1984 年 104 巻 11 号 p. 1147-1154
Several 1-alkyl-4-oxothianium salts were found to form the corresponding orthoketones in aqueous solvents at room temperature. Corresponding acetal and hemiacetal were prepared in absolute alcohol on heating and on standing at room temperature, respectively. The formation and stability of their orthoketones were investigated by in frared, nuclear magnetic resonance and differential thermal analysis. Oxothianium salts were prepared by methylation of 4-oxothiane with CH3I used as a solvent or by thermal dehydration of the corresponding orthoketones. It is shown that the ketone exists as the corresponding dideuteroxy species in D2O, whereas the contribution of the orthoketone decreases in dimethylsulfoxide-d6. The stability of orthoketone depends on the relative magnitude of the positive charge of their onium ion and the difference of their counter anions.