Solid Phase Chemistry: Direct Monitoring by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry. A Tool for Combinatorial Chemistry

In lieu of an abstract, this is the article's first paragraph. The rapid development of combinatorial chemistry has remarkably increased the complexities of the reactions carried out on the solid phase. This is clearly illustrated by the wide spread use of allyl chemistry in peptide cyclizations the recent reports of aldol, Suzuki, and Diels-Alder reactions on the solid phase as well as the ever increasing use of the solid phase for the synthesis of peptide mimetics, e.g., peptoids. This has brought with it a need to provide a simple and efficient means of monitoring and analyzing such reactions at the molecular level. One such approach has been the highly success-fully analysis of derivatized beads by both proton9 and carbon-13 NMR. Another ideal time and material efficient means of following solid phase reactions would be the direct mass spectrometric analysis from the solid support. Mass spectrometry, a considerably more sensi-tive analytical tool than other conventional techniques, such as NMR and IR, would provide us with the power to obtain the required information from just a single resin bead.