1: 99 percent / 0.5 N KOH / 2 h / 25 °C 2: 42 percent / triethylamine / dimethylformamide; H2O / 20 h / 100 °C 3: 65 percent / I2, KIO3, 5 N H2SO4 / H2O; acetonitrile / 0.5 h / 55 °C View Scheme

1: 99 percent / 0.5 N KOH / 2 h / 25 °C 2: 42 percent / triethylamine / dimethylformamide; H2O / 20 h / 100 °C 3: 65 percent / I2, KIO3, 5 N H2SO4 / H2O; acetonitrile / 0.5 h / 55 °C 4: 81 percent / 5 N H2SO4 / 36 h / 25 °C View Scheme

potassium hydroxide T=25°C; 2 h;