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Structure of Two Oxidation Products of β‐Lumicolchicine: A Remarkable Reaction with Active Manganese Dioxide
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Titel: |
Structure of Two Oxidation Products of β‐Lumicolchicine: A Remarkable Reaction with Active Manganese Dioxide |
In: | Liebigs Annalen der Chemie, 1989, 1989, 11, S. 1075-1079 |
veröffentlicht: |
Wiley
|
Umfang: | 1075-1079 |
ISSN: |
0170-2041 |
DOI: | 10.1002/jlac.198919890271 |
Zusammenfassung: | <jats:title>Abstract</jats:title><jats:p>Two unusual reaction types of MnO<jats:sub>2</jats:sub> and of <jats:italic>m</jats:italic>‐chloroperbenzoic acid with the tetrasubstituted CC bond of β‐lumicolchicine (<jats:bold>1</jats:bold>‐β) are presented. Active MnO<jats:sub>2</jats:sub> oxidizes the 7a,10b cyclobutene double bond by adding a hydroxy group to the position 10b while the acetamido side chain is used to close a 2‐oxazoline ring in position 7a (<jats:bold>2</jats:bold>). <jats:italic>m</jats:italic>‐Chloroperoxybenzoic acid splits the cyclobutene ring of <jats:bold>1</jats:bold>‐β and forms a ketonic 1:1 adduct (<jats:bold>3</jats:bold>) instead of an epoxide. X‐ray structure analysis of <jats:bold>2</jats:bold> reveals <jats:italic>intermolecular</jats:italic> interaction between the hydroxy groups and the nitrogen atoms. 2D‐INADEQUATE <jats:sup>13</jats:sup>C‐NMR spectroscopy establishes structure <jats:bold>2</jats:bold> in solution, proves the structure of <jats:bold>3</jats:bold>, and allows also to assign the <jats:sup>13</jats:sup>C‐NMR signals of the tetracyclic skeleton of the stereoisomeric lumicolchicines <jats:bold>1</jats:bold>‐β and <jats:bold>1</jats:bold>‐γ. Furthermore, <jats:sup>13</jats:sup>C,<jats:sup>13</jats:sup>C coupling constants were determined for <jats:bold>2</jats:bold> and <jats:bold>3</jats:bold>.</jats:p> |
Format: | E-Article |
Quelle: | Wiley (CrossRef) |
Sprache: | Englisch |