1. Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Panepistimiopolis, Athens 15771, Greece, Chemical Laboratories, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece, and Department of Technical Chemistry and Biotechnology, Institute of Chemistry and Biochemistry, Greifswald University, Soldmannstr. 16, D-17487 Greifswald, Germany