Benzo(B)Thiophene → 2-Acetylbenzo[b]thiophene

HRID 2183630Notes

Reaction equation

HRID 2183630 reaction equation
C([Li])CCC.[S:6]1[CH:10]=[CH:9][C:8]2[CH:11]=[CH:12][CH:13]=[CH:14][C:7]1=2.CON(C)[C:18](=[O:20])[CH3:19].[Cl-].[NH4+]>CCOCC>[S:6]1[C:10]([C:18](=[O:20])[CH3:19])=[CH:9][C:8]2[CH:11]=[CH:12][CH:13]=[CH:14][C:7]1=2

Participants

6

Reactant 4

HCID 7221Benzo(B)ThiopheneHCID 25517Ammonium ChlorideHCID 537505N-Methoxy-N-methylacetamideHCID 178418339Butyllithium

Product 1

HCID 898052-Acetylbenzo[b]thiopheneYield 57%

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent2×

Conditions

Temperature
-70 °C

Procedure

n-Butyllithium (1.6 M solution in hexanes; 74.6 ml) was added dropwise under nitrogen at 0° C. to a stirred solution of benzo[b]thiophene (25.0 g) in ether (350 ml), then the mixture cooled to −70° C. and a solution of N-methoxy-N-methylacetamide (19.21 g) in ether (100 ml) was added dropwise. The mixture was stirred at ambient temperature for 18 hours, then it was poured into saturated aqueous ammonium chloride solution (400 ml). The organic phase was separated, washed with water (300 ml) and saturated aqueous sodium chloride solution (300 ml), dried (Na2SO4) and the solvents were removed in vacuo. The residue was triturated with petroleum ether (b.p. 60-80° C.) (50 ml) and the resulting solid was collected by filtration and dried in vacuo to give 1-(benzo[b]thiophen-2-yl]ethan-1-one (18.7 g) as a brown solid, m.p. 78-81° C.

Workup

  1. customThe organic phase was separated
  2. washwashed with water (300 ml) and saturated aqueous sodium chloride solution (300 ml)
  3. dry with materialdried (Na2SO4)
  4. customthe solvents were removed in vacuo
  5. customThe residue was triturated with petroleum ether (b.p. 60-80° C.) (50 ml)
  6. filtrationthe resulting solid was collected by filtration
  7. customdried in vacuo

Sources & evidence

ORD record
ord-f607a3b6505d4778884eadc7ae9236f1
Source dataset
uspto-grants-2005_05
Patent number
US06900216B2

Reaction notes

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