Ethanol → HCID 56637922, compound

Participants

Reaction Steps

40 ml of absolute ethanol and 0.75 g of p-toluenesulphonic acid are placed in a round flask which is fitted with a stirrer, thermometer, condenser and dropping funnel. Now, there are added dropwise within 15 minutes while stirring 120 g of p-methoxy-propiophenone and subsequently within 1 hour 108 g of triethyl orthoformate. The temperature is held below 3° C. The mixture is subsequently stirred for a further 22 hours at room temperature. The mixture is adjusted to pH 8 with 3.6 g of triethylamine and then poured into 40 ml of 5% bicarbonate solution and 60 g of ice. The aqueous phase is separated and extracted with ether. The combined organic phases are washed with 5% bicarbonate solution and, after the addition of 0.2 g of sodium carbonate, the solvent is removed by evaporation under a vacuum and the residue is distilled over a 15 cm column. There are obtained 36.7 g of p-methoxy-propiophenone diethyl ketal (yield: 21% of theory). B.p.= 83°-84° C./0.4 mmHg; nD20 =1.4858; d420 =0.9988.

Provenance & Evidence