1,2-Dibromoethane → 7-Chloro-2,3-dihydrobenzo[b][1,4]dioxine-5-carbaldehyde

関与物質

反応条件

反応手順

5-Chloro-2,3-dihydroxybenzaldehyde (6.0 g, 34.7 mmol) was dissolved in DMF (100 mL) and to the solution were added 1,2-dibromoethane (8.0 g, 42.5 mmol) and potassium carbonate (10.0 g, 70 mmol). The mixture was stirred at 100° C. for one hour, cooled to room temperature and then diluted with water (200 mL). After extraction twice with ethyl acetate (200 mL) the combined organic solutions were washed with brine and then dried over Na2SO4. The solvent was removed by evaporation and the solid residue treated with methanol. After filtration and drying there was obtained 6.5 g (94%) of 7-chloro-2,3-dihydro-1,4-benzodioxine-5-carbaldehyde. 1H NMR (300 MHz, CDCl3): 4.3-4.4 (m, 4H), 7.1 (d, 1H), 7.3 (d, 1H), 10.3 (s, 1H).

情報源と証拠