METHYL 4-(1H-PYRAZOL-3-YL) BENZOATE synthesis

Yield:179057-10-4 8.15 g

Reaction Conditions:

with hydrazine hydrate in ethanol at 50 - 60; for 54 h;

Steps:

43 Example 43. Preparation of methy -(lH-pyrazol-3-yl)benzoate (B41)

Example 43. Preparation of methy -(lH-pyrazol-3-yl)benzoate (B41) To a solution of crude (i^-methyl 4-(3-(dimethylamino)acryloyl)benzoate (28.1 mmol) in EtOH (100 mL) was added hydrazine monohydrate (1.50 mL, 30.9 mmol) and the reaction was heated at 50 °C for 24 hours. The reaction temperature was then increased to 60 °C for 24 hours. Additional hydrazine monohydrate (1.5 mL) was added, and the reaction was heated at 60 °C for an additional 6 hours. The reaction was cooled, concentrated, and dried in a vacuum oven at 45 °C overnight to yield methyl 4-(lH-pyrazol-3-yl)benzoate as an orange solid (8.15 g, quantitative): mp 106 °C (dec); ^]H NMR (400 MHz, CDC1₃) δ 8.15 - 8.05 (m, 2H), 7.91 - 7.83 (m, 2H), 7.65 (d, J = 2.4 Hz, 1H), 6.71 (d, J = 2.3 Hz, 1H), 3.94 (s, 3H); ^1JC NMR (101 MHz, CDC1₃) δ 166.91 , 136.89, 131.83, 130.13, 129.37, 125.50, 103.35, 52.14, 22.46; EIMS m/z 202.

References:

WO2014/11429,2014,A1 Location in patent:Page/Page column 51