Propargyl bromide → tert-Butyl 4-(prop-2-yn-1-yl)piperazine-1-carboxylate

Participants

Reaction Steps

To a solution of 10.0 g (54.8 mmol) of tert-butyl-1-piperazine carboxylate in 60 mL acetonitrile was added 5.20 mL (60.4 mmol) propargyl bromide and 37.9 g (274 mmol) anhydrous potassium carbonate. Additional propargyl bromide, 1.5 mL, was added after stirring for 36 hours at room temperature. The residue was evaporated to dryness. Dichloromethane, 50 mL, and water, 50 mL, were added. The reaction mixture was extracted with CH2Cl2, 4×40 mL, dried over magnesium sulfate, and evaporate to provide a brown oil. The oil was dissolved in dichloromethane and purify with a RT Scientific system using hexane/ethyl acetate gradient to yield 5.5 g (46%) of yellow oil, which ultimately crystallized upon standing.

Provenance & Evidence