The general procedure for synthesizing propionamidine hydrochloride from propionitrile was as follows: with reference to the preparation of propionamide hydrochloride in Example 28, hydrogen chloride gas was passed into a solution of propionitrile (10 g, 142 mmol) in ethanol (8.4 mL) until the total amount was increased by 7.9 g, and the reaction mixture was stirred at room temperature for 21.5 hours. Upon completion of the reaction, the solvent was removed by concentration under reduced pressure, the residue was suspended in ethanol (5.5 mL) and the suspension was cooled to -10 °C. A methanol solution of 8N ammonia (17.8 mL) was slowly added to the cooled suspension and stirring was continued for 28 hours at room temperature. At the end of the reaction, the insoluble material was removed by filtration, and the filtrate was concentrated under reduced pressure to give propionamidine hydrochloride (10.8 g, 70% yield) in white crystal form. The product was characterized by 1H NMR (300 MHz, DMSO-d6): δ 1.17 (3H, t, J = 7.6 Hz), 2.40 (2H, q, J = 7.7 Hz), 8.77 (2H, br s), 9.07 (2H, br s).
