Potassium Carbonate → tert-butyl 4-[(4-oxopiperidin-1-yl)methyl]tetrahydro-2H-pyran-4-carboxylate

Beteiligte Stoffe

Reaktionsschritte

To a refluxing mixture of tert-butyl 4-(aminomethyl)tetrahydro-2H-pyran-4-carboxylate (8.00 g, 0.0372 mol, step 2) and K2CO3 (0.51 g, 0.0372 mol) in EtOH-H2O (2:1, 240 mL) was added dropwise 1-ethyl-1-methyl-4-oxopiperidinium iodide (12.0 g, 0.0445 mol, J. Org. Chem. 1995, 60, 4324-4330) in EtOH-H2O (2:1, 150 mL), and the resulting mixture was stirred at the same temperature (reflux) for 1 h. After cooling to room temperature, the solvent was removed in vacuo. The residue was poured into sat. NaHCO3 aq. (200 mL), and the mixture was extracted with CH2Cl2 (200 mL×three times). The extracts were dried over Na2SO4 and concentrated. The residue was chromatographed on a column of silica gel eluting with hexane/ethyl acetate (3:1 to 2:1) to give 10.77 g (98%) of the title compound as a colorless syrup.

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