1. Institute of Pharmaceutical Chemistry; University of Szeged; H-6720 Szeged Eötvös utca 6 Hungary
2. Institute of Chemistry; Eötvös Loránd University; P.O. Box 32 H-1518 Budapest−112 Hungary
3. MTA-SZTE Stereochemistry Research Group; Hungarian Academy of Science; Eötvös u. 6 H-6720 Szeged Hungary
4. Interdisciplinary Centre of Natural Products; University of Szeged; H 6720 Szeged Hungary