反应详情

3-Oxo-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-ethyl ester. A mixture of 1-benzyl-3-oxo-piperidine-4-carboxylic acid ethyl ester (11.31 g, 38 mmol), di-t-butyl dicarbonate (8.78 g, 40.2 mmol), Et3N (5.4 mL, 38.7 mmol) and Pd(OH)2 on carbon (20% on dry basis-Pearlman's catalyst) (1.3 g) were taken into EtOH (110 mL). The mixture was hydrogenated at 60 psi for 24 h in a Parr bottle. The catalyst was removed by filtration and the filtrate was concentrated to dryness to tan solid. Crude residue was shaken well with hexane (100 mL) and filtered. The filtrate was concentrated to yield the title compound (9.70 g, 94.25%). MS (ESI) mass calcd. for C13H21NO5, 271.32; 1H NMR (400 MHz, CDCl3) 4.24 (q, J=7.1, 2H), 4.03 (s br, 2H), 3.49 (t, J=5.6, 2H), 2.32 (m, 3H), 1.47 (s, 9H), 1.31 (t, J=7.1, 3H).

1. customThe catalyst was removed by filtration
2. concentrationthe filtrate was concentrated to dryness to tan solid
3. filtrationfiltered
4. concentrationThe filtrate was concentrated