Citric Acid → HCID 117700524, compound

Participants

Reaction Steps

1,1′-Carbonyldiimidazole (104 mg, 0.64 mmol) was added to a solution of the 3-ethyl-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]pyridine-2-carboxylic acid produced in Example 13 (267 mg, 0.49 mmol) in DMF (5.3 ml) at room temperature, and the mixture thus obtained was then stirred at the same temperature as above for 1.5 hours. Thereafter, methanesulfonamide (60.7 mg, 0.64 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (0.096 ml, 0.64 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 3 hours. Thereafter, an aqueous solution of citric acid (472 mg, 2.46 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 (128 mg, yield: 42%).

Provenance & Evidence