1: 1.) NaOH / 1.) dioxane, water, 70 deg C, 16 h, 2.) dioxane, water, room temperature, 2 h 2: 16 mg / diethyl ether 3: CrO3, H2SO4 / acetone / 1 h / 0 °C 4: 9 mg / diethyl ether 5: KOH / tetrahydrofuran / 12 h / Ambient temperature 6: 4.5 mg / trifluoroacetic acid / CH2Cl2 / 12 h View Scheme