Triethylamine → 2-[(8-Difluoromethoxyquinolin-5-yl)carbonyl]-4,4,6,6-tetramethylcyclohexane-1,3,5-trione

Participants

Reaction Conditions

Reaction Steps

0.4 g (1.7 mmol) of 8-difluoromethoxy-5-quinolinecarboxylic acid was dissolved in 20 ml of acetonitrile, 0.4 g (1.9 mmol) of N,N-dicyclohexylcarbodiimide and 0.3 g (1.7 mmol) of 2,2,4,4-tetramethylcyclohexane-1,3,5-trione were added and the mixture was stirring at 25° C. for 20 hours. 0.4 g (4.0 mmol) of triethylamine and 2 drops of trimethylsilyl cyanide were then added, and stirring was continued at 30–35° C. for a further 3 hours. The precipitate was filtered off, and the filtrate was concentrated, 20 ml of 5% strength potassium carbonate solution were added and the mixture was washed with methyl tert-butyl ether. The aqueous phase was subsequently adjusted to pH 3 using concentrated hydrochloric acid and extracted with ethyl acetate. The solvent was removed and the residue was chromatographed over silica gel (mobile phase: methylene chloride/methanol). This gave 0.2 g of a colorless powder;

Provenance & Evidence