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

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Reaction Steps

tert-Butyl 4-propargylpiperazine-1-carboxylate of step 2(ii) above (570 mg, 2.545 mmol) was dissolved in trifluoroacetic acid (10 ml) and water (2.5 ml). The mixture was then stirred at room temperature overnight. The solution was evaporated to dryness in vacuum. The residue was dissolved in water (10 ml) and then basified with Na2CO3 (pH 11), and extracted with Et2OAc (3×50 ml). The organic layer was washed with brine (2×50 ml) and dried over Na2SO4 overnight. Evaporation in vacuum gave N-propargylpiperazine (D7) as white solid. (crude, 193 mg, 62% yield). H1 NMR (250 MHz, CDCl3) 1.64 (s, 1NH), 2.26 (m, 1H), 2.55 (dd, J=4.73, 4.50 Hz, 4H), 2.93 (dd, J=4.96, 4.84 Hz, 4H), 3.29 (d, J=2.44 Hz, 2H).

Provenance & Evidence