1. D(-)-Arabinose

D(-)-Arabinose(10323-20-3) is a kind of reducing sugar, it is degraded by Escherichia coli B via some of the L-fucose pathway enzymes and a D-ribulokinase which is distinct from the L-fuculokinase of the L-fucose pathway.The specification of D(-)-Arabinose is as follows:

2. Preparation of D(-)-Arabinose

A solution of 100 g. (0.26 mole) of pentaacetyl glucononitrile (p. 690) in 150 ml. of chloroform in a 1-l. Erlenmeyer flask is chilled to -12℃. A chilled (-12℃) solution of 16 g. (0.7 gram atom) of sodium in 250 ml. of anhydrous methanol is added with continual shaking and chilling to the chloroform solution of the nitrile. The mixture soon solidifies to a pale yellow gelatinous mass. After 10 minutes at −12° this is broken up with a heavy glass rod and dissolved in 600 ml. of a suspension of ice in water. The resulting solution is acidified with an ice-cold mixture of 33 g. (18 ml, 0.32 mole) of 95% sulfuric acid, 5 ml. of acetic acid, and 45 g. of ice. The aqueous layer is separated, washed once with 50 ml. of chloroform, and evaporated without delay under reduced pressure. The residual heavy syrup is dissolved in 300 ml. of water and again evaporated as completely as possible under reduced pressure, in order to remove residual hydrogen cyanide. The highly viscous residue, which contains some crystals of sodium sulfate, is dissolved in 500 ml. of hot methanol. After about 10 minutes the sodium sulfate is filtered with suction and washed with two 25-ml. portions of methanol. The filtrate is concentrated under reduced pressure at 40℃ to a heavy syrup which is poured while warm into a 200-ml. Erlenmeyer flask. The distilling flask is rinsed twice with 20-ml. portions of hot ethanol, and this rinse is added to the filtrate. The resulting ethanol solution soon begins to deposit crystals of arabinose; it is stirred by hand during the crystallization and gradually diluted with more ethanol until 100 ml. in all has been added during the course of an hour. The mixture is allowed to stand for 4-5 hours; the crystals are then filtered, washed with two 25-ml. portions of ethanol, and dried at 40℃. The yield of colorless D-arabinose, m.p. 158–158.5°, [α]D20 −105° (final value), is 23.5-26.3 g. (61-68%).

3. D(-)-Arabinose price

Due to the widely use of D(-)-Arabinose, its request is large at present. And the D(-)-Arabinose price is as for reference is offered by Hangzhou Chemfar Ltd.