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Glyceraldehyde

Glyceraldehyde
L-glyceraldehyde
L-glyceraldehyde
IUPAC name 2,3-Dihydroxypropanal
Other names Glyceraldehyde
Glyceric aldehyde
Identifiers
CAS number [367-47-5]
SMILES OCC(O)C=O
Properties
Molecular formula C3H6O3
Molar mass 90.08 g/mol
Density 1.455 g/cm³
Melting point

145 °C

Boiling point

140-150 °C at 0.8 mmHg

Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Glyceraldehyde is a triose monosaccharide with chemical formula C3H6O3. It is the simplest of all common aldoses. It is a sweet colorless crystalline solid that is an intermediate compound in carbohydrate metabolism. The word comes from combining glycerine and aldehyde, as glyceraldehyde is merely glycerine with one hydroxide changed to an aldehyde.

Glyceraldehyde has a chiral center and therefore exists as two different enantiomers with opposite optical rotation:

  • R from Latin rectus meaning right, or
  • S from Latin sinister meaning left
Name of enantiomer D-glyceraldehyde
(R)-glyceraldehyde
(+)-glyceraldehyde
L-glyceraldehyde
(S)-glyceraldehyde
(−)-glyceraldehyde
Fischer projection D-glyceraldehyde L-glyceraldehyde
Skeletal formula D-glyceraldehyde L-glyceraldehyde
Ball-and-stick model D-glyceraldehyde L-glyceraldehyde

While the optical rotation of glyceraldehyde is (+) for R and (−) for S, this is not true for all monosaccharides. The stereochemical rotation can only be determined by the chemical structure, whereas the optical rotation can only be determined empirically (by experiment).

Glyceraldehyde is used as the configurational standard for carbohydrates. Monosaccharides with an identical conformation at the last stereocentre, for example, C5 for glucose, to (R)-glyceraldehyde are assigned the stereo-descriptor D, those similar to (S)-glyceraldehyde are assigned a L. Both, D and L, should be small capital letters.

Glyceraldehyde can be prepared, along with dihydroxyacetone, by the mild oxidation of glycerol, for example with hydrogen peroxide and a ferrous salt as catalyst.

It was by a lucky guess that the D molecular geometry was assigned to (+)-glyceraldehyde in the late 19th century, as confirmed by x-ray crystallography in 1951.

See also

References

  • Merck Index, 11th Edition, 4376.

Further reading

 

The content of this section is licensed under the GNU Free Documentation License (local copy). It uses material from the Wikipedia article "Glyceraldehyde" modified March 22, 2008 with previous authors listed in its history.