Water → E-1-crotonoyl-2,2,6-trimethylcyclohexane

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Reaction Steps

A solution of 320 g (1.5 moles) of the ketol prepared in Example 2 in 1000 ml of benzene containing 2 g p-toluene-sulphonic acid is heated in an apparatus for azeotropical water separation (Dean-Stark) till no more water separates. The reaction mixture is washed with a solution of sodium bicarbonate till neutral reaction and dried over anhydrous sodium sulfate. The solvent is removed by distillation at reduced pressure and the residue is distilled through a short Vigreux column. The product, cis, E-1-crotonoyl-2,2,6-trimethyl-cyclohexane (III, contains about 10% of the trans isomer) is collected at 76° C/1 mm; yield 273 g (94%). Recrystallization from pentane gives cis, E-1-crotonoyl-2,2,6-trimethylcyclohexane in high purity (m.p. 27°-28° C).

Provenance & Evidence