Hideki Kageyama

Crystalline sodium seleno- and telluro-carboxylates: Localization of negative charge on electropositive chalcogeno atoms

Abstract Crystalline sodium seleno- and telluro-carboxylates were prepared from the corresponding bis(acyl)selenide and tellurides with sodium ethoxide. The salts have the unsymmetrical ionic structure where the negative charge is localized on the selenium or tellurium atom.

Isolation and characterization of Se-organolead selenocarboxylates

Abstract Se-organolead selenocarboxylates were characterized after they were obtained from the reactions of alkali metal or piperidinium selenocarboxylates with organolead chlorides in moderate to good yields. The reactions of triphenyllead selenocarboxylates with benzeneselenenyl bromide afforded acyl phenyl diselenides.

Reactions of O-silyl selenocarboxylates; IR and NMR spectra of heteroatom-substituted selenocarboxylates

O-Silyl selenocarboxylates 1 react readily with acyl chlorides to give selenoanhydrides. Attempts to synthesize unsymmetrical selenoanhydrides selectively gave mixtures of the desired products with symmetrical selenoanhydrides. Ph3GeCl, Ph3SnCl, Ph3PbCl, Ph2PCl and Ph2AsCl were treated with 1 to give the corresponding selenocarboxylates containing a Se–heteroatom bond. Reactions with ArSCI, PhSeBr and PhTel afforded the corresponding arenechalcogenyl selenocarboxylates. The CO stretch of these derivatives showed a shift to lower frequency in moving from lighter to heavier atoms within a group of the Periodic Table. This may partly be due to the delocalization of an electron lone pair on selenium to form a diene type of conjugated system involving the CO and Se–heteroatom bonds. A downfield shift in the signals in the 77Se NMR spectra was observed in going from group 14 to group 16 elements; in contrast, the 13C NMR signals of the CO moiety were almost independent of the heteroatom attached to Se.

Selenocarboxylic Acids and their Alkali Metal Salts: Synthesis and Structure

A series of selenocarboxylic acids and their alkali metal salts were prepared. The potassium, rubidium and cesium salts are foundamentaly dimeric structure. Selenocarboxylic acids exist predominantly in selenon acid (selon acid) at low temperature in polar solvent. Selenocarboxylic acids readily react with aryl isocyanates to acyl carbamoyl selenides in good yields.

Triorganogermanium Selenocarboxylates: Synthesis and Reactions

A series of triphenylgermanium selenocarboxylates 3 were synthesized and characterized. The esters 3 are thermally stable, but labile towards moisture and oxygen. They react with arenesulfenyl chlorides and areneselenenyl bromides at room temperature to afford the corresponding acyl arenesulfenyl selenides and acyl aryl diselenides in moderate yields.

Isolation of Crystalline Potassium Alkanecarboselenoates

A series of potassium alkanecarboselenoates (2) were isolated as crystals from the reaction of the corresponding bis(acyl) selenides with potassium methanolate. The salts 2 readily react with alkyl iodides at 0°C to afford the corresponding alkyl alkanecarboselenoates (3) in quantitative yields.

Aliphatic Bis(acyl) Selenides — Synthesis and Characterization

A series of aliphatic bis(acyl) selenides 1 were isolated from the reaction of acyl chlorides with sodium selenide and characterized.