- FUMARIACEAE ALKALOIDS INCLUDING THE BIOGENETIC PRECURSOR OF CULARINE
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Key Word Index - Corydalis claviculata; Fumariaceae;benzylisoquinoline alkaloids; cularines; (+)-crassifoline; (+)-sarcocapnidine; (+)-claviculine; (+)-O-methylcularicine. - Corydalis claviculata has yielded (+)-crassifoline, the first 7,8,3',4'-oxygenated benzylisoquinoline and biogenetic precursor of cularine, as well as the new cularine alkaloids (+)-sarcocapnidine, (+)-claviculine and (+)-O-methylcularicine.
- Blaschke, Gottfried,Scriba, Gerhard
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- Total Synthesis of (S)-Cularine via Nucleophilic Substitution on a Catechol
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Catechols are part of many essential chemicals and are valuable, typically nucleophilic intermediates used in synthesis. Here we describe an unexpected transformation in which they play the role of the electrophile in a formal nucleophilic aromatic substitution. We made this discovery while studying a seven-membered dioxepin ring formation during a synthesis of the benzyltetrahydroisoquinoline (S)-cularine. We suggest a chain mechanism for this new transformation that is triggered by molecular oxygen and that propagates an electrophilic ortho-quinone.
- Huang, Zheng,Ji, Xiang,Lumb, Jean-Philip
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p. 236 - 241
(2021/01/09)
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- Diastereoselective Synthesis of Cularine Alkaloids via Enium Ions and an Easy Entry to Isoquinolines by Aza-Wittig Electrocyclic Ring Closure
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In preliminary communications, we reported the diastereoselective synthesis of cularine and sarcocapnine via the intramolecular ring closure of nitrenium and oxenium ions, a new highly diastereoselective reductive methylation with (+)-8-phenylmenthyl chloroacetate followed by reduction with sodium borohydride, and a facile entry to the isoquinoline precursors by aza-Wittig electrocyclic ring closure. We now report the full details of the syntheses of (+)-O-demethylcularine, (+)-cularine, (+)-sarcocapnidine, (+)-sarcocapnine, and (+)-crassifoline and describe different methods of synthesis of their precursors.
- Rodrigues, J. Augusto R.,Abramovitch, Rudolph A.,De Sousa, Joana D. F.,Leiva, Genaro C.
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p. 2920 - 2928
(2007/10/03)
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