2-Imino-1-((2-methyl-4-methylene-5-oxotetrahydro-2-furanyl)methyl)-1,2,3,9-tetrahydro-6H-purin-6-one 5'-Methyl-5'-(guanin-1-ylmethyl)-2'-oxo-3'-methylene- tetrahydrofuran AIDS-130600 AIDS130600 NSC606496