反应详情

温度

70 °C

A mechanically stirred mixture of 49.0 g (0.43 mole) of 1,2-difluorobenzene, 20.6 g (0.19 mole) of pyridine-4-carboxaldehyde and 80 ml of concentrated H2SO4 was heated at 70° C. for 21 hours. The reaction mixture was poured over ice, and the icy mixture was made basic with 50% NaOH. The resulting mixture was extracted with CH2Cl2 and the CH2Cl2 solution was dried (MgSO4). The solvent was removed in vacuo to give 54.94 g (89.8%) of a solid. This was recrystallized from a mixture of CH2Cl2 and hexane to give 44.82 g (74.3%) of a crystalline solid, mp 79°-82° C. Proton NMR showed that this sample contained ~5% of the 2,3-difluoro isomer.

1. additionThe reaction mixture was poured over ice
2. extractionThe resulting mixture was extracted with CH2Cl2
3. dry with materialthe CH2Cl2 solution was dried (MgSO4)
4. customThe solvent was removed in vacuo