反应详情

28.4 g (0.2 mole) of 2-methyl-4-acetoxy-2-butenal is dripped into a mixture of 23.3 g (0.22 mole) of o-formic acid methyl ester, 12.8 g (0.4 mole) of methanol and 0.35 g (2millimoles) of p-toluene-sulfonic acid. Acetalization takes place while the temperature rises. After 1 hour 2 g (15 millimoles) of quinoline is added and the whole is heated at 185° to 190° C (internal temperature) and at a pressure of 200 mm Hg for 20 minutes The methanol which is eliminated is distilled off in a 20-cm column. Then the pressure is adjusted to 20 mm Hg with the result that 23.2 g of 1-acetoxy-3-methyl-4-methoxy-1,3-butadiene in the form of a mixture of two geometric iosmers is obtained. The yield is 75% of the theory.

1. temperaturethe whole is heated at 185° to 190° C (internal temperature)
2. distillationat a pressure of 200 mm Hg for 20 minutes The methanol which is eliminated is distilled off in a 20-cm column