1. Institute of Exact Sciences, Department of Chemistry Federal University of Minas Gerais, UFMG 31270‐901 Belo Horizonte MG Brazil
2. Division of Bioorganic Chemistry School of Pharmacy University of Saarland 66123 Saarbruecken Germany
3. Department of Chemistry Federal University of Santa Catarina 88040‐900 Florianópolis SC Brazil
4. Oswaldo Cruz Institute FIOCRUZ 21045‐900 Rio de Janeiro RJ Brazil
5. Institute of Chemistry University of Brasilia 70904‐970 Brasilia DF Brazil
6. Department of Physiology and Pharmacology School of Pharmacy Federal University of Ceará 60430‐270 Fortaleza CE Brazil
7. Institut für Organische und Biomolekulare Chemie Georg‐August‐Universität Tammannstraße 2 37077 Göttingen Germany