title: A novel oxidative dimer from protocatechuic esters: contribution to the total radical scavenging ability of protocatechuic esters.
abstract: A novel oxidative dimer was isolated as a major product from a reaction mixture of methyl protocatechuate and DPPH radical in methanol. Its unusual benzobicyclo[3.2.1]octane structure was elucidated by extensive spectral analysis. This result suggests that the regeneration of catechol structures by the nucleophilic addition of an alcohol molecule on o-quinones and subsequent dimerization is one of the key reactions in the high radical-scavenging activity of protocatechuic esters in an alcoholic solvent.
authors.affiliation: Laboratory of Food Biochemistry, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo, Japan.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Saito
authors.forename: Jun
authors.initials: J
authors.lastname: Kawabata
mesh_terms: D001713:Biphenyl Compounds / Q000737:chemistry*; D002396:Catechols / Q000737:chemistry; D019281:Dimerization; D016166:Free Radical Scavengers / Q000737:chemistry*; D006834:Hydrazines / Q000737:chemistry*; D062385:Hydroxybenzoates / Q000737:chemistry*; D015394:Molecular Structure; D016877:Oxidants / Q000138:chemical synthesis*; D010851:Picrates
chemical_list: D001713:Biphenyl Compounds; D002396:Catechols; D016166:Free Radical Scavengers; D006834:Hydrazines; D062385:Hydroxybenzoates; D016877:Oxidants; D010851:Picrates; C531013:protocatechuic acid methyl ester; C004931:1,1-diphenyl-2-picrylhydrazyl