4-chloro-N-methoxy-N-methylbenzo[b]thiophene-2-carboxamide → 1-(4-Chlorobenzo[b]thien-2-yl)ethanone

HRID 240886Notes

Reaction equation

HRID 240886 reaction equation
[CH3:1][Mg+].[Br-].[Cl:4][C:5]1[C:13]2[CH:12]=[C:11]([C:14](N(OC)C)=[O:15])[S:10][C:9]=2[CH:8]=[CH:7][CH:6]=1>C1COCC1>[Cl:4][C:5]1[C:13]2[CH:12]=[C:11]([C:14](=[O:15])[CH3:1])[S:10][C:9]=2[CH:8]=[CH:7][CH:6]=1

Participants

4

Reactant 2

HCID 224738924-chloro-N-methoxy-N-methylbenzo[b]thiophene-2-carboxamideHCID 178418689HCID 178418689, compound

Product 1

HCID 123986281-(4-Chlorobenzo[b]thien-2-yl)ethanoneYield 86.9%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Add a solution of CH3MgBr (3 M in THF, 1.7 ml, 4.99 mmol) to a suspension of 4-chloro-N-methoxy-N-methylbenzo[b]thiophene-2-carboxamide (0.85 g, 3.33 mmol) in dry THF (10 mL) at 0° C. Then stir the mixture for overnight at ambient temperature. Quench the reaction with saturated NH4Cl aqueous solution (15 mL) and extract the aqueous mixture with EtOAc (10 mL×3). The combined organic layers are washed with brine, dried over anhydrous Na2SO4 and concentrated under vacuum. Purify the residue by silica gel chromatograph (PE:EtOAc=6:1) to afford 1-(4-chlorobenzo[b]thiophen-2-yl)ethanone as white solid (0.6 g, 86.9%). 1H NMR (400 MHz, CDCl3) δ 8.10-8.07 (s, 1H), 7.75 (d, J=5.2, 1H), 7.47-7.36 (m, 2H), 2.72-2.68 (s, 3H).

Workup

  1. customQuench
  2. customthe reaction with saturated NH4Cl aqueous solution (15 mL)
  3. extractionextract the aqueous mixture with EtOAc (10 mL×3)
  4. washThe combined organic layers are washed with brine
  5. dry with materialdried over anhydrous Na2SO4
  6. concentrationconcentrated under vacuum
  7. customPurify the residue by silica gel chromatograph (PE:EtOAc=6:1)

Sources & evidence

ORD record
ord-9423639a6cfa4555928ac81de8a15f6f
Source dataset
uspto-grants-2014_02
Patent number
US08648081B2

Reaction notes

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