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[email protected] 2639 Current Organic Chemistry, 2016, 20, 2639-2646 RESEARCH ARTICLE ISSN: 1385-2728 eISSN: 1875-5348 Impact Factor: Anomalous Products in the Halogenation Reactions of Vinca Alkaloids 1.949 BENTHAM SCIENCE András Keglevich,1 László Hegeds,2 Lilla Péter,1 Judit Gyenese,1 Csaba Szántay, Jr.,3 Zsófia Dubrovay,3+ Miklós Dékány,3 Áron Szigetvári,3 Ana Martins,4++ József Molnár,4 Attila Hunyadi,5 Péter Keglevich1* and László Hazai1* 1Department of Organic Chemistry and Technology, University of Technology and Economics, Budapest, Hungary, H-1111 Budapest, Gellért tér 4. Hungary; 2MTA–BME Organic Chemical Technology Research Group, Hungarian Academy of Sciences, Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary; 3Spectroscopic Research Division, Gedeon Richter Plc., H-1475 Budapest 10, P. O. Box 27, Hungary; 4Department of Medical Microbiology and Immunobiology, University of Szeged, 6720 Szeged, Dóm tér 10., Hungary; 5Institute of Pharmacognosy, University of Szeged, H-6720 Szeged, Eötvös u. 6., Hungary Abstract: Halogenation reactions of vindoline and 14,15-dihydrovindoline and its hydro- chloric salt were investigated and the anomalous reductions were discussed. Performing the hydrogenation in the presence of chlorine-containing solvent, e.g. dichloromethane, hydrogenolysation reaction of chlorine also took place. In this case unexpected chlorin- ated product could be observed. Performing the hydrogenation reaction only in the pres- ence of methanol, the expected reduced derivative was obtained. Upon bromination of vindoline with excess NBS, oxidation products with ring contraction and developing an oxygen bridge were isolated. The fluorination reactions of vinblastine using Selectfluor® and xenon difluoride as the fluorination reagents were unsuccessful because of the de- composition of the starting material.