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Communication | Regular issue | Vol 9, No. 1, 1978, pp.11-16
Published online, 1st January, 1970
DOI: 10.3987/R-1978-01-0011
Synthesis of Pyrimido[4,5-c]pyridazine Derivatives

Sadao Nishigaki, Misuzu Ichiba, Junko Sato, Keitaro Senga,* Mitsuko Noguchi, and Fumio Yoneda

*Pharmaceutical Institute, School of Medicine, Keio University, Shinanomachi 35, Shinjuku, Tokyo 160-0016, Japan


Treatment of 6-hydrazino-l,3-dimethyluracil (I) with phenacyl bromides afforded the corresponding 3-aryl-6,8-dimethylpyrimido[4,5-c]pyridazine-5,7(1H,2H,6H,8H)-diones (IIa-e) and 3-aryl-6,8-dimethylpyrimido[4,5-c]pyridazine-5,7(6H,8H)-diones (IIIa-e) , respectively. The oxidation of II with diethyl azodicarboxylate provided III. The reaction of 6-benzylidene-l,3-dimethyluracils with dimethylformamide dimethylacetal also gave III.