反应详情

温度

25 °C

75.7 ml (0.44 mol) of 33% strength HBr in glacial acetic acid were added to 200 ml of glacial acetic acid, and 50 g (0.44 mol) of 1-methylpiperidin-4-one (III) were then rapidly added dropwise at 20-25° C. with ice-cooling. 70.4 g (0.44 mol) of bromine were added dropwise at 20-25° C. in the course of 30 min to the suspension of the hydrobromide obtained in this way, a clear, yellowish solution being obtained. This was stirred at 25° C. for a further 15 min and 67.2 g (0.40 mol) of 1,3,5-trimethoxybenzene (V) were then added to the reaction solution. It was then stirred at 25° C. for 1 h. After this, 300 ml of methyl tert-butyl ether were allowed to run in, the product being deposited in oily form. The supernatant was decanted off, the residue was stirred again with 300 ml of methyl tert-butyl ether and the supernatant was decanted off. The residue was then stirred with 150 ml of dichloromethane, the product crystallizing out. The 3(R,S)-bromo-1-methyl-4-(2,4,6-trimethoxyphenyl)-1,2,3,6-tetrahydropyridine hydrobromide (VI) obtained was filtered off with suction, washed with 50 ml of dichloromethane and dried in vacuo.

1. additionwere then rapidly added dropwise at 20-25° C. with ice-
2. temperaturecooling
3. customobtained in this way
4. customa clear, yellowish solution being obtained
5. stirringIt was then stirred at 25° C. for 1 h
6. customThe supernatant was decanted off
7. stirringthe residue was stirred again with 300 ml of methyl tert-butyl ether
8. customthe supernatant was decanted off
9. stirringThe residue was then stirred with 150 ml of dichloromethane
10. customthe product crystallizing out