From Telluraxanthene

Telluraxanthene was oxidized to telluraxanthone with chromium trioxide or potassium dichromate in glacial acetic acid. 

9-OxoteUuraxanthene Te.r -Diacetate A solution of 2.94 g (10 mmol) of telluraxanthene and 5.88 g (20 mmol) of potassium dichromate in 30 ml of glacial acetic acid is heated under reflux for 8 h. The mixture is cooled, poured into 100 ml of cold water, and the precipitate is filtered off, washed with water, and dried yield 2.7 g (63%) m.p. 233° (dec. from chlorobenzene). 

9-OxoteIluraxanthene 7V,re-Dichloride 365 mg (1 mmol) of telluraxanthene Te.r -dichloride and 700 mg (7 mmol) of chromium trichloride in 15 m/ of glacial acetic acid are heated under reflux for 4 h, 50 ml of ice/water are then added, and the mixture is allowed to stand overnight. The precipitate is filtered off yield 180 mg (47%) m.p. 285° (dec. from dilute acetic acid). 

9- (4-Methylphenylimino) telluraxanlhene was isolated as one of the products when 9-azido-9-(4-methylphenyl)telluraxanthene was heated in refluxing xylene.  

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Telluraxanthene dihalides were also obtained from telluraxanthene and copper(II) chloride or copper(II) bromide in aqueous acetone3. 

A telluronium salt could not be obtained from telluraxanthene and methyl iodide. However, the telluronium perchlorate was formed in high yields when silver perchlorate was added to the reaction mixture3. 

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