1. Department of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy
2. Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
3. Department of Pharmacy, University of Salerno, 84084 Fisciano, Italy