Author: David James Barden
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Studies Directed Towards the Synthesis of (-)-ebelactone-A.
Author: David James Barden
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Studies Directed Towards the Synthesis of ( - )-Ebelactone-A.
Author: Colin Frederick Foster
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
This thesis describes work concerning the total synthesis of ebelactone-a 16, and in particular the synthesis of one of the retrosynthetic fragments (fragment A 20) and its coupling to the combined fragment BC 115 formed from the other two. We repeated the synthesis of enantiomerically enriched 20 devised by Williams, employing a Mukaiyama aldol reaction directed by Oppolzer's sultam to establish the anti-anti stereotriad of the fragment. We modelled the coupling of this to 115 using isobutyraldehyde in place of 20 and vinyl iodide 133 in place of 115, and verified that the Nozaki-Kishi method using chromium(II) chloride and catalytic nickel(II) chloride was effective. By this method, we successfully coupled 133 to 20. Model work was unsuccessful in establishing a methodology for removing the hydroxy group from alcohols 188/189 without disrupting either the position or geometry of the adjacent C=C bond. We also established a completely new route to fragment A, utilising the features of organosilicon chemistry to control the stereochemistry. An intermediate 213 containing two different silyl groups, in which we hoped to transform one selectively into a hydroxy group with retention of configuration by Fleming's method, proved too unstable for synthesis, but we were able to modify the route and produce alcohol 254 in enantiomerically pure form (Oppolzer's sultam was once again used as the chiral auxiliary), and we expect future workers to be able to take this through to fragment A.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
This thesis describes work concerning the total synthesis of ebelactone-a 16, and in particular the synthesis of one of the retrosynthetic fragments (fragment A 20) and its coupling to the combined fragment BC 115 formed from the other two. We repeated the synthesis of enantiomerically enriched 20 devised by Williams, employing a Mukaiyama aldol reaction directed by Oppolzer's sultam to establish the anti-anti stereotriad of the fragment. We modelled the coupling of this to 115 using isobutyraldehyde in place of 20 and vinyl iodide 133 in place of 115, and verified that the Nozaki-Kishi method using chromium(II) chloride and catalytic nickel(II) chloride was effective. By this method, we successfully coupled 133 to 20. Model work was unsuccessful in establishing a methodology for removing the hydroxy group from alcohols 188/189 without disrupting either the position or geometry of the adjacent C=C bond. We also established a completely new route to fragment A, utilising the features of organosilicon chemistry to control the stereochemistry. An intermediate 213 containing two different silyl groups, in which we hoped to transform one selectively into a hydroxy group with retention of configuration by Fleming's method, proved too unstable for synthesis, but we were able to modify the route and produce alcohol 254 in enantiomerically pure form (Oppolzer's sultam was once again used as the chiral auxiliary), and we expect future workers to be able to take this through to fragment A.
Studies Towards the Synthesis of -Ebelactone-A And -Maurenone
Author: Ravindar Kontham
Publisher: LAP Lambert Academic Publishing
ISBN: 9783848449583
Category :
Languages : en
Pages : 164
Book Description
This monograph features the studies directed towards the total synthesis of architecturally and biologically interesting polypropionate natural products (-)-Ebelactone-A and (-)-Maurenone utilizing desymmetrization as a key strategy. ( )-Ebelactone A, show structural characteristics in common with macrolide antibiotics. Ebelactones act as potent inhibitors of esterase s, lipases and N-formylmethionine amino peptidases, and they have shown to produce enhance immune responses. They are also reported to inhibit cutinases produced by fungal pathogens. Novel biological activity combined with unique and challenging structure of Ebelactone, made this compound an exciting target for the total synthesis. Secondly, this book described an efficient synthetic protocol for polypropionate natural product (-)-Maurenone, which was isolated by Faulkner et al. in 1986 from specimens of the pulmonate mollusc Siphonaria maura. This monograph is unique in dealing with many interesting synthetic protocols including full experimental procedures, analytical data for all synthetic materials and complete reference sections. This monograph can be served as a good hand book for synthetic organic chemists.
Publisher: LAP Lambert Academic Publishing
ISBN: 9783848449583
Category :
Languages : en
Pages : 164
Book Description
This monograph features the studies directed towards the total synthesis of architecturally and biologically interesting polypropionate natural products (-)-Ebelactone-A and (-)-Maurenone utilizing desymmetrization as a key strategy. ( )-Ebelactone A, show structural characteristics in common with macrolide antibiotics. Ebelactones act as potent inhibitors of esterase s, lipases and N-formylmethionine amino peptidases, and they have shown to produce enhance immune responses. They are also reported to inhibit cutinases produced by fungal pathogens. Novel biological activity combined with unique and challenging structure of Ebelactone, made this compound an exciting target for the total synthesis. Secondly, this book described an efficient synthetic protocol for polypropionate natural product (-)-Maurenone, which was isolated by Faulkner et al. in 1986 from specimens of the pulmonate mollusc Siphonaria maura. This monograph is unique in dealing with many interesting synthetic protocols including full experimental procedures, analytical data for all synthetic materials and complete reference sections. This monograph can be served as a good hand book for synthetic organic chemists.
Studies Towards the Synthesis of Ebelactone B.
Author: Rhonan Lee Ford
Publisher:
ISBN:
Category :
Languages : en
Pages : 284
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 284
Book Description
Approaches Towards the Synthesis of Ebelactone-a Using Organosilicon Chemistry
Author: Sarah Catherine Archibald
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Approaches to the Synthesis of Ebelactone-A
Author: Anna Beatrice Zwicky
Publisher:
ISBN:
Category : Organic compounds
Languages : en
Pages : 81
Book Description
Publisher:
ISBN:
Category : Organic compounds
Languages : en
Pages : 81
Book Description
Part A. Studies Directed Towards the Total Synthesis of (±) A-23187 ; Part B. Formal Total Synthesis of (±) A-23187
Author: Eric L. Williams
Publisher:
ISBN:
Category : Organic compounds
Languages : en
Pages : 164
Book Description
Publisher:
ISBN:
Category : Organic compounds
Languages : en
Pages : 164
Book Description
Approaches Towards the Synthesis of Ebelactone A Using Silicon Reagents
Author: Jerome Fernand Yves Bazin
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Studies Directed Towards the Synthesis of Irroratin A and Studies Directed Towards the Synthesis of Rocaglamide and Silvestrol
Author: Trevor James Rainey
Publisher:
ISBN: 9780549016618
Category :
Languages : en
Pages : 245
Book Description
The use of a Nazarov reaction for the diastereoselective synthesis of silvestrol and rocaglamide was also studied. A model compound lacking the 6,8-oxygenation present in the natural products was synthesized and subjected to a variety of Lewis and Bronsted acids; in all cases no Nazarov cyclization was observed, but rather (typically) retro Friedel-Crafts acylation. In an attempt to bias the reaction towards the desired pathway more activated substrates were made; however, cyclization was again unsuccessful.
Publisher:
ISBN: 9780549016618
Category :
Languages : en
Pages : 245
Book Description
The use of a Nazarov reaction for the diastereoselective synthesis of silvestrol and rocaglamide was also studied. A model compound lacking the 6,8-oxygenation present in the natural products was synthesized and subjected to a variety of Lewis and Bronsted acids; in all cases no Nazarov cyclization was observed, but rather (typically) retro Friedel-Crafts acylation. In an attempt to bias the reaction towards the desired pathway more activated substrates were made; however, cyclization was again unsuccessful.
Studies Directed Towards the Total Synthesis of the Natural Products Avarol and Capentin
Author: Thomas Elliott Jacks
Publisher:
ISBN:
Category :
Languages : en
Pages : 406
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 406
Book Description