N-Galactonic acid

In most cases, after the hydrogen bromide had been removed, the resulting solutions were treated with various carbonates or with ammonium hydroxide to form the desired salts. The salts could be recrystallized directly from water or precipitated into ethanol. The choice of salt depended on circumstances thus, calcium D-gluconate crystallized well, but in the case of n-galactonic acid, the cadmium salt was preferable. The lead or cadmium salt was preferred when the free acid was desired since treatment of the aqueous solution or suspension with hydrogen sulfide easily removed the cation. The barium salts could be treated with the calculated amount of sulfuric acid and the calcium salts with oxalic acid for the same purpose. 

The condensation of fatty acids with o-phenylenediamine has been carried out effectively by refluxing the components in 4 N hydrochloric acid.19 Moore and Link, in their second paper on the preparation of benzimidazoles,20 stated that this procedure gave less satisfactory yields with the aldonic acids, the yield from D-galactonic acid being only 24%. 

Another method of preparing keto aldonic acids, those of the 2-keto type, is by oxidation of the corresponding osone. Neuberg and Kitasato obtained 18 g. of calcium 2-keto-D-gluconate from 20 g. of the osone by the action of bromine at 20 . Similarly, 2-keto-n-galactonic and 2-keto-maltobionic acids were prepared by Kitasato. The substances were characterized generally as the brucine salts because of the amorphous nature of the calcium salts. 

These crystal-structure analyses are concerned with the following molecules o-D-glucopyranose monohydrate/ D-xylopyranose/ methyl yS-D-xylopyranoside, di-jS-n-fructopyranose-strontium chloride trihydrate, cellobiose (independent determination), D-glucaric acid, D-galactonic acid, methyl a-D-lyxofuranoside, /3-D-lyxopyranose, methyl 3,4,6-tri-0 - acetyl - 2 - (chloromercuri) - 2 - deoxy - j3 - d - glucopyranoside, D-glu-copyranosyl (potassium sodium phosphate) tetrahydrate," and methyl 6-bromo-6-deoxy-a-D-galactopyranoside. ... 

The removal of acetone by hydrolysis would then yield n-tagaturonic acid (LXXVa), which may also be named 5-keto-L-galactonic acid or... 

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