1. Department of Medicinal Chemistry, Royal Danish School of Pharmacy, Universitetsparken 2, DK-2100 Copenhagen, Denmark, Department of Chemistry, Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-2500-Valby, Denmark, Department of Chemistry, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871 Frederiksberg, Denmark