反应详情

温度

-10 °C

With vigorous stirring, 9.15 g (0.065 mole) of 2-fluoro-4-methoxyaniline (Example 3, Step B) was added to 60 mL of concentrated hydrochloric acid that had been cooled to -10° C. A solution of 4.83 g (0.070 mole) of sodium nitrite in 30 mL of water was slowly added dropwise, while the temperature was kept at or below -10° C. Upon completion of addition, the reaction mixture was stirred at -10° C. for one hour, after which 33.85 (0.150 mole) of tin(II) chloride dihydrate in 50 mL of concentrated hydrochloric acid Was added slowly, dropwise, while the temperature was kept below -5° C. After the reaction mixture had stirred for one hour as it warmed to ambient temperature, the crude product was filtered from the mixture and dissolved in 250 mL of water. This solution was made basic with 4N sodium hydroxide and extracted with methylene chloride. The combined extracts were dried over anhydrous sodium sulfate and filtered. The filtrate was placed on a silica gel column and eluted with methylene chloride to remove colored impurities and then with ethyl acetate to obtain the desired product. The solvent was evaporated under reduced pressure to yield 6.30 g of 2-fluoro-4-methoxyphenylhydrazine. The NMR spectrum was consistent with the proposed structure.

1. custombelow -10° C
2. additionUpon completion of addition
3. customwas kept below -5° C
4. stirringAfter the reaction mixture had stirred for one hour as it
5. temperaturewarmed to ambient temperature
6. filtrationthe crude product was filtered from the mixture
7. dissolutiondissolved in 250 mL of water
8. extractionextracted with methylene chloride
9. dry with materialThe combined extracts were dried over anhydrous sodium sulfate
10. filtrationfiltered
11. washeluted with methylene chloride
12. customto remove colored impurities