反应详情

温度

70 °C

To a stirred solution of intermediate B (8.8 g.) in a mixture of tetrahydrofuran (28 ml.), water (9.5 ml.) and hydrofluoroboric acid (38.5 ml. of 42% w/v acid) was slowly added a solution of sodium nitrite (2.7 g.) in water (4.5 ml.) whilst maintaining the temperature of the reaction mixture below 5°C. The mixture was then stirred for a further period of 20 minutes at 0° - 5°C. The resulting diazonium fluoroborate was collected by filtration, washed with hydrofluoroboric acid (20 ml. of 10% w/v acid) and then with methanol/ether (60 ml. of 10% methanol in ether), and finally dried in vacuo. This product was suspended in xylene (85 ml.) and the suspension heated to 70°C. at which point decomposition took place. When the reaction had subsided the mixture was refluxed for 45 minutes, after which the xylene was removed by distillation in vacuo. The residue was extracted with hot benzene. The resulting extract was cooled, washed with dilute aqueous sodium carbonate and then water, dried over anhydrous sodium carbonate, and evaporated. The residue was distilled in vacuo to give a product, b.p. 146° - 156°C./0.2 mm. which solidified on cooling. This product was recrystallized from ethanol to give 4-acetyl-2-fluoro-4'-methoxybiphenyl, m.p. 103° - 106°C. (novel intermediate C).

1. temperaturewhilst maintaining the temperature of the reaction mixture below 5°C
2. filtrationThe resulting diazonium fluoroborate was collected by filtration
3. washwashed with hydrofluoroboric acid (20 ml. of 10% w/v acid)
4. dry with materialwith methanol/ether (60 ml. of 10% methanol in ether), and finally dried in vacuo
5. temperaturewas refluxed for 45 minutes
6. customafter which the xylene was removed by distillation in vacuo
7. extractionThe residue was extracted with hot benzene
8. extractionThe resulting extract
9. temperaturewas cooled
10. washwashed with dilute aqueous sodium carbonate
11. dry with materialwater, dried over anhydrous sodium carbonate
12. customevaporated
13. distillationThe residue was distilled in vacuo
14. customto give a product, b.p. 146° - 156°C./0.2 mm
15. temperatureon cooling
16. customThis product was recrystallized from ethanol