1.1: zinc; acetic acid / 5 h / 80 °C 1.2: 70 percent / piperidine / 1.5 h / 100 °C 2.1: H2 / Pd/C / methanol / 8 h / 65 °C / 10343 Torr 3.1: aq. HBr / 5 h / Heating 3.2: 78 percent / H2SO4 / methanol / 2 h / Heating View Scheme