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

HRID 2391980Notes

Reaction equation

Br[C:2]1[CH:3]=[C:4]([C:7]([OH:9])=[O:8])[S:5][CH:6]=1.C([O-])([O-])=O.[K+].[K+].CC1(C)COB([C:23]2[N:27]([CH3:28])[N:26]=[CH:25][CH:24]=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>[CH3:28][N:27]1[C:23]([C:2]2[CH:3]=[C:4]([C:7]([OH:9])=[O:8])[S:5][CH:6]=2)=[CH:24][CH:25]=[N:26]1

Participants

Conditions

Temperature: 80 °C

Procedure

To a solution of 4-bromo-2-thiophenecarboxylic acid (1 g, 4.83 mmol) in dioxane/H2O (5:1, 16 mL) was added K2CO3 (2.7 g, 19 mmol), tetrakistriphenylphosphine Pd(0) (279 mg, 0.241 mmol) and 5-(5,5-dimethyl-1,3,2-dioxaborinane-2-yl)-1-methyl-1H-pyrazole (1.2 g, 6.27 mmol). The reaction mixture was heated to 80° C. in a sealed tube for 2 h and additional tetrakistriphenylphosphine Pd(0) (279 mg, 0.241 mmol) and 5-(5,5-dimethyl-1,3,2-dioxaborinane-2-yl)-1-methyl-1H-pyrazole (1.2 g, 6.27 mmol) were added. After 12 h, the reaction was 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.): LCMS (ES) m/z=209 (M+H)+.

Workup

customthe reaction was 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-f56488e98c0245cd9acadc152202e8d6
Source dataset: uspto-grants-2012_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08273782B2

Reaction notes

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