1. Pharmaceutical Institute, Department of Pharmaceutical and Medicinal Chemistry, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
2. Research Training Group 1873, University of Bonn, 53127 Bonn, Germany
3. Research Training Group 2873, University of Bonn, 53121 Bonn, Germany
4. Department of Technology and Biotechnology of Drugs, Faculty of Pharmacy, Jagiellonian University Medical College, Pl 30-688 Kraków, Poland