1. Institute of Pharmacy, University of Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
2. Department of Chemistry and Pharmacy, Medicinal Chemistry, Friedrich-Alexander-University of Erlangen-Nürnberg, 91058 Erlangen, Germany
3. Department of Neurology, University of Minnesota, Minneapolis, Minnesota 55455, United States
4. Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota 55414, United States