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

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Reaction Steps

Propargyl bromide (356.9 mg, 3 mmol) was slowly added to a mixture of tert-butyl 1-piperazinecarboxylate obtained in step 2(i) above (558.8 mg, 3 mmole) and diisopropylethylamine (407.1 mg, 3.15 mmol) in CHCl3 (25 ml) at 0° C. The mixture was stirred for 24 h at room temperature. 50 ml of CHCl3 was then added and the solution was washed with 5% NaHCO3 (3×50 ml), brine (2×50 ml), and then dried over Na2SO4. The solution was filtered and evaporated to dryness. The residue was crystallized from a mixture of benzene-hexane (1:1) to give tert-butyl 4-propargylpiperazine-1-carboxylate (D6) (crude 337 mg, 86%). H1 NMR (250 MHz, CDCl3): 1.42 (s, 9H), 2.22(s, 1H), 2.46 (s, 4H), 3,26 (s, 2H), 3.41 (s, 4H).

Provenance & Evidence