General procedure for the synthesis of methyl 5-amino-1-methylpyrazole-3-carboxylate from methyl 1-methyl-5-nitro-1H-pyrazole-3-carboxylate: Methyl 1-methyl-5-nitro-1H-pyrazole-3-carboxylate (136 mg, 0.74 mmol) obtained in Preparation Example 21 was dissolved in 2 mL of methanol, and 14 mg of 10% palladium/charcoal catalyst was slowly added dropwise. The reaction was stirred at room temperature for 1 hour under hydrogen pressure of 50 atm. Upon completion of the reaction, the reaction mixture was filtered through a pad of diatomaceous earth to remove the catalyst and the filtrate was concentrated under reduced pressure to afford 94 mg (82% yield) of the target compound, methyl 5-amino-1-methylpyrazole-3-carboxylate. The product was characterized by 1H NMR (300 MHz, CDCl3): δ 6.12 (s, 1H, pyrazole ring H), 3.99 (s, 3H, OCH3), 3.84 (s, 3H, N-CH3), 3.72 (brs, 2H, NH2).
