- Chemical Transformation of Protoberberines. I. Conversion of Tetrahydroberberine and Dihydroberberine into Noroxyhydrastinine by Photooxygenation
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Simple and biomimetic conversions of tetrahydroberberine (1) and dihydroberberine (6) into noroxyhydrastinine (3), an isoquinolone alkaloid, are described.Photooxygenation of 1 afforded berberal (2), 3, and O-methylpseudopianic acid (4).The same products were obtained more efficiently by photooxygenation of 6.Keywords-photooxygenation; singlet oxygen; biomimetic conversion; protoberberine alkaloid; tetrahydroberberine; dihydroberberine; isoquinolone alkaloid; noroxyhydrastinine
- Hanaoka, Miyoji,Mukai, Chisato,Hamanaka, Itsuko,Seki, Kazue,Arata, Yoshio
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p. 2793 - 2796
(2007/10/02)
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- Reaction of Protoberberine-type Alkaloids. Part 13. Biogenetic Conversion of Protoberberine Alkaloids into Phthalideisoquinoline Alkaloids
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A new convenient and biogenetic-type conversion of the protoberberine alkaloids into the phthalideisoquinoline alkaloids is described.The phthalideisoquinoline 5,6-dimethoxy-3-(6,7-dimethoxyisoquinolin-1-yl)isobenzofuran-1(3H)-one (4) was derived from 8-norcoralyne chloride (1) via 13-oxidonorcoralyne (3) in a one-pot reaction consisting of dye-sensitized photo-oxygenation followed by treatment with sodium borohydride.The conversion of berberine chloride into (+/-)-β-hydrastine (21) was performed by a reaction sequence involving conversion of 8,13a-epidioxy-9,10-dimethoxy- 2,3-methylenedioxy-13-oxo-5,6,13,13a-tetrahydro-8H-dibenzoquinolizine (9) into 1-(2-carboxy-3,4-dimethoxybenzoyl)-3,4-dihydro-6,7-(methylenedioxy)isoquinoline (11) using pyridinium chloride, followed by methylation and reductive cyclization.
- Kondo, Yoshikazu,Imai, Jiro,Nozoe, Shigeo
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p. 919 - 926
(2007/10/02)
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