英文别名2-Amino-9-((1S,3S,4R)-4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopentyl)-1,9-dihydro-6H-purin-6-one; 2-amino-9-[(1S,3S,4R)-4-hydroxy-3-(hydroxymethyl)-2-methylidenecyclopentyl]-1H-purin-6-one; 2-amino-9-((1S,3S,4R)-4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopentyl)-1H-purin-6(9H)-one; 2-Amino-9-[(1S,3S,4R)-4-hydroxy-3-(hydroxymethyl)-2-methylidenecyclopentyl]-3,9-dihydro-6H-purin-6-one; Entecavir Impurity 2; (1S,3S,4R)-ent-Entecavir; Entecavir (S,S,R)-Isomer 
