Sodium Bicarbonate → Ethyl 2-[6-[3-[4-(diphenylmethoxy)piperidino] propylamino]imidazo[1,2-b]pyridazin-2-yl]-2-methylpropionate difumarate

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Reaction Steps

4.2 g of 4-(diphenylmethoxy)-1-piperidinepropanamine and 1.76 g of ethyl 2-(6-chloroimidazo[1,2-b]pyridazin-2-yl)-2-methylpropionate were stirred at 190-200° C. for 3.5 hours. After cooling, aqueous sodium bicarbonate was added, followed by extraction with ethyl acetate; the extract was washed with saturated saline, dried over magnesium sulfate and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography and eluted with ethyl acetate:methanol:triethylamine (100:5:1). The desired fraction was collected, dissolved in 16 ml of ethyl acetate; a solution of 867 mg of fumaric acid in 16 ml of methanol was added, followed by concentration. Acetone was added to the residue; the crystal precipitated was collected by filtration, washed with acetone and dried to yield 2.30 g of the title compound.

Provenance & Evidence