Sodium Carbonate → Ethyl 2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl)propanoate

HRID 407026Notes

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.Br[CH:16]([CH3:22])[C:17]([O:19][CH2:20][CH3:21])=[O:18].C(=O)([O-])[O-].[Cs+].[Cs+].C([O-])([O-])=O.[Na+].[Na+]>C(#N)C>[CH3:1][C:2]1([CH3:14])[C:6]([CH3:7])([CH3:8])[O:5][B:4]([C:9]2[CH:13]=[N:12][N:11]([CH:16]([CH3:22])[C:17]([O:19][CH2:20][CH3:21])=[O:18])[CH:10]=2)[O:3]1

Participants

Conditions

Temperature: 90 °C

Procedure

A mixture of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (0.40 g, 2.1 mmol, Aldrich, Cat. 525057), ethyl 2-bromopropanoate (290 μL, 2.3 mmol), and cesium carbonate (1.5 g, 4.6 mmol) in acetonitrile (8 mL) was stirred at 90° C. for 4 h. After cooling, the reaction mixture was worked up with aqueous Na2CO3, extracted with ethyl acetate (3×20 mL), and washed with brine. The combined organic layers were dried over MgSO4, filtered and concentrated under reduced pressure. The residue was purified by flash chromatography on a silica gel column with ethyl acetate in hexanes (0-50%) to afford the desired product (0.42 g, 61%). LCMS (M+H)+: m/z=295.1.

Workup

temperatureAfter cooling
extractionextracted with ethyl acetate (3×20 mL)
washwashed with brine
dry with materialThe combined organic layers were dried over MgSO4
filtrationfiltered
concentrationconcentrated under reduced pressure
customThe residue was purified by flash chromatography on a silica gel column with ethyl acetate in hexanes (0-50%)

Sources & evidence

ORD record: ord-00cfaec1078d40d49742995cf4de3719
Source dataset: uspto-grants-2014_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08754114B2

Reaction notes

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