3-Pyridinecarboxamidine

Preparation

A flask containing 6.0 gm (0.058 mole) of 3-cyanopyridine dissolved in 50 ml of dry chloroform and 3.0 gm (0.065 mole) of absolute ethyl alcohol is cooled to 0°C while dry hydrogen chloride saturates the reaction mixture. The contents are allowed to stand at 0°C for 16 hr and then poured into a separatory funnel containing enough of an ice-cold 50% sodium hydroxide solution to give an alkaline solution. The mixture is shaken vigorously, then the chloroform layer is separated, washed with water until neutral, dried over potassium carbonate, and concentrated to give the crude imidate. The latter is dissolved in 20 ml of 75% aqueous ethanol containing 1.2 gm (0.0224 mole) of ammonium chloride and heated at 70°C for 4 hr, charcoal filtered, and diluted with 2 - 3 volumes of acetone. The unreacted ammonium chloride that separates is filtered, and the filtrate is again diluted with acetone until the cloud point. After standing for several hours at 0°C, 4 gm (100%), m.p. 190°C, of product separates (colorless needles).