Citric Acid → HCID 78324918, compound

Participants

Reaction Steps

1,1′-Carbonyldiimidazole (99.5 mg, 0.61 mmol) was added to a solution of the 6-[4-methoxy-2-methyl-3-(3,3,6,6-tetramethyl-1,8-dioxo-2,3,4,5,6,7,8,9-octahydro-1H-xanthen-9-yl)phenyl]-4-methylpyridine-2-carboxylic acid produced in Example 32-3 (250 mg, 0.47 mmol) in DMF (5 ml) at room temperature, and the mixture thus obtained was then stirred at the same temperature as above for 1 hour and 30 minutes. Thereafter, methanesulfonamide (58.4 mg, 0.61 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (0.092 ml, 0.61 mmol) were added to the resulting solution at room temperature, and the mixture thus obtained was then stirred at the same temperature as above for 2 hours. Thereafter, an aqueous solution of citric acid (454 mg, 2.36 mmol) was added to the reaction solution, and the mixed solution was then extracted with ethyl acetate. The organic layer thus obtained was washed with water, and was then dried over anhydrous sodium sulfate. The solvent was distilled away under reduced pressure, and the residue thus obtained was then purified by silica gel column chromatography (methanol:dichloromethane=0:1 to 1:9, v/v). The solid thus obtained was washed with diethyl ether, followed by collection by filtration and drying, to obtain the title compound (230 mg, yield: 80%).

Provenance & Evidence