1: 65 percent / pyridine / 1 h / Heating 2: 72 percent / phosphorus oxychloride / 3 h / Heating 3: 2 h / 160 °C View Scheme

1: 72 percent / phosphorus oxychloride / 3 h / Heating 2: 2 h / 160 °C View Scheme

1: 54 percent / pyridine hydrochloride / 0.5 h / 220 - 230 °C / Heating 2: 65 percent / pyridine / 1 h / Heating 3: 72 percent / phosphorus oxychloride / 3 h / Heating 4: 2 h / 160 °C View Scheme

T=160°C; 2 h;