1: 88 percent / pyridine / 2 h / Ambient temperature 2: 60 percent / KOAc / dimethylformamide / 6 h / 90 - 100 °C 3: 72 percent / 18-crown-6, NH4Cl / dimethylsulfoxide; H2O / 1.5 h / 85 - 90 °C 4: 90 percent / HCl / H2O / 2 h / Heating 5: 40 percent / H2SO4 / 2 h / Heating View Scheme

1: 88 percent / pyridine / 2 h / Ambient temperature 2: 60 percent / KOAc / dimethylformamide / 6 h / 90 - 100 °C View Scheme

pyridine 2 h; Ambient temperature;