(2R,5S)-4-Benzyl-2-methyl-5-(2-oxo-pyrrolidin-1-ylmethyl)-piperazine-1-carboxylic acid tert-butyl ester → (2R,5S)-2-Methyl-5-(2-oxo-pyrrolidin-1-ylmethyl)-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Steps

(2R,5S)-4-Benzyl-2-methyl-5-(2-oxo-pyrrolidin-1-ylmethyl)-piperazine-1-carboxylic acid tert-butyl ester (5.9 g, 15.25 mmol) and 10% Pd/C (2.13 g, 1.5 mmol) were dissolved in glacial acetic acid/ethanol (27.2 mL/72.6 mL) and stirred under hydrogen at 1 bar for 1 h. The mixture was filtered and the filtrate concentrated. Saturated aqueous sodium hydrogen carbonate and EtOAc were added. The EtOAc layer was separated and the aqueous phase extracted with DCM (3×). The combined DCM layers were dried with sodium sulfate, filtered and concentrated. The residue was azeotroped with toluene, to give the title compound (3.9 g), 1H NMR (CDCl3): 4.23-4.08 (1H, m), 3.95-3.77 (1H, m), 3.69 (1H, d), 3.59-3.46 (1H, m), 3.46-3.34 (1H, m), 3.34-3.07 (3H, m), 3.07-2.89 (1H, m), 2.55-2.39 (3H, m), 2.15-1.92 (2H, m), 1.48 (9H, s), 1.23 (3H, d).

Provenance & Evidence