- Thiones as superdipolarophiles. Rates and equilibria of nitrone cycloadditions to thioketones
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1,3-Dipolar cycloadditions of N-methyl-C,C-diphenylnitrone (15) and N-methyl-C-phenylnitrone (16) with aliphatic thioketones are equilibrium reactions. The 1,4,2-oxathiazolidines were characterized and their dissociation constants measured by 1
- Huisgen, Rolf,Fisera, Lubor,Giera, Henry,Sustmann, Reiner
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p. 9671 - 9678
(2007/10/02)
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- Action d'un Tetrafluoroborate d'Oxaziridinium sur les Amines et les Imines
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The Oxaziridinium salt 1 derived from dihydroisoquinolin is an oxygen transfer reagent to primary amines leading to nitrosoderivatives (if R = Alkyl) or nitro compounds (if R = Aryl), to tertiary amines leading to N-oxides, and to secondary amines and imines leading to the corresponding nitrone.
- Hanquet, Gilles,Lusinchi, Xavier
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p. 12185 - 12200
(2007/10/02)
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- Reaction of Oximes with Dimethyl Carbonate: A New Entry to 3-Methyl-4,5-disubstituted-4-oxazolin-2-ones
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The reaction of ketone oximes with dimethyl carbonate (DMC) carried out in an autoclave at 180-190 deg C and in the presence of K2CO3 yields 3-methyl-4,5-disubstituted-4-oxazolin-2-ones.The reaction can be applied to both aliphatic and aromatic ketone oximes, provided that a methylene group be present near the C=N bond.Nonoptimized yields range from 22 to 48percent.The reaction seems to be a sigmatropic rearrangement where DMC plays a key role in causing the initial N-methylation of the oximes.
- Marques, C. A.,Selva, M.,Tundo, P.,Montanari, F.
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p. 5765 - 5770
(2007/10/02)
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- Imines and Derivatives. Part 24. Nitrone Synthesis by Imine Oxidation using either a Peroxyacid or Dimethyldioxirane
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The oxidation of N-alkyl imines by m-chloroperoxybenzoic acid to yield nitrones was facilitated by (i) the presence of C-aryl substituents, (ii) steric inhibition of attack at the imino C-atom, (iii) electron donating para-substituents on the C-aryl substituent, (iv) non-hydroxylic solvents, (v) optimal conjugation between C-aryl substituents and the imino group, and (vi) less bulky N-alkyl groups. The oxidation of N-alkyl imines by dimethyldioxirane (DMD) in dichloromethane-acetone solution yielded nitrones without evidence of oxaziridine formation.The yields of isolated nitrones were higher for C,C-diaryl imines and for imines bearing less bulky N-alkyl substituents.N-H substituted ketimines were found to yield oximes after reaction with dimethyldioxirane.
- Boyd, Derek R.,Coulter, Peter B.,McGuckin, M. Rosaleen,Sharma, Narain D.,Jennings, W. Brian,Wilson, Valerie E.
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p. 301 - 306
(2007/10/02)
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- A CONVENIENT SYNTHESIS OF NITRONES BY N-ALKYLATION OF O-TRIMETHYLSILYLOXIMES
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Aldoxime and ketoxime-O-trimethylsilyl ethers can be alkylated with trialkyl-oxonium tetrafluoroborates and alkyl triflates at or below room temperature to produce nitrones in good yields.
- LeBel, Norman A.,Balasubramanian, N.
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p. 4331 - 4334
(2007/10/02)
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