The isoprostanes, a new class of natural products: Synthesis and biosynthesis
A new class of natural products called isoprostanes are formed in humans as a result of non-enzymatic free-radical-catalyzed lipid peroxidation. Isoprostanes possess biological activity and can be used as an index of five- radical lipid peroxidation and as a marker of oxidative stress. We report here a new and general synthetic methodology for the syntheses of isoprostanes, using the four key lactones which are constructed from D- and L-glucose by a thionocarbonate-mediated radical cyclization reaction. These lactose possess the required stereochemistry and the right functional groups for the syntheses of isoprostanes.
A novel synthesis of 12-epi-PGF2α 5 is described. The key synthon 11, which has been used as a starting point for the synthesis, is produced by a radical cyclization process using thionocarbonate 9a. The radical cyclization of 9a to 11 has been studied in some detail.