Water → HCID 86612344, compound

Participants

Reaction Steps

A solution of (2,2,4,5,7-pentamethyl-3-oxo-2,3-dihydro-1-benzofuran-6-yl)formamide obtained in Reference Example 73 (600 mg, 2.43 mmol) in THF (5 mL) was added dropwise to a solution of benzylmagnesium chloride (a 2.0 M THF solution, 10.0 mL, 20.0 mmol) in THF (20 mL) under argon atmosphere, and the mixture was stirred at room temperature for 2 hours. Water was added thereto, which was extracted with ethyl acetate. The organic layer was washed with 1 N hydrochloric acid, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=4:1) to obtain (3-benzyl-3-hydroxy-2,2,4,5,7-pentamethyl-2,3-dihydro-1-benzofuran-6-yl)formamide. To a mixture of said compound with trifluoroacetic acid (5 mL) was added triethylsilane (0.5 mL, 3.2 mmol) with ice-cooling, and the mixture was stirred at room temperature for 30 minutes. The reaction solution was concentrated under reduced pressure, and to the residue was added a saturated sodium hydrogen carbonate solution to alkalify the aqueous layer, which was extracted with ethyl acetate. The organic layer was washed with water and saturated brine, dried over anhydrous sodium sulfate and then concentrated under reduced pressure. To a solution of the obtained residue in methanol (20 mL) was added concentrated hydrochloric acid (10 ml), and the mixture was heated under reflux for 2 hours. The solvent was distilled off under reduced pressure and the residue was neutralized with a 12 N aqueous sodium hydroxide solution. After extracting with ethyl acetate, the organic layer was washed with water and saturated brine, dried over anhydrous sodium sulfate and then concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (hexane:ethyl acetate 4:1) to obtain 440 mg (yield 62%) of the title compound. Melting point: 75-76° C. (ethyl acetate-hexane).

Provenance & Evidence