1: 63 percent / barium oxide / toluene / Heating 2: Zn dust, AcOH / H2O / 70 °C 3: 2n Na2CO3 / tetrahydrofuran / 0 °C 4: 87 percent / barium hydroxide / H2O; dioxane / Heating 5: 68 percent / thionyl chloride 6: 76 percent / sodium borohydride / dimethylformamide / 80 °C 7: 85 percent / aqueous hydrobromic acid View Scheme