The general procedure for the synthesis of 5-methyl-3,4-diaminopyridine from 4-amino-5-methyl-3-nitropyridine was as follows: a mixture of 4-amino-5-methyl-3-nitropyridine (1.198 g), iron powder (1.748 g), ethanol (52 mL), and hydrochloric acid (13 mL) was heated and refluxed for 3 hours. After completion of the reaction, the mixture was cooled to room temperature and ethanol was removed by distillation. The resulting suspension was diluted to 50 mL with water and the pH was adjusted to 13 by slow addition of 2N NaOH solution. extraction was carried out with ethyl acetate (3 x 70 mL), the organic phases were combined and dried with anhydrous sodium sulfate. Finally, the solvent was evaporated to give 0.579 g (60% yield) of 5-methyl-3,4-diaminopyridine.
