反应详情

温度

0 °C

2 g (7.59 mmol) of 1-benzyl piperidine-1,3-dicarboxylate, 1.31 g (9.11 mmol) of 2,2-dimethyl-1,3-dioxolane-4,6-dione and 1.85 g (15.19 mmol) of 4-dimethylamino-pyridine are initially charged in 12 ml of dichloromethane, and the mixture is cooled to 0° C. 1.60 g (8.35 mmol) of (3-dimethylaminopropyl)ethylcarbodiimide hydrochloride are added. The mixture is stirred at 0° C. for one hour and then at room temperature for 18 hours. The reaction mixture is diluted with dichloromethane (50 ml) and washed successively with water (20 ml), 1N hydrochloric acid (30 ml), saturated aqueous sodium bicarbonate solution (30 ml) and saturated aqueous sodium chloride solution. The organic phase is dried over anhydrous magnesium sulfate. The solution is concentrated under reduced pressure. The residue (1.2 g) is dissolved in 30 ml of ethanol, 0.13 ml (0.61 mmol) of 37% strength hydrochloric acid is added and the mixture is stirred under reflux for one hour. After cooling, 0.59 g (3.18 mmol) of guanidinium carbonate is added and the reaction mixture is stirred at reflux (oil bath temperature 93° C.) for 18 hours. The solution is concentrated. The crude product is purified on a silica gel column using dichloromethane/methanol 20:1. This gives 0.68 g (27% of theory) of product.

1. waitat room temperature for 18 hours
2. washwashed successively with water (20 ml), 1N hydrochloric acid (30 ml), saturated aqueous sodium bicarbonate solution (30 ml) and saturated aqueous sodium chloride solution
3. dry with materialThe organic phase is dried over anhydrous magnesium sulfate
4. concentrationThe solution is concentrated under reduced pressure
5. dissolutionThe residue (1.2 g) is dissolved in 30 ml of ethanol
6. addition0.13 ml (0.61 mmol) of 37% strength hydrochloric acid is added
7. stirringthe mixture is stirred
8. temperatureunder reflux for one hour
9. temperatureAfter cooling
10. stirringthe reaction mixture is stirred
11. temperatureat reflux (oil bath temperature 93° C.) for 18 hours
12. concentrationThe solution is concentrated
13. customThe crude product is purified on a silica gel column