1,4-Dimethylpyrazole → 1,4-dimethyl-5-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

HRID 589045Notes

Reaction equation

[CH3:1][N:2]1[CH:6]=[C:5]([CH3:7])[CH:4]=[N:3]1.C([Li])CCC.C(O[B:17]1[O:21][C:20]([CH3:23])([CH3:22])[C:19]([CH3:25])([CH3:24])[O:18]1)(C)C>C1COCC1.CCOC(C)=O>[CH3:1][N:2]1[C:6]([B:17]2[O:21][C:20]([CH3:23])([CH3:22])[C:19]([CH3:25])([CH3:24])[O:18]2)=[C:5]([CH3:7])[CH:4]=[N:3]1

Participants

Conditions

Temperature: 0 °C

Procedure

1,4-Dimethyl-1H-pyrazole (50 mg, 0.5 mmol) was stirred in THF (2 mL) and cooled to 0° C. A solution of 1.6 M n-butyllithium in hexanes (390 mL) was added dropwise by syringe and the mixture was allowed to warm to room temperature for 2 h. The mixture was cooled to −78° C. and 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (110 mL, 0.52 mmol) was added dropwise by syringe. The mixture was stirred at −78° C. for 15 min. and at 0° C. for 3 h. The mixture was diluted with EtOAc and washed with brine, dried over sodium sulfate, filtered and concentrated under reduced pressure. Purification by chromatography on silica gel using EtOAc in hexanes gave the sub-title compound. LCMS calc. for C11H20BN2O2 (M+H)+: m/z=223.2. found: 223.0.

Workup

temperatureto warm to room temperature for 2 h
temperatureThe mixture was cooled to −78° C.
washwashed with brine
dry with materialdried over sodium sulfate
filtrationfiltered
concentrationconcentrated under reduced pressure
customPurification by chromatography on silica gel

Sources & evidence

ORD record: ord-90d264228a804bfbabedb89e1d5a4ecd
Source dataset: uspto-grants-2016_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09227985B2

Reaction notes

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