反应详情

温度

15 °C

A solution of 4-bromo-2-methylanisole (0.984 g, 4.9 mmol) in tetrahydrofuran (3 mL) was added dropwise to magnesium powder (0.127 g, 5.2 mmol) in tetrahydrofuran (1 mL) at room temperature. Under external heating the reaction mixture was brought up to reflux. After complete addition, reflux was maintained for 1 hour. Thereafter the mixture was cooled to 15° C., then diluted with tetrahydrofuran (1 mL) before a solution of 3-bromo-5-ethoxy-N-methoxy-N-methyl-benzamide (1.238 g, 4.3 mmol) in tetrahydrofuran (3 mL) was added dropwise. After complete addition, the mixture was heated to reflux for 1.5 hours. For the working-up, it was cooled to 5° C. and hydrolysed with a saturated solution of ammonium chloride (25 mL). The aqueous layer was extracted twice with ethyl acetate (2×50 mL), thereupon, the organic layers combined, washed with brine, dried over sodium sulfate and evaporated under reduced pressure. The crude product was chromatographed on silica gel using a gradient of heptane/ethyl acetate=100/0 to 6/1 as the eluent. There were obtained 1.16 g (77% of theory) of the title compound as a colourless oil. Mass (calculated) C17H17BrO3 [348]; (found) [M+H]+=349, 351.

1. temperatureUnder external heating the reaction mixture
2. temperatureto reflux
3. additionAfter complete addition
4. temperaturereflux
5. temperaturewas maintained for 1 hour
6. additionwas added dropwise
7. additionAfter complete addition
8. temperaturethe mixture was heated
9. temperatureto reflux for 1.5 hours
10. extractionThe aqueous layer was extracted twice with ethyl acetate (2×50 mL)
11. washwashed with brine
12. dry with materialdried over sodium sulfate
13. customevaporated under reduced pressure
14. customThe crude product was chromatographed on silica gel using a gradient of heptane/ethyl acetate=100/0 to 6/1 as the eluent