@article{SawatzkyDrakopoulosRoelzetal.2016,
  author    = {Sawatzky, Edgar and Drakopoulos, Antonios and R{\"o}lz, Martin and Sotriffer, Christoph and Engels, Bernd and Decker, Michael},
  title     = {Experimental and theoretical investigations into the stability of cyclic aminals},
  series = {Beilstein Journal of Organic Chemistry},
  volume    = {12},
  journal   = {Beilstein Journal of Organic Chemistry},
  doi       = {10.3762/bjoc.12.221},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-160976},
  pages     = {2280-2292},
  year      = {2016},
  abstract  = {Background: Cyclic aminals are core features of natural products, drug molecules and important synthetic intermediates. Despite their relevance, systematic investigations into their stability towards hydrolysis depending on the pH value are lacking. Results: A set of cyclic aminals was synthesized and their stability quantified by kinetic measurements. Steric and electronic effects were investigated by choosing appropriate groups. Both molecular mechanics (MM) and density functional theory (DFT) based studies were applied to support and explain the results obtained. Rapid decomposition is observed in acidic aqueous media for all cyclic aminals which occurs as a reversible reaction. Electronic effects do not seem relevant with regard to stability, but the magnitude of the conformational energy of the ring system and pK a values of the N-3 nitrogen atom. Conclusion: Cyclic aminals are stable compounds when not exposed to acidic media and their stability is mainly dependent on the conformational energy of the ring system. Therefore, for the preparation and work-up of these valuable synthetic intermediates and natural products, appropriate conditions have to be chosen and for application as drug molecules their sensitivity towards hydrolysis has to be taken into account.},
  language  = {en}
}
@article{DrakopoulosDecker2020,
  author    = {Drakopoulos, Antonios and Decker, Michael},
  title     = {Development and Biological Applications of Fluorescent Opioid Ligands},
  series = {ChemPlusChem},
  volume    = {85},
  journal   = {ChemPlusChem},
  number    = {6},
  doi       = {10.1002/cplu.202000212},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-216068},
  pages     = {1354 -- 1364},
  year      = {2020},
  abstract  = {Opioid receptors (ORs) are classified among the oldest and best investigated drug targets due to their fundamental role in the treatment of pain and related disorders. ORs are divided in three conventional subtypes (μ, κ, δ) and the non-classical nocicepetin receptor. All ORs are family A G protein-coupled receptors (GPCRs), and are located on the cell surface. Modern biophysical methods use light to investigate physiological processes at organismal, cellular and subcellular level. Many of these methods rely on fluorescent ligands, thus highlighting their importance. This review addresses the advancements in the development of opioid fluorescent ligands and their use in biological, pharmacological and imaging applications.},
  language  = {en}
}
@article{ChristianSeierDrakopoulosetal.2020,
  author    = {Christian, Gentzsch and Seier, Kerstin and Drakopoulos, Antonios and Jobin, Marie-Lise and Lanoisel{\´e}e, Yann and Koszegi, Zsombor and Maurel, Damien and Sounier, R{\´e}my and H{\"u}bner, Harald and Gmeiner, Peter and Granier, S{\´e}bastien and Calebiro, Davide and Decker, Michael},
  title     = {Selective and Wash-Resistant Fluorescent Dihydrocodeinone Derivatives Allow Single-Molecule Imaging of μ-Opioid Receptor Dimerization},
  series = {Angewandte Chemie International Edition},
  volume    = {59},
  journal   = {Angewandte Chemie International Edition},
  number    = {15},
  doi       = {10.1002/anie.201912683},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-212398},
  pages     = {5958-5964},
  year      = {2020},
  abstract  = {μ-Opioid receptors (μ-ORs) play a critical role in the modulation of pain and mediate the effects of the most powerful analgesic drugs. Despite extensive efforts, it remains insufficiently understood how μ-ORs produce specific effects in living cells. We developed new fluorescent ligands based on the μ-OR antagonist E-p-nitrocinnamoylamino-dihydrocodeinone (CACO), that display high affinity, long residence time and pronounced selectivity. Using these ligands, we achieved single-molecule imaging of μ-ORs on the surface of living cells at physiological expression levels. Our results reveal a high heterogeneity in the diffusion of μ-ORs, with a relevant immobile fraction. Using a pair of fluorescent ligands of different color, we provide evidence that μ-ORs interact with each other to form short-lived homodimers on the plasma membrane. This approach provides a new strategy to investigate μ-OR pharmacology at single-molecule level.},
  language  = {en}
}