1H-Pyrazole, 1-methyl- → 5-(5,5-Dimethyl-1,3,2-dioxaborinan-2-YL)-1-methyl-1H-pyrazole

Participants

Reaction Steps

To a solution of 1-methylpyrazole (4.1 g, 50 mmole) in THF (100 mL) at 0° C. was added n-BuLi (2.2M in THF, 55 mmole). The reaction solution was stirred for 1 hour at RT and then cooled to −78° C. [J. Heterocyclic Chem. 41, 931 (2004)]. To the reaction solution was added 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (12.3 mL, 60 mmole). After 15 min at −78° C., the reaction was allowed to warm to 0° C. over 1 hour. The reaction was diluted with saturated NH4Cl solution and extracted with DCM. The organic fractions were washed with H2O (2×100 mL), dried over Na2SO4 and concentrated under vacuum to afford a tan solid (8.0 g, 77%) which was used without further purification.

Provenance & Evidence