54605-72-0

1126-00-7

68-12-2

54605-72-0

1) Add 7.3 g (0.1 mmol) of N,N-dimethylformamide (DMF) to a 250 mL three-necked flask and cool in an ice water bath with stirring. 15.4 g (0.1 mmol) of phosphorus triclosan was slowly added dropwise and stirring was continued for 1 hour after completion of the drop. Subsequently, 2.88 g (0.02 mmol) of 1-phenylpyrazole was added and the reaction was heated to 100°C and refluxed for 3-6 h. The reaction was monitored by TLC.2) Upon completion of the reaction, the reaction mixture was poured into ice-water and the pH was adjusted to neutral with sodium carbonate solution. It was extracted with ethyl acetate (3 x 50 mL), and the combined organic phases were washed with 50 mL of saturated brine.3) The organic phase was purified by column chromatography (the eluent was a solvent mixture of ethyl acetate and petroleum ether (60-90°C), 1:5, v/v/v), and was concentrated under reduced pressure to give 3.10 g of the white solid product, 1-phenyl-1H-pyrazole-4-carbaldehyde, in 90.0% yield.