Lithium hydroxide, monohydrate → 4-Chlorobenzo(b)thiophene-2-carboxylic Acid

HRID 240884Notes

Reaction equation

HRID 240884 reaction equation
[Cl:1][C:2]1[C:10]2[CH:9]=[C:8]([C:11]([O:13]C)=[O:12])[S:7][C:6]=2[CH:5]=[CH:4][CH:3]=1.O[Li].O>CO.O>[Cl:1][C:2]1[C:10]2[CH:9]=[C:8]([C:11]([OH:13])=[O:12])[S:7][C:6]=2[CH:5]=[CH:4][CH:3]=1

Participants

5

Reactant 2

HCID 168937Lithium hydroxide, monohydrateHCID 22473622Methyl 4-chloro-1-benzothiophene-2-carboxylate

Product 1

HCID 38545164-Chlorobenzo(b)thiophene-2-carboxylic AcidYield 100%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 962WaterSolvent

Procedure

Stir a mixture of methyl 4-chlorobenzo[b]thiophene-2-carboxylate (1.0 g, 4.44 mmol) and LiOH—H2O (0.56 g, 13.3 mmol) in MeOH (30 mL) and water (10 mL) at room temperature overnight. Concentrate the reaction mixture under vacuum and then dilute the residue with ice water (20 mL). Acidify the aqueous mixture with conc. HCl solution to pH=1. Extract the resultant mixture with EtOAc (15 mL×3). The combined organic layers are washed with brine, dried over anhydrous Na2SO4 and evaporate under vacuum to afford 4-chlorobenzo[b]thiophene-2-carboxylic acid as a white solid (0.94 g, 100%). 1H NMR (400 MHz, CDCl3) δ 8.10-8.02 (m, 2H), 7.61-7.51 (m, 2H)

Workup

  1. concentrationConcentrate the reaction mixture under vacuum
  2. additiondilute the residue with ice water (20 mL)
  3. extractionExtract the resultant mixture with EtOAc (15 mL×3)
  4. washThe combined organic layers are washed with brine
  5. dry with materialdried over anhydrous Na2SO4
  6. customevaporate under vacuum

Sources & evidence

ORD record
ord-f0e0bfcd00a041c7b2f87bc5428300ad
Source dataset
uspto-grants-2014_02
Patent number
US08648081B2

Reaction notes

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