General procedure for the synthesis of 2-methyl-4-nitroimidazole from 4-iodo-2-methyl-5-nitro-1H-imidazole: (1) In a 5 mL microreaction flask, 50 mg of 4-bromo-2-methyl-5-nitroimidazole prepared in Example 1 was added, followed by the addition of 3 mL of methanol to dissolve it completely. Then, 5 mg of 10% palladium carbon (Pd/C) was added as a catalyst. The reaction flask was placed on a hydrogenation unit and high purity hydrogen was passed through, displacing it three times to ensure that the reaction system was free of oxygen. The reaction pressure was adjusted to 100 mmHg and the reaction was stirred at 25 °C for 30 h. The reaction pressure was adjusted to 100 mmHg. Upon completion of the reaction, the Pd/C catalyst was removed by centrifugation and the remaining liquid was concentrated by evaporation under reduced pressure to obtain the target product 2-methyl-5-nitroimidazole. The yield of this step was 47% by HPLC analysis.
