D-半乳糖醇, 衛矛醇, 半乳糖醇, 甜醇, Dulcitol, Galactitol

Galactitol, also known as dulcitol or dulcose, belongs to the class of organic compounds known as sugar alcohols. These are hydrogenated forms of carbohydrate in which the carbonyl group (aldehyde or ketone, reducing sugar) has been reduced to a primary or secondary hydroxyl group. Galactitol exists as a solid, soluble (in water), and a very weakly acidic compound (based on its pKa). Galactitol has been found in human brain tissue, and has also been detected in most biofluids, including urine, saliva, feces, and blood. Galactitol can be biosynthesized from D-galactose; which is catalyzed by the enzyme aldose reductase. In humans, galactitol is involved in the galactose metabolism pathway. Galactitol is also involved in the metabolic disorder called the galactosemia pathway. Outside of the human body, galactitol can be found in a number of food items such as pine nut, oil palm, sapodilla, and ucuhuba. This makes galactitol a potential biomarker for the consumption of these food products. Galactitol is a potentially toxic compound.

Galactitol is an optically inactive hexitol having meso-configuration. It has a role as a metabolite, a human metabolite, an Escherichia coli metabolite and a mouse metabolite.

A naturally occurring product of plants obtained following reduction of GALACTOSE. It appears as a white crystalline powder with a slight sweet taste. It may form in excess in the lens of the eye in GALACTOSEMIAS, a deficiency of GALACTOKINASE.

Title: Galactitol

CAS Registry Number: 608-66-2

Additional Names: Dulcitol; dulcite; dulcose; euonymit; melampyrite; melampyrum; melampyrin

Molecular Formula: C6H14O6

Molecular Weight: 182.17

Percent Composition: C 39.56%, H 7.75%, O 52.70%

Literature References: Found in dulcite or Madagascar manna (Melampyrum nemorosum L.) and in other species of Melampyrum, Scrophulariaceae, and Evonymus atropurpureus Jacq., Celastraceae. Isoln: Hünefeld, Ann. 24, 241 (1837); Bouchardat, Ann. Chim. Phys. 27, 68 (1872); Fischer, Hertz, Ber. 25, 1261 (1892); Rogerson, J. Chem. Soc. 101, 1040 (1912). Prepn by catalytic isomerization of D-glucitol: Wright, Hartmann, J. Org. Chem. 26, 1588 (1961). Synthesis: Lespieau, Bull. Soc. Chim. Fr. [5] 1, 1374 (1934); Delepine, Horeau, ibid. 4, 1524 (1937); Wiemann, Gordon, ibid. 1958, 433. Structure: R. L. Lohmar "The Polyols" in W. Pigman, The Carbohydrates (Academic Press, New York, 1957) p 247.

Properties: Crystals from methanol + water, mp 188-189°. Slightly sweet taste. d20 1.47. bp1 275-280°. One gram dissolves in 30 ml water, in 2 ml boiling water. Slightly sol in alc. Ka at 18° = 3.5′10-14.

Melting point: mp 188-189°

Boiling point: bp1 275-280°

Density: d20 1.47

Derivative Type: Hexa-O-acetylgalactitol

Molecular Formula: C18H26O12

Molecular Weight: 434.39

Percent Composition: C 49.77%, H 6.03%, O 44.20%

Properties: Crystals from ethanol, mp 168-169°.

Melting point: mp 168-169°

Derivative Type: Hexanitrate

Additional Names: Nitrodulcitol

Properties: mp 94-95°. Has explosive properties: Taylor, Rinkenbach, J. Franklin Inst. 204, 374 (1927).

Melting point: mp 94-95°