toluene-4-sulfonic acid in acetone T=0 - 5°C; 3 h;

1: 48 percent / 40percent NaOH, Na2S2O4 / methanol; H2O / 8 h / Heating 2: 99 percent / POCl3 / CHCl3 / 6 h / Heating 3: 96 percent / tetrahydrofuran / 3 h / Ambient temperature 4: 87 percent / p-toluenesulfonic acid monohydrate / acetone / 3 h / 0 - 5 °C View Scheme

1: 58 percent / Br2 / CCl4 / 0.5 h / 70 °C 2: 84 percent / CuI / dimethylformamide; methanol / 30 h / Heating 3: 99 percent / POCl3 / CHCl3 / 6 h / Heating 4: 96 percent / tetrahydrofuran / 3 h / Ambient temperature 5: 87 percent / p-toluenesulfonic acid monohydrate / acetone / 3 h / 0 - 5 °C View Scheme

1: 99 percent / POCl3 / CHCl3 / 6 h / Heating 2: 96 percent / tetrahydrofuran / 3 h / Ambient temperature 3: 87 percent / p-toluenesulfonic acid monohydrate / acetone / 3 h / 0 - 5 °C View Scheme

1: 84 percent / CuI / dimethylformamide; methanol / 30 h / Heating 2: 99 percent / POCl3 / CHCl3 / 6 h / Heating 3: 96 percent / tetrahydrofuran / 3 h / Ambient temperature 4: 87 percent / p-toluenesulfonic acid monohydrate / acetone / 3 h / 0 - 5 °C View Scheme

1: 96 percent / tetrahydrofuran / 3 h / Ambient temperature 2: 87 percent / p-toluenesulfonic acid monohydrate / acetone / 3 h / 0 - 5 °C View Scheme

in tetrahydrofuran; diethyl ether 3 h; Ambient temperature;

1: 86 percent / diethyl ether; tetrahydrofuran / 3 h / Ambient temperature 2: 70 percent / cerium(IV) ammonium nitrate / CHCl3; acetonitrile; H2O / 0.17 h / Ambient temperature View Scheme

1: 86 percent / diethyl ether; tetrahydrofuran / 3 h / Ambient temperature 2: 70 percent / cerium(IV) ammonium nitrate / CHCl3; acetonitrile; H2O / 0.17 h / Ambient temperature 3: 27 percent / AgO, 40percent HNO3 / acetone / 0.17 h / Ambient temperature View Scheme