1: 86 percent / dimethylformamide / 12 h / Ambient temperature 2: 94 percent / aq. Na2S2O4 / tetrahydrofuran / 1 h / Ambient temperature 3: 48 percent / 1 N NaOH / tetrahydrofuran / 96 h / Ambient temperature View Scheme

1: 89 percent / conc. HNO3, conc. H2SO4 / 3 h / Ambient temperature 2: 91 percent / CH2Cl2 / 5 h / Ambient temperature 3: 60 percent / NaH / dimethylformamide / 1.) r.t., 1 h, 2.) r.t., 12 h 4: 86 percent / dimethylformamide / 12 h / Ambient temperature 5: 94 percent / aq. Na2S2O4 / tetrahydrofuran / 1 h / Ambient temperature 6: 48 percent / 1 N NaOH / tetrahydrofuran / 96 h / Ambient temperature View Scheme

1: 57 percent / acetic acid / 14 h / 100 °C 2: 72 percent / 10percent sodium methoxide / methanol / 14 h / 70 °C 3: 54 percent / polyphosphoric acid / 2 h / 180 °C View Scheme

1: 72 percent / 10percent sodium methoxide / methanol / 14 h / 70 °C 2: 54 percent / polyphosphoric acid / 2 h / 180 °C View Scheme

1: 94 percent / Na2S2O4 2: 48 percent / NaOH / ethanol View Scheme

1: 45 percent / SnCl4 / nitromethane / 3 h / 60 °C 2: 75 percent / NaOMe / methanol / Ambient temperature; pH 13 View Scheme