Benzyl Bromide → HCID 86723936, compound

Participants

Reaction Steps

Cs2CO3 (3.4 g, 10.5 mmol) was added to a solution of (2R,5S)-4-carboxymethyl-5-ethyl-2-methyl-piperazine-1-carboxylic acid tert-butyl ester triethylamine salt (3.9 g, 9.6 mmol) in DMF (20 mL). After stirring for 2 h at room temperature, a solution of benzyl bromide (1.25 mL, 10.5 mmol) in DMF (10 mL) was added over 30 minutes. The reaction mixture was stirred overnight at room temperature and the resulting solid was filtered off and the filtrate was evaporated in vacuo. The residue was dissolved in EtOAc and washed with water. The organic phase was dried (MgSO4), filtered and concentrated and the residue was purified by SiO2 chromatography (EtOAc:Petrol 1:1) to give (2R,5S)-4-benzyloxycarbonylmethyl-5-ethyl-2-methyl-piperazine-1-carboxylic acid tert-butyl ester (2.8 g) as a pale yellow oil. 1H NMR (CDCl3): 7.45-7.29 (5H, m), 5.26-5.08 (2H, m), 4.27-4.08 (1H, m), 3.89 (1H, d), 3.52-3.22 (3H, m), 2.75 (1H, dd), 2.68-2.40 (2H, m), 1.47 (11H, d), 1.26 (3H, d), 0.90 (3H, t).

Provenance & Evidence