反应详情

225 g of sodium carbonate and 0.15 g of PdCl2(PPh3)2 in 450 ml of methanol are heated to reflux temperature. A solution of 342 g of 4-bromo-3-methylacetanilide and 270 g of the ethylene glycol ester of phenylboronic acid in 225 ml of methanol, which has been heated to 50° C., is added dropwise over a period of 60 minutes. During the addition, methanol is distilled off in such an amount that the internal temperature can be kept at at least 85° C. After addition is complete, a further 0.1 g of the Pd catalyst is added and the reaction mixture is refluxed for another 6 hours. After this time, the monitoring of the reaction by HPLC indicates a conversion of 99.9%. The remaining methanol is distilled off as completely as possible (620 ml), with the reaction mixture having to remain stirrable. 1250 ml of chlorobenzene are subsequently added. Hydrolysis is carried out by addition of 85 ml of water. At 70-80° C., the phases are separated and the aqueous phase is discarded. The organic phase is washed once with 50 ml of water and is subsequently filtered through a 0.5 cm thick layer of aluminum oxide. The chlorobenzene is distilled off at 300-500 mbar. The residue of crude 2-methyl-4-acetaminobiphenyl which remains is used further without further purification. The yield is quantitative.

1. temperatureto reflux temperature
2. additionis added dropwise over a period of 60 minutes
3. distillationis distilled off in such an amount that the internal temperature
4. customcan be kept at at least 85° C
5. additionAfter addition
6. additiona further 0.1 g of the Pd catalyst is added
7. temperaturethe reaction mixture is refluxed for another 6 hours
8. customAfter this time, the monitoring of the reaction by HPLC
9. distillationThe remaining methanol is distilled off as completely as possible (620 ml)
10. addition1250 ml of chlorobenzene are subsequently added
11. customHydrolysis
12. customAt 70-80° C., the phases are separated
13. washThe organic phase is washed once with 50 ml of water
14. filtrationis subsequently filtered through a 0.5 cm thick layer of aluminum oxide
15. distillationThe chlorobenzene is distilled off at 300-500 mbar
16. customThe residue of crude 2-methyl-4-acetaminobiphenyl which remains is used further without further purification