The Alkaloids of Other Vinca Species

Continuation of the French work on the alkaloids of F. difformis has led to the isolation of vellosimine ([aJu -f-56° in MeOH) which was identified by direct comparison and conversion to 10-deoxysarpagine (42). A second base, a 2-acyI indole, vincadiffine, obtained in a very small quantity (42), was assigned the structure, 3-oxo-4-methyl-3,4-secoaku-ammidine (IV), a deduction based on its NMR- and mass spectra (see Chart IV, and Chapter 2 of this volume). The configuration of C-16 substituents followed directly from the chemical shift of the ester-methyl 2.57 ppm (methyl-shielded by the aromatic group). 

Further examples of the ajmaline-sarpagine group of alkaloids have been isolated and studied (Table III). It is interesting that vincamajor- 

Majdine after treatment with acetic anhydride and hydrolysis gives isomajdine (mp 204°-206° [a]D —90° in MeOH). This transformation 

Vincadiffine C. Other compounds 230 -121° (CHCI3) 2-Acylindole see Chapter 2 d (42) [48] 

Reference dealing with isolation of the alkaloids given in parentheses those referring to structure appear in brackets. Described as majoroxine by J. L. Kaul and J. Trojanek, 25th Intern. Congr. Pharra. Sci., Prague, 1965. 

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