146369-73-5 2',3'-Dedehydro-2',3'-dideoxythymidine triphosphate 2',3'-Dideoxy-2',3'-dehydrothymidine 5'-triphosphate 2,3-Ddddttp 26194-89-8 Dddttp Thymidine 5'-(tetrahydrogen triphosphate), 2',3'-didehydro-3'-deoxy-