Aryl Sulphoxides Research Articles

Liquid-liquid extraction of yttrium(III) from thiocyanate solutions with sulphoxides and their mixtures. Computeraided analysis.

The extraction of yttrium(III) from thiocyanate solutions by alkyl and aryl sulphoxides and tri-n-octyl phosphine oxide and their mixtures in benzene has been studied. Synergistic effects have been observed with a mixture of extractants which are ascribed to the formation of mixed ligand complexes. These extraction data have been analysed theoretically by taking into account aqueous-phase speciation and all plausible complexes extracted into the organic phase. The extraction behaviour of yttrium(III) has also been compared with that of some lanthanides. It was observed that yttrium(III) behaves like a lighter rare earth in thiocyanate solutions during extraction with dialkyl sulphoxides. Separation factors have also been evaluated. The influence of metal ion concentration and of the diluent on the extraction of yttrium(III) has also been investigated.

Fluorine influence in the mass spectrometric patterns in β‐hydroxy alkyl aryl sulphoxides. Part 5

AbstractThe electron ionization mass spectrometry of some β‐hydroxy alkyl aryl sulphoxides halogenated in the γ‐position is described and the mechanism of the common fragmentation patterns are discussed with the aid of linked scans at constant B/E, mass‐analysed ion kinetic energy spectra and labelling experiments. The influence of the presence of halogens is also discussed.

Novel use of organosilanes and boranes in natural product synthesis

Abstract

Mass spectrometry of sulphur‐containing compounds. 3. The behaviour of some diastereomeric β‐hydroxy‐γ‐fluoro alkyl aryl sulphoxides

AbstractThe electron ionization and chemical ionization mass spectrometry of some diastereomeric β‐hydroxy‐γ‐fluoro alkyl aryl sulphoxides is described and the mechanisms of the common fragmentation patterns are discussed with the aid of linked scans at constant B/E and at constant B2/E, mass‐analysed ion kinetic energy spectra and labelling experiments.

Contribution of electronic effects to the lipophilicity determined by comparison of values of log P obtained by high-performance liquid chromatography and calculation

In a series of 49 aryl sulphoxides, the partition coefficients (log P) estimated by high-performance liquid chromatography were compared with log P values calcualted according to the hydrophobic fragmental method of Rekker and a modification of the method of Moreau. Moderate correlations were found. The introduction of Hammett sigma values as a measure of electronic effects proved to be good correction factors for the calculated log P values. In the presence of strong electron-withdrawing substituents, the sulphoxide moiety is far less hydrophobic than in the absence of such groups.

Deoxygenation of Sulpxoxides with Triethylpvosphite/Iodine/Nai

Abstract A variety of alkyl and aryl sulphoxides have been successfully deoxygenated under mild condition with triethylphosphite/Iodine/Sodium Iodide in good yields.

Solvent extraction separation of Cr(VI)–Mo(VI)–W(VI), Zr(IV)–Hf(IV), and Se(IV)–Te(IV) with sulphoxides

Solvent extraction studies have been made on some metals in the same periodic group: Cr(VI)–Mo(VI)–W(VI), Zr(IV)–Hf(IV), and Se(IV)–Te(IV) from hydrochloric acid solutions by dialkyl and aryl sulphoxides. Separation of these metals from one another can be achieved by suitable choice of extraction conditions. The nature of extractable metal species has been elucidated.

Synthesis and stereomutation of optically active α-cyanosulphoxides

Reaction of (–)-menthyl(S)-toluene-p-sulphinate with nitriles and lithium NN-di-isopropylamide (LDA) in 1:1:1 and 1:2:1 ratios affords optically active α-cyano- and α-cyano-β-imino-sulphoxides, respectively. α-Cyanobenzyl sulphoxide racemizes through a homolytic process in a temperature range (35–50 °C) well below that required for benzyl aryl sulphoxides.

The oxygen exchange between sulphoxides and sulphides. The hydrogen chloride catalysed reaction between p-chlorophenyl methyl sulphoxide and dibutyl sulphide

Alkyl aryl sulphoxides are reduced by dialkyl sulphides in 2 : 1 methanol–water in the presence of 4M-HCl. The kinetics of the reaction between p-chlorophenyl methyl sulphoxide and dibutyl sulphide and the basic properties of the sulphoxide have been investigated in detail. Reaction orders, acid catalysis, and comparison of the reduction rate with that of the loss of optical activity by the (+)-R-sulphoxide indicate a predominant role for the chlorosulphonium cation. A mechanism is suggested in which the changes of the oxidation states occur through the reaction between the sulphide and this intermediate.

Solvent extraction of cerium(III) from ammonium thiocyanate solutions by sulphoxides and their solutions

The extraction of cerium(III) from ammonium thiocyanate solutions by alkyl and aryl sulphoxides, tri-n-octyl phosphine oxide (TOPO), 2-thenoyltrifluoroacetone (TTA), and their solutions has been studied. The species extracted were found to be Ce(SCN)3·4S (where S = di-n-pentyl sulphoxide (DPSO), di-n-octyl sulphoxide (DOSO), diphenyl sulphoxide (DPhSO), or tri-n-octyl phosphine oxide (TOPO)). Synergic effects have been observed which are ascribed to the formation of mixed ligand metal complexes. The extraction of the metal is inversely dependent upon the initial metal concentration and temperature of the system.

ChemInform Abstract: ASYMMETRIC SELECTION VIA ELIMINATION, A NOVEL ROUTE TO PARTIALLY RESOLVED SULPHOXIDES

Elimination reactions between β-halogenoethyl aryl sulphoxides and optically active bases provide a useful route to partically resolved sulphoxides whose configuration is dependent upon the nature of the chiral reagent and of the leaving group.

Asymmetric selection via elimination. A novel route to partially resolved sulphoxides

Elimination reactions between β-halogenoethyl aryl sulphoxides and optically active bases provide a useful route to partically resolved sulphoxides whose configuration is dependent upon the nature of the chiral reagent and of the leaving group.

Carbon–sulphur bond cleavage in the reaction of benzyl and t-butyl sulphoxides with N-halogenosuccinimides

Benzyl and t-butyl alkyl or aryl sulphoxides react with NBS or NCS in CHCI3–ethanol (1%) at 25° to give benzyl or t-butyl halides and ethyl esters of alkyl or aryl sulphinic acids.

Mechanism of formation of alkyl aryl sulphoxides by oxidation of alkyl aryl sulphides with bromine

Bromine reacts with substituted methyl phenyl sulphides and isopropyl phenyl sulphide in 2 : 1 methanol–water (v/v) to give the corresponding sulphoxides. The reaction follows second-order kinetics, first order in bromine and first order in sulphide. The reaction rate is increased by the presence of NaOAc and decreased by addition of NaBr in solution. The reaction is very sensitive to structural factors. It is favoured by electron-donating substituents in the phenyl ring (ρ=–3·2). On the other hand isopropyl phenyl sulphide reacts about 30 times more slowly than methyl phenyl sulphide. A mechanism involving preliminary fast formation of a bromosulphonium cation followed by its rate-determining hydrolysis is suggested.