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Barbituric acid

Barbituric acid
Barbituric-acid-structural.svg
Barbituric-acid-3D-balls.png
Names
IUPAC name
pyrimidine-2,4,6(1H,3H,5H)-trione
Other names
  • 2,4,6(1H,3H,5H)-pyrimidinetrione
  • 2,4,6-trioxohexahydropyrimidine
  • 2,4,6-trihydroxypyrimidine
  • 2,4,6-trioxypyrimidine
  • 2,4,6-pyrimidinetriol
  • 2,4,6-pyrimidinetrione
  • pyrimidinetriol
  • 2,4,6-trihydroxy-1,3-diazine
  • N,N-malonylurea
  • malonylurea
  • 6-hydroxyuracil
  • 6-hydroxy-hydrouracil
  • N,N-(1,3-dioxo-1,3-propanediyl)urea
Identifiers
3D model (Jmol)
ChEBI
ChemSpider
ECHA InfoCard 100.000.598
EC Number 200-658-0
KEGG
PubChem CID
UNII
Properties
C4H4N2O3
Molar mass 128.09 g·mol−1
Appearance White crystals
Melting point 245 °C (473 °F; 518 K)
Boiling point 260 °C (500 °F; 533 K)
142 g/l (20 °C)
  • -78.6·10−6 cm3/mol crystal+2H20
  • -53.8·10−6 cm3/mol Anhy.
Hazards
Safety data sheet External MSDS
R-phrases (outdated) R36/38, R43
S-phrases (outdated) S22, S26, S28
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY  (what is YesYN ?)
Infobox references

Barbituric acid or malonylurea or 6-hydroxyuracil is an organic compound based on a pyrimidine heterocyclic skeleton. It is an odorless powder soluble in water. Barbituric acid is the parent compound of barbiturate drugs, although barbituric acid itself is not pharmacologically active.

It remains unclear why the German chemist Adolf Baeyer chose to name the compound that he discovered "barbituric acid". In his textbook Organic Chemistry, the American organic chemist Louis Frederick Fieser (1899–1977) initially speculated that the name stemmed from the German word Schlüsselbart (literally, the beard (Bart ; Latin: barba) of a key (Schlüssel) ; that is, the bit of a key), because Baeyer had regarded barbituric acid as central (or "key") to understanding uric acid and its derivatives. However, Fieser subsequently decided that Baeyer had named the compound after a young lady whom he'd met and who was called "Barbara" ; hence the name "barbituric acid" was a combination of the name "Barbara" and "uric acid". Other sources claim that Baeyer named the compound after Saint Barbara, either because he discovered it on the feast day of St. Barbara (December 4th) or because he sometimes lunched with artillery officers and St. Barbara is their patron saint.

Barbituric acid was first prepared and named in 1863 by the German chemist Adolf von Baeyer, by reducing what Baeyer called Alloxanbromid (alloxan dibromide ; now: 5,5-dibromobarbituric acid) with hydrocyanic acid, and later by reducing dibromobarbituric acid with a combination of sodium amalgam and hydrogen iodide. In 1879, the French chemist Édouard Grimaux synthesized barbituric acid from malonic acid, urea, and phosphorus oxychloride (POCl3). Malonic acid has since been replaced by diethyl malonate, because using the ester avoids the problem of having to deal with the acidity of the carboxylic acid and its unreactive carboxylate.


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Wikipedia

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