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ChemicalBook CAS DataBase List 5-Bromo-1,3-difluoro-2-nitrobenzene
147808-42-2

5-Bromo-1,3-difluoro-2-nitrobenzene synthesis

3synthesis methods
Sodium perborate tetrahydrate (18.5 g, 0.12 mol, 5.0 eq) was suspended in glacial acetic acid (125 mL) and heated to 65 °C. 4-Bromo-2,6-difluoroanilline(5.0 g, 24.0 mmol, 1.0 eq) dissolved in glacial acetic acid (50 mL) was added slowly through a funnel over 4 h. After the addition, the reaction mixture was heated for 3 h additional hours before a second portion of NaBO3·4H2O (6.0 g, 30.0 mmol) was added. Then, the mixture was stirred for 14 h, and a third portion of oxidating agent (9.0 g, 45.0 mmol) was added. 9 h after the third addition full consumption of the starting material was indicated by TLC. After cooling the mixture to room temperature, the formed solid was removed by filtration. The filtrate was poured into ice-cold water (300 mL). The precipitated solid was filtered off and dried to give the product 5-Bromo-1,3-difluoro-2-nitrobenzene as a yellow solid (3.40 g 60percent).
67567-26-4 Synthesis
4-Bromo-2,6-difluoroaniline

67567-26-4
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$5.00/1g

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Yield:147808-42-2 68%

Reaction Conditions:

Stage #1:4-bromo-2,6-difluoroaniline with sodium perborate in acetic acid at 65 - 70; for 72 h;Heating / reflux;
Stage #2: with water at 0;

Steps:

24
To a suspension of sodium perborate tetrahydrate (1.78 mmol, 0.27 g) in 10 ml of acetic acid stirred at 650C was added a solution of (4-bromo-2,6-difluorophenyl)amine (1.78 mmol, 0.42 g, 1 eq.) in 5 ml of acetic acid over one hour dropwise. The reaction was heated at 650C over 3 days. Sodium perborate tetrahydrate (2 eq., 3.56 mmol, 0.54 g) was added again. After 3 hours, sodium perborate tetrahydrate (1eq., 1.78 mmol, 0.27 g) was added again. Additional sodium perborate tetrahydrate (3eq., 5.34 mmol, 0.81 g) was again added. The reaction was then left overnight at 7O0C under reflux and under argon. The solution was then cooled to room temperature and poured onto ice and extracted with ethyl acetate (2x). The combined organics were washed with water and brine. The organics were dried over MgSO4, filtered and the organic solvent was removed under reduced pressure to afford the crude product which was purified by silica chromatography (ethyl acetate-4% n-hexane 96%) to afford the title compound, 0.29 g, 68%. 1H NMR δ (d6DMSO, 400MHz): 7.964 (2H, d)

References:

GLAXO GROUP LIMITED WO2007/36715, 2007, A2 Location in patent:Page/Page column 51

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