Barbituric acid

From Sciencemadness Wiki
Jump to: navigation, search
Barbituric acid
Barbituric acid bottle and sample.jpg
Barbituric acid on a watchglass
Names
IUPAC name
Pyrimidine-2,4,6(1H,3H,5H)-trione
Other names
1,3-Diazinane-2,4,6-trione; 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; 2,4,6-Trihydroxy-1,3-diazine; 6-Hydroxy-hydrouracil; 6-Hydroxyuracil; Malonylurea; Pyrimidinetriol; N,N-(1,3-dioxo-1,3-propanediyl)urea; N,N-Malonylurea
Properties
C4H4N2O3
Molar mass 128.09 g/mol
Appearance White solid
Odor Slight
Melting point 245 °C (473 °F; 518 K)
Boiling point 260 °C (500 °F; 533 K) (decomposes)
14.2 g/100 ml (20 °C)
Solubility Soluble in formaldehyde 37%, conc. formic acid
Slightly soluble in pyridine
Almost insoluble in HCl 37%
Insoluble in glacial acetic acid, acetone, acetonitrile, alcohols, ammonia 25%, chloroform, dichloromethane, ethyl acetate, heptane, hexane, methyl acetate, toluene, xylene
Hazards
Safety data sheet Sigma-Aldrich
Lethal dose or concentration (LD, LC):
5,000 mg/kg (rat, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Barbituric acid or malonylurea is an organic compound based on a pyrimidine heterocyclic skeleton. Barbituric acid is the parent compound of barbiturate drugs, although barbituric acid itself is not pharmacologically active.

Properties

Chemical

Barbituric acid will form a colored complex with pyridine and cyanide.

Physical

Barbituric acid is a white solid, moderate soluble in water and insoluble in most organic solvents, but shows good solubility in aq. formaldehyde and conc. formic acid. Solutions of barbituric acid will oxidize in air, turning yellow then brownish after several hours and days. It has a weak odor.

Availability

Barbituric acid is sold by chemical suppliers, however it is classified as controlled substance in most countries, making it near impossible for the amateur chemist to acquire it freely.

Preparation

Barbituric acid can be synthesized from the reaction of malonic acid, urea and phosphoryl chloride. For better yields, diethyl malonate can be used instead of malonic acid.

Another way to synthesize barbituric acid can be prepared by reducing 5,5-dibromobarbituric acid with HCN or sodium amalgam and hydrogen iodide.

Projects

  • Make vitamin B2 (riboflavin)
  • Make pyridine/barbituric acid reagent (cyanide detection)

Handling

Safety

Barbituric acid should be handled with care and proper protection.

Overdose of barbituric acid can cause respiratory problems and death. Barbituric acid derivatives are considered DEA Schedule III controlled substances.

Storage

In closed bottles.

Disposal

Can be poured down the drain.

References

Relevant Sciencemadness threads