Methoxyamine is the organic compound with the formula CH3ONH2. Also called O-methylhydroxylamine, it is a colourless volatile liquid that is soluble in polar organic solvent and in water. It is a derivative of hydroxylamine with the hydroxyl hydrogen replaced by a methyl group. Alternatively, it can be viewed as a derivative of methanol with the hydroxyl hydrogen replaced by an amino group. It is an isomer of N-methylhydroxylamine and aminomethanol. It decomposes in an exothermic reaction (-56 kJ/mol) to methane and azanone unless stored as a hydrochloride salt.
Methoxyamine is prepared via O-alkylation of hydroxylamine derivatives. For example, it is obtained by O-methylation of acetone oxime followed by hydrolysis of the O-methylated oxime:[1]
(CH3)2CNOCH3 + H2O → (CH3)2CO + H2NOCH3
The other broad method involves methanolysis of hydroxylamine sulfonates:
H2NOSO3− + CH3OH → H2NOCH3 + HSO4−
Analogous to the behavior of hydroxylamine, methoxyamine condenses with ketones and aldehydes to give imines.
Methoxyamine is used as a synthon for NH2+. It undergoes deprotonation by methyl lithium to give CH3ONHLi. This N-lithio derivative is attacked by organolithium compounds to give, after hydrolysis, amines:[2]
H2NOCH3 + CH3Li → LiHNOCH3 + CH4
LiHNOCH3 + RLi → RNHLi + LiOCH3
RNHLi + H2O → RNH2 + LiOH
Methoxyamine has potential medicinal uses. It covalently binds to apurinic/apyrimidinic (AP) DNA damage sites and inhibits base excision repair (BER), which may result in an increase in DNA strand breaks and apoptosis.This agent may potentiate the anti-tumor activity of alkylating agents.[3]
Examples of drugs incorporating the methoxyamine unit are brasofensine and gemifloxacin.