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Amine oxide



  An amine oxide, also known as amine-N-oxide and N-oxide, is a chemical compound that contains the functional group R3N+-O (sometimes written as R3N=O or R3N→O). In the strict sense the term amine oxide applies only to oxides of tertiary amines including nitrogen-containing aromatic compounds like pyridine, but is sometimes also used for the analogous derivatives of primary and secondary amines.

Amine oxides are used as protecting group for amines and as chemical intermediates. Long-chain alkyl amine oxides are used as nonionic surfactants and foam stabilizers.

Amine oxide are highly polar molecules have a high polarity close to that of quaternary ammonium salts. Small amine oxides are very hydrophilic and have an excellent water solubility and a very poor solubility in most organic solvents.

Amine oxides are weak bases with a pKa of around 4.5 that form R3N+-OH, cationic hydroxylamines, upon protonation at a pH below their pKa.

Pyridine N-oxide is a crystalline solid with melting point 62-67°C and soluble in water N-Methylmorpholine N-oxide is an oxidant.

Additional recommended knowledge

Contents

Synthesis

Amine oxides are prepared by oxidation of tertiary amines or pyridine analogs with hydrogen peroxide (H2O2), Caro's acid or peracids like mCPBA in N-oxidation [1].

Reactions

Metabolites

Amine oxides are common metabolites of medication and psychoactive drugs. Examples include nicotine, Zolmitriptan, and morphine.

Amine oxides of anti-cancer drugs have been developed as prodrugs that are metabolized in the oxygen deficient cancer tissue to the active drug.

See also

References

  1. ^ Recent trends in the chemistry of pyridine N-oxides Shaker Youssif Arkivoc 2001 Link
  2. ^ J. Meisenheimer, Ber. 52. 1667 (1919)
  3. ^ March's Advanced Organic Chemistry: Reactions, Mechanisms, and Structure Michael B. Smith, Jerry March Wiley-Interscience, 5th edition, 2001, ISBN 0-471-58589-0
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Amine_oxide". A list of authors is available in Wikipedia.
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