反应详情

Ethyl (S)-Piperidine-3-carboxylate (25 g, 159.02 mmol) in anhydrous DCM (500 mL) was cooled down to 0° C. and treated with Et3N. A solution of isovaleryl chloride (23.27 mL, 190.08 mmol, 1.2 eq.) in anhydrous DCM (200 mL) was added dropwise at 0° C. The resulting reaction mixture was kept on the cooling bath and allowed to warm up slowly to room temperature. After 6 hrs the reaction was washed subsequently with aqueous HCl solution (2M), saturated NaHCO3, brine, dried over Na2SO4, filtered, concentrated under vacuum and purified by filtration over a short silica gel column using EtOAc as solvent. The solvent was removed under vacuum to yield the desired product as pale yellow oil (37.4 g, 154.97 mmol, 97.5%) that was used in the next step without further purification. 1H NMR (400 MHz, DMSO-d6, 20° C.) δ0.88 (pseudo d, J=6.4 Hz, 6H), 1.13-1.23 (m, 3H), 1.26-1.45 (m, 1H), 1.47-1.75 (m, 2H), 1.82-2.03 (m, 2H), 2.10-2.28 (m, 2H), 2.28-2.39 (m, 0.5H), 2.45-2.56 (m, 0.5H), 2.84 (dd, J=10.0, 12.8 Hz, 0.5H), 2.97-3.11 (m, 1H), 3.38 (dd, J=8.8, 13.6 Hz, 0.5H), 3.63-3.83 (m, 1.5H), 4.00-4.14 (m, 2H), 4.26-4.36 (dm, 0.5H). MS 242 (MH).

1. customThe resulting reaction mixture
2. washAfter 6 hrs the reaction was washed subsequently with aqueous HCl solution (2M), saturated NaHCO3, brine
3. dry with materialdried over Na2SO4
4. filtrationfiltered
5. concentrationconcentrated under vacuum
6. filtrationpurified by filtration over a short silica gel column
7. customThe solvent was removed under vacuum