ORGN 28 |
| Polystyrene-IIDQ is a polymer-supported coupling reagent synthesized in three steps from Merrifield resin in 86% overall conversion. This reagent couples carboxylic acids to amines in good yields and high purity without the requirement of a pre-activation step. Importantly the order of addition of the amine, acid or coupling agent makes no difference to the efficiency of the coupling reaction. PS-IIDQ is more efficient than commercially available polymer-supported carbodiimides PS-EDC and PS-DCC, and gives higher yields than HATU for general amide bond formation, including anilines and hindered substrates, such as aminoisobutyric acid or phenylglycine, even when employing an activation time for HATU. PS-IIDQ was also evaluated on a library of five carboxylic acids and ten amines, including secondary amines, giving an average isolated yield of 73%. Further characteristics of the reagent include stability under normal laboratory storage conditions and the possibility for easy recycling.
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Combinatorial, Parallel, and Solid-Phase Chemistry
8:00 AM-11:40 AM, Sunday, 13 March 2005 Convention Center -- Room 10, Oral
Division of Organic Chemistry |
