1: With trichlorophosphate T=70°C; Vilsmeier-Haack reaction; 2: With sodium hydroxide T=80°C;

1.1: 99 percent / 4-chloropyridine hydrochloride / dioxane / 100 °C 2.1: 43 percent / Heating 3.1: 99 percent / sodium hydride / dimethylformamide / 25 °C 4.1: phosphorus oxychloride / 70 °C 4.2: 86 percent / aq. sodium hydroxide / 80 °C View Scheme

1.1: 43 percent / Heating 2.1: 99 percent / sodium hydride / dimethylformamide / 25 °C 3.1: phosphorus oxychloride / 70 °C 3.2: 86 percent / aq. sodium hydroxide / 80 °C View Scheme

1.1: 99 percent / sodium hydride / dimethylformamide / 25 °C 2.1: phosphorus oxychloride / 70 °C 2.2: 86 percent / aq. sodium hydroxide / 80 °C View Scheme

1.1: 40 percent / N-bromosuccinimide; acetic acid / CHCl3 / 1.5 h / 20 °C 2.1: 99 percent / 4-chloropyridine hydrochloride / dioxane / 100 °C 3.1: 43 percent / Heating 4.1: 99 percent / sodium hydride / dimethylformamide / 25 °C 5.1: phosphorus oxychloride / 70 °C 5.2: 86 percent / aq. sodium hydroxide / 80 °C View Scheme