Pentobarbital Chemical Properties

Melting point:

129.5°C

Boiling point:

367.89°C (rough estimate)

Density 

1.1376 (rough estimate)

refractive index 

1.4620 (estimate)

Flash point:

9℃

storage temp. 

2-8°C

solubility 

Very slightly soluble in water, freely soluble in ethanol. It forms water-soluble compounds with alkali hydroxides and carbonates and with ammonia.

pka

pK1:8.11(0) (25°C)

form 

A neat solid

Water Solubility 

679 mg/L

CAS DataBase Reference

76-74-4(CAS DataBase Reference)

NIST Chemistry Reference

Pentobarbital(76-74-4)

EPA Substance Registry System

Pentobarbital (76-74-4)

Safety Information

Hazard Codes 

T,F

Risk Statements 

25-63-39/23/24/25-36/38-23/24/25-11

Safety Statements 

7-16-36/37-45-36/37/39-22

RIDADR 

UN 2811 6.1/PG 3

WGK Germany 

3

RTECS 

CQ5775000

HazardClass 

6.1(b)

PackingGroup 

III

HS Code 

2933530000

Hazardous Substances Data

76-74-4(Hazardous Substances Data)

Toxicity

A barbiturate that causes CNS depression, apparently due to a facilitation of GABA-ergic inhibition. It appears that the site of action of pentobarbital may be the macromolecular complex made up of a GABA receptor, chloride channel, benzodiazepine-binding site, and picrotoxin-binding site. Barbiturates have been shown to compete for dihydropicrotoxinin-binding sites. In clinical use, barbiturates such as pentobarbital have been largely replaced as sedative-hypnotics by the much safer benzodiazepines. The sedative-hypnotic properties of barbiturates may lead to abuse, as tolerance and dependence are known to occur. In animals, pentobarbital is routinely used for its anesthetic and anticonvulsant properties, as well as for euthanasia. Pentobarbital, like other barbiturates, can induce the metabolism of other compounds by altering cytochrome P450 activity. The oral LD50 in rats is 118 mg/kg.

MSDS

• Language:English Provider:5-Ethyl-5-(1-methylbutyl)barbituric acid
• Language:English Provider:SigmaAldrich

Pentobarbital Usage And Synthesis

Description

Pentobarbital (CRM) (Item No. 20966) is a certified reference material categorized as a barbiturate. Pentobarbital is regulated as a Schedule II compound in the United States. Pentobarbital (CRM) (Item No. 20966) is provided as a DEA exempt preparation. This product is intended for research and forensic applications.

Chemical Properties

A white or almost white, crystalline powder or colourless crystals

Originator

Nembutal,Abbott,US

Uses

Sedative-hypnotic.

Definition

ChEBI: A member of the class of barbiturates, the structure of which is that of barbituric acid substituted at C-5 by ethyl and sec-pentyl groups.

Manufacturing Process

Sodium (9.6 parts) was dissolved in butanol (192 parts) and di-n-butyl ethyl 1-methyl-n-butylmalonate (62.8 parts) and urea (14.4 parts) were added to the warm solution with agitation. The mixture was then heated to reflux temperature in three quarters of an hour and maintained for 2 hours. The reaction mass was kept, water (150 parts) added, the aqueous portion separated, and the butanol layer extracted with water (3 x 50 parts). The combined aqueous extracts were then given 3 small extractions with benzene, the aqueous liquors separated, charcoaled, filtered and precipitated with concentrated hydrochloric acid (acid to congopaper). The solid was collected, washed with water, dissolved in N-sodium hydroxide and reprecipitated with carbon dioxide. On recrystallization, from aqueous alcohol, the pentobarbitone was obtained.

brand name

Nembutal(Ovation)[Name previously used: Pentobarbitone.];Aethaminalum;Barbityral;Barbopent;Burtylonel;Cafergot p.b.;Calpental;Di-barbs;Dipental;Distonocalm;Ergobel plus;Hypnol;Hypnotal;Hyptonal;Insom rapido;Isoamytal;Isom rapido;Iturate;Narcoren;Nembudeine;Nicaphlogyl;Novarectal;Nova-rectal;Novopentobarb;Novo-pentobarb;Or-trin;Palpent;Pembul;Penbon;Pentalgin;Pentanca;Pentodormol;Pentogen;Pentolos;Petab;Petonel;Praecicalm;Prodormol;Somnophyt;Somnotol;S-spac;Stopp-15;Wans;Wigraine-pb;Yastyl.

Therapeutic Function

Hypnotic, Sedative

World Health Organization (WHO)

Pentobarbital is a short-acting barbiturate which is controlled under Schedule III of the 1971 Convention on Psychotropic Substances. See WHO comment for barbiturates. (Reference: (UNCPS3) United Nations Convention on Psychotropic Substances (III), , , 1971)

Purification Methods

A solution of the sodium salt in 10% HCl is prepared, and the acid is extracted with ether. Evaporation of the extract gives a solid which is then purified by repeated crystallisation from CHCl3. It sublimes at 95-105o/10-12mm. [Bucket & Sandorfy J Phys Chem 88 3274 1984.] The (+)-and (-)-enantiomers crystallise from 50% aqueous EtOH with m 120-121o and have [] 25 +4.73o to –4.93o (EtOH) [Kleiderer & Shonle J Am Chem Soc 56 1772 1934]. [Beilstein 24

Pentobarbital(76-74-4)Related Product Information

• n-Butyllithium
• Ethyl formate
• Ethanol
• 4-(Diethylamino)salicylaldehyde
• Sulfadiazine
• Pralmorelin
• Diphenolic acid
• Ethyl acetate
• Ethyl maltol
• Hydroxyethyl Cellulose
• 5-Chlorovaleric acid
• Hydroxyethyl starch
• Barbituric acid
• DL-α-Tocopherol
• butyl rubber
• Tetrabutylammonium bromide
• Ethyl acrylate
• Ethylparaben