Unusual tellurium(iv) mediated cyclisation diols into dihydroxazoles with potential anticancer activity

The role of tellurium in medicinal chemistry has recently grown in importance due to the discovery of the anticancer properties of SAS and AS-101, two inorganic compounds based on Te(iv). Here we describe an unprecedented isolation of a series of tetramethyl-dihydroxazole tellurium hexachloride salts whose structure has been indentified and characterised with several techniques including X-ray crystallography. The novelty resides on the role of tellurium that mediate the cyclisation of 1,1,2,2-tetramethylethylene into duhydroxazole in the presence of nitriles. Reaction mechanism, physiological stability and preliminary cytotoxicity results are discussed.