Phenylhydroxylamine

Phenylhydroxylamine, sometimes called β-phenylhydroxylamine or N-phenylhydroxylamine, is C6H5NHOH. It is an intermediate in the redox-related pair C6H5NH2 and C6H5NO. Phenylhydroxylamine should not be confused with its isomer α-phenylhydroxylamine or O-phenylhydroxylamine, is C6H5ONH2.

Preparation and derivatives
This compound can be prepared by the reduction of C6H5NO2 with zinc in the presence of NH4Cl followed by crystallization as yellowish needles from salt-saturated water. Alternatively, it can be prepared by transfer hydrogenation of C6H5NO2 using hydrazine as an H2 source over a rhodium catalyst. The product can be purified from contaminating NaCl by extraction into benzene followed by precipitation with petroleum ether. C6H5NHOH is unstable to heating.

The compound condenses with benzaldehyde to form diphenylnitrone, a well-known 1,3-dipole:
 * C6H5NHOH +  C6H5CHO →  C6H5N(O)=CHC6H5  +  H2O