吡啶并[2,3-D]嘧啶-4-胺

1,3-dimethylpyrido[2,3-d]pyrimidine-2,4-dione

4-硫氧-3,4-二氢吡啶并[2,3-d]嘧啶-2(1H)-酮

2-三氧代-2,3-二氢吡啶并[2,3-d]嘧啶-4(1h)-酮