1. Pharmaceutical Institute, Pharmaceutical and Cell Biological Chemistry, University of Bonn, An der Immenburg 4, 53121Bonn, Germany
2. Institute for Drug Discovery, Medical Faculty, Leipzig University, Brüderstraße 34, 04103Leipzig, Germany
3. Department of Pediatric Oncology, Hematology and Clinical Immunology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstrasse 5, 40225Düsseldorf, Germany
4. Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania19104-6323, United States
5. Department of Medicine, Yangzhou Polytechnic College, West Wenchang Road 458, Yangzhou225009, P. R. China