Threose

Threose[1]
D-Threose
L-Threose
IUPAC name (2S,3R)-2,3,4-Trihydroxybutanal (D) (2R,3S)-2,3,4-Trihydroxybutanal (L)
Other names Threotetrose
Identifiers
CAS number	95-43-2 (D) Y, 95-44-3 (L) Y
PubChem	439665 (D)
ChemSpider	388736 Y
ChEBI	CHEBI:28587 Y
Jmol-3D images	Image 1 Image 2
SMILES O=C[C@@H](O)[C@H](O)CO (D) OC[C@H](O)[C@@H](O)C=O (L)
InChI InChI=1S/C4H8O4/c5-1-3(7)4(8)2-6/h1,3-4,6-8H,2H2/t3-,4-/m1/s1 Y Key: YTBSYETUWUMLBZ-QWWZWVQMSA-N Y InChI=1/C4H8O4/c5-1-3(7)4(8)2-6/h1,3-4,6-8H,2H2/t3-,4-/m1/s1 Key: YTBSYETUWUMLBZ-QWWZWVQMBY
Properties
Molecular formula	C4H8O4
Molar mass	120.1 g mol−1
Appearance	Syrup
Solubility in water	Very soluble
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
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".^[3]

Fischer projections depicting of the two enantiomers of threose

References

1. ^ Merck Index, 11th Edition, 9317
2. ^ Formulas Using Other Configurational Notations, W. Rausch, accessed 1 March 2011
3. ^ ibid. 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.

See also

• Threonic acid
• Threose nucleic acid