Vincamine-type alkaloids

Subsequent Reactions of Strictosidine Classification and Structural Types of Indole Alkaloids Formation of the Major Indole Alkaloid Types Summary of Pathways Leading to Major Types of Monoterpene-Derived Indole Alkaloids Chemosystematic and Phylogenetic Application Monoterpenoid Indole Alkaloids of Pharmacologic Significance Vincamine... 

Sensitivity of DNA and RNA viruses to alkaloids may differ. Ozgelik et al. (2011) investigated various alkaloids namely yohimbine and vincamine (indole-type), scopolamine and atropine (tropane-type), colchicine (tropolone-type), aUantoin... 

Trifluorinated analogues of monomorin, an indolizidin-type alkaloid that is an ant pheromone,and of vincamine derivatives have been described (Figure 4.54). ... 

Further variants on the terpenoid indole alkaloid skeleton (Figure 6.82) are found in ibogaine from Tabemanthe iboga, vincamine from Vinca minor, and ajmaline from Rauwolfia serpentina. Ibogaine is simply a C9 Iboga type alkaloid, but is of interest as an experimental drug to treat heroin addiction. In a number of European countries, vincamine is used clinically as a vasodilator to increase cerebral blood flow in cases of senility, and ajmaline for cardiac arrhythmias. Ajmaline... 

The knowledge of the key fragmentation routes of eburnamine and some related alkaloids confirmed or elucidated the structures of the alkaloids 11-methoxy-vincamine,100 vincaminine,102 and vinci-nine,102 of the same skeletal type as eburnamine. Alkaloids of the mavacurine-pleiocarpamine group (212)103 are characterized by a key fragment corresponding to the loss of the ester group and... 

In the laboratory of A.G. Schultz during the asymmetric total synthesis of two vincane type alkaloids, (+)-apovincamine and (+)-vincamine, it was necessary to construct a crucial c/s-fused pentacyclic diene intermediate. The synthesis began by the Birch reduction-alkylation of a chiral benzamide to give 6-ethyl-1-methoxy-4-methyl-1,4-cyclohexadiene in a >100 1 diastereomeric purity. This cyclohexadiene was first converted to an enantiopure butyrolactone which after several steps was converted to (+)-apovincamine. 

A new line to the synthesis of the eburnamine type alkaloids has produced (Scheme 17) ( + )-vincamine (105a), ( )-eburnamine (105b), and ( + )-eburnamonine " (105c). Acid-catalysed rearrangement of the carbinolamide (107) gave homoeburnamenine (106) which contained all the carbons necessary for the formation of vincamine. 

Almost all the alkaloids isolated from V. minor are derived from the type III moiety 41) belonging to the vincamine, Aspidosperma, and quebrachamine subclasses. In this sense there is more uniformity among the alkaloids of V. minor than the other Vinca species. The alkaloids are also unusual in that amongst the three subclasses are found racemic alkaloids, namely, d(-eburnamine (vincanorine), dZ-A-methylquebrach-amine d -vincadifformine and its dZ-l-methyl derivative (minovine) (see Table II). 

Vincamine is an Aspidosperma type of alkaloid supposedly produced through two chemical reactions beginning with the catalytic reduction of tabersonine, an alkaloid extract of voacanga seeds. The resulting product, vincadiformine is oxidized forming vincamine [34]. 

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