1-Tert-butyl 3-ethyl piperidine-1,3-dicarboxylate → 1-tert-Butyl 3-ethyl 3-methylpiperidine-1,3-dicarboxylate

Temperature

-50 °C

To a cold (−78° C.) solution of lithium diisopropylamide (LDA) (23.3 mmol) in THF (10 mL) under an argon atmosphere was added dropwise a solution of 1-tert-butyl 3-ethyl 1,3-piperidinedicarboxylate (3.0 g, 11.6 mmol) in THF (5 mL), then stirred at −50° C. for 2 hrs. To the resulting mixture was added a solution of Mel (1.98 g, 14 mmol) in THF at −50° C. The reaction mixture was allowed to warm to room temperature, and quenched with saturated aqueous NH4Cl solution. The mixture was concentrated under reduced pressure, and the residue was partitioned between ethyl acetate and water. The organic phase was separated, dried over MgSO4, filtered and concentrated under reduced pressure. The crude product was purified by column chromatography on silica gel (hexane:ethyl acetate, 9:1) to give 1-tert-butyl 3-ethyl 3-methyl-1,3-piperidinedicarboxylate as a pale yellow oil (2.27 g, yield; 72%).

1. temperatureto warm to room temperature
2. customquenched with saturated aqueous NH4Cl solution
3. concentrationThe mixture was concentrated under reduced pressure
4. customthe residue was partitioned between ethyl acetate and water
5. customThe organic phase was separated
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure
9. customThe crude product was purified by column chromatography on silica gel (hexane:ethyl acetate, 9:1)

ORD record

ord-9b29b16f33bf46d3a5ab585b5c466c6c

Source dataset

uspto-grants-2007_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07232909B2