3-Trifluoromethylthio-benzoyl chloride → 3-Trifluoromethylthio-benzaldehyde

関与物質

反応手順

A solution of 56.9 g (237 mmols) of 3-trifluoromethyl-thiobenzoic acid chloride in 285 ml of anhydrous toluene and 5.7g of 5 percent strength palladium on barium sulphate is introduced into a 1 liter three-necked flask equipped with a condenser, a mechanical stirrer and a gas bubbler tube. This mixture is heated, with stirring, for 12 hours at the reflux temperature, while a gentle stream of hydrogen is bubbled through it. The catalyst is filtered off and washed with diethyl ether. 125 ml of a solution of sodium bisulphite (d = 1.33) are added to the filtrate. This mixture is stirred vigorously for 24 hours and the bisulphite compound is filtered off, washed with diethyl ether and introduced into a three-necked flask. A solution of 80 g of potassium carbonate in 500 ml of water is added and the mixture is boiled, so as to steam distill the aldehyde as it is formed. The distillate is extracted twice in succession with diethyl ether. The combined ether phases are dried over sodium sulphate and filtered. The solvent is evaporated in vacuo on a water bath and the residue is rectified. 33.3g (67 % yield) of 3-trifluoromethylthio-benzaldehyde, as an oil, b.p. 108°-111° C./30-38 mm.Hg, are thus obtained.

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