105500-11-6Relevant articles and documents
SYNTHESIS OF STEREOISOMERIC VINCAMINES
Koblicova, Zdena,Holubek, Jiri,Trojanek, Jan
, p. 2722 - 2730 (2007/10/02)
The synthesis of (+/-)-vincamine (I), (+/-)-16-epi-vincamine (XVIII) and (+/-)-16-epi-21-epivincamine (XVII) from 1-ethyl-2,3,4,6,7,12-hexahydroindoloquinolizine (IV) and 2-chloroacrylonitrile is described.It is characterized by a novel method of oxidation of the key intermediates, (+/-)-deoxyvincamine (II) and (+/-)-16-epi-21-epi-deoxyvincamine (XIII) with oxodiperoxymolybdenum (pyridine) (hexamethylphosphoric triamide).The deoxy derivatives II and XIII were prepared by direct or stepwise acid or alkaline hydrolysis od stereoisomeric (+/-)-eburnane-16-carbonitriles IX-XII, obtained by reduction of the primary immonium salt V, and subsequent esterification.In some cases, the hydrolysis is accompanied by epimerization at C(16).