1: 81 percent / H2O2 / dioxane / 1 h / Ambient temperature 2: 73.79 percent / Dowex 50WX8 H(1+) / ethanol / Heating 3: 1.) RuO2, NaOCl; 2.)(CH3)2CHOH / 1.) 2 h, CHCl3; 2.) r.t. 10 min 4: 81.09 percent / HCl / ethanol / 4 h / Heating View Scheme