Oxidative chemistry of hydroxytyrosol: isolation and characterisation of novel methanooxocinobenzodioxinone derivatives

Autoxidation or tyrosinase-catalysed oxidation of the natural antioxidant hydroxytyrosol (1) in phosphate buffer at pH 7.4 leads to the formation of two main regioisomeric products which could be isolated and identified as the novel methanooxocinobenzodioxinone derivatives 2a,b by extensive spectral analysis.