1: 92 percent / PTSA / methanol / 3 h / 20 °C 2: 80 percent / DMAP / CH2Cl2 / 4 h / 0 °C 3: 78 percent / lithium aluminium hydride / tetrahydrofuran / 6 h / 0 - 20 °C 4: 85 percent / hydrogen / Pd/C / methanol / 20 °C View Scheme