Organotellurium compounds of biological interest-unique properties of the N-chlorosuccinimide oxidation product of 9-telluraheptadecanoic acid

The product formed by N-chlorosuccinimide (NCS) oxidation of 9-telluraheptadecanoic acid (9-THDA) is insoluble in organic solvents and appears to have an oligomeric or polymeric structure. The product is solubilized in dilute base to the sodium salt of the monomer, the Te(IV) geminal diol of 9-THDA. While the insoluble oxidation product cannot be analyzed directly, it has been converted to products of known structure. Treatment with HBr gives the dibromide of 9-THDA, and treatment wit acetic anhydride forms the Te(IV) geminal diacetate of 9-THDA. Similar NCS oxidation of the methyl ester of 9-THDA or dioctyl telluride in each case gives the Te(IV) geminal diols that exhibit normal solubility in organic solvents and the expected physical properties. In contrast, NCS oxidation of 9-selenaheptadecanoic acid (9-SHDA) gives a selenoxide (Se=O) that is readily soluble in organic solvents. The contrasting properties of the oxidation products of 9-THDA and 9-SHDA correlate directly with the heart specificity and degree of retention in the heart muscle after intravenous administration of the radiolabeled compounds 9-(/sup 125m/Te)THDA and 9-/sup 75/Se)SHDA to experimental animals. The radiolabeled tellurium fatty acid shows pronounced heart uptake and prolonged retention (trapping) and represents a new type of imaging agent for the potential clinical evaluationmore » of heart disease. The present studies suggest that the trapping of tellurium fatty acids in the heart may result from the formation of an insoluble oxidation product after entry into the cells of the heart muscle.« less