With Replacement of an Oxo or a Hydroxy Group

3-Oxo-2,3-hydrobenzotellurophene reacted, probably in its tautomeric 3-hydroxybenzo-tellurophene form, with carbon tetrachloride and carbon tetrabromide in the presence of triphenylphosphine to give 3-halobenzotellurophenesf 

3-Oxo-2,3-dihydrobenzotellurophene was reduced by sodium borohydride in an ethanolic medium to benzotellurophene.  

Benzotellurophene 3.3 g (13.4 mmol) of 3-oxo-2,3-dihydrobcnzotellurophene are dissolved in 30 m/ of ethanol, 1.2 g (35 mmol) of solid sodium borohydride are added, and the mixture is stirred at 20° for 2 h. The resultant mixture is poured into water, the pH is adjusted to 6 by addition of acetic acid, and extracted with chloroform. The extract is evaporated and the residue is distilled from potassium hydrogen phosphate yield 0.6 g (20%) b.p. 115°/0.6 torr. 

3-Oxo-2,3-dihydrobenzotellurophene reacted with hydroxylamine, 2,4-dinitrophenylhy-drazine, and semicarbazide to give the expected products.  

However, with phenylhydrazine, 10H-[l]benzotellurophene[3,2-b]indole was formed.  

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