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Threose is a four-carbon monosaccharide with molecular formula C4H8O4. It has a terminal aldehyde group rather than a ketone in its linear chain, and so is considered part of the aldose family of monosaccharides. The threose name can be used to refer to both the D- and L-stereoisomers, and more generally to the racemic mixture (D/L-, equal parts D- and L-) as well as to the more generic threose structure (absolute stereochemistry unspecified).

IUPAC names
(2S,3R)-2,3,4-Trihydroxybutanal (D)
(2R,3S)-2,3,4-Trihydroxybutanal (L)
Other names
3D model (JSmol)
ECHA InfoCard 100.002.199
Molar mass 120.104 g·mol−1
Appearance Syrup
Very soluble
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

The prefix "threo" which derives from threose (and "erythro" from a corresponding diastereomer erythrose) offer a useful way to describe general organic structures with adjacent chiral centers, where "the prefixes... designate the relative configuration of the centers".[2] As is depicted in a Fischer projection of D-threose, the adjacent substituents will have a syn orientation in the isomer referred to as "threo", and are anti in the isomer referred to as "erythro".[2][3]

Fischer projections depicting the two enantiomers of threose

See alsoEdit


  1. ^ Merck Index, 11th Edition, 9317
  2. ^ a b Formulas Using Other Configurational Notations, W. Rausch, accessed 1 March 2011
  3. ^ Prof. Rausch helpfully notes that the prefixes "may be applied to racemic compounds, as well as pure enantiomers and meso compounds", and that when depicted in the common "zig-zag" representation, adjacent "substituents may lie on the same side of the carbon chain... [syn] or on opposite sides... [anti]", which is opposite of their depiction in a Fischer projection.