1. Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, Helsinki 00014, Finland
2. Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, Helsinki 00014, Finland
3. Department of Chemistry, The Center for Chemical Methodologies and Library Development, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States