Hydrochloric Acid → 5-(4-Carboxy-phenyl)-thiophene-2-carboxylic acid ethyl ester

HRID 545493Notes

Reaction equation

Br[C:2]1[S:6][C:5]([C:7]([O:9][CH2:10][CH3:11])=[O:8])=[CH:4][CH:3]=1.[C:12]([C:15]1[CH:20]=[CH:19][C:18](B(O)O)=[CH:17][CH:16]=1)([OH:14])=[O:13].C(=O)([O-])[O-].[K+].[K+].Cl>O.[Br-].C([N+](CCCC)(CCCC)CCCC)CCC.C([O-])(=O)C.[Pd+2].C([O-])(=O)C>[CH2:10]([O:9][C:7]([C:5]1[S:6][C:2]([C:18]2[CH:19]=[CH:20][C:15]([C:12]([OH:14])=[O:13])=[CH:16][CH:17]=2)=[CH:3][CH:4]=1)=[O:8])[CH3:11]

Participants

Conditions

Temperature: 70 °C

Procedure

Ethyl 5-bromothiophene-2-carboxylate (318 mg, 1.35 mmol) and 4-carboxyphenyl boronic acid (203 mg, 1.23 mmol) were suspended in 1 mL of water under nitrogen atmosphere. Tetrabutylammonium bromide (403 mg, 1.25 mmol), palladium acetate (2 mg, 0.009 mmol) and potassium carbonate (422 mg, 3.05 mmol) were added and the mixture stirred at 70° C. for 1 h. The solution was brought to pH 2 by addition of 1M HCl and the product extracted into 10% MeOH in EtOAc. The organic phase was dried and the solvent was removed. The solid was tritured with ethyl acetate, leaving a solid product. 1H-NMR (CDCl3): δ=7.99 (d, J=8.6 Hz, 2H), 7.88 (d, J=8.6 Hz, 2H), 7.83 (d, J=4 Hz, 1H), 7.49 (d, J=4 Hz, 1H), 4.31 (q, J=7.4 Hz, 2H), 1.31 (t, J=7.4 Hz, 3H). MS (EI): cal'd 277 (MH+), exp 277 (MH+).

Workup

extractionthe product extracted into 10% MeOH in EtOAc
customThe organic phase was dried
customthe solvent was removed
customleaving a solid product

Sources & evidence

ORD record: ord-6ce7d7380d68476bb949f815a9d0cdbd
Source dataset: uspto-grants-2011_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07935724B2

Reaction notes

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