Cesium carbonate → ethyl 2-methyl-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl)propanoate

HRID 2400346Notes

Reaction equation

[CH3:1][C:2]1([CH3:14])[C:6]([CH3:8])([CH3:7])[O:5][B:4]([C:9]2[CH:10]=[N:11][NH:12][CH:13]=2)[O:3]1.C(=O)([O-])[O-].[Cs+].[Cs+].[CH2:21]([O:23][C:24](=[O:29])[C:25](Br)([CH3:27])[CH3:26])[CH3:22]>CN(C=O)C>[CH2:21]([O:23][C:24](=[O:29])[C:25]([CH3:27])([N:12]1[CH:13]=[C:9]([B:4]2[O:5][C:6]([CH3:7])([CH3:8])[C:2]([CH3:14])([CH3:1])[O:3]2)[CH:10]=[N:11]1)[CH3:26])[CH3:22]

Participants

Conditions

Temperature: 90 °C

Procedure

To a stirred mixture of 4-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (5.0 g, 25.8 mmol) and Cesium carbonate (12.6 g, 38.7 mmol) in dry DMF (50 ml) was added 2-Bromo-2-methyl-propionic acid ethyl ester (5.5 g, 28.2 mmol). The reaction mixture was heated at 90° C. under N2 for 18 h, before being allowed to cool to room temperature. The mixture was partitioned between EtOAc and H2O, the organic layer separated and washed with H2O (×2) and brine (×1), dried (Na2SO4), filtered and the solvent removed in vacuo. This afforded the crude product as a yellow oil, which was used directly in the next step (4.7 g, 15.3 mmol).

Workup

temperatureto cool to room temperature
customThe mixture was partitioned between EtOAc and H2O
customthe organic layer separated
washwashed with H2O (×2) and brine (×1)
dry with materialdried (Na2SO4)
filtrationfiltered
customthe solvent removed in vacuo

Sources & evidence

ORD record: ord-f22afa26e12b4a7f821db3433fd1c82a
Source dataset: uspto-grants-2014_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08796244B2

Reaction notes

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