7-Amino-3-(2,5-dimethoxyphenacyl)-1-methylpyrimido-(4,5-c)pyridazine-4,5(1H, 6H)-dione
7-Amino-4-[2-(2,5-dimethoxy-phenyl)-2-oxo-ethyl]-1-methyl-1,2-dihydro-pyrimido[4,5-c]pyridazine-3,5-dione
8-Amino-5-(2,5-dimethoxy-phenyl)-1-methyl-6-oxo-6,7-dihydro-1H-pyrimido[4,5-c][1,2]diazepine-3-carboxylic acid methyl ester