• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Total syntheses of ?-lactone containing natural products: I. total synthesis of belactosin C II. synthetic studies toward spongiolactone

Cho, Sung Wook 15 May 2009 (has links)
The recently isolated bacterial metabolites, belactosins A-C from a fermentation broth of Streptomyces sp. UCK14, uniquely contain a β-lactone dipeptide motif and exhibit anticancer activities. The enantioselective synthesis of (-)-belactosin C and derivatives was accomplished in a concise manner employing the tandem, Mukaiyama aldol-lactonizaton (TMAL) process and test their bioactivities. . One approach involved a distal double diastereoselective TMAL reaction with a dipeptide glyoxamide, whereas a second approach involved amide coupling of a dipeptide with a β-lactone carboxylic acid, obtained via the TMAL process employing a chiral silyl ketene acetal. Enzymatic assays showed that the belactosins act as the dual inhibitors of the proteasome and the thioesterase domain of fatty acid synthase. Spongiolactone which uniquely contains a cyclopentyl-fused β-lactone was isolated in 1986 from Spongi-onellagracilis No biological activity have been reported for this compound; however, the acylating potential of the resident β-lactone warrants screening for potential activity. After many setbacks in the synthesis of spongiolactone, significant progress has been made. Importantly, NCAL process also enabled a concise construction of [3.2.0]-bicyclo β-lactone, which is the key structure in the spongiolactone synthesis and only a few steps remained to complete the synthesis.

Page generated in 0.0395 seconds