page_title: Hydroxylamine
section_title: Functional group
hierarchical_section_title: Hydroxylamine / Functional group
context_page_description: Hydroxylamine is an inorganic compound with the formula NH₂OH. The pure material is a white, unstable crystalline, hygroscopic compound. However, hydroxylamine is almost always provided and used as an aqueous solution. It is used to prepare oximes, an important functional group. It is also an intermediate in biological nitrification. In biological nitrification, the oxidation of NH₃ to hydroxylamine is mediated by the enzyme ammonia monooxygenase. Hydroxylamine oxidoreductase further oxidizes hydroxylamine to nitrite.
context_section_description: Substituted derivatives of hydroxylamine are known. If the hydroxyl hydrogen is substituted, this is called an O-hydroxylamine, if one of the amine hydrogens is substituted, this is called an N-hydroxylamine. In general N-hydroxylamines are the more common. Similarly to ordinary amines, one can distinguish primary, secondary and tertiary hydroxylamines, the latter two referring to compounds where two or three hydrogens are substituted, respectively. Examples of compounds containing a hydroxylamine functional group are N-tert-butyl-hydroxylamine or the glycosidic bond in calicheamicin. N,O-Dimethylhydroxylamine is a coupling agent, used to synthesize Weinreb amides.
  Synthesis
  The most common method for the synthesis of substituted hydroxylamines  is the oxidation of an amine with benzoyl peroxide. Some care must be taken to prevent over-oxidation to a nitrone. Other methods include:
  Hydrogenation of an oxime
  Alkylation of hydroxylamine
  The thermal degradation of amine oxides via the Cope reaction
caption: N-hydroxylamine functional group
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