PPA T=100°C; 4 h;

1: 76 percent / polyphosphoric acid / 4 h / 100 °C 2: 1) Mg / 1) THF, 25 deg C, 20 min, 2) 60 deg C, 2,5 h 3: 91 percent / SOCl2 / CHCl3 / 0.5 h / 0 °C 4: 44 percent / hexamethylphosphoamide / 1 h / 70 °C 5: 41 percent / 1) KOH powder, ethyleneglycol, 2) ice-water, 12 N HCl / 5 h / 175 °C 6: 68 percent / 30percent H2O2 / acetic acid / 1 h / 25 °C View Scheme

1: 76 percent / polyphosphoric acid / 4 h / 100 °C 2: 1) Mg / 1) THF, 25 deg C, 20 min, 2) 60 deg C, 2,5 h 3: 91 percent / SOCl2 / CHCl3 / 0.5 h / 0 °C 4: 44 percent / hexamethylphosphoamide / 1 h / 70 °C 5: 41 percent / 1) KOH powder, ethyleneglycol, 2) ice-water, 12 N HCl / 5 h / 175 °C View Scheme