1. Theoretical Chemistry, Faculty of Chemistry and Pharmacy, University of Innsbruck, Innrain 52a, A-6020 Innsbruck, Austria, Department of Lead Discovery, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse 65, D-88397 Biberach/Riss, Germany, and Department of Pharmaceutical Chemistry, Institute of Pharmacy for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 52c, A-6020 Innsbruck, Austria