hydrate entecavir hydrate 2-amino-9-[(1S,3R,4S)-4-hydroxy-3-(hydroxymethyl)-2-methylidenecyclopentyl]-1,9-dihydro-6H-purin-6-one--water (1/1) 295.128 295.29450 9-((1S,3R,4S)-4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopentyl)guanine monohydrate C12H17N5O4 CAS:209216-23-9 CHEBI:59902 DrugBank:DB00442 InChI=1S/C12H15N5O3.H2O/c1-5-6(3-18)8(19)2-7(5)17-4-14-9-10(17)15-12(13)16-11(9)20;/h4,6-8,18-19H,1-3H2,(H3,13,15,16,20);1H2/t6-,7-,8-;/m0./s1 KEGG:D04008 O.Nc1nc2n(cnc2c(=O)[nH]1)[C@H]1C[C@H](O)[C@@H](CO)C1=C The monohydrate form of entecavir. A synthetic analogue of 2'-deoxyguanosine, entecavir is a nucleoside reverse transcriptase inhibitor with selective antiviral activity against hepatitis B virus. It is phosphorylated intracellularly to the active triphosphate form, which competes with deoxyguanosine triphosphate, the natural substrate of hepatitis B virus reverse transcriptase, inhibiting every stage of the enzyme's activity, although it has no activity against HIV. Enteclavir is used for the treatment of chronic hepatitis B. YXPVEXCTPGULBZ-WQYNNSOESA-N chebi_ontology entecavir entecavir monohydrate