GENERAL STEPS: Sodium bisulfite (24 g, 0.23 mol) was slowly added to 25 mL of 40% aqueous methylglyoxal solution, followed by the dropwise addition of 86 mL of aqueous solution containing sodium hydroxide (0.86 g, 0.021 mol). The reaction mixture was heated to 80 °C and maintained for 1 hour. Subsequently, 2-aminomalonamide (18 g, 0.15 mol) was added and the reaction temperature was maintained at 80 °C with continued stirring for 2 hours. Next, sodium acetate (32.78 g, 0.4 mol) was added and after cooling the reaction mixture to 20 °C, 25 mL of 30% hydrogen peroxide solution was slowly added dropwise at 60-65 °C. After completion of the reaction, the reaction was cooled to room temperature, the product was separated and washed with cold water to afford 5-methyl-3-oxo-3,4-dihydropyrazine-2-carboxamide (8.5 g, 36% yield), which could be used in subsequent steps without further purification. NMR hydrogen spectrum (400 MHz, DMSO-d6) δ 13.21 (s, 1H), 8.75 (s, 1H), 8.03 (s, 1H), 7.83 (s, 1H), 2.37 (s, 3H).
