1.65 g (55 mmol) of sodium hydride (80% in oil) and 50 ml of DMF are introduced into a flask. A solution of 23.6 g (50 mmol) of allyl 2-hydroxy-4-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthoyl methoxy)benzoate in 200 ml of DMF is added dropwise and the mixture is stirred until evolution of gas has ceased. 6.3 ml (55 mmol) of 2-methoxy ethoxymethyl chloride are then added dropwise and the reaction mixture is stirred for 2 hours. It is poured into water and extracted with ethyl ether, and the organic phase is separated, dried over magnesium sulphate and evaporated. The residue obtained is purified by chromatography on a silica column, eluted with a mixture of dichloromethane/ethyl ether (98:2). After evaporation of the solvents, 19.2 g (69%) of the expected ester are collected in the form of a slightly yellow oil.
