Methyl iodide → 1-(1,2,4-Trimethyl-1H-pyrrol-3-yl)ethanone

Reaction equation

[C:1]([C:4]1[C:8]([CH3:9])=[CH:7][NH:6][C:5]=1[CH3:10])(=[O:3])[CH3:2].[H-].[Na+].I[CH3:14]>CN(C=O)C>[CH3:14][N:6]1[CH:7]=[C:8]([CH3:9])[C:4]([C:1](=[O:3])[CH3:2])=[C:5]1[CH3:10]

Participants

Procedure

A solution of 3-acetyl-2,4-dimethylpyrrole (2.0 g) in dry DMF (30 ml) was added dropwise, with stirring, to a suspension of sodium hydride (78% dispersion in oil; 565 mg) in dry DMF (15 ml) at 0° under nitrogen and stirring was continued at room temperature for 1 h. Iodomethane (1.14 ml) was added dropwise at 0° and stirring was continued for 1.5 h. The suspension was evaporated, treated with 8% aqueous sodium bicarbonate (80 ml) and extracted with ethyl acetate (2×80 ml). The combined, dried organic extracts were evaporated to give a solid (2.1 g) which was dissolved in dichloromethane (20 ml) and adsorbed onto silica gel (Merck 7734, 6 g). This was applied to an FCC column and elution with System B (1:3) afforded the title compound (1.89 g) as crystals, m.p. 68°-70°.