Multi-step reaction with 5 steps 1.1: NaBH4; isobutyric acid / toluene / 3 h / 0 °C1.2: HBr / ethyl acetate; propionic acid / 0 °C1.3: 49 percent / aq. NaHCO3 2.1: 82 percent / Na / ethanol / 15 h / 80 °C3.1: 3.44 g / HCl / ethyl acetate; dioxane / 0 - 20 °C4.1: LiOH*H2O / tetrahydrofuran; ethanol; H2O / 36 h / 0 °C5.1: HCO2NH4 / Pd/C / methanol / 2 h / Heating