1. Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg SE-412 96, Sweden
2. Chemistry Department, College of Natural and Applied Sciences, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania
3. Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, Q1d 4111, Australia
4. Department of Chemistry, University of Jyvaskyla, P.O. Box 35, FI-40014, Jyvaskyla, Finland
5. Department of Chemistry−BMC, Uppsala University, SE-751 23 Uppsala, Sweden