pyridine; thionyl chloride in chloroform 1) -40 deg C to -25 deg C, 2) 60 deg C, 1 h;

pyridine; thionyl chloride T=60°C; 1 h;

1: 80 percent / NEt3 / tetrahydrofuran / 1) r.t., 1 h, 2) reflux, 10 min 2: 65 percent / NaH / dimethylformamide / 1 h / 65 °C 3: 93 percent / methanol / 1 h / Heating 4: 92 percent / conc. HCl / 0.25 h 5: 92 percent / SOCl2, pyridine / CHCl3 / 1) -40 deg C to -25 deg C, 2) 60 deg C, 1 h View Scheme

1: 65 percent / NaH / dimethylformamide / 1 h / 65 °C 2: 93 percent / methanol / 1 h / Heating 3: 92 percent / conc. HCl / 0.25 h 4: 92 percent / SOCl2, pyridine / CHCl3 / 1) -40 deg C to -25 deg C, 2) 60 deg C, 1 h View Scheme

1: 92 percent / conc. HCl / 0.25 h 2: 92 percent / SOCl2, pyridine / CHCl3 / 1) -40 deg C to -25 deg C, 2) 60 deg C, 1 h View Scheme

1: 93 percent / methanol / 1 h / Heating 2: 92 percent / conc. HCl / 0.25 h 3: 92 percent / SOCl2, pyridine / CHCl3 / 1) -40 deg C to -25 deg C, 2) 60 deg C, 1 h View Scheme