Pyrimidopyridazines. 3. Preferential Formation of 8-Amino-1H-pyrimido-1,2-diazepin-6(7H)-ones by Cyclizations with α,γ-Diketo Esters

Article abstract of DOI:10.1021/jo00343a013

6-(1-Methylhydrazino)isocytosine cyclizes with α,γ-diketo esters to give pyrimido<4,5-c>pyridazines and 1H-pyrimido<4,5-c>-1,2-diazepines, the latter being predominant in each case.The pyrimidodiazepines are susceptible to ring-opening/ring-closure rearra