Potassium Carbonate → 4-bromo-5-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylic Acid

HRID 1961179Notes

Reaction equation

[Br:1][C:2]1[CH:3]=[C:4]([C:8]([OH:10])=[O:9])[S:5][C:6]=1Br.C([O-])([O-])=O.[K+].[K+].CC1(C)COB([C:24]2[N:28]([CH3:29])[N:27]=[CH:26][CH:25]=2)OC1>O1CCOCC1.O.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1>[Br:1][C:2]1[CH:3]=[C:4]([C:8]([OH:10])=[O:9])[S:5][C:6]=1[C:24]1[N:28]([CH3:29])[N:27]=[CH:26][CH:25]=1

Participants

Conditions

Temperature: 80 °C

Procedure

To a solution of 4,5-dibromo-2-thiophenecarboxylic acid (3.30 g, 11.54 mmol) in dioxane/H2O (4:1, 100 mL) was added K2CO3 (5.5 g, 40.0 mmol), tetrakistriphenylphosphine Pd(0) (671 mg, 0.58 mmol) and 5-(5,5-dimethyl-1,3,2-dioxaborinane-2-yl)-1-methyl-1H-pyrazole (2.66 g, 13.71 mmol). The reaction mixture was heated to 80° C. in a sealed tube for 12 hours. The reaction mixture was partitioned between H2O and CHCl3. The pH of the aqueous phase was adjusted to ˜3 with 6N HCl and washed several times with CHCl3. The combined organic fractions were dried (Na2SO4), concentrated under vacuum and used directly without further purification (3.3 g, quant.): LC-MS (ES) m/z=289 (M+H)+.

Workup

customThe reaction mixture was partitioned between H2O and CHCl3
washwashed several times with CHCl3
dry with materialThe combined organic fractions were dried (Na2SO4)
concentrationconcentrated under vacuum
customused directly without further purification (3.3 g, quant.)

Sources & evidence

ORD record: ord-9f8880d85ea64552abd879463e132733
Source dataset: uspto-grants-2013_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08410158B2

Reaction notes

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