Yield:1175275-82-7 77%

Reaction Conditions:

with 1,8-diazabicyclo[5.4.0]undec-7-ene in acetonitrile at 0 - 20; for 2 h;

Steps:

Intermediate 1 7a: Methyl 3-(4-iodo- 1H-pyrazol- 1-yl)propanoate

To a solution of methyl 4-iodo-1H-pyrazole (3.00 g, 15.5 mmol) in acetonitrile (45 mL) was added 1,8-diazabicyclo[5.4.0]undec-7-ene (1.17 g, 7.73 mmol) at 0°C, followed by methyl acrylate (2.65 g, 30.9 mmol). After stirred at room temperature for 2 hours, thereaction mixture was quenched with 1 M hydrochloride aqueous solution (30 mL) and extracted with ethyl acetate (30 mL) twice. The combined organic layers were washed with water (20 mL) and brine (20 mL) twice, dried over Na2 SO4() and filtered. The filtrate was concentrated under reduced pressure to give the title compound (1.00 g, 77 % yield) as brown solids. ‘H NIVIR (400 1VIHz, CDC13) 7.50 (s, 2H), 4.42 (t, J 6.4 Hz,2H), 3.69 (s, 3H), 2.88 (t, J= 6.4 Hz, 2H).

References:

WO2019/1420,2019,A1 Location in patent:Page/Page column 116; 117