1. Stratingh Institute for Chemistry,
Faculty of Mathematics and Natural Sciences, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The
Netherlands
2. DSM Innovative Synthesis, PO Box 18, 6160 MD Geleen, The Netherlands
3. Catexel Ltd., BioPartner Center
Leiden, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands