反应详情

Add hexamethylenetetramine (7.10 g, 50.6 mmol) portion wise to a solution of 2,3,6-trifluorophenol (5.00 g, 33.7 mmol) in TFA (35 ml) at ambient temperature and reflux for 15 hours. After cooling, treat the reaction mixture with water (60 ml), followed by 50% aq. H2SO4 (30 ml), and stir at ambient temperature for 30 minutes. Extract with EtOAc (2×) and wash with 1N aq. HCl (3×) and water. Extract the organic with 2N aq. NaOH (2×) and acidify the alkaline extract with conc. HCl while cooling in an ice/water bath. Collect the resulting solid via filtration and dry to give 2,3,5-trifluoro-4-hydroxy-benzaldehyde (2.97 g) as an off-white solid.

1. temperaturereflux for 15 hours
2. temperatureAfter cooling
3. extractionExtract with EtOAc (2×)
4. washwash with 1N aq. HCl (3×) and water
5. extractionExtract the organic with 2N aq. NaOH (2×)
6. extractionextract with conc. HCl
7. temperaturewhile cooling in an ice/water bath
8. customCollect the resulting solid
9. filtrationvia filtration
10. customdry