text: Substituted derivatives of hydroxylamine are known. When the hydroxyl or an amine hydrogen is substituted, such a molecule is called (respectively) an O- or N-hydroxylamine. In general N-hydroxylamines are more common. Examples are N-tert-butylhydroxylamine or the glycosidic bond in calicheamicin. N,O-Dimethylhydroxylamine is a precursor to Weinreb amides.
  Similarly to amines, one can distinguish hydroxylamines by their degree of substitution: primary, secondary and tertiary. When stored exposed to air for weeks, secondary hydroxylamines degrade to nitrones.
  N-organylhydroxylamines, , where R is an organyl group, can be reduced to amines :