1 B9X [(2r,3s,5r)-5-(6-aminopurin-9-yl)-2-(phosphonooxymethyl)oxolan-3-yl] 3-(2-ethoxyethoxy)propanoate 1.000 2 7NO [(2~{R},3~{S},4~{R},5~{R})-5-(6-aminopurin-9-yl)-4-oxidanyl-2-(phosphonooxymethyl)oxolan-3-yl] (2~{S})-2-azanyl-4-methylsulfanyl-butanoate 0.703