p-Toluenesulfonic acid → beta-Damascenone

참여 물질

반응 단계

In a 100 ml. three-necked flask fitted with a mechanical stirrer and a Dean-Stark water separator provided with a reflux condenser, a solution of 7 g. of 2,6,6-trimethyl-3-acetoxy-1-(3-acetoxy-but-1-ynyl)cyclohex-1ene in 70 ml. of methylene chloride is refluxed while stirring. Then 0.7 g. of p-toluenesulfonic acid is added and the reaction mixture is refluxed for an additional 7 hours. The reaction mixture is cooled and then poured into 70 ml. of water. The organic layer is separated, washed with 10% sodium bicarbonate solution and water. Drying over sodium sulfate and subsequent concentration yields 5 g. of a residue which gives, upon distillation using a short Vigreux column, 3 g. or 60% yield of 1-crotonoyl-2,6,6-trimethylcyclohexa-1,3-diene, b.p. 75°-80° C./0.1 mm, nD20 1.5150.

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