title: Five phloroglucinol-monoterpene adducts from Eucalyptus grandis.
abstract: Five new euglobals possessing the phloroglucinol-monoterpene structure, euglobals G8-G12, together with a known euglobal-IIc were isolated from the hexane fraction of the methanol extract of the leaves of Eucalyptus grandis. Euglobal-G8 is an adduct of formyl-isovaleroyl-phloroglucinol and gamma-terpinene whereas -G9, -G10 and -G11 have the same phloroglucinol moiety fused with alpha-terpinene, while Euglobal-G12 has terpinolene fused with the same phloroglucinol moiety. The structures of these compounds were elucidated on the basis of spectral evidences. Biomimetic synthesis of euglobals suggests that these compounds are derived biogenetically by the Diels-Alder type cycloaddition of the corresponding terpenes with an ortho-quinone methide generated from grandinol.
authors.affiliation: Department of Applied Biological Chemistry, Shizuoka University, 836 Ohya, 422-8529, Shizuoka, Japan
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Umehara
authors.forename: Inder Pal
authors.initials: IP
authors.lastname: Singh
authors.forename: Hideo
authors.initials: H
authors.lastname: Etoh
authors.forename: Midori
authors.initials: M
authors.lastname: Takasaki
authors.forename: Takao
authors.initials: T
authors.lastname: Konoshima