• Buchwald-Hartwig versus Microwave-Assisted Amination of Chloroquinolines: En Route to the Pyoverdin Chromophore

      Seubert, Philipp; Freund, Marcel; Rudolf, Richard; Lin, Yulin; Altevogt, Luca; Bilitewski, Ursula; Baro, Angelika; Laschat, Sabine; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Thieme Verlag, 2020-07-22)
      The reaction of 2-chloro-3-nitroquinoline and a series of amines and aminoalkanoates under basic microwave-mediated conditions and Buchwald-Hartwig amination conditions is reported. The microwave irradiation favored the reaction with amines, resulting in yields up to 80%, while amino acid functionalization gave yields comparable to those of BuchwaldHartwig amination. (2R)-4-[(6,7-dimethoxy-3-nitroquinolinyl)amino]-2-hydroxybutanoate could be successfully cyclized to the pyoverdin chromophore, a subunit of siderophores.
    • Synthesis and Biological Evaluation of a Library of AGE-Related Amino Acid Triazole Crosslinkers

      Icik, Esra; Jolly, Anthony; Löffler, Paul; Agelidis, Nektarios; Bugdayci, Bakiye; Altevogt, Luca; Bilitewski, Ursula; Baro, Angelika; LASCHAT, SABINE; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Wiley-VCH, 2020-08-10)
      Three N‐Boc‐protected amino acids, l‐serine, l‐aspartic, and l‐glutamic acid, were either converted into their methyl azidoalkanoates or various alkynes via Bestmann‐Ohira strategy or via reaction with propargylamine and propargyl bromide, respectively. The Cu‐catalyzed click reaction provided a library of amino acid based triazoles, which were further N‐methylated to triazolium iodides or deprotected and precipitated as free amino acid triazole dihydrochlorides. The biological properties of all derivatives were investigated by cytotoxicity assay (against L929 mouse fibroblasts) and broth microdilution method (E. coli ΔTolC and S. aureus). First results reveal complete inactivity for triazolium iodides with cell viabilities and microbial growths nearly 100 %, indicating them as possible analogs of advanced glycation endproducts (AGEs).