Sodium hydride → tert-butyl 4-[4-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl]piperidine-1-carboxylate

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Reaction Steps

To a solution of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (4.12 g, 21.2 mmol, Aldrich, Cat. 525057) in N,N-dimethylformamide (20 mL) was added sodium hydride (1.78 g, 44.5 mmol) at 0° C. The resulting solution was stirred at r.t. for one hour, and then tert-butyl 4-[(methylsulfonyl)oxy]piperidine-1-carboxylate (6.3 g, 22 mmol) in DMF (2 mL) was added. The reaction mixture was heated at 90° C. overnight. Then the reaction mixture was cooled to r.t., quenched with water, and extracted with ethyl acetate. The organic layer was washed with NaHCO3 aqueous solution and brine successively, dried over MgSO4, and concentrated under reduced pressure. The residue was purified by flash column chromatography on a silica gel column using 30% ethyl acetate in hexane as eluent to afford the desired compound (2.30 g, 28.74%). LCMS (M+H)+: m/z=378.4.

Provenance & Evidence