Barbital: Structure , Synthesis , SAR , Mechanism , 5 Uses

Barbital

Structure – 

it , also known as Veronal, has a chemical formula of C8H12N2O3 and a molecular weight of 188.2 g/mol. It has a crystalline structure and belongs to the class of organic compounds known as barbiturates. The molecular structure of barbital consists of a pyrimidine ring (a six-membered aromatic heterocyclic ring containing four carbon atoms and two nitrogen atoms) fused to a barbituric acid moiety (a five-membered heterocyclic ring containing two oxygen atoms, one nitrogen atom, and two carbon atoms).

The structural formula of barbital is:

Barbital

Synthesis –

Barbital is a barbiturate derivative and is a sedative-hypnotic drug. The synthesis of barbital involves a series of chemical reactions as follows:

  1. Condensation of diethyl malonate and urea: Diethyl malonate and urea are condensed in the presence of sodium ethoxide to form ethyl barbituric acid.
  2. Ethylation of ethyl barbituric acid: Ethyl barbituric acid is ethylated with ethyl iodide and potassium carbonate to form diethylbarbituric acid.
  3. Cyclization of diethylbarbituric acid: Diethylbarbituric acid is cyclized by heating with acetic anhydride and glacial acetic acid to form barbital.

The overall reaction can be represented as:

Diethyl malonate + Urea + Ethyl iodide + Potassium carbonate + Acetic anhydride + Glacial acetic acid → Barbital + Diethyl carbonate + Potassium iodide + Carbon dioxide + Water

The synthesis of it should be performed by qualified chemists in a properly equipped laboratory, and it is important to note that barbiturates are controlled substances and their use is strictly regulated. Therefore, this information is for educational purposes only, and it is not intended to encourage or promote the synthesis or use of barbital or any other controlled substance.

SAR –

  • it is a sedative and hypnotic medication that was first introduced in 1903. The SAR (structure-activity relationship) of barbital refers to the relationship between the chemical structure of the compound and its pharmacological activity.
  • it belongs to a class of compounds known as barbiturates, which are characterized by a five-membered ring structure with two oxygen atoms and a nitrogen atom in the ring. The pharmacological activity of barbital is primarily due to its ability to bind to and activate GABA-A receptors in the brain, leading to sedation and hypnotic effects.
  • The SAR of barbital has been extensively studied, and modifications to its chemical structure have been made to produce other barbiturates with similar or different pharmacological properties. For example, the introduction of substituents at various positions on the ring structure can alter the potency, duration of action, and side effect profile of the compound. Similarly, modifications to the side chains attached to the ring can also affect the pharmacological activity of the compound.
  • Overall, the SAR of barbital has provided important insights into the design and development of other sedative and hypnotic medications, including newer drugs such as benzodiazepines and non-benzodiazepine hypnotics.

Mechanism –

it is a barbiturate drug that acts as a central nervous system depressant. It works by enhancing the activity of the neurotransmitter gamma-aminobutyric acid (GABA) in the brain.

GABA is an inhibitory neurotransmitter that reduces the activity of neurons in the brain, thereby promoting relaxation and reducing anxiety. Barbiturates like barbital bind to specific sites on GABA receptors in the brain, increasing the affinity of GABA for these receptors.

This enhances the inhibitory effects of GABA on neuronal activity, resulting in sedation, hypnosis, and anesthesia. it also acts as an anticonvulsant by reducing the excitability of neurons in the brain and spinal cord.

it is metabolized in the liver and excreted in the urine. Its effects last for several hours, depending on the dose and individual factors such as age, weight, and liver function. However, prolonged use of barbiturates can lead to physical and psychological dependence, tolerance, and withdrawal symptoms.

Uses –

it , also known as Veronal, is a barbiturate medication that was once commonly used as a sedative and hypnotic agent. However, due to its potential for abuse and addiction, it is now rarely used in modern medicine.

Some historical uses of barbital include:

  • Sedation: it was used as a sedative to calm patients and promote sleep. It was often prescribed for people with anxiety, insomnia, or other sleep disorders.
  • Epilepsy: Barbiturates like barbital were once used to treat seizures in people with epilepsy.
  • Anesthesia: In the early days of anesthesia, barbiturates like barbital were used to induce unconsciousness during surgery.
  • Euthanasia: iy has been used as a euthanasia agent for animals, particularly in veterinary medicine.

It is important to note that the use of barbiturates like barbital has largely been replaced by safer and more effective medications, and their use is now heavily regulated.

 

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