66852-01-5Relevant academic research and scientific papers
Site-Selective, Late-Stage C?H 18F-Fluorination on Unprotected Peptides for Positron Emission Tomography Imaging
Yuan, Zheliang,Nodwell, Matthew B.,Yang, Hua,Malik, Noeen,Merkens, Helen,Bénard, Fran?ois,Martin, Rainer E.,Schaffer, Paul,Britton, Robert
supporting information, p. 12733 - 12736 (2018/09/12)
Peptides are often ideal ligands for diagnostic molecular imaging due to their ease of synthesis and tuneable targeting properties. However, labelling unmodified peptides with 18F for positron emission tomography (PET) imaging presents a number of challenges. Here we show the combination of photoactivated sodium decatungstate and [18F]-N-fluorobenzenesulfonimide effects site-selective 18F-fluorination at the branched position in leucine residues in unprotected and unaltered peptides. This streamlined process provides a means to directly convert native peptides into PET imaging agents under mild aqueous conditions, enabling rapid discovery and development of peptide-based molecular imaging tools.
Enantioselective solid-phase peptide synthesis using traceless chiral coupling reagents and racemic amino acids
Kolesinska, Beata,Kasperowicz-Frankowska, Katarzyna,Fraczyk, Justyna,Kaminski, Zbigniew J.
, p. 2084 - 2098 (2013/02/23)
The enantioselective condensing reagent 4,6-dimethoxy-1,3,5-triazine (DMT)/strychnine/BF-4 was obtained by treatment of 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) with strychnine tetrafluoroborate. The reagent was useful under typical conditions of solid-phase peptide synthesis (SPPS) with enantiomerically homogeneous substrates. By SPPS, desired dipeptides were obtained in 84-94% yield using 4 equiv. of racemic Fmoc-Ala, Fmoc-Phe, and/or Fmoc-Tyr for 1 equiv. of Wang resin loaded with Gly, Ala, Leu, Phe, Glu(tBu), and/or Pro, respectively. For all three Fmoc-protected amino acids, the configuration of the enantiomer preferred under SPPS conditions was independent of the structure of the acylated component and identical to that established in condensations proceeding in solution. In all cases, the enantiomer ratios L/D (er) were in a similar range, and varied from 9: 92 to 2: 98 for alanine, and from 90: 10 to 100: 0 for aromatic amino acids. The synthesis of Ac-L-Lys(Ac)-D-Ala-D-Ala-OH from racemic Fmoc-Ala gave an L/D ratio of 10: 90 for the esterification of Wang resin, and 0: 100 for the formation of peptide bonds.
