Acetic Acid → 1-(2-Fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carboximidamide

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Reaction Steps

108.00 g (0.43 mol) of 1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-carbonitrile (example I, step 4) are dissolved in one liter of methanol and added dropwise to a solution of 94.73 g (1.67 mol; purity: 95%) of sodium methoxide in 3 l of methanol. After stirring at RT for 2 hours, 28.83 g (0.54 mol) of ammonium chloride are added, and subsequently 100.03 g (1.67 mol) of glacial acetic acid are added dropwise. This solution is stirred under reflux overnight. The solvent is removed in vacuo, the residue is twice suspended in acetone and the insoluble solid is filtered off with suction. The latter is dissolved in 1.5 l of ethyl acetate, and 590 ml of an aqueous 20% strength sodium carbonate solution are added. Stirring for 20 minutes is followed by dilution with 200 ml of 1N sodium hydroxide solution. The organic phase is washed with saturated aqueous sodium chloride solution, dried over magnesium sulfate and filtered. The solvent is removed in vacuo. 99.10 g (86% of theory) of the product are obtained.

Provenance & Evidence