2H-PYRIMIDO[1,2-B]PYRIDAZIN, 2-CHLORO-7,8-DIMETHYL- synthesis

Yield:17412-26-9 56%

Reaction Conditions:

in ethanol;Inert atmosphere;Reflux;

Steps:

44.1 Step 1: 6-Chloro-2 ,3-dimethylimidazo [ 1 ,2-b] pyridazine

A mixture (clear light brown solution) of 6-chloropyridazin-3 -amine (500mg, 3.86 mmol) and 3- bromobutan-2-one (758 mg, 5.02 mmol) in EtOH (10 ml) under an argon atmosphere was heated to reflux and stirring was continued for overnight. The mixture was concentrated and the residue was taken up in 20 ml 10 % KHCO3. The precipitated solid was collected by filtration, washed with H₂0 and dried to provide the title compound (392 mg 56 %) as off-white solid. MS: M = 182.1 (M+H)+

References:

WO2013/178569,2013,A1 Location in patent:Page/Page column 55