Hydrochloric Acid → Ethyl (1-hydroxy-3,3,5-trimethylcyclohexyl)acetate

Participants

Reaction Steps

300 ml of absolute ether, 150 ml of dry benzene and 170 g of magnesium shavings are added to a 6 liter flask which is fitted with a stirrer, thermometer, dropping funnel and reflux condenser. Now, there is introduced dropwise a mixture of 1.100 kg of dihydroisophorone and 960 g of ethyl chloroacetate dissolved in 1.200 l of ether and 600 ml of benzene. (If the reaction does not begin during the addition of the first 200 ml and warming at slight reflux does not begin spontaneously, then a few small crystals of iodine are added). The beginning of the reaction is recognizable by turbidity and heat-evolution. The addition of the reagents is continued in such a manner that the mixture boils only moderately, the addition being completed within 11/4 hours. Thereafter, the mixture is held at reflux temperature for a further 31/2 hours and, after cooling, added to 2.5 kg of ice and 1.2 l of concentrated hydrochloric acid. The organic phase is separated and washed with water (containing 1% concentrated hydrochloric acid), with water and several times more with 10% sodium carbonate solution. After evaporating the solvent in vacuo, there remain behind 1.69 kg of crude product which are distilled. The main fraction (1.250 kg) is washed with 10% sodium carbonate solution and again distilled (100° C./3 mm Hg). There are thus obtained 1.046 kg of ethyl 1-hydroxy-3,3,5-trimethyl-cyclohexylacetate.

Provenance & Evidence