1. Department of Pharmaceutical Sciences, University of Padua, Via F. Marzolo 5, 35131 Padua, Italy, Department of Organic Chemistry, University of Padua, Via F. Marzolo 3, 35131 Padua, Italy, and Computer-aided Systems Laboratory, Department of Chemical Engineering, University of Trieste, Piazzale Europa 1, 34127 Trieste, Italy