High Yielding Preparation of a Stable Precursor of Hydroxytyrosol by Total Synthesis and from the Natural Glycoside Oleuropein

The unprecedented acetonide of the antioxidant hydroxytyrosol has been synthesized through a two-steps high yielding procedure and found both easy purificable by chromatography and stable in a wide range of pH. The protection stabilizes hydroxytyrosol against oxidation, so allowing long term storage, but can be quantitatively removed, under non-aqueous conditions, to afford free and pure hydroxytyrosol suitable for use as an additive in food and cosmetic preparations. Extension of the same methodology to the natural and easy accessible glycoside oleuropein, followed by saponification of the resulting complex mixture of acetonides, allowed the recovery of hydroxytyrosol acetonide in high yields. This constitutes a new interesting methodology to obtain the antioxidant hydroxytyrosol.