1. Division of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland, Division of Pharmacology and Toxicology, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland, Finnish Biological NMR Center, Institute of Biotechnology, University of Helsinki, FI-00014 Helsinki, Finland, Centre for Drug Research, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland