Redox reactions in non-aqueous media: determination of organic isothiocyanates alone, in formulations and in important mixtures.
A simple potentiometric method for the determination of organoisothiocyanates is described. The isothiocyanate is treated in acetonitrile medium with an excess of primary amine to convert it into a substituted thiourea and the surplus amine is converted into a dithiocarbamate by addition of carbon disulphide. The solution is then titrated with a copper(II) solution in acetonitrile. The three-step titration curve enables the results to be calculated on the bash of the dithiocarbamate and/or thiourea formed. The method has been successfully applied to the analysis of a commercial insecticide formulation based on isothiocyanate and important mixtures containing isothiocyanates.
Analytical applications of copper(II) and copper(I) in acetonitrile: potentiometric and spectrophotometric determination of dithiocarbamates.
The use of copper(II) perchlorate and tetra-acetonitrilocopper(I) perchlorate (in acetonitrile) for the potentiometric and spectrophotometric determination of dithiocarbamates in acetonitrile medium is described. The proposed methods are simple, accurate and reliable and show promise of wide applicability. They are recommended for routine determination of dithiocarbamates. Their advantages over the carbon disulphide evolution method, commonly employed for the determination of these compounds, are discussed.
Highly enantio- and diastereoselective synthesis of β-methyl-γ-monofluoromethyl-substituted alcohols.
Enanatiopure β-methyl-γ-monofluoromethyl alcohols were prepared from the allylic alkylation between fluorobis(phenylsulfonyl)methane with Morita-Baylis-Hillman carbonates. The reaction was catalyzed by using the Cinchona alkaloid derivative, (DHQD)(2)AQN. The origin of the stereoselectivity was verified by DFT methods. Calculated geometries and relative energies of various transition states strongly support the observed stereoselectivity.