反应详情

温度

-35 °C

Diisopropyl ethylamine (6.5 ml) in dry THF (25 ml) was cooled to −10° C. then N-butyl lithium (1.6 molar, 23 ml) was added drop wise under nitrogen atmosphere and maintain the reaction at −10° C. for 45 minutes then cool the reaction to −75° C. for 15 minutes then 1-tert-butyl 4-ethyl piperidine-1,4-dicarboxylate (Above step 1, 5 g in 30 ml THF) was added and stirred the reaction at same temp for 30 minutes, again raise the reaction temperature to −35° C. and stirred for 45 minutes then again cool the reaction to −75° C. then ethyl iodide (3.5 g in 20 ml THF) was added drop wise and slowly allowed the reaction to room temperature and stirred the reaction at room temperature for about 12 hours. After completion of the reaction (monitored by TLC), the reaction mixture was quenched with saturated ammonium chloride and extracted with ethyl acetate. The organic layer was washed with saturated NaHCO3 followed by brine and the organic layer dried over Na2SO4 and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using 3% ethyl acetate in hexane as eluent to furnish the title compound as a light yellow color liquid. 1H NMR (300 MHz, CDCl3): 1.16-1.18 (t, 3H); 1.44 (s, 9H); 2.07-2.11 (m, 2H); 2.28 (s, 1H); 2.82 (s, 2H); 2.92-2.95 (m, 1H); 3.46-3.52 (m, 3H); 4.09-4.11 (m, 2H); ES Mass: 308 (100%) [M+Na].

1. temperaturemaintain
2. customthe reaction at −10° C. for 45 minutes
3. temperaturethen cool
4. customthe reaction to −75° C. for 15 minutes
5. customthe reaction at same temp for 30 minutes
6. stirringstirred for 45 minutes
7. temperaturethen again cool
8. customthe reaction to −75° C.
9. customthe reaction to room temperature
10. stirringstirred
11. customthe reaction at room temperature for about 12 hours
12. customAfter completion of the reaction (monitored by TLC)
13. customthe reaction mixture was quenched with saturated ammonium chloride
14. extractionextracted with ethyl acetate
15. washThe organic layer was washed with saturated NaHCO3
16. dry with materialthe organic layer dried over Na2SO4
17. concentrationconcentrated under reduced pressure
18. customThe residue was purified by silica gel column chromatography