1-Bromo-2-methylpropane → 1-Isobutyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

HRID 2278711Notes

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].Br[CH2:16][CH:17]([CH3:19])[CH3:18].C([O-])([O-])=O.[Cs+].[Cs+]>C(#N)C>[CH2:16]([N:9]1[CH:8]=[C:7]([B:5]2[O:6][C:2]([CH3:14])([CH3:1])[C:3]([CH3:13])([CH3:12])[O:4]2)[CH:11]=[N:10]1)[CH:17]([CH3:19])[CH3:18]

Participants

Conditions

Temperature: 80 °C

Procedure

A mixture of 4-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (1 g, 5.15 mmol, 1.00 equiv), 1-bromo-2-methylpropane (1.05 g, 7.66 mmol, 1.49 equiv) and Cs2CO3 (3.36 g, 10.31 mmol, 2.00 equiv) in acetonitrile (60 mL) was stirred at 80° C. for 4 h. The reaction was cooled to room temperature and the solid material was removed by filtration. The filtrate was diluted with ethyl acetate (30 mL) and then washed with brine (40 mL). The organic layer was dried over anhydrous sodium sulfate and concentrated under vacuum to give 1.14 g (88%) of 1-iso-butyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole as a colorless oil. 1H-NMR (300 MHz, CDCl3): δ 7.78 (s, 1H), 7.65 (s, 1H), 3.91 (d, J=7.2 Hz, 2H), 2.24-2.19 (m, 1H), 1.32 (s, 12H), 0.90 (d, J=7.2 Hz, 6H) ppm. LCMS (method D, ESI): RT=1.51 min, m/z=251.0 [M+H]+.

Workup

temperatureThe reaction was cooled to room temperature
customthe solid material was removed by filtration
additionThe filtrate was diluted with ethyl acetate (30 mL)
washwashed with brine (40 mL)
dry with materialThe organic layer was dried over anhydrous sodium sulfate
concentrationconcentrated under vacuum

Sources & evidence

ORD record: ord-ac4921faaba1429bb78182d45702faad
Source dataset: uspto-grants-2015_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09133189B2

Reaction notes

Loading…