Daldoses

Daldoses is not a standard term in contemporary carbohydrate chemistry. In some sources, it is used as shorthand for D-aldoses, that is, aldose monosaccharides that have the D configuration at the stereocenter farthest from the aldehyde group. Aldoses themselves are monosaccharides containing an aldehyde functional group (a carbonyl at carbon 1) and multiple hydroxyl groups, with the number of carbons ranging from three to seven or more.

The D- and L- prefixes refer to the stereochemistry at the chiral carbon farthest from the aldehyde. D-aldoses share the same configuration as D-glyceraldehyde at that carbon and are the most common forms found in nature, while L-aldoses are the enantiomeric counterparts that occur less frequently in biological systems. Both sets are possible for any given carbon count, and they can be produced synthetically as needed for research or industrial purposes.

Examples commonly cited as D-aldoses include D-ribose and D-xylose (aldopentoses) and the aldohexoses D-glucose, D-galactose, and D-mannose. Other entries in the D-aldose family include D-erythrose (a tetrose) and D-allose (a rare aldohexose). In biological contexts, D-aldoses serve as vital building blocks; for instance, D-ribose forms part of RNA backbones, while D-glucose is a central energy source.

See also: aldose, monosaccharide, stereochemistry, D- and L- forms.