1. Department of Chemistry University of Zurich 8057 Zürich Switzerland
2. Department of Microbial Natural Products Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) Helmholtz Centre for Infection Research (HZI) Department of Pharmacy Saarland University, Campus Campus E8.1 66123 Saarbrücken Germany
3. German Center for Infection Research (DZIF) Partner Site Hannover-Braunschweig 38124 Braunschweig Germany