Definition
An aldohexose that is isomeric with glucose, tallose, allose, and others.
Purification Methods
Crystallise D-altrose from aqueous EtOH. If it is obtained by the hydrolysis of the acetate, then it may contain sodium and acetate ions. Ions are best removed by dissolving in H2O, passing through suitable columns of ion-exchange resins, e.g. Amberlite IR-120 and Duolite A, and concentrating in a vacuum to a syrup. This is dissolved in MeOH, filtered and evaporated in a vacuum desiccator over granular CaCl2. The thick syrup is inoculated with seed crystals, stirred, and before it sets to a magma of crystals, transfer the crystals with MeOH to a Büchner funnel. Recrystallise them in the same way. -D-Altrofuranoside has initial [] D ~-69o (c 4, H2O) which mutarotates to +33o. [Richtmeyer Methods in Carbohydrate Chemistry I 107 Academic Press 1962, Beilstein 1 IV 4301, see Angyal Adv Carbohydrate Chem Biochem 42 15 1984 for ratio of anomers in solution.]
