Allose is an
aldohexose
In chemistry, a hexose is a monosaccharide (simple sugar) with six carbon atoms. The chemical formula for all hexoses is C6H12O6, and their molecular weight is 180.156 g/mol.
Hexoses exist in two forms, open-chain or cyclic, that easily convert ...
sugar. It is a rare
monosaccharide
Monosaccharides (from Greek ''monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built.
They are usually colorless, water-solub ...
that occurs as a 6-O-cinnamyl glycoside in the leaves of the African shrub ''
Protea
''Protea'' () is a genus of South African flowering plants, also called sugarbushes (Afrikaans: ''suikerbos'').
Etymology
The genus ''Protea'' was named in 1735 by Carl Linnaeus, possibly after the Greek god Proteus, who could change his form a ...
rubropilosa''. Extracts from the fresh-water alga ''Ochromas malhamensis'' contain this sugar but of unknown absolute configuration. It is soluble in water and practically insoluble in
methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...
.
Allose is a C-3
epimer
In stereochemistry, an epimer is one of a pair of diastereomers. The two epimers have opposite configuration at only one stereogenic center out of at least two. All other stereogenic centers in the molecules are the same in each. Epimerization is ...
of
glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...
.
Notes
References
* Carbohydrates, edited by P.M. Collins, Chapman and Hall,
Aldohexoses
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