General procedure for the synthesis of (1H-imidazol-4-yl)methanamine hydrochloride from 4-imidazolecarboxaldehyde: 12.0 g (124 mmol) of 4-formylimidazole with 750 mg of Nguyenne nickel catalyst was added to 1000 mL of ammonia in a methanolic solution and shaken for 30 min at 40 °C. Subsequently, the mixture was transferred to a Parr reactor and hydrogenated under hydrogen atmosphere at 5 bar pressure and 40 °C for 14 hours. Upon completion of the reaction, 750 mg of Nguyenay nickel catalyst was added additionally and the reaction conditions were adjusted to 50 °C and 5 bar hydrogen pressure and the hydrogenation was continued for 14 hours. At the end of the reaction, the mixture was filtered and concentrated under reduced pressure. Methanol, toluene and ethanol were sequentially added to the residue and each addition was concentrated under reduced pressure to completely remove the solvent. Subsequently, the residue was mixed with a methanolic solution of ether hydrochloric acid and concentrated again under reduced pressure. Finally, the residue was mixed with methanol and dichloromethane, respectively, and concentrated under reduced pressure after each addition. The product 21.2 g (quantitative yield) was obtained with an Rt value of 0.49 min (D). The molecular formula of the product was C4H7N3-2HCl (molecular weight: 170.04/97.12), and the (M+H)+ peak was detected by mass spectrometry with m/z=98.
