5,6-diamino-1-(3-hydroxypropyl)-1,3-dihydropyrimidine-2,4-dione 、 5,6-diamino-1-(4-fluorobutyl)-1,3-dihydropyrimidine-2,4-dione 、
5,6-diamino-1-(2-ethylcarboxyethyl)-1,3-dihydropyrimidine-2,4-dione 、 5,6-diamino-1-ethenyl-1,3-dihydropyrimidine-2,4-dione 、
5,6-diamino-1-cyclopentyl-1,3-dihydropyrimidine-2,4-dione 、 5,6-diamino-1-(3-hydroxycyclopentyl)-1,3-dihydropyrimidine-2,4-dione 、 5,6-diamino-1-cyclohexyl-1,3-dihydropyrimidine-2,4-dione 、 1-cyclopropylmethyl-5,6-diaminouracil 生成 5,6-diamino-1-(2-methoxyethyl)-1,3-dihydropyrimidine-2,4-dione