Methohexitalnatrium

methohexital sodium Chemische Eigenschaften,Einsatz,Produktion Methoden

• Beschreibung

  Methohexital sodium, sodium 5-allyl-1-methyl-5-(1-methyl-2-pentynyl)- barbiturate, The free acid forms colorless crystals, mp 6 0 – 6 4?C. It is prepared by condensing diethyl allyl(1-methyl-2-pentynyl)malonate with N-methylurea .

• Originator

  Brevital,Lilly,US,1960

• Verwenden

  Amobarbital is used as anesthetics for perioperative sedation as well as in the short-term treatment of insomnia, anxiety, psychosis, control of seizures, and alcohol withdrawal. These agents are also exploited in abuse settings. Abuse of barbiturates started in the 1940s as they were liberally given to military personnel stationed in the South Pacific in order to help them cope with harsh conditions. They were called ‘goofballs’ in this context. After World War II, many servicemen needed detoxification and treatment for barbiturate dependence upon returning to the United States. Reported barbiturate abuse peaked in the 1970s, but has since declined with the increased use of other sedatives such as benzodiazepines. Use of certain long-acting barbiturates as anticonvulsants, however, continues. Phenobarbital is currently the most commonly prescribed anticonvulsant in use worldwide. Pentobarbital has been used in the United States for lethal injection during executions. Phenobarbital is also used for the treatment of alcohol withdrawal and compares favorably to other agents including benzodiazepines.

• Verwenden

  Anesthetic (intravenous).

• Definition

  ChEBI: The sodium salt of methohexital.

• Manufacturing Process

  Preparation of 3-Hexyne-2-ol: A solution of ethyl magnesium bromide was prepared by the reaction of 229 g of ethyl bromide and 48.6 g of magnesium in 750 ml of anhydrous ether. To the ether solution was then added with stirring a solution of 108 g of ethyl acetylene in 250 ml of cold anhydrous ether. The addition required approximately 3 hours, and the mixture was stirred and refluxed for a further period of 3? hours. Thereafter there was added to the reaction mixture a solution of 88 g of freshly distilled acetaldehyde in 170 ml of anhydrous ether, over a period of about 45 minutes and at a temperature in the range of about -10° to 0°C.
  The resulting reaction mixture was poured over about 1 kg of crushed ice, and neutralized with 10% aqueous hydrochloric acid. The organic phase of the resulting mixture was separated, and the aqueous phase was extracted 3 times with 250 ml portions of ether. The combined organic phase and ether washings were washed twice with water and dried over anhydrous potassium carbonate. The dried ether solution was fractionally distilled, and the 3- hexyne-2-ol formed in the reaction was collected as a fraction boiling at about 79° to 80°C at the pressure of 60 mm of mercury.
  Preparation of 2-Bromo-3-Hexyne: A solution of 138 g of 3-hexyne-2-ol and 9 g of pyridine in 138 ml of anhydrous ether was treated with 175 g of phosphorus tribromide, added dropwise over a period of about 20 minutes at a temperature of about -10°C. The reaction mixture was permitted to come to room temperature while stirring for about 3 hours, and was then heated to refluxing for about 1 hour. After cooling, the reaction mixture was poured over about 50 g of crushed ice. A two-phase system formed, and the ether layer was separated, washed with dilute sodium bicarbonate solution, dried over anhydrous potassium carbonate and fractionally distilled. The 2-bromo-3- hexyne formed in the reaction was collected at 75°C at the pressure of 50 mm of mercury.
  Preparation of Diethyl (1-Methyl-2-Pentynyl) Malonate: To a solution of 28.6 g of sodium in 430 ml of absolute ethanol were added 200 g of diethyl malonate. About half of the alcohol was removed by distillation in vacuo, and thereafter a solution of 200 g of 2bromo-3-hexyne in 100 ml of anhydrous ether was added slowly to the reaction mixture.
  The heat of reaction brought about refluxing during the addition of the 2- bromo-3-hexyne, and when the addition was complete the reaction mixture was heated to refluxing for a further period of 30 minutes. A sufficient amount of water was then added to the reaction mixture to dissolve the sodium bromide which had formed, and the only organic layer was separated, washed with water and dried over anhydrous magnesium sulfate. The dried organic layer was then fractionally distilled under reduced pressure, and the diethyl (1-methyl-2-pentynyl) malonate formed in the reaction was collected at about 117° to 120°C at the pressure of 2 mm of mercury.
  Preparation of Diethyl Allyl (1-Methyl-2-Pentynyl) Malonate: A solution of 12.1 g of sodium in 182 ml of absolute ethanol was prepared, and thereto were added 126.6 g of diethyl (1-methyl-2-pentynyl) malonate. Most of the ethanol was then distilled off under reduced pressure, and the residue was cooled and 63.5 g of allyl bromide were slowly added thereto. After completion of the addition, the mixture was refluxed for about 1 hour. The reaction mixture was cooled, treated with about 100 ml of water, and the oily organic layer which formed was removed, washed with water and dried over anhydrous magnesium sulfate. The dried oily organic material was fractionally distilled in vacuo, and diethyl allyl (1-methyl-2-pentynyl) malonate boiling at 105° to 107°C at the pressure of 1 mm of mercury was recovered.
  Preparation of 1-Methyl-5-Allyl-5-(1-Methyl-2-Pentynyl) Barbituric Acid: A solution of 23.8 g of sodium in 360 ml of absolute alcohol was prepared and thereto were added 38.3 g of methyl

• Trademarks

  Brevital Sodium (King).

• Therapeutic Function

  Anesthetic

• Allgemeine Beschreibung

  White powder.

• Air & Water Reaktionen

  Water soluble.

• Reaktivität anzeigen

  Solutions of methohexital sodium are incompatible with silicone and acid. .

• Brandgefahr

  Flash point data are not available for methohexital sodium, but methohexital sodium is probably combustible.

• Clinical Use

  Methohexital sodium is a short-acting anesthetic administered intravenously. It is very potent and has the shortest duration of action among the barbiturates used. A disturbing factor is that rather frequently it causes hiccups directly after injection. Patients are reported to recover rapidly from anesthesia. Abuse can lead to addiction.

• Sicherheitsprofil

  Poison by intravenous and implant routes. Human systemic effects by intravenous route: blood pressure lowering, gastrointestinal effects, and allergc dermatitis. An FDA proprietary drug. Cazltion: Excessive use may lead to addction or habituation. Allergenic effects by intravenous route. When heated to decomposition it emits toxic fumes of Na2O and NOx. See also BARBITURATES.

• Veterinary Drugs and Treatments

  Methohexital is sometimes used in small animals as an ultrashort acting anesthetic agent, but, propofol has largely supplanted methohexital’s use in small animals. However, because it is not dependent on redistribution to fat to reverse its effect, it may be useful in canine sight hound breeds. Because methohexital can induce anesthesia very rapidly, it may also be useful when general anesthesia must be administered to a patient with a full stomach, as an ET tube may be placed rapidly before aspiration of vomitus can occur.

methohexital sodium Upstream-Materialien And Downstream Produkte

Methohexitalnatrium Anbieter Lieferant Produzent Hersteller Vertrieb Händler.

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