Cesium carbonate → 2-[4-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl]methylpyrazine

HRID 1485760Notes

Reaction equation

[CH3:1][C:2]1([CH3:14])[O:6][B:5]([C:7]2[CH:8]=[N:9][NH:10][CH:11]=2)[O:4][C:3]1([CH3:13])[CH3:12].Cl.Cl.Br[CH2:18][C:19]1[CH:24]=[N:23][CH:22]=[CH:21][N:20]=1.C(=O)([O-])[O-].[Cs+].[Cs+]>C(#N)C>[CH3:1][C:2]1([CH3:14])[O:6][B:5]([C:7]2[CH:8]=[N:9][N:10]([CH2:18][C:19]3[CH:24]=[N:23][CH:22]=[CH:21][N:20]=3)[CH:11]=2)[O:4][C:3]1([CH3:13])[CH3:12]

Participants

Conditions

Temperature: 70 °C

Procedure

A 100-mL round-bottom flask was charged with a solution of 4-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (265 mg, 1.37 mmol), acetonitrile (40 mL), 2-(bromomethyl)pyrazine dihydrochloride (500 mg, 2.03 mmol) and cesium carbonate (2.23 g, 6.84 mmol). The resulting mixture stirred overnight at 70° C. After cooling to room temperature, the reaction mixture was filtered and the filtrate was concentrated under reduced pressure. The residue was purified by preparative thin layer chromatography (eluting with 2:1, ethyl acetate/petroleum ether) to afford 2-[[4-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl]methyl]pyrazine (0.12 g, 31%) as red oil.

Workup

temperatureAfter cooling to room temperature
filtrationthe reaction mixture was filtered
concentrationthe filtrate was concentrated under reduced pressure
customThe residue was purified by preparative thin layer chromatography (eluting with 2:1, ethyl acetate/petroleum ether)

Sources & evidence

ORD record: ord-67c4249a9a6c45d8b003c4d2801ec294
Source dataset: uspto-grants-2016_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09422281B2

Reaction notes

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