automated and manual synthesis, superior to those of HOBt and at least comparable to those of HOAt, and surpassing the latter coupling agent in the more demanding peptide models. Stability assays showed that there was no risk of capping the resin under standard coupling conditions. Finally, calorimetry assays (DSC and ARC) showed decomposition profiles for benzotriazole‐based additives that were consistent
Morpholine-Based Immonium and Halogenoamidinium Salts as Coupling Reagents in Peptide Synthesis<sup>1</sup>
作者:Ayman El-Faham、Fernando Albericio
DOI:10.1021/jo702622c
日期:2008.4.1
Here we describe a new family of N-form immonium-type coupling reagents that differ in their carbocation skeleton structure. The N-methylpiperazine derivative failed to form immonium salts, while the thiomorpholine derivative did not give better results than the coupling reagents currently used. The presence of the morpholine had a marked influence on the solubility and stability as well as the reactivity
new family of uronium salts (HTMU, HMMU, and HDmPyMU) based on isonitroso Meldrum's acid (HONM) are reported as stand-alone couplingreagents. Amide bond formation with the use of these reagents occurred more quickly than that with other uronium salts as a result of the presence of a neighboring group effect with a cyclic structure. Thus, these novel onium salts were often moreeffective in the acylation
situations a useful peptide coupling additive. Uronium and phosphonium salts with HODhat built into the system were also useful stand-alone couplingreagents. Comparisons with related additives and couplingreagents showed that the new systems were sometimes more and sometimes less effective than previously described systems in the case of stepwise and segment couplings. Applications to assembly of
BOP-OXy, BOP-OBt, and BOP-OAt: novel organophosphinic coupling reagents useful for solution and solid-phase peptide synthesis
作者:Ayman El-Faham、Sherine N. Khattab、Ramon Subirós-Funosas、Fernando Albericio
DOI:10.1002/psc.2579
日期:2014.1
Stand‐alone coupling reagents derived from bis(2‐oxo‐3‐oxazolidinyl)phosphorodiamidic chloride show efficient performance in solution and SPPS. In particular, the Oxyma Pure (Luxembourg Biotech., Tel Aviv, Israel) derivative shows the additional advantage of being highly soluble in DMF and even fairly soluble in CH3CN, which can extend its use for the synthesis of complex peptides. These new stand‐alone coupling