4,6-dimethyl-5,7-dioxo-4,5,6,7-tetrahydro-[1,2,5]selenadiazolo[3,4-d]pyrimidine 1-oxide

4,6-dimethyl-[1,2,5]oxadiazolo[3,4-d]pyrimidine-5,7(4H,6H)-dione 1-oxide

6-氯-1,3-二甲基脲嘧啶

6-acetoxyamino-1,3-dimethyl-1H-pyrimidine-2,4-dione