Synthesis
General procedure for the synthesis of methyl 5-phenylpyrazole-3-carboxylate from methyl 2,4-dioxo-4-phenylbutanoate: methyl 2,4-dioxo-4-phenylbutanoate (470 mg, 2.28 mmol) was dissolved in acetic acid (5 mL), followed by the addition of hydrazine hydrate (122 μL, 2.51 mmol). The reaction mixture was heated at reflux for 2 h at 118 °C. Upon completion of the reaction, the mixture was concentrated under vacuum to afford methyl 5-phenylpyrazole-3-carboxylate (320 mg, 69% yield), the product was a yellow solid.LCMS analysis result: ES+ 203.0 [MH]+.
References
[1] Patent: WO2014/20350, 2014, A1. Location in patent: Page/Page column 51
[2] Patent: WO2014/20351, 2014, A1. Location in patent: Page/Page column 36
[3] Journal of Medicinal Chemistry, 1998, vol. 41, # 13, p. 2390 - 2410
[4] Bioorganic and Medicinal Chemistry Letters, 2013, vol. 23, # 1, p. 273 - 280
[5] Patent: US2013/143870, 2013, A1. Location in patent: Paragraph 0547; 0548
