Hydrochloric Acid → 3-Methyl-1-(2-pyridinyl)-1,9-dihydro-4H-pyrazolo[3,4-b]quinolin-4-one

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Reaction Steps

To a solution of 4-chloro-3-methyl-1-(2-pyridinyl)-1H-pyrazolo[3,4-b]quinoline (34.9 g, 0.12 mol) in ethanol (500 mL) was added 6N hydrochloric acid (50 mL, 0.30 mol), and the mixture was heated and under reflux for 2 hours. The solution was cooled to room temperature, and the reaction solvent was concentrated and evaporated under reduced pressure. The residue was made basic by the addition of an aqueous sodium hydroxide solution, and organic matter was extracted with chloroform. The extract was washed with saturated brine and water, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue thus obtained was purified by silica gel column chromatography (chloroform:methanol=95:5) to give the title compound (25.8 g, 79% yield).

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