1. Institut für Chemie, Medizinische Universität zu Lübeck, Ratzeburger Allee 160, Lübeck 23538, Germany, Royal Danish School of Pharmacy, Department of Medicinal Chemistry, Universitetsparken 2, Copenhagen DK-2100, Denmark, Department of Chemistry, Carlsberg Laboratory, Gamle Carlsberg Vej 10, Valby DK-2500, Denmark, and Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada