3,4,9-trimethyl-1-phenyl-4H-purino[8,7-c][1,2,4]triazine-6,8-dione

9-methyl-1-phenyl-3-thiophen-2-yl-4H-purino[8,7-c][1,2,4]triazine-6,8-dione

8-bromo-3-methyl-7-(2-oxo-2-thiophen-2-ylethyl)purine-2,6-dione

8-bromo-3-methyl-7-(2-oxobutyl)purine-2,6-dione

8-bromo-3-methyl-7-(2-oxopropyl)purine-2,6-dione