四甲尿酸

4-羟基-2,5-二氧代-4-咪唑烷甲酰胺

3,8-dimethyl-7H-purine-2,6-dione

7,9-二氢-3,9-二甲基-1H-嘌呤-2,6,8(3H)-三酮

8-methoxy-1,3,7-trimethylpurine-2,6-dione