1. Department of Pharmaceutical Biology and Biotechnology, Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, Stefan-Meier-Straße 19, 79104 Freiburg, Germany
2. Faculty of Biology, Schänzlestraße 1, 79104 Freiburg, Germany
3. Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston K7L 3N6, Ontario, Canada
4. Organic Chemistry, University of Siegen, Adolf-Reichwein-Straße 2, 57068 Siegen, Germany