A Combination of Different Spectroscopic Techniques to Monitor the ™in situ ∫ Solid-phase Synthesis of Organic Molecules

The efficacy, limitations and scope of different spectro-scopic techniques to monitor solid-phase syntheses are discussed. The total solid-phase synthesis of a natural product derivative, 3,17-di-O-acetyllamellarin U, has been monitored by gel-phase NMR and HR-MAS NMR as appropriate. FT-IR and colorimetric tests also proved to be valuable tools for monitoring the progress of reactions. While the data obtained by FT-IR provided valuable information on some functional groups, the NMR data provided more specific structural information that allowed the progress of reactions to be monitored. After several reaction steps the ™aging ∫ of the resin only allowed the product covalently anchored to the resin to be investigated using an HR-MAS probe, a situation that severely limited the depth of analysis available.