Potassium Carbonate → methyl 4-(1-ethyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate

HRID 1845425Notes

Reaction equation

HRID 1845425 reaction equation
Br[C:2]1[CH:3]=[C:4]([C:7]([O:9][CH3:10])=[O:8])[S:5][CH:6]=1.C([O-])([O-])=O.[K+].[K+].[CH2:17]([N:19]1[C:23](B2OC(C)(C)C(C)(C)O2)=[CH:22][CH:21]=[N:20]1)[CH3:18]>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>[CH2:17]([N:19]1[C:23]([C:2]2[CH:3]=[C:4]([C:7]([O:9][CH3:10])=[O:8])[S:5][CH:6]=2)=[CH:22][CH:21]=[N:20]1)[CH3:18]

Participants

6

Reactant 3

HCID 11430Potassium CarbonateHCID 12752071Methyl 4-bromothiophene-2-carboxylateHCID 532172521-Ethylpyrazole-5-boronic acid, pinacol ester

Product 1

HCID 67066137methyl 4-(1-ethyl-1H-pyrazol-5-yl)-2-thiophenecarboxylateYield 66%

Reagents, catalysts & solvents 2

HCID 178418397HCID 178418397, compoundCatalystHCID 218864351,4-Dioxane--water (1/1)Solvent

Conditions

Temperature
70 °C

Procedure

To a solution of methyl 4-bromo-2-thiophenecarboxylate (1.0 g, 4.52 mmol) in dioxane/H2O (5:1, 6 mL) was added K2CO3 (1.86 g, 13.5 mmol), tetrakistriphenylphosphine Pd(0) (260 mg, 0.23 mmol) and 1-ethyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (1.3 g, 5.85 mmol). The reaction mixture was heated to 70° C. in a sealed tube. After 2 h, the reaction mixture was concentrated under vacuum and purified on silica (hex/EtOAc, 20-40%) to afford methyl 4-(1-ethyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (0.7 g, 66%) as a light yellow solid: LC-MS (ES) m/z=237 (M+H)+.

Workup

  1. concentrationthe reaction mixture was concentrated under vacuum
  2. custompurified on silica (hex/EtOAc, 20-40%)

Sources & evidence

ORD record
ord-5852322e9ad3419d8a8bbc410f7eec8a
Source dataset
uspto-grants-2015_02
Patent number
US08946278B2

Reaction notes

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