Synthesis
General procedure for the synthesis of methyl 1-methyl-4-aminopyrazole-3-carboxylate from ethyl 1-methyl-4-nitropyrazole-3-carboxylate: a mixture of methyl 1-methyl-4-nitro-1H-pyrazole-3-carboxylate (500 mg, 2.7 mmol) and 10% palladium carbon (50 mg) in methanol (25 mL) was placed in a Parr reactor at 60 psi of hydrogen pressure for 24 hours. Upon completion of the reaction, the mixture was filtered through a diatomaceous earth pad and washed with methanol. The filtrate was concentrated under reduced pressure to afford methyl 1-methyl-4-amino-1H-pyrazole-3-carboxylate (402 mg, 96% yield) as an off-white solid.
References
[1] Patent: US2004/14766, 2004, A1
[2] Patent: WO2003/106459, 2003, A1. Location in patent: Page 162
[3] ACS Medicinal Chemistry Letters, 2013, vol. 4, # 10, p. 979 - 984
[4] Patent: US2010/63106, 2010, A1. Location in patent: Page/Page column 11
[5] Patent: WO2017/15449, 2017, A1. Location in patent: Page/Page column 157
