Anomalous Products in the Halogenation Reactions of Vinca Alkaloids

作者：Keglevich Andras; Hegedus Laszlo; Peter Lilla; Gyenese Judit; Szantay Csaba Jr; Dubrovay Zsofia; Dekany Miklos; Szigetvari Aron; Martins Ana; Molnar Jozsef; Hunyadi Attila; Keglevich Peter^*; Hazai Laszlo^*

来源：Current Organic Chemistry, 2016, 20(24): 2639-2646.

DOI：10.2174/1385272820666160617080202

• Vindoline
• catharanthine
• halogenation
• Selectfluor (R)
• xenon difluoride
• quinoidal products

Halogenation reactions of vindoline and 14,15-dihydrovindoline and its hydrochloric 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 chlorinated product could be observed. Performing the hydrogenation reaction only in the presence 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 (R) and xenon difluoride as the fluorination reagents were unsuccessful because of the decomposition of the starting material. Reactions of vindoline with Selectfluor (R) a mixture of products were obtained. Using xenon difluoride as fluorination agent resulted in a pure quinoidal product containing the fluorine atom in the bridgehead carbon atom of the indole ring. The fluorination of catharanthine gave an anomalous indolenine type product.
Dedicated to the memory of Professor Csaba Szantay who passed away on January 17, 2016.

• 出版日期2016