Tetrahydrofuran → 2-Methyl-3-(3,4,5-trimethoxybenzoyl)-6-methoxy-7-isopropoxy-benzo[b]furan

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a stirred solution of 2-isopropoxy-3-methoxy-6-iodophenol (308 mg, 1.00 mmol) in dry tetrahydrofuran (2 mL) was added dropwise a solution of 1-propynyl magnesium bromide (5, 6 mL, 3 mmol, 0.5 M solution in THF) at 0° C. under nitrogen. Dichloro-bis-triphenylphosphine palladium catalyst (40 mg, 0.06 mmol) was added and the reaction mixture was heated to 70° C. for 3 hours (tlc). The solvent was removed under vacuum and the residue was dried under vacuum. Dry dimethylsulfoxide (8 mL) was added and the nitrogen atmosphere was replaced with carbon monoxide. 3,4,5-Trimethoxyiodobenzene 6 (310 mg 1.05 mmol) was added and the reaction mixture was stirred at 90° C. for 17 hours and then quenched with saturated ammonium chloride solution and extracted with ethyl acetate (2×25 mL). The organic layer was washed with water and dried over magnesium sulphate. The crude product was purified by flash chromatography (silica gel, eluent=hexane/diethyl ether; 8:2-7:3) to afford the title compound as a creamy white solid. The product was crystallized from methanol. Yield—290 mg, 70%; 1H NMR (300 MHz, CDCl3) δ-7.10 (s, 2H, benzoyl Hs), 7.07 (d, 1H), 6.85 (d, 1H, J=8.57), 4.74-4.68 (m, 1H), 3.93 (s, 3H, OMe), 3.87 (s, 3H, OMe), 3.83 (s, 6H, 2×OMe), 2.52 (s, 3H, Me), 1.37 (d, 6H, J=6.18 Hz).

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