1: 70.9 percent / dimethylformamide / 5 h / 180 °C 2: 41.1 percent / H2O/KOH / bis-(2-hydroxy-ethyl) ether / 24 h / Heating 3: 64.1 percent / polyphosphoric acid / 1 h / 100 °C View Scheme

1: 70.9 percent / dimethylformamide / 5 h / 180 °C 2: 41.1 percent / H2O/KOH / bis-(2-hydroxy-ethyl) ether / 24 h / Heating 3: 64.1 percent / polyphosphoric acid / 1 h / 100 °C 4: 67 percent / Ag2O / methanol; CHCl3 / 6 h / 60 °C View Scheme