Dimethylamine → 4-Fluoro-N,N-dimethyl-γ-oxobenzenebutanamide

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Reaction Steps

To a solution of 30.5 g (0.155 Mol) of 4-fluoro-γ-oxobenzenebutanoic acid in 470 ml tetrahydrofuran, 35.0 g (0.216 Mol) of N,N′-carbonyldiimidazole was added with stirring and at room temperature and held at room temperature for a further 2.5 hours. Then, 13.7 g (0.304 Mol) of dimethylamine was added under strong external cooling by means of an ice-ethanol mixture. After the mixture had stood at room temperature for 12 hours, the solvent was removed in vacuo, the residue was divided between dichloromethane and 10% aqueous citric acid solution, the organic phase was dried over sodium sulphate and once again evaporated down in vacuo. After purification by column chromatography (eluant:ethyl acetate) on silica gel the crude product yielded 30.22 g (87% of theory) of colourless crystals of Rf=0.31 (eluant:ethyl acetate/glacial acetic acid 99.99/0.01).

Provenance & Evidence