Synthesis of new heterocyclic ring systems via nucleophilic subsititution of pyrimido [4,5-d] pyridazines

✍ Scribed by K.J. Szabó; J. Császár; A. Toró

• Book ID: 104204593
• Publisher: Elsevier Science
• Year: 1989
• Tongue: French
• Weight: 856 KB
• Volume: 45
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)89084-0

✦ Synopsis

Hydroq groups at positions C5 and CS were replaced in a-phenyl-and 2-aminopyrimido[4,5-4 pyridasines by better leaving groups (Cl, 0SiMe-j and SMe, OSiMeg respectively), and the 5,S-disubstituted compounds were substituted by aminoalkanols. The 5-and S--mono(urhJrdroxyallcylamin) derivatives obtained in re ioselective reactions were cyclired into imidazo[1,2-b]pyrimidob,4-dlpyridazine, imidazo 1,2-b]pyrimido[4,56]pyridaeine, t dipyrimido(l,2-b:5',4'-dlpyridazine and dipyrimido[l,2-b:4 ',5'-d)pyridazine derivatives containin f new heterocyclic ring systems. Kinetic measurements and MNDO calculations showed that C site at the pyridazine ring is more reactive than Cs, and aminolysis follows by usual two-step SKAr mechanism.