1. Department of Chemistry, Bedson Building, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, U.K., Department of Organic Chemistry, Åbo Akademi University, Biskopsgatan 8, FIN-20500 Turku/Åbo, Finland, and Syngenta Central Toxicology Laboratory, Alderley Park, Macclesfield, SK10 4TJ, U.K.