Over-oxidation of Aldoses

Stepwise Oxidation of n-Glucose with Barium Hypohromite  

The preparation of 2-keto-D-gluconic acid from D-glucosone was reported by Myrback. The osone was oxidized in alkaline solution 

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. 

The last reaction was non-selective it was carried out for sixteen to twenty days at a low temperature (3-7°), and 25-30% of the unaltered starting material was recovered. A 25% yield of strontium n-methoxy-n -hydroxymethyldiglycolate dihydrate showed that the reagent attacked C2, C3 and C4, and split out formic acid at C3. This reaction is similar to the familiar one observed with periodic acid except that the product is a diacid and not a dialdehyde. 

A further degradation of methyl a-n-glucoside by the action of barium hypobromite was observed by Bergmann and Wolff. From 12 g. of the glycoside, 4.6 g. of glyoxylic acid benzylphenylhydrazone was obtained. The experimental conditions differed from those used in the preparation of menthol a-D-glucuronide in that about twice as much bromine was used. 

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