1. Department of Pharmacy, Division of Pharmaceutical Chemistry, POB 56, FIN-00014, University of Helsinki, Finland, Institute of Biotechnology, NMR Laboratory, FIN-00014, University of Helsinki, Finland, Orion Corporation, Orion Pharma, POB 65, FIN-02101 Espoo, Finland, and Finnish Institute of Occupational Health, FIN-00250 Helsinki, Finland