1: 64.1 percent / sodium ethoxide / ethanol / 6 h / Heating 2: 65.7 percent / anhydrous sodium carbonate / palladium(II) chloride / 2-methyl-propan-2-ol / 10 h / Heating View Scheme

piperidine; acetic acid in ethanol; water 2 h; Heating;

1.1: mercury(II) acetate / 21 h / 20 °C 1.2: 52.1 percent / 0.5 h / 180 °C 2.1: 94.3 percent / piperidine; acetic acid / ethanol; H2O / 2 h / Heating View Scheme