Threose

Threose^[1]

D-Threose
L-Threose
Names
IUPAC names (2S,3R)-2,3,4-Trihydroxybutanal (D) (2R,3S)-2,3,4-Trihydroxybutanal (L)
Other names Threotetrose
Identifiers
CAS Number	95-43-2 (D) 95-44-3 (L)
ChEBI	CHEBI:28587
ChemSpider	388736
Jmol interactive 3D	(D): Image (L): Image
PubChem	439665 (D)
InChI InChI=1S/C4H8O4/c5-1-3(7)4(8)2-6/h1,3-4,6-8H,2H2/t3-,4-/m1/s1 Key: YTBSYETUWUMLBZ-QWWZWVQMSA-N InChI=1/C4H8O4/c5-1-3(7)4(8)2-6/h1,3-4,6-8H,2H2/t3-,4-/m1/s1 Key: YTBSYETUWUMLBZ-QWWZWVQMBY
SMILES (D): O=C[C@@H](O)[C@H](O)CO (L): OC[C@H](O)[C@@H](O)C=O
Properties
Chemical formula	C4H8O4
Molar mass	120.10 g·mol^−1
Appearance	Syrup
Solubility in water	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

Threose is a four-carbon monosaccharide or carbohydrate 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).

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 also

• Threonic acid
• Threose nucleic acid

References

1. Merck Index, 11th Edition, 9317
2. 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.