1. Department of Pharmaceutical & Medicinal Chemistry, PharmaCenter Bonn, Pharmaceutical Institute, University of Bonn, Bonn, Germany
2. Laboratory for Medicinal Chemistry, Gent, Belgium
3. Department of Chemistry, College of Science, Sultan Qaboos University, Muscat, Oman
4. Institut für Biochemie und Molekularbiologie, University of Bonn, Bonn, Germany