p-Toluenesulfonic acid → 3-[(5,6-Difluoro-2-methyl-4-oxo-4H-chromen-8-yl)methylene]pentane-2,4-dione

Participants

Reaction Steps

250 mg (1.12 mmol) of 5,6-difluoro-2-methyl-4-oxo-4H-chromene-8-carbaldehyde, 0.14 ml (1.34 mmol) of 2,4-pentanedione and 212.1 mg (1.12 mmol) of para-toluenesulfonic acid are heated in 100 ml of toluene under reflux with a water trap for 10 h. After cooling, 100 ml of ethyl acetate are added, and the reaction mixture is washed with water and with brine. Drying of the organic phase and concentration result in 269.7 mg (79% of theory) of the title compound as beige-coloured crystals.

Provenance & Evidence