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
Ethyl 2-Cyano-2-(hydroxyimino)acetate (Oxyma): An Efficient and Convenient Additive Used with Tetramethylfluoroformamidinium Hexafluorophosphate (TFFH) to Replace 1-Hydroxybenzotriazole (HOBt) and 1-Hydroxy-7-azabenzotriazole (HOAt) during Peptide Synthesis
作者:Sherine N. Khattab
DOI:10.1246/bcsj.20100075
日期:2010.11.15
The appropriateness of ethyl 2-cyano-2-(hydroxyimino)acetate (Oxyma) as a substitute for benzotriazole-basedadditives, for use in the TFFH approach for peptidesynthesis, is discussed in terms of ...
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