Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233736
Title: New synthetic strategies towards cephalotaxus alkaloids
Author: Gardiner, John Michael
Awarding Body: Durham University
Current Institution: Durham University
Date of Award: 1988
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Abstract:
Michael alkylation, with methyl acrylate, of nitrocyclohexenes bearing functionalized aromatic substituents at the 2-position, was found to be highly stereo selective. Subsequent dissolving metal reductive cyclization was highly efficient, and these two steps thus provided a stereo specific entry to a substituted 1-azaspirocyclic system, related to the cephalotaxine skeleton. Application of this methodology to trans-4-(3,4-dimethoxy-6-carbo- methoxyraethylphenyl)-5-nitrocyclohexene afforded spirolactam ester 6-(3,4-dimethoxy-6-carboraethoxymethylphenyl)-2-oxo-l-azaspiro[4.5]dec-8-ene. On reduction with DIBAL-H at -78ºC, this cyclized in high yield, with high stereoselectivity to the corresponding 3-benzazepine-2-ol system.Similar methodology with trans-4-(3,4-methylenedioxy-6-nitrophenyl) -5-nitrocyclohexene, allowed for a formaldehyde insertion reaction to provide a 1,3-benzodiazepine analogue. Preliminary studies hold promise for allowing modification of the cyclohexene ring to known pre-targets of cephalotaxine. These findings bring the synthetic strategy towards providing a competitive route to (±) cephalotaxine, and also a range of analogues, including the unknown 11-aza and 10-hydroxy-8-oxo systems.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.233736  DOI: Not available
Keywords: Organic chemistry
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