Ethyl Acetate → 2-Chloromethyl-5-chlorobenzofuran

関与物質

反応手順

To a suspension of ethyl-5-chloro-benzofuran carboxylate (1.05 g), prepared according to Helv. Chim. Acta., 818 (1935), in tetrahydrofuran (10 ml) was added lithium aluminum hydride (0.1 g). The mixture was stirred at room temperature for 1 hour. Ethyl acetate (50 ml) was slowly added to the reaction mixture, and the whole mixture was poured onto water (50 ml). The organic extract was separated, washed with water (2×25 ml), dried and evaporated to obtain 2-hydroxymethyl-5-cnlorobenzofuran as an oil [0.87 g; 'HNMR (CDCl3, 60 MHz): 4.6 (s, 2H), 6.6-7.4 (m, 4H)]. This material was added to a solution of methanesulfonyl chloride (1.15 g) in methylene chloride (20 ml) containing pyridine (1 ml). After stirring the reaction overnight it was poured onto ice-water (20 ml) and the organic extract was first washed with 10% HCl (5 ml) and then with water (2×10 ml). The washed extract was dried and evaporated to obtain 2-chloromethyl-5-chlorobenzofuran as a clear oil (yield: 0.5 g); HNMR (CDCl3, 60 MHz): 4.65 (s, 2H), 6.6 (s, 1H), 6.8-7.4 (m, 3H).

情報源と証拠