Phenylglyoxal

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Phenylglyoxal
IUPAC name

Phenylglyoxal

Other names

oxo(phenyl)acetaldehyde, 1-phenylethanedione,

Identifiers
CAS number 1075-06-5 YesY, (monohydrate)
[1074-12-0] (anhydrous)
PubChem 14090
ChemSpider 13470 N
UNII N45G3015PA YesY
RTECS number KM5775180
Jmol-3D images Image 1
Properties
Molecular formula C8H6O2
Molar mass 134.13 g mol−1
Appearance yellow liquid (anhydrous)
white crystals (hydrate)
Density ? g/cm3
Melting point 76–79 °C (hydrate)
Boiling point 63–65° (0.5 mm, anhydrous)
Solubility in water forms the hydrate
Solubility in other solvents common organic solvents
Hazards
R-phrases 22-36/37/38
S-phrases 22-26-36
Main hazards toxic
Related compounds
Related aldehydes 3,4-Dihydroxyphenylacetaldehyde

Methylglyoxal
Phenylacetaldehyde

Related compounds benzil
glyoxal
acetophenone
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Phenylglyoxal is the organic compound with the formula C6H5C(O)C(O)H. It contains both an aldehyde and a ketone functional group. It is yellow liquid when anhydrous but readily forms a colorless crystalline hydrate. It has been used as a reagent to modify the amino acid, arginine.[1]

Properties

Like some other aldehydes, phenylglyoxal polymerizes upon standing, as indicated by solidification of the liquid. Upon heating, this polymer "cracks" to give back the yellow aldehyde. Dissolution of phenylglyoxal in water gives crystals of the hydrate:

C6H5C(O)COH + H2O → C6H5C(O)CH(OH)2

Upon heating, the hydrate loses water and regenerates the anhydrous liquid.

Preparation

Phenylglyoxal was first prepared by thermal decomposition of the sulfite derivative of the oxime:[2]

C6H5C(O)CH(NOSO2H) + 2 H2O → C6H5C(O)CHO + NH4HSO4

More conveniently, it can be prepared from methyl benzoate by reaction with KCH2S(O)CH3 to give PhC(O)CH(SCH3)(OH), which is oxidized with copper(II) acetate.[3] Alternatively, it can also be prepared by oxidation of acetophenone with selenium dioxide.[4]

References

  1. ↑ Kenji Takahashi (1968). "The Reaction of Phenylglyoxal with Arginine Residues in Proteins". J. Biol. Chem. 243 (23): 6171–9. PMID 5723461. 
  2. ↑ H. von Pechmann (1887). "Zur Spaltung der Isonitrosoverbindungen". Chem. Ber. 20 (2): 2904–2906. doi:10.1002/cber.188702002156. 
  3. ↑ Mikol, G. J.; Russell, G. A. (1973), "Phenylglyoxal", Org. Synth. ; Coll. Vol. 5: 937 
  4. ↑ Riley, H. A.; Gray, A. R. (1943), "Phenylglyoxal", Org. Synth. ; Coll. Vol. 2: 509 
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