1: 98 percent / pyridine / 3 h / Ambient temperature 2: 1percent HCl / methanol / 30 h / Ambient temperature 3: pyridine / 3 h / Ambient temperature 4: AcOH, conc. H2SO4 / Ambient temperature View Scheme

1: 98 percent / pyridine / 3 h / Ambient temperature 2: 1percent HCl / methanol / 30 h / Ambient temperature 3: pyridine / 3 h / Ambient temperature 4: AcOH, conc. H2SO4 / Ambient temperature View Scheme

1: 98 percent / pyridine / 3 h / Ambient temperature 2: 1percent HCl / methanol / 30 h / Ambient temperature 3: pyridine / 3 h / Ambient temperature 4: AcOH, conc. H2SO4 / Ambient temperature 5: 1.) HCl(g), AcCl, 2.) H2O / 1.) CH2Cl2, 0 deg C, 2.) CH3CN View Scheme

1: 98 percent / pyridine / 3 h / Ambient temperature 2: 1percent HCl / methanol / 30 h / Ambient temperature 3: pyridine / 3 h / Ambient temperature 4: AcOH, conc. H2SO4 / Ambient temperature 5: 1.) HCl(g), AcCl, 2.) H2O / 1.) CH2Cl2, 0 deg C, 2.) CH3CN 6: 1.) SO2Cl2 / 1.) CH2Cl2, DMF, from -40 deg C to RT, 3.5 h, 2.) CH2Cl2, DMF, RT, 15 h 7: 65 percent / KHF2, 48percent aq. HF / various solvent(s) / 1 h / 160 °C View Scheme