Acetic Anhydride → 1-[2-(2-Dimethylamino-ethyl)-benzo[b]thiophen-3-yl]-ethanone
Reaction equation
Br[C:2]1[C:3]2[CH:15]=[CH:14][CH:13]=[CH:12][C:4]=2[S:5][C:6]=1[CH2:7][CH2:8][N:9]([CH3:11])[CH3:10].CN(C)CCN(C)C.[Li]CCCC.[CH3:29][C:30](OC(C)=O)=[O:31]>C1(C)C=CC=CC=1>[CH3:10][N:9]([CH3:11])[CH2:8][CH2:7][C:6]1[S:5][C:4]2[CH:12]=[CH:13][CH:14]=[CH:15][C:3]=2[C:2]=1[C:30](=[O:31])[CH3:29]Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- -78 °C
Procedure
Compound 2a, [2-(3-bromo-benzo[b]thiophen-2-yl)-ethyl]-dimethyl-amine (17.5 mmol), was dissolved in anhydrous toluene (180 mL) and cooled to −78° C. Tetramethylethylenediamine (17.5 mmol) was added followed by n-BuLi (21.0 mmol, 1.6 M in hexanes). The mixture was stirred for 45 min at −78° C. Ac2O (70 mmol) was added and the mixture was allowed to slowly reach RT and was stirred overnight. The mixture was quenched with sat. NH4Cl, the pH of the aqueous layer was adjusted to 7-8 with sat. NaHCO3, and the reaction mixture was extracted with EtOAc (4×). The combined organic layer was washed with brine, dried over MgSO4, filtered and concentrated in vacuo. The crude material was purified by silica gel column chromatography in CH2Cl2 with a gradient up to CH2Cl2/MeOH=94/6 to afford Compound 6a, 1-[2-(2-dimethylamino-ethyl)-benzo[b]thiophen-3-yl]-ethanone (2.18 g, 50%); MS (MH+)=248.1.
Workup
- customwas allowed to slowly reach RT
- stirringwas stirred overnight
- customThe mixture was quenched with sat. NH4Cl
- extractionthe reaction mixture was extracted with EtOAc (4×)
- washThe combined organic layer was washed with brine
- dry with materialdried over MgSO4
- filtrationfiltered
- concentrationconcentrated in vacuo
- customThe crude material was purified by silica gel column chromatography in CH2Cl2 with a gradient up to CH2Cl2/MeOH=94/6
Sources & evidence
- ORD record
- ord-78c864bf15404158849d6d20266b6fd8
- Source dataset
- uspto-grants-2008_07
- Patent number
- US07393865B2
Reaction notes
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