N-Phenylhydroxylamine condensation

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-... 

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... 

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. 

A. N-Phenylhydroxylamine. Het, 5% rhodium on carbon (1.1 g) (Note 1), tetrahydrofuran (200 nt) (Note 2) and nitrobenzene (41.0 g) (Note 3) are Introduced Into a 500-mL, three-necked, round-bottomed flask fitted with a mechanical stirrer, thermometer and condenser. The mixture Is cooled to 15°C and hydrazine hydrate (17.0 g) (Note 4) is introduced Into the reaction mixture from a pressure-equalized addition funnel over 30 min. The temperature of the mixture 1s maintained at 25-30°C throughout the addition by means of an ice-water bath. After the mixture is stirred for a further 2 hr at 25-30 C, the reaction is complete (Note 5), The mixture Is filtered and the catalyst washed with a little tetrahydrofuran. The solution Is used immediately In the acylation step (Note 6). 

Chloro-N-phenylhydroxylamine added portion wise with swirling at -60° to HF, and allowed to stand overnight with evaporation of the HF and condensation of water in the polyethylene container 2-chloro-4-fluoroaniline. Y 39%. -Readily available startg. m. may compensate for low yields. F. e. s. T. B. Patrick,... 

I. Condensation of N-Monosubstituted Hydroxylamines with Carbonyl Compounds Condensation of N -monosubstituted hydroxylamines with carbonyl compounds is used as a direct synthesis of many acyclic nitrones. The synthesis of hydroxylamines is being carried out in situ via reduction of nitro compounds with zinc powder in the presence of weak acids (NH4CI or AcOH) (14, 18, 132). The reaction kinetics of benzaldehyde with phenylhydroxylamine and the subsequent reaction sequence are shown in Scheme 2.21 (133). 

Propanol with magnesium in reduction of chlorobenzene, 47, 104 Propionic acid, 2-(2,4,5,7-tetranitro-flcoken-9-ylideneamtnooxv)-, (+)- AND (-)-, 48, 120 Propionyl fluoride, 45, 6 Propiophenone, condensation with paraformaldehyde, 48, 91 -Propylaminc, 45, 85 -Propylhydrazine, 45, 85 C-( -Propyl)-N-phenylnitrone, generation from phenylhydroxylamine and -butyraIdehyde, 46, 97 Purification of tetrahydrofuran (Warning), 46,105 477- Pyran-4-0ne, 2-6-dimethyl-3,5-DIPHENYL-, 47, 54... 

---