1: 61 percent / 85percent aq. m-chloroperbenzoic acid / CHCl3 / 15 h / Ambient temperature 2: 51 percent / N,N-dimethylformamide / 12 h / 90 °C 3: 49 percent / H2 / Raney nickel / methanol / 2 h / Ambient temperature 4: 25 percent / aq. sodium hydroxide / 3 h / Heating View Scheme