal ions on the yield should be considered. If the product is volatile or slightly soluble, or is isolated either as a slightly soluble derivative or by extraction with organic solvents, the presence of metal ions should not reduce the yield. In the Case of certain methylhexosides34 which were oxidized by periodic acid formed from potassium metaperiodate and an equivalent of sulfuric add in aqueous solution, the presence of potassium ions was found to cause a low yield of the crystalline strontium salt prepared by the strontium hypobromite oxidation of the dialdehyde resulting from the periodic add reaction. Oxidation by pure periodic add, a solution of which is prepared either from crystalline paraperiodic add or by the previously mentioned method from potassium metaperiodate, is desirable when the presence of difficultly removed metal ions affects the yield adversely. 

Risgaard-Petersen, N., Rysgaard, S., and Revsbech, N. P. (1995). Combined microdiffusion-hypobromite oxidation method for determining nitrogen-15 isotope in ammonium. Soil Sci. Soc. Am.J. 59, 1077-1088. 

Bergmann and Wolff S reported a small yield (1 g.) of menthol a-D-glucuronide by the oxidation of 12 g. of menthol a-n-glucoside in pyridine solution with sodium hypobromite. Better yields were obtained by Smolenski, who oxidized methyl a-n-glucopyranoside with bromine and sodium carbonate a 30% yield of the methyl n-glucuronide (as the brucine salt) was reported. Jackson and Hudson obtained a 12% yield of the brucine salt of methyl a-n-mannuronide by the barium hypobromite oxidation of methyl a-n-mannopyranoside. 

Mol. wt. 360.48, in.p. 238°. Preparation by hypobromite oxidation of pregnenolone acetate (available from Syntex S. A.). The corresponding acid chloride has been used for the resolution of la-hydroxydicyclopentadiene, of cis,c(j-l-decalol, and of // flns-3-/-butylcyclohexanoP (in this case conventional resolution of acid phthalate salts with alkaloids failed). 

Diels acid is high melting and sparingly soluble and can be isolated easily even though present in very small amounts. One of us oxidized cholesterol with sodium dichromate dihydrate in benzene-acetic acid and isolated the Diels acid in yield of 2.97% along with 6 neutral oxidation products. One of these, A -cholestene-3-one, might be but is not a precursor of the Diels acid. Cholesteryl acid chromate would seem to offer an attractive possibility for intramolecular attack of the allylic /3-hydrogen at C,. The active species in the hypobromite oxidation may be the hypobromite of cholesterol. 

Oxidative cleavage of ketones. Levine and Stephens showed that hypohalite oxidation of ketones to acids is not limited to methyl ketones. Thus sodium hypobromite oxidizes propiophenone to benzoic acid in 96% yield, probably as follows ... 

Monocrotaline (45) was reduced (LiAlH4) to 2,3,4-trimethylpentane-l,2,3,5-tetraol (46). Periodate oxidation of (46), followed by hypobromite oxidation of the product, afforded 3-hydroxy-2-methylpropanoic acid, whose hydrazide (48) was shown to be enantiomeric with the known hydrazide" of -configuration. The hydrazide from monocrotaline therefore has the S-configuration and monocrotalic acid has the R-configuration at C-4. 

Hypobromite oxidation of 5-benzylaminotetrazole provides a useful preparation of benzyl-isonitrile. ... 

Discussion When a lead salt in which the metal has the valence 2 is treated with an alkaline solution of a hypochlorite or a hypobromite, oxidation takes place and lead dioxide is precipitated. In the preparation described below the hypobromite is prepared by dissolving bromine in a cold solution of sodium hydroxide ... 

Hypobromite oxidation of 5-benzylaminotetrazoles provides a useful synthesis of benzyl isonitriles, as illustrated below." ... 

As expected for a methyl ketone, hypobromite oxidation of A-benzoylisopelletierine gives bromoform (9). Attempts to prepare the compound C10H20NO2CI described by Hess have been unsuccessful (7,8). The procedure described by Hess (19) for the isolation of pelletierine from pomegranate root has been repeated (JJ) and a urethane different from synthetic 3-(2-piperidyl)propanal urethane but identical with synthetic (2-piperidyl)-2-propanone urethane was isolated. 

Oxidation of 1 mol of the anomeric methyl aldopentopyranosides with 2 mol of periodate or lead tetraacetate yields one of a pair of dialdehydes, a dextrorotatory product 48 being derived from a-D- or p-L-glycosides and levo-rotatory 49 from p-D or a-L isomers. In turn, hypobromite oxidation affords either dicarboxylic acid 47 or 50. Additional possibilities for configurational correlation accrue from the fact that a methyl aldotetrofuranoside similarly yields 48 or 49, whereas a methyl aldopentofuranoside gives 44 or 45 as the final product. 

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