1. Instituto
de Química
de São Carlos, Universidade de São Paulo, CP 780, São Carlos-São Paulo, Brazil
2. Department of Chemistry, Hanoi University of Science, 19 Le Thanh Tong, Hanoi,
Vietnam
3. Institute of Chemistry
and Biochemistry, Freie Universität Berlin, Fabeckstr. 34-36,
D-14195 Berlin, Germany
4. Institute of Pharmacy, Freie Universität Berlin, Königin-Louise-Str.
2 and 4, D-14195 Berlin, Germany