Patent ID: 8809357

Claim:
A compound of formula (I), or a tautomer thereof, or a pharmaceutically acceptable salt of said compound or said tautomer; wherein: R 1 is selected from the group consisting of hydroxyl, thiol, alkylthiol, arylthiol, selenol, alkylseleno, arylseleno, tellurol, alkyltelluro, aryltelluro, amino, alkylamino, arylamino and acylamino; R 2 is selected from the group consisting of oxygen, sulfur, selenium, tellurium, amino, alkylamino, arylamino and acylamino; R 3 is a hydrogen or a hydroxyl group; X 1 is tellurium; X 2 is linear or branched alkyl, or aryl; X 3 is selected from the group consisting of hydrogen, halogen, alkyl, aryl, hydroxyl, thiol, amino, alkyloxyl, aryloxyl, acyloxyl, alkylthiol, arylthiol, alkylseleno, arylseleno, alkyltelluro, aryltelluro, alkylamino, arylamino and acylamino; and n is a subscript selected from 0 to 20.