Molecules (Jun 2022)

Carbodiimide-Mediated Beckmann Rearrangement of Oxyma-B as a Side Reaction in Peptide Synthesis

  • Andrea Orlandin,
  • Ivan Guryanov,
  • Lucia Ferrazzano,
  • Barbara Biondi,
  • Francesca Biscaglia,
  • Claudia Storti,
  • Marzio Rancan,
  • Fernando Formaggio,
  • Antonio Ricci,
  • Walter Cabri

DOI
https://doi.org/10.3390/molecules27134235
Journal volume & issue
Vol. 27, no. 13
p. 4235

Abstract

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The suppression of side reactions is one of the most important objectives in peptide synthesis, where highly reactive compounds are involved. Recently, the violuric acid derivative Oxyma-B was introduced into peptide synthesis protocols as a promising additive to efficiently control the optical purity of the amino acids prone to racemization. However, we discovered a side reaction involving the Beckmann rearrangement of Oxyma-B during the coupling reaction, which compromises the yield and purity of the target peptides. Here, we present the investigation of the mechanism of this rearrangement and the optimization of the coupling reaction conditions to control it. These results can be taken into account for the design of novel efficient oxime-based coupling reagents.

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