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Kopsidine A, B, C and kopsinganol were synthesised from kopsingine in good yields via the stable imminium salt obtained from electrochemical oxidation of kopsingine. Electrooxidation of dihydrokopsingine on the other hand gave the 17-to-5 and 17-to-3 oxo-bridged alkaloids directly, while 3-oxokopsingine was inert to electrooxidation in the potential range employed.
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