General procedure: 5-Aminopyrazine-2-carboxamide was synthesized from 5-chloropyrazine-2-carboxamide by microwave-assisted ammonolysis reaction. The procedure was as follows: 5-chloropyrazine-2-carboxamide (150 mg, 0.952 mmol), 25% ammonia (2 mL, excess) and methanol (2 mL) were mixed in a thick-walled tube for microwave reactor. After ensuring that the mixture was homogeneous, the tube was sealed and fitted with a stirrer. Subsequently, the reaction tube was placed in the microwave reactor and the reaction conditions were set to PowerMAX mode with 200 W output power, 95 °C reaction temperature and 30 min reaction time. After completion of the reaction, it was cooled to room temperature for subsequent processing.
