''tert''-Amyl alcohol (TAA) or 2-methylbutan-2-ol (2M2B), is a branched pentanol. Historically TAA has been used an

anesthetic An anesthetic (American English) or anaesthetic (British English; see spelling differences) is a drug used to induce anesthesia ⁠— ⁠in other words, to result in a temporary loss of sensation or awareness. They may be divided into two ...

and more recently used as a recreational drug. TAA is mostly a positive allosteric modulator for GABA_A receptors in the same way as

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...

. The psychotropic effects of TAA and ethanol are similar, though distinct. Impact on coordination and balance are proportionately more prominent with TAA, which is significantly more potent by weight than ethanol. TAA is a colorless liquid with a burning flavor and an unpleasant odor similar to

paraldehyde Paraldehyde is the cyclic trimer of acetaldehyde molecules. Formally, it is a derivative of 1,3,5-trioxane, with a methyl group substituted for a hydrogen atom at each carbon. The corresponding tetramer is metaldehyde. A colourless liquid, it ...

with a hint of camphor. TAA remains as a liquid at room temperature making it a useful alternative solvent to ''tert''-butyl alcohol.

Production

TAA is primarily made by the hydration of 2-methyl-2-butene in the presence of an acidic

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

Natural occurrence

Fusel alcohol Fusel alcohols or fuselol, also sometimes called fusel oils in Europe, are mixtures of several higher alcohols (those with more than two carbons, chiefly amyl alcohol) produced as a by-product of alcoholic fermentation. The word ''Fusel'' is Ge ...

s like TAA are grain fermentation byproducts and therefore trace amounts of TAA are present in many alcoholic beverages. Traces of TAA have been detected in other foods, like fried bacon,

cassava ''Manihot esculenta'', commonly called cassava (), manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America. Although a perennial plant, cassava is extensively cultivated ...

and

rooibos tea Rooibos ( ; , meaning "red bush"), or ''Aspalathus linearis'', is a broom-like member of the plant family Fabaceae that grows in South Africa's fynbos biome. The leaves are used to make a herbal tea that is called rooibos (especially in So ...

. TAA is also present in rabbit

milk Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. Immune factors and immune-modula ...

and seems to play a role of

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

inducing suckling in the newborn rabbit.

History

From about 1880s to 1950s, TAA was used as an

with the contemporary name of ''amylene hydrate'', but was rarely used solely because of the existence of more efficient drugs. In the 1930s, TAA was mainly used as a solvent for the primary anesthetic

tribromoethanol 2,2,2-Tribromoethanol, often called just tribromoethanol, is a chemical compound with formula . Its molecule can be described as that of ethanol, with the three hydrogen atoms in position 2 (on the methyl group) replaced by bromine. It is a wh ...

(TBE). Like chloroform, TBE is toxic for the liver, so the use of such solutions declined in the 1940s in humans. TBE-TAA-solutions remained in use as short-acting anesthetics for

laboratory mice The laboratory mouse or lab mouse is a small mammal of the order Rodentia which is bred and used for scientific research or feeders for certain pets. Laboratory mice are usually of the species ''Mus musculus''. They are the most commonly used ...

and

rats Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...

. Such solutions are sometimes called ''Avertin'', which was a brand name for the now discontinued TAA and TBE solution with a volume ratio of 0.5:1 made by the Winthrop Laboratories. Nowadays TAA has found use as a recreational drug.

Use and effects

Ingestion or inhalation of TAA causes euphoria, sedative, hypnotic, and anticonvulsant effects similar to

. When ingested, the effects of TAA may begin in about 30 minutes and can last up to 1–2 days. 2–4 grams of TAA causes unconsciousness. About 100 g of ethanol induces a similar level of unconsciousness.

Overdose and toxicity

The smallest known dose of TAA that has killed a person is 30 mL. An overdose produces symptoms similar to

alcohol poisoning Alcohol intoxication, also known as alcohol poisoning, commonly described as drunkenness or inebriation, is the negative behavior and physical effects caused by a recent consumption of alcohol. In addition to the toxicity of ethanol, the main ps ...

and is a medical emergency due to the sedative/depressant properties which manifest in overdose as potentially lethal respiratory depression. Sudden loss of consciousness, simultaneous

respiratory The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies gre ...

and

metabolic acidosis Metabolic acidosis is a serious electrolyte disorder characterized by an imbalance in the body's acid-base balance. Metabolic acidosis has three main root causes: increased acid production, loss of bicarbonate, and a reduced ability of the kidneys ...

fast heartbeat Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (su ...

increased blood pressure Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...

, pupil constriction, coma, respiratory depression and death may follow from an overdose. The oral in rats is 1 g/kg. The subcutaneous LD₅₀ in mice is 2.1 g/kg.

Metabolism

In rats, TAA is primarily

metabolized Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

via

glucuronidation Glucuronidation is often involved in drug metabolism of substances such as drugs, pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids, fatty acid derivatives, retinoids, and bile acids. These linkages involve gl ...

, as well as by oxidation to 2-methyl-2,3-butanediol. It is likely that the same path is followed in humans, though older sources suggest TAA is excreted unchanged. 2-Methyl-2-butanol oxidation

The use of TAA cannot be detected with general ethanol tests or other ordinary drug tests. Its use can be detected from a blood or a urine sample by using

gas chromatography–mass spectrometry Gas chromatography–mass spectrometry (GC-MS) is an analytical method that combines the features of gas-chromatography and mass spectrometry to identify different substances within a test sample. Applications of GC-MS include drug detection, ...

for up to 48 hours after consumption.

References

{{DEFAULTSORT:Amyl alcohol, tert- Alcohol solvents Tertiary alcohols Sedatives Designer drugs GABAA receptor positive allosteric modulators Alkanols