- Catalytic Rearrangement of O,S-Dialkyl Dithiocarbonates to S,S-Dialkyl Dithiocarbonates by Pyridine N-Oxides. The Reaction Mechanism
-
The reaction of O-alkyl S-methyl dithiocarbonates (xanthates) (I) with pyridine N-oxides (II) gave the corresponding S-alkyl S-methyl dithiocarbonates (dithiolcarbonate) (III) together with the symmetric S,S-dialkyl and S,S-dimethyl dithiocarbonates in good yields.Pyridine N-oxides bearing electron-donating substituents are efficient catalysts for rearrangement of I to III.The reaction is pseudo-first-order and the apparent first-order rate constant is proportional to the concentration of II.The role of pyridine N-oxides and the reaction behavior of O,S-dialkyldithiocarbonates are discussed on the basis of kinetic and molecular orbital calculation data.The rearrangement may proceed by nucleophilic attack of -SCOSR derived from a complex of I and II on the O-alkyl group of xanthates.The reaction provides a useful preparation method for alkanethiols by aminolysis of the products with ethanolamine.Keywords O,S-dialkyl dithiocarbonate; S,S-dialkyl dithiocarbonate; pyridine N-oxide; thiol; charge transfer; catalytic rearrangement; kinetics; ethanolamine; frontier molecular orbital
- Harano, Kazunobu,Shinohara, Ikuo,Sugimoto, Shin-ichiro,Matsuoka, Toshikazu,Hisano, Takuzo
-
p. 576 - 581
(2007/10/02)
-