Telluronium Picrate

Mixing aqueous solutions of triaryl or alkyl aryl telluronium halides and picric acid or sodium picrate precipitates triorgano telluronium picrates that crystallize easily. Trialkyl telluronium pricrates appear to be more soluble than the triaryl telluronium picrates8. 

Trimethyl Telluronium Picrate1 Trimethyl telluronium iodide, prepared from 1.6 g of dimethyl tellurium diiodide, potassium sulfite, and methyl iodide, is dissolved in water and a saturated aqueous solution of picric acid is added until precipitation of the telluronium picrate ceases. The solid is filtered off, washed with cold water, and dried in air yield 0.3 g (20% based on dimethyl tellurium diiodide) m.p. 127° (dec.). 

Examples of similarly prepared triorgano telluronium picrates are ... 

The telluronium salt 142 obtained from telluroisochromane and o -bromo-4-chloroacetophenone upon treatment with silver o-bromcamphor-sulfonate produced two diastereomers which were separated by crystallization from ethanol and then converted to their enantiomeric picrates. Racemization due to inversion of their pyramidal configuration at the tricoordinate tellurium center occurs slowly and was accomplished at room temperature over 20 days (45JCS37). 

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