1-ethyl-8-methyl-2-phenyl-6H-imidazo<1,2-f>xanthine
3-Methyl-7-(2-oxo-2-phenyl-ethyl)-3,7-dihydro-purine-2,6-dione
1-Methyl-7-phenyl-1H-oxazolo[2,3-f]purine-2,4-dione
8-β-hydroxyethyl-3-methyl-7-phenylimidazo[1,2-f]xanthine
[3-Methyl-2,6-dioxo-7-(2-oxo-2-phenyl-ethyl)-2,3,6,7-tetrahydro-1H-purin-8-ylsulfanyl]-acetic acid