ORGN 636 |
| Five membered ring heterocycles are important scaffolds in many biologically active compounds. Syntheses of such rings are carried out primarily by a reaction between open-chain bifunctional precursors and a heteroatom containing reagent (applying Knorr, Paal-Knorr synthesis or Lawesson reagent). In batch, these reactions take usually a long time (from 1 to 48 hours). The reaction rate can be accelerated by increasing the temperature. However, in many cases the reagents (e.g. hydrazine derivatives) decompose and form gaseous by-products which evolve in the reaction vessel. Application of high pressure hinders the formation of such by-products and raising the temperature increases the reaction rate. In the presentation we demonstrate the utility of a high temperature, high pressure continuous-flow reactor in the synthesis of various five-membered heterocyclic building blocks. It can heat and compress solutions up to 350°C and 200 bar, safely, thus, many conventional solvents can be made supercritical under these conditions. |
|
Heterocycles and Aromatics, Asymmetric Reactions and Syntheses and Total Synthesis of Complex Molecules
7:00 PM-9:00 PM, Wednesday, August 19, 2009 Walter E. Washington Convention Center -- Ballroom C, Poster
Division of Organic Chemistry |