title: Syntheses of methylated catechins and theaflavins using 2-nitrobenzenesulfonyl group to protect and deactivate phenol.
abstract: An efficient and versatile synthetic method for labile polyphenols was established using 2-nitrobenzenesulfonate (Ns) as a protecting group for phenol. This methodology provides regio- and stereoselective access to a range of methylated catechins, such as methylated epigallocatechin gallates, that are not readily available from natural sources. In addition, biomimetic synthesis of theaflavins from catechins was accomplished using Ns protection to minimize undesired side reactions of electron-rich aromatic rings during oxidation, enabling construction of the complex benzotropolone core in a single-step oxidative coupling reaction. Availability of these compounds will aid detailed structure-biological activity relationship studies of catechins.
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Asakawa
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kawabe
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yoshida
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Aihara
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Tamiko
authors.initials: T
authors.lastname: Manabe
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Hirose
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Asuka
authors.initials: A
authors.lastname: Sakurada
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Inai
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Hamashima
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.|Institute for Chemical Research, Kyoto University, Kyoto, Japan.
authors.forename: Takumi
authors.initials: T
authors.lastname: Furuta
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.|Faculty of Pharmaceutical Sciences, Hokkaido University, Hokkaido, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Wakimoto
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kan
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D001557:Benzenesulfonates / Q000737:chemistry*; D044946:Biflavonoids / Q000138:chemical synthesis* / Q000737:chemistry; D002392:Catechin / Q000031:analogs & derivatives / Q000138:chemical synthesis* / Q000737:chemistry; D008745:Methylation; D010084:Oxidation-Reduction; D059808:Polyphenols / Q000138:chemical synthesis*; D013329:Structure-Activity Relationship
chemical_list: D000975:Antioxidants; D001557:Benzenesulfonates; D044946:Biflavonoids; D059808:Polyphenols; C508389:benzotropolone; C056068:theaflavin; D002392:Catechin; C045651:epigallocatechin gallate