This work involves studies of hydrogen-bonded materials that serve as catalysts and/or additives for the solid-phase synthesis of peptides; we obtained large quantities of these materials from a collaborator at PerSeptive Biosystems, Dr. Steve Kates. This work may be viewed as an important "spin-off" from our studies of hydrogen-bonded cocrystals. The most surprising result has been the discovery that the most-used additives for solid-phase peptide synthesis, HATU and HBTU do not have the uronium salt structures 1,2 proposed in the literature for over two decades but rather ar guanidinium N-oxides 3,4 !
This result has created quite a stir among workers in solid-phase peptide synthesis. Note below the structures of the guanidinium cations for 3 and 4. Despite the fact that these two materials have quite different crystal structures, the molecular structures of the guanidinium N-oxide cations are virtually identical!
This material is based upon work supported by the National Science Foundation under Grant No. DMR-0089257. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation (NSF).