Some transformations of mitraphylline and ajmalicine

WiTKOP, B., Zur Konstitution des Yohimbins und seiner Abbauprodukte, Justus Liebigs Ann. Chem., 554, 83 (1943). 

The principal members of this group (Chart 6.1) are derived mainly from the Wieland-Gumlich aldehyde (or its equivalent). An alternate ring closure gives the closely related aspidosperma-tine class of which condylocarpine is a member. None of the biosynthetic steps are known but might proceed according to the experimentally realized ftw-Mannich condensation (Chapter III, p. 25) equivalent to the hypothetical scheme in Chart 2.2 or by the routes sketched in Charts 2.3 or 12.2. 

The chemistry of strychnine has not played as direct a role in the development of heterocyclic chemistry as morphine because its structure for so long defied exact description. It did, however, generate some important theoretical questions and was there, for half the twentieth century as one of the great chemical challenges and upon it almost every useful reaction in degradative chemistry has been applied usually with some success. Although its structure is now known with certainty by degradation, synthesis and X-ray 

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