1. Department of Chemical Sciences, University of Camerino, Via S. Agostino 1, 62032 Camerino (MC), Italy, Pharmaco-Chemistry Department, University of Bari, Via E. Orabona 4, 70126 Bari, Italy, Research and Development Division, Recordati S.p.A., Via Civitali 1, 20148 Milano, Italy, and Department of Pharmaceutical Sciences, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy