تفاعل #1005310

معادلة التفاعل

intermediate B

4-acetyl-2-amino-4'-methoxybiphenyl

hydrofluoroboric acid

sodium nitrite

→

4-acetyl-2-fluoro-4'-methoxybiphenyl

المذيبات

tetrahydrofuran

water

water

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةwhilst maintaining the temperature of the reaction mixture below 5°C
2. 2
   ترشيحThe resulting diazonium fluoroborate was collected by filtration
3. 3
   غسيلwashed with hydrofluoroboric acid (20 ml. of 10% w/v acid)
4. 4
   تجفيفwith methanol/ether (60 ml. of 10% methanol in ether), and finally dried in vacuo
5. 5
   درجة الحرارةwas refluxed for 45 minutes
6. 6
   أخرىafter which the xylene was removed by distillation in vacuo
7. 7
   استخلاصThe residue was extracted with hot benzene
8. 8
   استخلاصThe resulting extract
9. 9
   درجة الحرارةwas cooled
10. 10
    غسيلwashed with dilute aqueous sodium carbonate
11. 11
    تجفيفwater, dried over anhydrous sodium carbonate
12. 12
    أخرىevaporated
13. 13
    workup.DISTILLATIONThe residue was distilled in vacuo
14. 14
    أخرىto give a product, b.p. 146° - 156°C./0.2 mm
15. 15
    درجة الحرارةon cooling
16. 16
    أخرىThis product was recrystallized from ethanol

الإجراء التجريبي

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).

المصدر