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ChemicalBook CAS DataBase List 1-Methyl-4-pyrazole boronic acid pinacol ester
761446-44-0

1-Methyl-4-pyrazole boronic acid pinacol ester synthesis

11synthesis methods
1-Methylpyrazole-4-boronic acid pinacol ester is a reagent used in drug synthesis, including the preparation of selective and orally bioavailable LRRK2 inhibitors for the treatment of Parkinson's disease. It can be synthesised by the reaction of 4-Bromo-1-methylpyrazole and Bis(pinacolato)diboron.
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Yield:761446-44-0 93%

Reaction Conditions:

with sodium hydride in tetrahydrofuran at 0 - 20; for 4 h;

Steps:

Intermediate 108: 1-methyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H- pyrazole

To the solution of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (0.40 g, 2.06 mmol) in THF (10 mL) was added NaH (0.1.00 g, 4.12 mmol) followed by methyl iodide (0.25 mL, 4.12 mmol) at 0° C and the reaction mixture was stirred at ambient temperature for 4 hr. The reaction was quenched with saturated NH4Cl solution (20 mL) and extracted with ethyl acetate (2 x 50 mL). The combined organic layers were washed with brine (20 mL), dried over sodium sulfate, and distilled under reduced pressure to obtain Intermediate 108 (0.40 g, 93.00%) as yellow viscous liquid.1H NMR (400 MHz, CDCl3) δ ppm 1.31 (s, 12 H), 3.91 (s, 3 H), 7.65 (s, 1 H), 7.77 (s, 1 H). LCMS (Method-D): retention time 1.58 min, [M+1] 209.1.

References:

WO2018/93569,2018,A1 Location in patent:Page/Page column 189

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