N-Phenylhydroxylamine

N-phenylhydroxylamine, PhNHOH and further reduction can give azoxybenzene, azobenzene, hydrazobenzene and aniline. The most important outlet commercially for the nitro-compounds is the complete reduction to the amines for conversion to dyestufTs. This is usually done in one stage with iron and a small amount of hydrochloric acid. 

The reaction of a dibromochalcone with hydroxylamine hydrochloride in pyridine gave three products with the expected 2-isoxazoline product as the predominate compound. A ring bromination product and an isoxazole were also isolated (70UC796). The reaction of hydroxylamine with /S-thiosulfates of propiophenone at reflux produced 3-phenyl-2-isoxazo-line (455). At room temperature a bis-Michael product (456) was produced. The reaction with N -phenylhydroxylamine yielded a mono-Michael type product (457) (74CPB1990). 

Benzaldehyde, condensation with N-phenylhydroxylamine, 46,127 reaction with tnphenylphosphine and sodium chlorodifhioroacetate, 47, SO... 

B-Butyraldehyde, condensation with N-phenylhydroxylamine, 46, 96 -Butyric acid, reaction with iron powder to yield 4-heptanone, 47, 75 Butyric acid, 7-bromo-, ethyl ester, 46, 42... 

N, -Diphenylmtrone, by condensation of N-phenylhydroxylamine with bcnzaldchyde, 46,127 1,3-dipolar cycloaddition to styrene, 46,128... 

N Phenylhydroxylamine condensation, with benzaldehyde to form N,a-diphenylmtronc, 46,127 with n-butyraldehyde, 46, 96 Phenyl lsothiocyanate, 46, 21 Phenylhthium, 46, 109 N-Phenylmaleimide, conversion to 3-phenyl-3 -propylisoxazolidinc-... 

If the ligand X2 in a pentacoordinate triorganotin compound is potentially bidentate, such as the anion of l,3-diphenyl-l,3-propanedione or ofiV-benzoyl-N-phenylhydroxylamine, the tin atom is constrained to a cis-RsSnXj type of geometry, e.g., the triphenylstannyl derivatives of... 

Additions of silyl-substituted synthons 965 to nitrones such as 962 a in the presence of LDA result in the products 966 which eliminate the lithium salt of O-tri-methylsilyl-N-phenylhydroxylamine 968 to give the olefins 967a or 967b in 72 and 39% yield, respectively [68, 69] (Scheme 7.20). The intermediate lithium salt 968 dimerizes with elimination of LiOSiMe3 98 to form azobenzene and azoxybenzene 961 [68, 69]. 

Dyrssen, D., Studies on the extraction of metal complexes. IV. The dissociation constants and partition coefficients of 8-quinolinol (oxine) and N-nitroso-N-phenylhydroxylamine (cupferron), Sv. Kern. Tidsks. 64, 213-224 (1952). 

Saitoh, T. Yamazaki, Y. Kamidate, T. Watanabe, H. Haraguchi, K. Steric effect of alkyl substituent on the extraction of nickel(II) and cobalt(II) by N-alkylcarbonyl substituted N-phenylhydroxylamines. Anal. Sci. 1992, 8, 767-771. 

Benzaldehyde, condensation, with N-phenylhydroxylamine, 46,127 with chloroform, 48, 27 reaction with triphenylphosphine and sodium chlorodifluoroacetate, 47, 50... 

A totally different picture is presented by 3-phenylazo-2-naphthol. This unusual isomer cannot be prepared by a normal coupling procedure but has been obtained by reaction of 3-amino-2-naphthol with thionyl chloride to give the N-sulphinylamine (4-24), condensation of which with N-phenylhydroxylamine yields the desired product [59]. Here, assumption of a ketohydrazone form would entail loss of aromatic character in both rings of the naphthalene nucleus and the energetic unfavourability of this situation ensures that the compound exists solely in the hydroxyazo form. 

The transfer of such sequences to various acceptor-substituted allenes 214 and to O-deprotonated N-phenylhydroxylamines 215 was investigated thoroughly by Ble-chert [255, 256]. After the nucleophilic addition forming the intermediate 216, the [3,3]-sigmatropic isomerization takes place at low temperature in only a few minutes... 

The corresponding reaction of diethyl 1,2-propadienyl phosphonates (sulfones or sulfoxides) with N-phenylhydroxylamine afforded a-anionic N-phenylvinyloxyamine 159, which upon [3,3]-sigmatropic rearrangement led to anionic 2-(2 -oxoalkyl)phe-nylamine 160. Further cyclization provides an efficient synthesis of indole derivatives 161 [84]. 

Ci4Hio1"3M02 N-m-Tiifluoromethylbenzoyl- N-phenylhydroxylamine Extraction-separation Al, Cu, Fe, Mn, V 3... 

C22H37N02 A -(2-Hexyldecanoyl)-N- phenylhydroxylamine Extraction separation Lanthanides 3... 

Okamoto and co-workers noted that N-phenylhydroxylamine gave predominately diphenylamine on treatment with benzene in TFA but mostly 4-aminobiphenyl and 2-aminobiphenyl in the stronger acid trifluoromethane-sulfonic acid (TFSA). Similar results were obtained if benzene was replaced by toluene or anisole. The authors suggested that the reaction in TFA proceeded through O-protonated hydroxylamine either via a direct Sn2 displacement on N by the aromatic nucleophile or via attack of the aromatic compound on the N of a nitrenium ion. In TFSA they favored a mechanism in which the diprotonated hydroxylamine lost water to generate an iminium-benzenium dication (11, Scheme 5), a protonated nitrenium ion. " This... 

The similarity of the results obtained with phenyl azide and N-phenyl-hydroxylamine in benzene/TFA indicates that both reactions proceed by similar mechanisms, but N-phenylhydroxylamine in benzene/TFSA produces a higher yield of the C-substitution products 27 and 28 As previously suggested (Scheme 5), N-phenylhydroxylamine can be doubly protonated to yield the dication 11 in strong acids, but the more weakly basic phenyl azide is less likely to be doubly protonated. The differences observed between the behavior of N-phenylhydroxylamine and phenyl azide in TFSA may be due to the inability of phenyl azide to directly generate 11. 

Takeuchi and co-workers showed that the ratio of N- to C-substitution on the apparent intermediate 75a by a series of aromatics in arene/TFA mixtures was sensitive to the structure of the precursor to 75a (phenyl azide, N-phenylhydroxylamine or O-trifluoroacetyl-N-phenylhydroxylamine) even though the decomposition rates of these precursors were unaffected by the identity of the arene. This result is consistent with the characterization of 75a from N3 and Br trapping studies as a short-lived intermediate that will usually react through ion pair or preassociation processes that may be leaving-group dependent. ... 

As a last example we may mention the rearrangement of an arylhy-droxylamine, such as N-phenylhydroxylamine, which when heated with sulfuric acid is converted into p-aminophenol ... 

N-Phenylhydroxylamine (11 g., 0.10 mole)2 (Note 1) and N-phenylmaleimide (17.4 g., 0.10 mole)3 are suspended in 40 ml. of ethanol contained in a 200-ml. Erlenmeyer flask. To the mixture is added immediately (Note 2) 8.98 g. (11.2 ml., 0.124 mole) of freshly distilled w-butyraldehyde. An exothermic reaction ensues, and the mixture spontaneously heats to the boiling point. A clear slightly yellow solution results which, upon cooling, deposits an almost colorless crystalline cake. The mixture is allowed to stand in the ice box for 1 day it is then filtered through a Buchner funnel, and the crystals are washed twice with 25-ml. portions of ice-cold ethanol. The yield of air-dried product, m.p. 99-101°, is 31-32 g. (92-95%). For further purification the crude material is dissolved in 60 ml. of boiling ethanol on the steam bath, and the resulting solution is allowed to cool slowly to room temperature. If crystallization does not spontaneously begin in 5-10 minutes, it can then be induced by... 

The preparation of 2-phenyl-3- -propylisoxazolidine-4,5-cis-dicarboxylic acid N-phenylimide from -butyraldehyde, N-phenylhydroxylamine, and N-phenylmaleimide is new and is described by Hauck.4 The intermediate, C-( -propyl)-N-phenyl-nitrone, is an unstable compound and is difficult to purify. The procedure described avoids the isolation of the nitrone by adding it in situ to a suitable dipolarophile. 

The N-phenylhydroxylamine should be free of sodium chloride. This is easily attained by dissolution of the compound in benzene followed by filtration and then addition of petroleum ether to cause rapid crystallization. 

N,on-Diphenylnitrone was first obtained by Bamberger4 from N-phenylhydroxylamine and benzaldehyde. The procedure described above is analogous to that of Wheeler and Gore.6... 

N-octylhydroxylamine, A050 N-phenylhydroxylamine, AH25 N-propylhydroxylamlne, ACI7... 

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