反応 #580327

反応方程式

3

3,3,5-Tribromo-1,3-dihydro-pyrrolo[2,3-b]pyridin-2-one

→

4

収率 72.0%

5-Bromo-1,3-dihydro-pyrrolo[2,3-b]pyridin-2-one

収率 72.0%

溶媒

acetic acid

反応条件

後処理

1. 1
   その他strongly exothermic reaction
2. 2
   温度external ice bath cooling)
3. 3
   workup.ADDITIONAddition
4. 4
   温度Cooling bath
5. 5
   その他was removed
6. 6
   workup.WAITwas continued at r.t. for 2 h
7. 7
   ろ過The solid was filtered off
8. 8
   洗浄washed with toluene (50 mL)
9. 9
   その他triturated with CH2Cl2
10. 10
    その他The solution was decanted off
11. 11
    workup.ADDITIONtreated with 1.0 M aqueous Na2CO3 solution (170 mL)
12. 12
    workup.STIRRINGAfter stirring for 1 h the two layers
13. 13
    その他were separated
14. 14
    洗浄The organic layer was washed again with 1.0 M aqueous Na2CO3 solution (50 mL)
15. 15
    抽出The combined aqueous layers were extracted with CH2Cl2
16. 16
    乾燥Combined organic solutions were dried with MgSO4 (200 g)
17. 17
    濃縮concentrated
18. 18
    workup.DISSOLUTIONThe residual solid was dissolved in THF (2000 mL)
19. 19
    ろ過insoluble material was filtered off
20. 20
    濃縮The filtrate was concentrated to dryness in vacuum

実験手順

Zinc dust (34.0 g, 0.52 mol) was added in small portion to a stirred suspension of 3 (40.85 g, 0.111 mol) in glacial acetic acid (1000 mL) at such a rate that the temperature was maintained between 20-25° C. (strongly exothermic reaction; external ice bath cooling). Addition took about 20 min. Cooling bath was removed and stirring was continued at r.t. for 2 h. The solid was filtered off, washed with toluene (50 mL) and triturated with CH2Cl2:MeOH=4:1 (2.5 L). The solution was decanted off and treated with 1.0 M aqueous Na2CO3 solution (170 mL). After stirring for 1 h the two layers were separated. The organic layer was washed again with 1.0 M aqueous Na2CO3 solution (50 mL). The combined aqueous layers were extracted with CH2Cl2:MeOH=4:1 (10×100 mL). Combined organic solutions were dried with MgSO4 (200 g) and concentrated. The residual solid was dissolved in THF (2000 mL) and insoluble material was filtered off. The filtrate was concentrated to dryness in vacuum to afford 4 (16.93 g, 72%) as tan solid. 1H NMR (400 MHz, DMSO-d6) δ 3.57 (s, 2H), 7.75 (m, 1H), 8.14 (m, 1H), 11.13 (bs, 1H).

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