Lithium hydroxide, monohydrate → 4-[4-Methoxy-3-(3,3,6,6-tetramethyl-1,8-dioxo-2,3,4,5,6,7,8,9-octahydro-1H-xanthen-9-yl)phenyl]pyridine-2-carboxylic acid

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Reaction Steps

A solution of lithium hydroxide monohydrate (21.7 mg, 0.52 mmol) in water (2.4 ml) was added to a solution of the methyl 4-[4-methoxy-3-(3,3,6,6-tetramethyl-1,8-dioxo-2,3,4,5,6,7,8,9-octahydro-1H-xanthen-9-yl)phenyl]pyridine-2-carboxylate produced in Example 2-1 (121 mg, 0.23 mmol) in THF (4.8 ml) at room temperature, and the mixed solution was then stirred at the same temperature as above for 1 hour. Thereafter, water was added to the reaction solution, and the mixed solution was then washed with diethyl ether. A 1 N aqueous solution of hydrochloric acid (0.52 ml) was added to the water layer, and the mixed solution was then extracted with dichloromethane four times. The organic layer thus obtained was dried over anhydrous sodium sulfate. Thereafter, the solvent was distilled away under reduced pressure, and the residue thus obtained was then washed with a mixed solution of diethyl ether and hexane, followed by collection by filtration and drying, to obtain the title compound (84.5 mg, yield: 72%).

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