N-(6-氨基-1,3-二甲基-2,4-二氧代-1,2,3,4-四氢-5-嘧啶基)-4-硝基苯甲酰胺

1,3,9-三甲基-8-硫代-7H-嘌呤-2,6-二酮

茶碱

4,6-dimethyl-[1,2,5]selenadiazolo[3,4-d]pyrimidine-5,7-dione

8-(furan-2-yl)-1,3-dimethyl-7H-purine-2,6-dione