Tellurin and Derivatives

6-Disubstiluted 4//-tellurins were obtained by reduction of 4-oxo-4/f-tellurins with diisobutyl aluminum hydride in tetrahydrofuran at 0° h 

The yellow crystals were recrystallized from hexanes and indentified as 4-[2,6-di-tert.-butyl-4H-tellurin-4-yl]- 

When the 4//-tellurins were heated in glacial acetic acid on a steam bath in the presence of hexafluorophosphoric acid, tellurinium hexafluorophosphates were formed (p. 813). 

The electrochemical reduction of the 4-(4//-tellurinyl)-4//-tellurin produced a tellurinium salt  

6-Diorgano-4-oxo-4H-tellurins were formed in 37 67% yield from dilithium or disodium telluride and bis[organoethynyl] ketones .  

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TELLURIN AND DERIVATIVES OF 4-H-TELLURINS AND 4-OXO-4-H-TELLURINS (TELLUROPYRAN-4-ONES)... 

Oxidizing agents such as nitric acid, air, hydrogen peroxide, and lead tetraacetate convert ditellurium compounds to tellurinic acid derivatives. Diphenyl ditellurium suspended in hot dilute nitric acid formed benzenetellurinic acid nitrate5. Air oxidizes dissolved diaryl ditellurium compounds to tellurinic acid anhydrides6. Diphenyl ditellurium and lead tetraacetate in benzene solution form phenyl tellurium triacetate7,8. 

Organo tellurium trihalides are the best known and most numerous compounds among the tellurinic acid derivatives. Most of the other derivatives are represented only by a few compounds, some of which have not been adequately characterized. Frequently, different products are claimed for similar reactions with identical starting materials. Much more work needs to be done with the various hydrolysis products of organo tellurium halides before this area of organic tellurium chemistry can be considered to be adequately explored. 

Tellurinic Acids and Derivates Organo Tellurium Trihalides... 

A direct synthetic route to 4//-7-hydroxybcnzo[ ]tellurin-4-ones 138 involves acid-promoted dehydration of the corresponding (Z)-unsaturated carboxylic acid derivatives 137 (Scheme 14) <19980M3588>. These precursors can be readily prepared by a metallation-telluration sequence. Previous attempts to prepare molecules of this type, particularly the telluroflavones (R = Ph), were unsuccessful due to the unexpected reactivity of the C-Te bond relative to the C-Se and C-S bonds. 

Tellurinic acids and their derivatives contain tetravalent tellurium. The following types of compounds are known ... 

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