Ammonium Chloride → 9-{3-[6-(Hydroxymethyl)pyridin-2-yl]-2-methoxyphenyl}-3,3,6,6-tetramethyl-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione

Participants

Reaction Conditions

Reaction Steps

1,1′-Carbonyldiimidazole (38.8 mg, 0.239 mol) was added to a solution of the 6-[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 obtained in Example 1-2 (100 mg, 0.199 mmol) in THF (1.0 mL) at room temperature, and the mixture thus obtained was then stirred at the same temperature as above for 30 minutes. Subsequently, the reaction solution was cooled to 0° C., sodium borohydride (7.5 mg, 0.199 mmol) and water (0.1 mL) were then added thereto, and the mixture thus obtained was then stirred at the same temperature as above for 30 minutes. Thereafter, a saturated aqueous solution of ammonium chloride was added to the reaction solution, and the mixed solution was then extracted with ethyl acetate twice. The organic layer thus obtained was washed with brine, and was then dried over anhydrous sodium sulfate. The solvent was distilled away under reduced pressure. The residue thus obtained was purified by silica gel column chromatography (hexane:ethyl acetate=3:1 to 3:7, v/v), and was then solidified with a mixed solution of diethyl ether-hexane to obtain the title compound (76.3 mg, yield: 78%).

Provenance & Evidence