Cesium carbonate → ethyl (2R)-2-methyl-4-(3-methyl-4-phenyl-1H-pyrazol-1-yl)-2-(methylsulfonyl)butanoate

HRID 2405919Notes

Reaction equation

[CH3:1][C:2]1[C:6]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)=[CH:5][NH:4][N:3]=1.C(=O)([O-])[O-].[Cs+].[Cs+].Br[CH2:20][CH2:21][C@@:22]([CH3:32])([S:28]([CH3:31])(=[O:30])=[O:29])[C:23]([O:25][CH2:26][CH3:27])=[O:24]>C1COCC1>[CH3:32][C@@:22]([S:28]([CH3:31])(=[O:29])=[O:30])([CH2:21][CH2:20][N:4]1[CH:5]=[C:6]([C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][CH:12]=2)[C:2]([CH3:1])=[N:3]1)[C:23]([O:25][CH2:26][CH3:27])=[O:24]

Participants

Conditions

Temperature: 70 °C

Procedure

To a solution of the 3-methyl-4-phenylpyrazole (400 mg, 2.53 mmol, 1 eq) in THF (25 mL) was added cesium carbonate (2.52 g, 7.70 mmol, 3 eq) and (R)-ethyl 4-bromo-2-methyl-2-(methylsulfonyl)butanoate (950 mg, 3.31 mmol, 1.3 eq). The resulting suspension was heated to 70° C. and stirred overnight. The reaction was filtered through celite, and the filter pad was washed with ethyl acetate (2×100 mL). Combined filtrates were concentrated and the crude material was purified on a Analogix SF15-24 g column using an eluant of ethyl acetate in heptane (0-80%) to give ethyl (2R)-2-methyl-4-(3-methyl-4-phenyl-1H-pyrazol-1-yl)-2-(methylsulfonyl)butanoate (178 mg, 19.3%). LC-MS M+H+365.1.

Workup

filtrationThe reaction was filtered through celite
washthe filter pad was washed with ethyl acetate (2×100 mL)
concentrationCombined filtrates were concentrated
customthe crude material was purified on a Analogix SF15-24 g column

Sources & evidence

ORD record: ord-926f536d45bc495998689291880df33e
Source dataset: uspto-grants-2014_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08809333B2

Reaction notes

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