反应详情

To a stirred solution of 17.5 g (123 mmol) of 2,5-difluorobenzaldehyde (Aldrich) in 615 mL of DMSO at ambient temperature was added 6.2 g (135 mmol) of lithium sulfide (Aldrich). The dark red solution was stirred at 75 C. for 1.5 hours, or until the starting material was completely consumed, and then 34 g (135 mmol) of dibutyl mesylate aldehyde was added at about 50 C. The reaction mixture was stirred at 75 C. for three hours or until the reaction was completed. The cooled solution was poured into water and extracted with ethyl acetate. The combined extracts were washed with water several times, dried (MgSO4) and concentrated in vacuo. Silica gel chromatographic purification of the crude product gave 23.6 g (59%) of fluorobenzene dialdehyde as a yellow oil: 1H NMR (CDCl3) d 0.87 (t, J=7.05 Hz, 6H), 1.0-1.4 (m, 8H), 1.5-1.78 (m, 4H), 3.09 (s, 2H), 7.2-7.35 (m, 1H), 7.5-7.6 (m, 2H), 9.43 (s, 1H), 10.50 (d, J=2.62 Hz, 1H).

1. customuntil the starting material was completely consumed
2. stirringThe reaction mixture was stirred at 75 C
3. waitfor three hours
4. extractionextracted with ethyl acetate
5. washThe combined extracts were washed with water several times
6. dry with materialdried (MgSO4)
7. concentrationconcentrated in vacuo
8. customSilica gel chromatographic purification of the crude product