Water → 1-Ethynylcyclohexene

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Reaction Steps

21.5 g of ethynylcyclohexene are added dropwise to a suspension of 6 g of 80% strength sodium hydride in 200 ml of tetrahydrofuran under reflux, and the reaction mixture is kept under reflux conditions until no further gas is evolved. 28 g of 2,3,6-trimethyl-cyclohexanone are then added dropwise at room temperature and the mixture is left overnight, whilst being stirred, in order to complete the reaction. Water is added to the reaction mixture, the reaction product is taken up in ether and the ether solution is washed with water, dried and concentrated. Fractional distillation gives 9 g of unconverted ethynylcyclohexene, 8 g of starting ketone, and 22 g of 1-(2,3,6-trimethyl-1-hydroxy-cyclohexyl)-2-(cyclohex-1-en-1-yl)-acetylene of boiling point 120° C/0.1 mm Hg and refractive index nD25 = 1.5143. This corresponds to a yield of 68% of theory, based on trimethylcyclohexanone converted. Fragrance note: faint, tart, herbaceous.

Provenance & Evidence