- A synthesis of N-alkyl and N,N-dialkyl O-ethyl thiocarbamates from diethyl dixanthogenate using different oxidants
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A novel synthesis of N-alkyl and N,N-dialkyl O-ethyl thiocarbamates from diethyl dixanthogenate and primary and secondary amines, using three oxidizing systems, has been developed on the laboratory scale, and the method using sodium hypochlorite has been applied on a semi-industrial scale. The effect of the oxidizing agents, sodium hypochlorite, in-situ-generated peracetic acid, and the manganese(II) acetate/oxygen system on product purity and yield was studied. The results obtained by use of these three methods were compared with those obtained by reaction of sodium ethyl xanthogenacetate and amines, and of sodium ethyl xanthate with amines in the presence of sulfated nickel zeolite catalyst. The reaction mechanism of sodium hypochlorite oxidation has been established on the basis of isolation of reaction intermediates and determination of their structure by use of Fourier-transform infrared, 1H and 13C NMR, and mass spectrometric methods. The suggested sodium hypochlorite and manganese(II) acetate/oxygen systems have many advantages in comparison with commercial and catalytically promoted synthetic methods, because they are new ecologically friendly syntheses. Springer-Verlag 2010.
- Milosavljevic, Milutin M.,Sovrlic, Milica,Marinkovic, Aleksandar D.,Milenkovic, Dragan D.
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experimental part
p. 749 - 755
(2011/07/08)
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- Solvolysis of N,N-dimethylthiocarbamoyl chloride: Effect of sulfur-for-oxygen substitution upon kinetics and product partitioning
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A study of the solvolyses of N,N-dimethylcarbamoyl chloride (1) was extended to the solvolyses of N,N-dimethylthiocarbamoyl chloride (2). The specific rates of solvolysis of 2 at 0.0°C are two to three orders of magnitude greater than those for 1. Analysis of the data using the extended Grunwald-Winstein equation leads to sensitivities l and m and an l/m ratio which are lower for 2 than those previously reported for 1. Product selectivities in mixtures of water with ethanol or methanol indicate a greater preference for reaction with alcohol for 2. All observations can be rationalized in terms of the formation of a more stable carbocation from 2, leading to an earlier transition state, reduced nucleophilic solvation and the possibility of extensive progression to a free carbocation prior to product formation. Copyright
- Kevill, Dennis N.,Rudolph, Todd M.,D'Souza, Malcolm J.
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p. 192 - 196
(2007/10/03)
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- Alkyl Shifts in 1,4-Dipoles from Tosyl Iso(thio)cyanate and Imido(thio)carbonates or Isoureas
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O-->N alkyl shifts are observed in the dipoles 3, 13 from tosyl isocyanate (2a) and imido(thio)carbonates 1 (12) to give (thio)allophanates 5 (14).Similary, addition of tosyl isothiocyanate (2b) to isourea 24a leads to the product 28 of an O-->S methyl shift.A cross-over experiment involving 2a and imidothiocarbonates 12b,c gives the four products 14a-d proving the intermolecular nature of the rearrangement.However, on mixing 2a and isoureas 24a,b or 2b and imido(thio)carbonates 1 (12), the reaction stops at the stage of dipoles 8, 19, 25a,b.
- Schaumann, Ernst,Dietz, Joerg,Kausch, Erwin,Schmerse, Gerd C.
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p. 339 - 344
(2007/10/02)
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- Some Reactions of Alkoxythiocarbonyl Derivatives with N,N-Dimethylhydrazine
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The reactions of xanthate (dithiocarbonate) esters with N,N-dimethylhydrazine leads to mixtures of the derived thionocarbamates and thionocarbazates whereas alkoxythiocarbonylimidazoles give cleanly the thionocarbazates.The outcome of these reactions is determined by the nature of the intermediate formed by expulsion of the leaving group.
- Barton, Derek H. R.,Boivin, Jean,Legreneur, Soizic,Motherwell, William B.
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p. 1005 - 1007
(2007/10/02)
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