反应详情

A suspension of 0.19 g (0.5 mmol) of bis(benzo-nitril) dichloro-palladium (II) and 0.2 g 1,4-bis(di-phenylphosphino)butane in 10 mL of toluene was heated at reflux with stirring for 1 h under nitrogen. The suspension was cooled to room temperature. One gram (6.6 mmol) of 3A, 1.57 g of 3,4-dichlorobenzene boronic acid (8.2 mmol), 2.5 mL EtOH and 5 mL of 1 M Na2CO3 were added and the mixture heated to reflux for 20 h. The reaction mixture was cooled and diluted with 100 mL Et2O. The suspension was filtered through a plug of silica gel and the cake washed with an additional 100 mL of Et2O. The ether was evaporated and the residue chromatographed over silica gel (10% EtOAc/hexane). A fraction containing 0.72 g (32%) of 2,5-dichloro-4-(3,4-dichlorophenyl)pyrimidine was isolated as a white solid. (m.p. 125-126° C.)

1. temperaturewas heated
2. temperatureat reflux
3. temperaturethe mixture heated
4. temperatureto reflux for 20 h
5. temperatureThe reaction mixture was cooled
6. filtrationThe suspension was filtered through a plug of silica gel
7. washthe cake washed with an additional 100 mL of Et2O
8. customThe ether was evaporated
9. customthe residue chromatographed over silica gel (10% EtOAc/hexane)
10. additionA fraction containing 0.72 g (32%) of 2,5-dichloro-4-(3,4-dichlorophenyl)pyrimidine
11. customwas isolated as a white solid