Molecular Design and Development of New Synthetic Methods of Novel Thio-, Seleno-, Tellurocarboxylic Acid Derivatives

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In recent years, much attention has been paid to a series of chalcogenocarboxylic acid derivatives because of their biological activity such as brain blocking agent as well as of industrial materials such as photo-sensitizing agents and additives to lubricants. However, in spite of these useful properties, only a limited number of fundamental data have been studied. Accordingly, the prime objective of the present research was to disclose their basic features from the synthetic and structural point of view. The results obtained through the present research are as follows.1.X-ray molecular structure analyzes of thio-, seleno-and tellurocarboxylic acid lithium, rubidium, and cesium salts were successful. The results have shown they adopt the structures where the metal resides on sulfur, selenium, or tellurium atom in a solid state.2.Tellurocarboxylic acid was generated at low temperature from the corresponding Cesium salts. The acids exist predominantly as a telluro form in nonpolar solvents, whereas the telluoxo form was a predominant species in polar solvents. The similar trends were also observed for thio- and selenocarboxylic acids3.Se-Arsanyl selenocarboxylates were found to undergo the addition reaction to conjugated terminal acetylenes with high regio- and stereoselectivity.4.The stability trends of a series of selenothioic acid S-esters have been disclosed.