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

HRID 1961011Notes

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 (1 g, 3.5 mmol) in dioxane/H2O (5:1, 18 mL) was added K2CO3 (1.9 g, 13.98 mmol), tetrakistriphenylphosphine Pd(0) (201 mg, 0.175 mmol) and 5-(5,5-dimethyl-1,3,2-dioxaborinane-2-yl)-1-methyl-1H-pyrazole (678 mg, 3.5 mmol). The reaction mixture was heated to 80° C. in a sealed tube for 12 h and was then partitioned between 6N NaOH and DCM. The pH of the aqueous phase was adjusted to ˜3 with 3M HCl and washed several times with DCM. The combined organic fractions were dried (Na2SO4), concentrated under vacuum and used directly without further purification (˜1 g, quant.): LC-MS (ES) m/z=288 (M+H)+.

Workup

customwas then partitioned between 6N NaOH and DCM
washwashed several times with DCM
dry with materialThe combined organic fractions were dried (Na2SO4)
concentrationconcentrated under vacuum
customused directly without further purification (˜1 g, quant.)

Sources & evidence

ORD record: ord-747ad90030374cf19675dfd330013c84
Source dataset: uspto-grants-2013_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08410158B2

Reaction notes

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