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Alkanolamines are chemical compounds that contain both hydroxy (-OH) and amino (-NH2, -NHR, and -NR2) functional groups on an alkane backbone. The term alkanolamine is a broad class term that is sometimes used as a subclassification.[1]


Chemical structure of ethanolamine, a simple amino alcohol.

2-Aminoalcohols are an important class of organic compounds that contain both an amine and an alcohol functional groups. They are generated often by the reaction of amines with epoxides. Such compounds find a variety of industrial applications. Simple alkanolamines are used as solvents, synthetic intermediates, and high-boiling bases.[2]

Common amino alcohols

Beta blockers[edit]

A subclass of beta blockers is often called alkanolamine beta blockers. Typical examples are:


1-Aminoalcohols or geminal amino alcohols are rarely encountered as pure materials in an oxygen environment but are important intermediates in both the conversion of aldehydes to imines and the reverse reaction, the hydrolysis of imines and are important for prebiotic chemistry and abiogenesis in ammonia and methane solvents.

The simplest example and the parent compound of the hemiaminals is aminomethanol/methanolamine, (H2NCH2OH), a structural isomer of N-methylhydroxylamine and methoxyamine. Aminomethanol is formed by mixing formaldehyde with ammonia in a nitrogen atmosphere, and in oxygen, aminomethanol dissociates back into formaldehyde and ammonia. Aminomethanol can be converted into the amino acid glycine by a condensation reaction with formic acid:[citation needed]


One example is 1-aminoethanol (CH3CH(NH2)(OH)), a structural isomer of 2-aminoethanol (ethanolamine). These two compounds differ in the position of the amino group. Since the central carbon atom in 1-aminoethanol has four different substitutents, the compound has two stereoisomers, L-aminoethanol and R-aminoethanol. 1-Aminoethanol is formed by a reaction of acetaldehyde and ammonia in a nitrogen atmosphere, and dissociates into either acetamide and water or acetaldehyde and ammonia in the presence of oxygen. 1-Aminoethanol can be converted into the amino acid alanine by a condensation reaction with formic acid:[citation needed]


Geminal amino alcohols are essential to prebiotic chemistry[citation needed] because they are the precursors to amino acids,[citation needed] and can be used in proteins just like amino acids.[dubious ] If solvated by ammonia or methane, they can easily polymerize into highly variable polypeptides capable of catalyzing reactions.[citation needed] If exposed to oxygen, the polymers decompose to formaldehyde, formamide, acetaldehyde, acetamide, and other amides and aldehydes, releasing water. Amino alcohols are formed naturally from the reaction of methane, ammonia, and water in a nitrogen atmosphere.[citation needed] A full list of geminal amino alcohols can be found at hemiaminal.

Amino alcohols are relevant to the Great Oxygenation Event.[citation needed] Prior to the addition of oxygen to Earth's atmosphere, Earth had a nitrogen atmosphere with organics like methane much like Titan does now, and reaction of methane, ammonia, and water formed amino alcohols,[citation needed] which polymerized and made simple functional proteins.[dubious ] Addition of oxygen to the atmosphere resulted in one of the largest extinction events in the history of the Earth, with almost all amino alcohol using life going extinct as the oxygen broke down their proteins. The exception were the species that learned to use formic acid to convert their amino alcohols into amino acids, which survived and now are the only type of life on Earth.

Amino alcohol (corresponding amino acid):

Natural products[edit]

Most proteins and peptides contain both alcohols and amino groups. Two amino acids are alkanolamines, formally speaking: serine and hydroxyproline.

2-Amino alcohols from Amino acids[edit]

In principle each amino acid can be hydrogenated to the corresponding 2-aminoalcohol. The names of these derivatives are listed below:

See also[edit]


  1. ^ Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, ISBN 0-471-72091-7 
  2. ^ Matthias Frauenkron, Johann-Peter Melder, Günther Ruider, Roland Rossbacher, Hartmut Höke “Ethanolamines and Propanolamines” in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a10_001

External links[edit]