From 4-Oxo-4-tellurines

Malonitrile condensed with 4-oxo-4//-tellurin diacetates in the presence of diisopropyleth-ylamine to form 4-dicyanomethylidene-4H-teUurins.  

An additional product, 2,6-diphenyl-l-cyanomethylidene-4-dicyanomethylidene-4H-tellunn (11% yield m.p. 259-262°) was isolated from the reaction of the 2,6-diphenyl-4-oxo-4//-tellurin and malonitrile. 4-Oxo-4//-tellurins also condensed with 4-alkylchalcogenium salts to yield 4-alkylidene-4//-tellurins  

6-Diphenylseleninium-4-yl)ethylidene]-2,6-diphenyl-4-oxo-4//-telliirin 0.50 g (1,4 mmol) 2,6-diphenyl-4-oxo-477-tellurin and 0,5 g (1.1 mmol) of 2,6-diphenyl-4-ethylseleninium hexafluorophosphate are heated in 2 ml acetic anhydride for 10 min on a steam bath. The mixture is diluted with 5 ml of acetonitrile and 40 ml of diethyl ether. The product precipitates in the form of green crystals on cooling. The crystals are isolated by filtration yield 33% m.p. 151-156°. 

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