6-Cycloamino-3-(pyridazin-4-yl)imidazo[1,2-b]-pyridazine compounds (I) and their base and acid addition salts are new. 6-Cycloamino-3-(pyridazin-4-yl)imidazo[1,2-b]-pyridazine compounds of formula (I) and their base and acid addition salts are new. R 2aryl (optionally substituted by one or more halo, 1-6C alkyl, 1-6C alkyloxy, 1-6C alkylthio, 1-6C fluoroalkyl, 1-6C fluoroalkyloxy or CN)； A : 1-7C alkylene (optionally substituted by 1 or 2 R1a)； B 11-7C alkylene (optionally substituted by R1a), where C of A, B 1is optionally substituted by one or more R1f； L : N (optionally substituted by R1c or R1d) or C (substituted by R1e, R1d, or 2 R2e)； R1aR1a : 1-6C alkylene； R1aR1b, R1aR1c, R1bR1c : bond or 1-6C alkylene； R1d : H, 1-6C alkyl, 3-7C cycloalkyl, 3-7C cycloalkyl-1-6C alkyl, hydroxy-1-6C alkyl, 1-6C alkyloxy-1-6C alkyl, 1-6C alkylthio-1-6C alkyl, 1-6C fluoroalkyl or benzyl； R1e : -NR 4R 5or cyclic monoamine group (optionally including O, and substituted by one or more F or 1-6C alkyl, 1-6C alkyloxy or OH)； C+R2eR2e : cyclic monoamine group (optionally including O, and substituted by one or more R1f)； R1f : 1-6C alkyl, 3-7C cycloalkyl, 3-7C cycloalkyl-1-6C alkyl, 1-6C alkyloxy-1-6C alkyl, hydroxy-1-6C alkyl, 1-6C fluoroalkyl or benzyl； R 4, R 5H, 1-6C alkyl, 3-7C cycloalkyl or 3-7C cycloalkyl-1-6C-alkyl； and R 7, R 8H or 1-6C alkyl. Independent claims are included for the preparations of (I). [Image] ACTIVITY : Hypnotic； Antiaddictive； Cytostatic； CNS-Gen； Neuroprotective； Antidepressant； Neuroleptic； Tranquilizer； Nootropic； Antismoking. MECHANISM OF ACTION : Casein kinase 1 epsilon inhibitor； Casein kinase 1 delta inhibitor. The ability of (I) to inhibit casein kinase 1 delta was tested in human using fluorescence resonance energy transfer assay. The result showed that IC 5 0value of 2-(4-fluoro-phenyl)-6-(piperazin-1-yl)-3-(pyridazin-4-yl)-imidazo[1,2-b]pyridazine was 1 nM.
