1: 58 percent / pulverized potassium hydroxide / dimethylsulfoxide / Ambient temperature 2: 86 percent / 2M hydrochloric acid / dioxane / 8 h / Heating 3: 95 percent / sodium borohydride / ethanol / 2 h / Ambient temperature 4: 19 percent / aqueous 5percent sodium hydroxide, tetrabutylammonium bromide / CH2Cl2 / 16 h / Heating View Scheme