Sodium Hydroxide → 2-(6-methylpyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylic acid

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Reaction Steps

A solution of 2-(6-methyl-pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylic acid ethyl ester (1.6 g, 5.9 mmol) and 2 N sodium hydroxide (6 mL, 29 mmol) in absolute ethanol (50 mL) is refluxed for 5 h. The mixture is cooled to room temperature and concentrated in vacuo. The residue is suspended in water and acidified to pH 5 with 1 N hydrochloric acid. The aqueous solution is extracted three times with dichloromethane. The organic extracts are combined, dried (sodium sulfate), filtered, and concentrated in vacuo to yield the title compound, 1.4 g (97%), as a white solid.

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