Pyrimido pyridazine

A typical example of the cme-amination is interaction of cinnoline-2-oxide with an excess of primary or secondary amines, producing 3-aminocinnolines in 26-98% yields (Scheme 47) [105]. The lowest yield corresponds to the most bulky isopropylamine. It is evident that the reaction proceeds via the intermediate adduct 71 followed by its aromatization with elimination of water. Interestingly, the reaction of cinnoline-2-oxide with propylamine or pyrrolidine, which takes place in the presence of AgPy2Mn04, also affords the corresponding 3-aminocinnolines as the only products in 60 and 95% yields, respectively. Thus, even under oxidative conditions the cine-substitution pathway prevails on the oxidative amination. At the same time, as it has been already mentioned in Sect. 3.2 (Scheme 29), pyrimido-pyridazine A(2)-oxide 46 is aminated in the presence of AgPy2Mn04 both with loss of the N-oxide function and with its retention. 

Pyrimidin-4-one, 2,5,6-triamino- N NMR, 3, 64 (78HCA2108) Pyrimido[4,5-d]pyridazin-5-amine, JV-benzyl-8-chloro-2-phenyl-pXa, UV, 3, 337 <76BSF(2)1549) Pyrimido[4,5-d]pyridazin-5-amine, JV-butyl-8-chloro-2-phenyl-... 

H NMR, 3, 335 (82JOC674) Pyrimido[4,5-c]pyridazin-5-one, 7-amino-1-methyl-4-phenyl-... 

Pyrimido[4,5-c]pyridazine, chlorohydroxy-reaction products, 3, 335 Pyrimido[4,5-c]pyridazine, dihydrooxidation, 3, 344 Pyrimido[4,5-c]pyridazine, N,N-dimethylaminophenyl-synthesis, 3, 344... 

Pyrimido[4,5-c]pyridazine-5,7-dione, 3-aryl-6,8-dimethyl-synthesis, 3, 357... 

Pyrimido[4,5-d]pyridazine-5,8-dione, 2-aryl-chlorination, 3, 345 Pyrimido[ 1,2-6]pyridazine-2,4-diones synthesis, 3, 355... 

Pyrimido[5,4-c]pyridazine-6,8-diones synthesis, 3, 357 Pyrimidopyridazines rearrangement, 5, 342 Pyrimido[ 1,2- 6]py ridazines HNMR, 3, 334 reactivity, 3, 343... 

H-Pyrimido[l, 2-6]pyridazin-2-one, chloro-nucleophilic displacement reactions, 3, 343 2H-Pyrimido[l,2-6]pyridazin-2-one, 7-chloro-synthesis, 3, 354... 

Pyrimido[5,4-c]pyridazin-8(2i/)-one, 6- N,N-dimethylamino)-2-phenyl-synthesis, 3, 357 Pyrimido[l, 2-6]pyridazin-2-ones H NMR, 3, 333 IR spectra, 3, 335 synthesis, 3, 354, 355 Pyrimido[ 1,2-6]pyridazin-4-ones synthesis, 3, 354, 355 Pyrimido[4,5-c]pyridazinones chlorination, 3, 344 Pyrimido[4,5-d]pyridazin-5-ones... 

When the pyrimido[4,5-c]pyridazine (211) was heated with phosphoryl chloride and dimethylaniline 212 was formed (71CPB1849). Some oxo derivatives appear to be resistant to chlorination e.g., the pyrimido [5,4-c]pyridazine derivative (213) would not react (68JHC523). 2- Arylpyrim-ido[4,5-[Pg.337]

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