Phenylhydroxylamine

Phenylhydroxylamine is the organic compound with the formula 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.

Phenylhydroxylamine

Names
Preferred IUPAC name N-Hydroxyaniline
Other names beta-phenylhydroxylamine; phenylhydroxylamine; N-hydroxybenzeneamine; hydroxylaminobenzene
Identifiers
CAS Number	100-65-2 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:28902 N
ChemSpider	7237 N
ECHA InfoCard	100.002.614
EC Number	209-711-2
KEGG	C02720 N
PubChem CID	7518
UNII	282MU82Z9A N
CompTox Dashboard (EPA)	DTXSID3025889
InChI InChI=1S/C6H7NO/c8-7-6-4-2-1-3-5-6/h1-5,7-8H N Key: CKRZKMFTZCFYGB-UHFFFAOYSA-N N InChI=1/C6H7NO/c8-7-6-4-2-1-3-5-6/h1-5,7-8H Key: CKRZKMFTZCFYGB-UHFFFAOYAK
SMILES ONC1=CC=CC=C1
Properties
Chemical formula	C6H7NO
Molar mass	109.1274 g/mol
Appearance	yellow needles
Melting point	80 to 81 °C (176 to 178 °F; 353 to 354 K)
Magnetic susceptibility (χ)	-68.2·10−6 cm3/mol
Related compounds
Related compounds	hydroxylamine, nitrosobenzene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Preparation

This compound can be prepared by the reduction of nitrobenzene with zinc in the presence of NH₄Cl.^[1][2]

Alternatively, it can be prepared by transfer hydrogenation of nitrobenzene using hydrazine as an H₂ source over a rhodium catalyst.^[3]

Reactions

Cupferron (N-nitroso-N-phenylhydroxylamine), a reagent for qualitative inorganic analysis, is prepared from phenylhydroxylamine.

Phenylhydroxylamine is unstable to heating, and in the presence of strong acids easily rearranges to 4-aminophenol via the Bamberger rearrangement. Oxidation of phenylhydroxylamine with dichromate gives nitrosobenzene.

Like other hydroxylamines it will react with aldehydes to form nitrones, illustrative is the condensation with benzaldehyde to form diphenylnitrone, a well-known 1,3-dipolar compound:^[4]

C₆H₅NHOH + C₆H₅CHO → C₆H₅N(O)=CHC₆H₅ + H₂O

Phenylhydroxylamine is attacked by NO⁺ sources to give cupferron:^[5]

C₆H₅NHOH + C₄H₉ONO + NH₃ → NH₄[C₆H₅N(O)NO] + C₄H₉OH

References

1. E. Bamberger “Ueber das Phenylhydroxylamin” Chemische Berichte, volume 27 1548-1557 (1894). E. Bamberger, "Ueber die Reduction der Nitroverbindungen" Chemische Berichte, volume 27 1347-1350 (1894) (first report)
2. O. Kamm (1941). "Phenylhydroxylamine". Organic Syntheses. 4: 57. doi:10.15227/orgsyn.004.0057.
3. P. W. Oxley, B. M. Adger, M. J. Sasse, M. A. Forth (1989). "N-Acetyl-N-Phenylhydroxylamine via Catalytic Transfer Hydrogenation of Nitrobenzene using Hydrazine and Rhodium on Carbon". Organic Syntheses. 67: 187. doi:10.15227/orgsyn.067.0187.{{cite journal}}: CS1 maint: multiple names: authors list (link)
4. I. Brüning, R. Grashey, H. Hauck, R. Huisgen, H. Seidl (1966). "2,3,5-Triphenylisoxazolidine". Organic Syntheses. 46: 127. doi:10.15227/orgsyn.046.0127.{{cite journal}}: CS1 maint: multiple names: authors list (link)
5. C. S. Marvel (1925). "Cupferron". Organic Syntheses. 4: 19. doi:10.15227/orgsyn.004.0019.