1. Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/E163, A-1060 Vienna, Austria, Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/E164, A-1060 Vienna, Austria, and Neurological and Urological Diseases Research, Pharmaceutical Products Division, Abbott Laboratories, Department 47W, Building AP-9A/311, 100 Abbott Park Road, Abbott Park, Illinois 60064-6125