Barbital

Barbital

Systematic (IUPAC) name
5,5-diethylpyrimidine-2,4,6(1H,3H,5H)-trione
Clinical data
MedlinePlus	a682221
Pregnancy cat.	?
Legal status	?
Routes	Oral
Pharmacokinetic data
Half-life	30.3 (± 3.2) hours
Identifiers
CAS number	57-44-3 Y
ATC code	N05CA04
PubChem	CID 2294
DrugBank	DB01483
ChemSpider	2206 Y
UNII	5WZ53ENE2P Y
KEGG	D01740 Y
ChEBI	CHEBI:31252 Y
ChEMBL	CHEMBL444 Y
Chemical data
Formula	C8H12N2O3
Mol. mass	184.193 g/mol
SMILES	eMolecules & PubChem
InChI InChI=1S/C8H12N2O3/c1-3-8(4-2)5(11)9-7(13)10-6(8)12/h3-4H2,1-2H3,(H2,9,10,11,12,13) Y Key:FTOAOBMCPZCFFF-UHFFFAOYSA-N Y
Y(what is this?)  (verify)

Barbital (marketed under the brand name Veronal), also called barbitone, was the first commercially marketed barbiturate. It was used as a sleeping aid (hypnotic) from 1903 until the mid-1950s. The chemical names for barbital are diethylmalonyl urea or diethylbarbituric acid. Veronal was prepared by condensing diethylmalonic ester with urea in the presence of sodium ethoxide, and then by adding at least two molar equivalents of ethyl iodide to the silver salt of malonylurea or possibly to a basic solution of the acid. The result was an odorless, slightly bitter, white crystalline powder.

Synthesis

Barbital was first synthesized in 1902 by German chemists Emil Fischer and Joseph von Mering. They published their discovery in 1903 and it was marketed in 1904 by the Bayer company as “Veronal”. A soluble salt of barbital was marketed by the Schering company as “Medinal.” It was dispensed for “insomnia induced by nervous excitability”.^{[1][unreliable source?]} It was provided in either capsules or cachets. The therapeutic dose was ten to fifteen grains (0.65-0.97 grams). 3.5 to 4.4 grams is the deadly dose but sleep has also been prolonged up to ten days with recovery.

Barbital can be synthesized in a condensation reaction from urea and a diethyl malonate derivative:

Pharmacology

Veronal was considered to be a great improvement over the existing hypnotics. Its taste was slightly bitter, but an improvement over the strong, unpleasant taste of the commonly used bromides. It had few side effects. Its therapeutic dose was far below the toxic dose. However, prolonged usage resulted in tolerance to the drug, requiring higher doses to reach the desired effect. Fatal overdoses of this slow acting hypnotic were not uncommon.

Notes

1. ^ [1]

 This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press. 

References

• Fischer, Emil and Joseph von Mering, “Ueber eine neue Klasse von Schlafmitteln”, Therap Gegenw 44:97-101, 1903.
• "Veronal", in Finley, Ellingwood, M.D. The American Materia Medica, Therapeutics and Pharmacognosy", 1919. [2], accessed 07 Nov 2005.