9H-purine-9-butanoic acid, 6-amino-, ethyl ester InChI=1/C11H15N5O2/c1-2-18-8(17)4-3-5-16-7-15-9-10(12)13-6-14-11(9)16/h6-7H,2-5H2,1H3,(H2,12,13,14 ethyl 4-(6-amino-9H-purin-9-yl)butanoate