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

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

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

3,4,9-trimethyl-1,7-bis(piperidin-1-ylmethyl)-4H-purino[8,7-c][1,2,4]triazine-6,8-dione

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