1. Institute of Organic Chemistry and Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic
2. Department of Organic Chemistry, Institute of Chemical Technology Prague, Technická 5, 166 28 Prague 6, Czech Republic
3. Department of Organic and Nuclear Chemistry, Charles University, Hlavova 2030, 128 40 Prague 2, Czech Republic
4. Zentiva k.s., U Kabelovny 130, 102 37 Praha 10, Czech Republic