1. Department of Organic Chemistry, Lund University, P.O.B. 124, SE−221 00 Lund, Sweden, Department of Medicinal Chemistry, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen, Denmark, NeuroSearch A/S, DK-2750 Ballerup, Denmark, and Novo Nordisk A/S, Novo Nordisk Park, DK-2760 Måløv, Denmark