2,5-Dihydrofuran → 6-(Cyclopropylmethoxy)-5-(4,5-dihydrofuran-2-yl)-pyridine-2-carboxylic acid methyl ester

関与物質

反応条件

反応手順

A mixture of 5-bromo-6-(cyclopropylmethoxy)-pyridine-2-carboxylic acid methyl ester (0.5 g, 1.7 mmol), 2,5-dihydrofuran (CAN 1708-29-8, 1.2 g, 17 mmol), palladium(II) acetate (CAN 3375-31-3, 0.02 g, 0.09 mmol), sodium acetate (0.17 g, 2 mmol) and tri-tert-butylphosphine (CAN 13716-12-6, 0.037 g, 0.2 mmol) in DMF (10 mL) was stirred at 120° C. for 2.5 h under a nitrogen atmosphere. Water was poured into the reaction mixture and the resulting mixture was extracted with ethyl acetate (3×30 mL). The combined organic extracts were washed with water and brine, dried over anhydrous sodium sulfate and evaporated. The residue was purified by column chromatography (silica gel, 10 g, eluting with 5% ethyl acetate in petroleum ether) to yield 6-(cyclopropylmethoxy)-5-(2,5-dihydrofuran-3-yl)-pyridine-2-carboxylic acid methyl ester (b1) and 6-(cyclopropylmethoxy)-5-(4,5-dihydrofuran-2-yl)-pyridine-2-carboxylic acid methyl ester (b2) (mixture b1:b2=3:2, 0.38 g, 1.4 mmol, 79%) as yellow oil; MS (EI): m/e=376.1 [M+H]+.

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