Violuric acid

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Violuric acid
Violursaure.svg
Violuric acid monohydrate.jpg
Names
IUPAC name
6-Hydroxy-5-nitroso-1H-pyrimidine-2,4-dione
Other names
2,4,5,6(1H,3H)-Pyrimidinetetrone 5-oxime
5-Hydroxyiminobarbituric acid
5-Isonitrosobarbituric acid
Alloxan 5-oxime
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.001.584 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 201-741-4
PubChem CID
UNII
  • InChI=1S/C4H3N3O4/c8-2-1(7-11)3(9)6-4(10)5-2/h(H3,5,6,8,9,10)
    Key: HRRVLSKRYVIEPR-UHFFFAOYSA-N
  • C1(=C(NC(=O)NC1=O)O)N=O
Properties
C4H3N3O4 (anhydrous)
C4H3N3O4·H2O (monohydrate)
Molar mass 157.08 g/mol (anhydrous)
175.10 g/mol (monohydrate)
AppearanceOff-white yellow or yellow cream solid
Odor Odorless
Melting point 247 °C (477 °F; 520 K) (decomposes)
Boiling point Decomposes
0.704 g/100 mL (20 °C) [1]
Solubility Soluble in alcohols
Vapor pressure ~0 mmHg
Acidity (pKa)4.7
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Irritant
GHS labelling:
GHS-pictogram-exclam.svg
Warning
H315, H319, H335
P261, P305+P351+P338
Related compounds
Related compounds
 Barbituric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Violuric acid is an organic compound with the formula HON=C(CONH)2CO. It crystallizes as white or off-white monohydrate. The compound has attracted attention because its salts are deeply colored. [2]

Contents

Reactions

It readily deprotonated to give salts of the anion [ON=C(CONH)2CO]−, which are often deeply colored. [3] [4]

Preparation

It was prepared by Adolf Baeyer by reaction of barbituric acid with nitrous acid. [5] It can also be produced by condensation of alloxan with hydroxylamine. [4] [6] as typical for forming the oxime of other carbonyl compounds.

Analytical reagents

Structure of the ferrous complex with three violurate ligands. FeV3anion.svg
Structure of the ferrous complex with three violurate ligands.

Violuric acid and many of its derivatives, such as thiovioluric acid, 1,3-dimethylvioluric acid, and diphenylthiovioluric acid, have historically been used as analytical reagents for spectrophotometric determination and titration of various metals and metal-ions. [8] It was also used as a novel staining/spraying agent for inorganic paper chromatography to identify and separate metals based on color. [9] Most derivatives of violuric acid will also typically form brightly colored salts with most metals and nitrogen bases. [10]

Because of the characteristic and diverse colors that violuric acid forms with alkali metals, it has been used photometrically to determine the amount of sodium in blood serum. [11]

References

  1. ↑ "Registration Dossier - ECHA".
  2. ↑ Guille, Kathy; Harrington, Ross W.; Clegg, William (2007). "Violuric acid monohydrate: A second polymorph with more extensive hydrogen bonding". Acta Crystallographica Section C Crystal Structure Communications. 63 (6): o327 –o329. Bibcode:2007AcCrC..63O.327G. doi:10.1107/S010827010701743X. PMID   17551193.
  3. ↑ Nichol, Gary S.; Clegg, William (2007). "Ammonium Violurate: A Compact Structure with Extensive Hydrogen Bonding in Three Dimensions". Acta Crystallographica Section C Crystal Structure Communications. 63 (10): o609 –o612. Bibcode:2007AcCrC..63O.609N. doi:10.1107/S0108270107044241. PMID   17917236.
  4. 1 2 Liebing, Phil; Stein, Franziska; Hilfert, Liane; Lorenz, Volker; Oliynyk, Karyna; Edelmann, Frank T. (2019). "Synthesis and Structural Investigation of Brightly Colored Organoammonium Violurates". Zeitschrift für Anorganische und Allgemeine Chemie. 645: 36–43. doi:10.1002/zaac.201800439. S2CID   104376844.
  5. ↑ Baeyer, Adolf (1863). "Untersuchungen über die Harnsäuregruppe". Annalen der Chemie und Pharmacie. 127 (2): 199–236. doi:10.1002/jlac.18631270214.
  6. ↑ Guinchard, J. (1899). "Ueber die farbigen Salze aus Violursäure und anderen ringförmigen Oximidoketonen". Berichte der Deutschen Chemischen Gesellschaft. 32 (2): 1723–1741. doi:10.1002/cber.18990320260.
  7. ↑ Raston, Colin L.; White, Allan H. (1976). "Salts of the Tris(violurato)ferrate(II) Ion: Crystal Structure of Ammonium Tris(violurato)ferrate(II) Hydrate". Journal of the Chemical Society, Dalton Transactions (19): 1915. doi:10.1039/DT9760001915.
  8. ↑ Taylor, M. E.; Robinson, R. J. (1962-04-01). "The Use of 1,3-Dimethylvioluric Acid in Spectrophotometric Titrations of Alkali and Alkaline Earth Salts". Analytical Chemistry. 34 (4): 533–536. doi:10.1021/ac60184a026. ISSN   0003-2700.
  9. ↑ Singh, A. K.; Katyal, Mohan; Singh, R. P. (1976). "Violuric Acids as Analytical Reagents". Current Science. 45 (11): 405–408. ISSN   0011-3891. JSTOR   24079761.
  10. ↑ Lorenz, Volker; Liebing, Phil; Engelhardt, Felix; Stein, Franziska; Kühling, Marcel; Schröder, Lea; Edelmann, Frank T. (2019-01-02). "Review: the multicolored coordination chemistry of violurate anions". Journal of Coordination Chemistry. 72 (1): 1–34. doi:10.1080/00958972.2018.1560431. ISSN   0095-8972. S2CID   104419386.
  11. ↑ Muraca, R.F. (1955). "Photometric determination of sodium in blood serum with violuric acid" . Chemist Analyst. 44: 38–42 – via CAB Direct.
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