1. Department of Chemistry, University of Paderborn, Warburger Strasse 100, 33098-Paderborn, Germany
2. HEJ Research Institute of Chemistry, International Centre for Chemical and Biological Sciences, University of Karachi, Karachi-75270, Pakistan
3. Department of Chemistry, University of Pisa, Via Risorgimento 35, I-56126 Pisa, Italy
4. Institute of Microbiology, Technical University of Braunschweig, Spielmannstrasse 7, 31806 Braunschweig, Germany
5. Department of Organic Chemistry, University of Debrecen, PO Box 20, H-4010 Debrecen, Hungary