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DERIVATIVES. 201
of sugars from another class, namely, the preparation of sugars poor in
carbon from those rich in carbon, for example, pentoses from hexoses
(see Wohl).
According to Ruff, by the action of hydrogen peroxide and the cata-
lytic action of ferric salts upon the carbohydrate monocarboxylic acids
the carbon chain can be shortened by the splitting off of the elements
of formic acid, and with the formation of the next lower aldose. Nki -
berg 1
has accomplished the same result by electrolysis, and by this
method has split glucose step by step into formaldehyde.
By the action of alkalies, even in small amounts, as also of carbonates
and lead hydroxide, a reciprocal transformation of the sugars, such as
d-glucose, d-fructose, and d-mannose, may take place (Lobry de Bruyn
and Alberda van Ekenstein 2
), and from each of these three varieties
of sugar the two others are produced so that after a certain time the
solution contains all three sugars.
The transformation of the different varieties of sugar into each other
also occurs in the animal body. Neuberg and Mayer 3
have shown by
experiments on rabbits the direct partial transformation of various
mannoses into the corresponding glucoses. Another example is, it
seems, the formation of galactose (or milk sugar) from glucose in the
mammary gland.
By the action of strong alkali the sugars are decomposed with the
formation of lactic acid and many other products.
With ammonia the glucoses may form compounds which have been
considered as osamines by Lobry de Bruyn, but to differentiate them
from the true osamines have been called osimines by E. Fischer.4
The
corresponding osaminic acid can be obtained from such an osimine by
the action of ammonia and hydrocyanic acid, and from the hydrochloric-
acid lactone of this acid the osamine is obtained by reduction with sodium
amalgam. In this manner E. Fischer and Leuchs artificially prepared
first d-arabinosimine from d-arabinose, then d-glucosaminic acid and
finally from its lactone d-glucosamine, which occurs in the animal
body. In a similar manner they 5
obtained ^-glucosamine from
/-arabinose.
Knoop and Windaus 6
have obtained large amounts of methylimida-
1
Ruff, Ber. d. d. chem. Gesellsch., 31 and 32; Neuberg, Biochem. Zeitschr., 7.
2
Ber. d. d. chem. Gesellsch., 28, 3078; Bull. soc. chim. de Paris (3), 15; Chem.
Centralbl., 1896, 2, and 1897, 2.
3
Zeitschr. f. physiol. Chem., 37.
4
Lobry de Bruyn, Ber. d. d. chem. Gesellsch., 28; E. Fischer, ibid., 35.
6
Ibid., 35, p. 3787, and 36, 24 (1903).
8
Ibid., 38, and Hofmeister’s Beitrage, 6.
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