1. Department of Organic Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary, Department of Chemistry and Chemical Informatics, Faculty of Education, University of Szeged, Boldogasszony sgt. 6, H-6725 Szeged, Hungary, and Department of Pharmacodynamics and Biopharmacy, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary