Citric Acid → HCID 117700629, compound

Participants

Reaction Conditions

Reaction Steps

A suspension of the [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]boronic acid produced in Example 1-1 (2.41 g, 5.68 mmol), 6-bromopyridine-2-carboxylic acid (1.17 g, 5.68 mmol), sodium carbonate (2.41 g, 22.7 mmol), and tetrakis(triphenylphosphine) palladium(0) (0.33 g, 0.28 mmol) in 1,2-dimethoxyethane (48.2 ml) and water (21 ml) was prepared at room temperature, and the prepared suspension was then stirred at 90° C. for 4 hours. After air-cooling, a 10% aqueous solution of citric acid was added to the reaction solution, and the mixed solution was then extracted with dichloromethane three times. The organic layer thus obtained was dried over anhydrous sodium sulfate. The solvent was distilled away under reduced pressure, and the residue thus obtained was then dissolved in THF (48 ml). Thereafter, an aqueous solution of lithium hydroxide monohydrate (524 mg, 12.5 mmol) was added to the solution obtained above, and the mixture thus obtained was then stirred at room temperature. Water was added to the reaction solution, and the resulting solution was then washed with diethyl ether. Thereafter, a 1 N aqueous solution of hydrochloric acid (12.5 ml) was added to the water layer, and the resultant was then extracted with dichloromethane four times. The organic layer thus obtained was 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=3:97 to 4:96, v/v). The solid thus obtained was washed with a mixed solution of diethyl ether and hexane, followed by collection by filtration and drying, to obtain the title compound (2.19 g, yield: 77%).

Provenance & Evidence