toluene-4-sulfonic acid; palladium on activated charcoal in ethanol; ethyl acetate T=80°C; 2 h;

2,3-dicyano-5,6-dichloro-p-benzoquinone in methanol; dichloromethane T=20°C; 1 h;

1.1: 66 percent / p-toluenesulfonic acid / dimethylformamide / 4 h / 80 °C 2.1: NaH / dimethylformamide / 2 h / 0 °C 3.1: 13 g / aq. HCl / methanol / 2 h / 50 °C 4.1: Bu2SnO / methanol / 2 h / Heating 4.2: 88 percent / dimethylformamide / 48 h / 20 °C 5.1: NaH / dimethylformamide / 0.5 h / 0 °C 5.2: 91 percent / dimethylformamide / 1 h / 0 °C 6.1: 87 percent / p-TsOH / Pd/C / ethyl acetate; ethanol / 2 h / 80 °C View Scheme

1.1: NaH / dimethylformamide / 2 h / 0 °C 2.1: 13 g / aq. HCl / methanol / 2 h / 50 °C 3.1: Bu2SnO / methanol / 2 h / Heating 3.2: 88 percent / dimethylformamide / 48 h / 20 °C 4.1: NaH / dimethylformamide / 0.5 h / 0 °C 4.2: 91 percent / dimethylformamide / 1 h / 0 °C 5.1: 87 percent / p-TsOH / Pd/C / ethyl acetate; ethanol / 2 h / 80 °C View Scheme

1.1: Bu2SnO / methanol / 2 h / Heating 1.2: 88 percent / dimethylformamide / 48 h / 20 °C 2.1: NaH / dimethylformamide / 0.5 h / 0 °C 2.2: 91 percent / dimethylformamide / 1 h / 0 °C 3.1: 87 percent / p-TsOH / Pd/C / ethyl acetate; ethanol / 2 h / 80 °C View Scheme

1.1: 13 g / aq. HCl / methanol / 2 h / 50 °C 2.1: Bu2SnO / methanol / 2 h / Heating 2.2: 88 percent / dimethylformamide / 48 h / 20 °C 3.1: NaH / dimethylformamide / 0.5 h / 0 °C 3.2: 91 percent / dimethylformamide / 1 h / 0 °C 4.1: 87 percent / p-TsOH / Pd/C / ethyl acetate; ethanol / 2 h / 80 °C View Scheme

1.1: NaH / dimethylformamide / 0.5 h / 0 °C 1.2: 91 percent / dimethylformamide / 1 h / 0 °C 2.1: 87 percent / p-TsOH / Pd/C / ethyl acetate; ethanol / 2 h / 80 °C View Scheme

1.1: NaH / dimethylformamide / 0.5 h / 0 °C 1.2: 89 percent / dimethylformamide / 1 h / 0 °C 2.1: 89 percent / DDQ / CH2Cl2; methanol / 1 h / 20 °C View Scheme