Phenyl methyl ketoxime

The pKi, values of a series of para- and meffl-substituted benzaldoximes and phenyl methyl ketoximes, ArCR=NOH (R=H, Me), have been measured in DMSO. The aldoximes exhibit pK. = 20.05 + 3.21ap. The homolytic bond dissociation energy of the O-H bond has been estimated as 88.3 (aldoximes) and 89.2kcal mol" (ketoximes) by relating the pK to the oxidation potential of the conjugate base (i.e. ox for ArCR=NO- ArCR=NO ). 

Beckmann Rearrangement.—When phenyl methyl ketoxime, aceto phenoxime, is treated with acid chlorides or phosphorus penta-chloride, it is converted into acet anilide. The steps in the reaction are as follows ... 

Isomerism of Ketoximes.—In the case of aromatic aldehydes they all yield these stereo-isomeric oximes. With the aromatic ketones the condition is different and some yield stereo-isomers and some do not. With symmetrical aromatic ketones in which the two radicals are alike such as di-phenyl ketone, CgHb—CO—C6H,5 no different space relation of the hydroxyl group is possible as the two forms will be identical. When, however, the ketone is unsymmetrical, i.e.j the two radicals are unlike, as in mixed aromatic-aliphatic ketones such as phenyl methyl ketone, CeHs—CO—CH3, or in unsymmetrical di-aryl ketones such as phenyl tolyl ketone, CeHs—CO—C6H4—CHz then the two stereo forms are possible though both forms are not known in all cases. 

The reduction of ketoxime ethers by borane in the presence of (—)-norephedrine yields (S)-amines from a/ i-kctoximcs and (/ )-isomers from. s i/ -ketoximes, e.g. from phenyl-4-tolyl-methyl ketoxime methyl ether40. 

The reaction of benzyl methyl ketoxime with excess acetylene (100°C, KOH) furnishes 2-methyl-3-phenyl-N-vinylpyrrole only (Scheme 1.106). The regioselectivity of the reaction is not violated even under harsher conditions (120°C) and when the reaction is carried out in the system LiOH/DMSO (120 C). Under these conditions, 2-methyl-3-phenyl-N-vinylpyrrole and its nonvinylated precursor are formed in approximately equal amounts (Scheme 1.106). Structural isomer, 2-benzylpyrrole, has been isolated only at increased concentrations of the reactants and base at 120 C. Thus, the methyl group also begins to participate in the construction of the pyrrole ring under these conditions (Schane 1.106). 

Other phosphorus compounds, e.g. PBrs, mixtures of PBrs and Br or PCI3/CI2 and phenyltetra-chlorophosphorane (PhPCU) have been used to convert amides to imidoyl halides. The formation of imidoyl halides proceeds under mild conditions by action of triphenylphosphine/CCU or triphenylphos-phine dihalides on secondary amides or ketoximes. The work-up procedure can be facilitated by use of polymer-supported triphenylphosphine/CCU. By the action of POCI3, phenyl- or methyl-phos-phonic acid dichloride on aminocarboxylic acid thiol esters in the presence of triethylamine the imidoyl chlorides (205 equation 114) are formed in moderate to good yields. The mechanism of this reaction has not been established. The methylene dialkylchlorophosphorane (206 equation 115) allows the conversion of secondary aromatic amides to imidoyl chlorides under very mild conditions. ... 

Mercaptopropionic acid Methylcyclohexanol Methyl ethyl ketoxime N-Nitrosodiethylamine N-Nitrosodimethylamine Nitrosophenylhydroxylamine ammonium salt Oat (Avena sativa) extract Octadecyl 3-mercaptopropionate Octylphenol 4,4(5H)-Oxazoledlmethanol, 2-(heptadecenyl)-Pansy (Viola tricolor) extract Phenyl neopentylene glycol phosphite Sodium citrate Sulfur dioxide a-Terpineol 2,2, 4,4 -Tetrahydroxy, 5,5 -di-t-butylbenzophenone Tetraisopropyl di (dioctylphosphito) titanate Thymol Toluhydroguinone 2,2,4-Trimethyl-1,2-dihydroquinoline Trimethyl quinoline 2,4,6-Tris (dimethylaminomethyl) phenol Ubiquinone Wheat (Triticum vulgare) germ oil Zeaxanthin Zinc dialkyl dithlophosphate antioxidant mfg. 

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