A mixture of sodium acrylate (2.5 g, 13.4 mmol), 4′-propyl-bicyclohexyl-4-carboxylic acid 3-bromo-propyl ester (synthesis described for preferred example 1) (5.0 g, 13.4 mmol) and sodium iodide (2.5 g, 16.7 mmol) in dimethylformamide (150 ml) is stirred at 130° C. overnight. The mixture is cooled to room temperature, poured into water, and this is extracted twice with diethyl ether. The ethereal solution is washed with water and then dried over sodium sulphate. The solution is evaporated to dryness and purified by flash column chromatography using DCM/petrol (1/1) as eluant to give upon evaporation of the appropriate fractions a colourless oil.
