반응 #61684

반응 방정식

1,5-dibromo-3-fluoro-6-methoxy-5-nitrobenzene

N2

→

2-Fluoro-5-methoxyaniline

수율 84.0%

용매

ethanol

반응 조건

후처리

1. 1
   기타The stirred reaction mixture
2. 2
   기타purge
3. 3
   기타The reaction mixture was evacuated
4. 4
   기타The reaction mixture was evacuated
5. 5
   workup.ADDITIONH2 was introduced until a pressure of 7 bars
6. 6
   온도to maintain the internal pressure at 7 bars (note that after 24 hours
7. 7
   기타the catalyst was removed by filtration through 2 glass microfibre pads under an atmosphere of N2
8. 8
   농축the filtrate was concentrated to dryness under reduced pressure at 45° C
9. 9
   workup.DISSOLUTIONThe resulting dark orange solid was dissolved in water (500 mL)
10. 10
    추출The resulting brown suspension was extracted with tert-butylmethylether (2×1 L)
11. 11
    세척The combined organic extracts were washed with water (500 mL)
12. 12
    건조dried over sodium sulfate
13. 13
    여과filtered
14. 14
    농축concentrated in vacuo at 40° C.

실험 절차

A 2.0 L pressure reactor was charged with 10% Pd/C (50% wet paste, 10 g). A solution of 1,5-dibromo-3-fluoro-6-methoxy-5-nitrobenzene (50 g, 0.152 mol) in ethanol (absolute grade, 1.5 L) was added to the catalyst under N2. The stirred reaction mixture was subjected to three cycles of vacuum followed by N2 purge. The reaction mixture was evacuated prior to the introduction of H2 at a pressure of 4 bars. The reaction mixture was evacuated and H2 was introduced until a pressure of 7 bars was reached. The reaction mixture was stirred at 25° C. for 48 hours, with periodic injections of H2 to maintain the internal pressure at 7 bars (note that after 24 hours, the catalyst was replaced). After the reaction had reached completion, the catalyst was removed by filtration through 2 glass microfibre pads under an atmosphere of N2 and the filtrate was concentrated to dryness under reduced pressure at 45° C. The resulting dark orange solid was dissolved in water (500 mL) and the pH of the resulting solution adjusted to >12 using aqueous NaOH (1N, 400 mL). The resulting brown suspension was extracted with tert-butylmethylether (2×1 L). The combined organic extracts were washed with water (500 mL), dried over sodium sulfate, filtered and concentrated in vacuo at 40° C. to afford 2-Fluoro-5-methoxyaniline (18.0 g, 84%) as a brown solid.

출처