Av. Gulevskaya et al., Purines, pyrimidines, and fused systems based on them 16. Oxidative amination of 6,8-dimethylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-dione, RUSS CHEM B, 48(6), 1999, pp. 1150-1153
6,8-Dimethylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-dione reacts with ammonia
or primary amines in the presence of an oxidant to give the corresponding 4
-amino derivatives. Reactions with secondary amines (dimethylamine, piperid
ine, or morpholine) proceed with difficulty, resulting in 3-amino derivativ
es.