Water → HCID 11264226, compound

Participants

Reaction Steps

121.6 g of crude (1R,4S,5R)-4-ethynyl-4-hydroxy-3,3,5-trimethylcyclohexyl acetate (prepared according to Example 9) were dissolved in 1 l of o-xylene under argon in a sulphonation flask having a water separator. The mixture was treated with 7.9 g of copper(II)sulphate and boiled and stirred intensively for 2 hours under reflux and with the separation of water. The reaction mixture was subsequently cooled to room temperature and the insoluble copper sulphate was filtered off (rinsing with 400 ml of hexane). The filtrate was washed with 400 ml of water and with 400 ml of semi-saturated sodium bicarbonate solution. The wash solutions were back-extracted twice with 300 ml of hexane each time. The organic phases were dried over sodium sulphate and filtered. The filtrate was concentrated to a volume of about 200-300 ml in a rotary evaporator at 80 Torr and 40°-60° C. bath temperature. Distillation of the residual xylene solution in a high vacuum gave at about 83° C./0.19- 0.09 Torr 96.5 g of (R)-4-ethynyl-3,5,5-trimethyl-3-cyclohexen-1-yl acetate (purity 98.1%) as a colourless oil; boiling point 78°-82° C./0.14 Torr. The chemical yield amounted to 93% based on (4R,6R)-4-hydroxy-2,2,6-trimethylcyclohexanone.

Provenance & Evidence