What Is Barbituric Acid?
Barbituric acid, a heterocyclic compound with a pyrimidine skeleton, is also known as malonyl uric acid. Discovered by Adolf von Beyer, it is a colorless, odorless solid synthesized by dehydrating malonic acid and urea under acidic conditions, with diethyl malonate currently used in its synthesis.
Physicochemical Properties of Barbituric Acid
1. Name:
English Name: Barbituric Acid
IUPAC Name: 1,3-diazinane-2,4,6-trione
2. Molecular Formula:
C4H4N2O3
3. Melting Point:
245°C (decomposes)
4. Solubility:
Slightly soluble in water and ethanol, insoluble in ether, soluble in hot water
Bioactivity of Barbituric Acid Derivatives (Barbiturates)
Barbiturates, derivatives of barbituric acid, have central nervous system depressant effects. Notable examples include barbital, phenobarbital, amobarbital, allobarbital, cyclobarbital, pentobarbital, thiopentanal, thiaminal, and hexobarbital. Barbituric acid itself, however, lacks CNS depressant effects.
Mechanism of Action of Barbiturates
Barbiturates bind to GABAA receptors, open chloride channels, and enhance inhibitory nerve function by depolarizing synaptic membranes.
Uses of Barbituric Acid Derivatives
Barbiturates were the primary sedatives and sleeping pills until the 1950s but have been largely replaced by benzodiazepine derivatives due to risks of dependence, withdrawal symptoms, and vitamin deficiencies. Currently, their use is limited to a few applications such as euthanasia and epilepsy treatment.