Transformations of Vindoline and Its Derivatives

The microbial transformations of vindoline and its derivatives have been further examined. Human caeruloplasmin and laccases of Polyporus anceps and Rhus vernicifera converted vindoline (44) into the known enamine 270 and the dimer 266 (201), which have been encountered in previous microbiological studies on vindoline. The dimer 266 is also formed by the action of horseradish peroxidase on vindoline (202). 

The dimer, 10,10 -bisvindoline, is the major product (60% yield) obtained when vindoline is oxidized electrochemically with the addition of trifluoro-acetic acid to the anodic compartment using a platinum anode and a graphite cathode, followed by controlled potential cathodic reduction. Two minor products, so far unidentified, were also obtained (205). 

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