Phenylhydroxylamine

Phenylhydroxylamine
Names
	IUPAC name N-phenylhydroxylamine
	Other names beta-phenylhydroxylamine; N-hydroxyaniline; phenylhydroxylamine; N-hydroxybenzeneamine; hydroxylaminobenzene
Identifiers
CAS Number	100-65-2 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:28902 ;
ChemSpider	7237 ;
ECHA InfoCard	100.002.614
EC Number	209-711-2;
KEGG	C02720 ;
PubChem CID	7518;
UNII	282MU82Z9A ;
CompTox Dashboard (EPA)	DTXSID3025889 ;
	InChI InChI=1S/C6H7NO/c8-7-6-4-2-1-3-5-6/h1-5,7-8H Key: CKRZKMFTZCFYGB-UHFFFAOYSA-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).

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.

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

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.

The compound condenses with benzaldehyde to form diphenylnitrone, a well-known 1,3-dipole:^[4] C₆H₅NHOH + C₆H₅CHO → C₆H₅N(O)=CHC₆H₅ + H₂O

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

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

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

References

^ 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)
^ O. Kamm (1941). "Phenylhydroxylamine". Organic Syntheses. 4: 57. doi:10.15227/orgsyn.004.0057.
^ 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.
^ I. Brüning, R. Grashey, H. Hauck, R. Huisgen, H. Seidl (1966). "2,3,5-Triphenylisoxazolidine". 46: 127. doi:10.15227/orgsyn.046.0127.
^ C. S. Marvel (1925). "Cupferron". Organic Syntheses. 4: 19. doi:10.15227/orgsyn.004.0019.

[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.

[4] I. Brüning, R. Grashey, H. Hauck, R. Huisgen, H. Seidl (1966). "2,3,5-Triphenylisoxazolidine". 46: 127. doi:10.15227/orgsyn.046.0127.

[5] C. S. Marvel (1925). "Cupferron". Organic Syntheses. 4: 19. doi:10.15227/orgsyn.004.0019.

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