Benzyl Bromide → Tert-butyl 4-benzyl-3-oxopiperazine-1-carboxylate

Participants

Reaction Steps

Sodium hydride (60%, 18.11 g, 452 mmol) in mineral oil was triturated with 35 hexanes, dried under a stream of nitrogen and taken up in 1500 mL of THF. To the slurry at 0° C. was added 3-oxo-piperazine-1-carboxylic acid tert-butyl ester (75.057 g, 200.4 mmol) in portions over 15 min. After 90 minutes benzyl bromide (71.01 g, 415.1 mmol) was added and the mixture was warmed to room temperature for 18 hours. The solution was quenched with H2O and extracted with Et2O. The combined organic layers were washed with H2O, washed with brine, dried over MgSO4. Concentration in vacuo gave a crude solid which was recrystallized from hexane to afford 4-benzyl-3-oxo-piperazine-1-carboxylic acid tert-butyl ester (83.5 g, 76%) as a white crystalline solid.

Provenance & Evidence