Potassium Hydroxide → HCID 54174755, compound

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Reaction Steps

A 500 ml., three-necked flask is fitted with reflux condenser, drying tube, stirrer and N2 inlet. To a mixture of 55.4 g. (0.39 mole) of 2,4-difluorobenzaldehyde and 56 ml. of propionic anhydride is added 38 g. (0.39 mole) of sodium propionate. The reaction mixture is heated at 135-140° (oil bath temp.) for 19 hours with stirring under nitrogen. The still warm solution is poured into 1 l. of water with stirring. A solid separates, which upon adding 56 g. of potassium hydroxide, dissolves. The solution is extracted with ether, and then heated on the steam bath to remove the ether. After cooling in an ice-bath, concentrated hydrochloric acid is added with stirring. The product which separates is collected and washed with cold water. After drying at 60° over KOH, 2,4-difluoro-α-methylcinnamic acid, M.P. 126-128° is obtained.

Provenance & Evidence