The bisulphite addition compound (1) of
5-amino-5-deoxy-D-xylose reacted with cyclohexylamine to form the acyclic derivative (11). With
ammonia, benzylamine, morpholine, and piperidine,
corresponding salts (IV) of the piperidine derivative D-ido(gluco)-3,4,5-trihydroxy-2-sulphopiperidine
(VIII), were isolated. Removal of the amine yielded the crystalline bisulphite
addition compound (VIII). Acetylation in the presence of pyridine of the
different amine salts (11, IV) and of (VIII) gave an identical acetate (VII),
l-acetyl-D-ido(gluco)-3,4,5-triacetoxy-2-sulphopiperidine,
isolated as the pyridine salt. Deacetylation of (VII)
with barium methoxide gave the barium salt (IX). Oxidation of (IX) with sodium
periodate liberated one mole of formic acid, confirming the presence of a
six-membered ring containing nitrogen.
The significance of these results in the
inhibition of non-enzymic browning by sulphur dioxide is discussed.
Mechanism of Reduction of Sulphur Dioxide by Formic Acid.