Barium hypobromite

In May, 1944, Onodera was promoted to Associate Professor. After 1950, the condition of scientific research in Japan gradually improved, and Onodera and his associates succeeded in publishing the following results deamination of D-glucosamine by barium hypobromite (1952) transgly-... 

L-arabinose and D-xylose in hemi-cellulose of sugar Cane, V, 279 Banana starch. See under Starch. Barium acid heparinate, III, 146 Barium 2-desoxy-D-gIuconate, III, 144 Barium D-gluconate, III, 144 Barium hypobromite, III, 163 Barium salts, in preparation of aldonic acids with NaCN, I, 23 Bark, tree, pentosan content, V, 271 Barley, alpha amylase of malted, V, 255-265... 

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. 

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. 

Jackson and Hudson obtained a dicarboxylic acid (104), isolated as its crystalline strontium salt, in a yield of 20% by oxidizing methyl a-n-mannopyranoside in an aqueous solution of barium hypobromite. This acid, which is normally obtained by oxidation of the dialdehyde obtained by periodate oxidation of the n-glucoside, is most probably another example of a product arising from the cleavage of a bond between adjacent keto groups. Heyns found that changing the pH, in the catalytic oxidation of benzyl S-n-arabinop3Tanoside, to pH 7.3 resulted in the formation of a dicarboxylic acid (105) (isolated as its crystalline barium salt) in 42% yield. He considered this to be a further oxidation product of the 4-keto compound normally formed. 

Goebel used barium hypobromite for the preparation of calcium gluconate and maltobionate 196), In methanol solution, high yields of the aldonic acids are obtained 197),... 

Reagents Nickelic hydroxide-paste Baryta water is treated with bromine water, and the resulting barium hypobromite is mixed with nickel sulfate solution and warmed. The proportions of Ba and Ni should be so adjusted that a gray precipitate is formed. It is filtered and well washed. The wet precipitate is stored in a weighing bottle with a well-fitting stopper. The paste can be kept for a long time. 

Crystalline barium bromite Ba(Br02)2-H20 was first isolated in 1959 it can be made by treating the hypobromite with Br2 at pH 11.2 and 0°C, followed by slow evaporation. Sr(Br02)2.2H20 was obtained similarly. 

Determination of sulphite by oxidation to sulphate and precipitation as barium sulphate Discussion. Sulphites may be readily converted into sulphates by boiling with excess of bromine water, sodium hypochlorite, sodium hypobromite, or ammoniacal hydrogen peroxide (equal volumes of 20-volume hydrogen peroxide and 1 1 ammonia solution). The excess of the reagent is decomposed by boiling, the solution acidified with hydrochloric acid, precipitated with barium chloride solution, and the barium sulphate collected and weighed in the usual manner (Section 11.72). 

Other additions to the double bond of compounds in this series have not been studied extensively, but reports now indicate that several such additions can be accomplished efficiently. Nitryl iodide is, however, not added92 to the double bond of compound 45, but bromination in methanol, in the presence of barium carbonate, gives crystalline methyl 4,6-0-benzylidene-2,3-dibromo-2,3-dideoxy-a-D-altropyranoside in 70% yield.93 On treatment with potassium tert-butoxide in refluxing xylene, this compound undergoes elimination of the elements of hydrogen bromide to give methyl 4,6-O-benzylidene-2-bromo-2,3-dideoxy-a-D-t/ireo-hex-3-enopyranoside (46, R = Br) in 90% yield. Likewise, compound 45 reacts with acetyl hypobromite to give methyl 3-0-acetyl-4,6-0-benzylidene-2-bromo-2-deoxy-a-D-glu-... 

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